Search term(s): swelling: wattles       Displaying results for: swelling: wattles, All Assets

   

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3.3.08.DSC_0301.JPG

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clinical sign

Edema (comb, wattles, eyelids). Congestion (comb, wattles)

  • congestion: skin
  • edema: skin
  • swelling: comb
  • swelling: wattles

comb, eyelid, periorbital region, wattles

Avian Influenza

chicken (Gallus gallus)

Morphologic Diagnosis

Subcutaneous tissues, eyelids: Mild edema. Wattle and combs: Edema and congestion.

Clinical Description

This image was taken 1 day post experimental inoculation with highly pathogenic avian influenza. This bird is exhibiting severe general depression. The swelling of the structures of the head (comb, wattles, and periocular regions) are one of the most frequent external findings associated with highly pathogenic avian influenza.

Pathologic Description

The subcutaneous tissues of the head are swollen. The eyelids are thickened, causing them not to open all the way. The wattle and comb are bright red and the comb is slightly swollen. The feather loss is due to normal molting.

MD-013A.jpg

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clinical sign

swelling (wattles)

  • swelling: wattles

wattles

Marek's Disease

chicken (Gallus gallus)

Clinical Description

Swelling of the wattles (shown here) and combs can also occur in Marek's disease if the lymphomas infiltrate the subcutaneous tissue of these nonfeathered areas.

MALEHEAD

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clinical sign

swelling (wattles)

  • swelling: wattles

wattles

Fowl Cholera

chicken (Gallus gallus)

Clinical Description

Severely swollen wattles resulting from a localized infection with chronic fowl cholera.

Face edema

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gross image

  • face
  • swelling: face
  • swelling: wattles

head, wattles

Fowl Cholera

chicken (Gallus gallus)

Clinical Description

Exudative inflammation of the face and wattles caused by fowl cholera. Chronically infected birds may be a reservoir for the infection for long periods of time. These carriers do not always exhibit clinical signs.

PAST-006A.jpg

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clinical sign

swelling (wattle)

  • swelling: wattles

wattles

Fowl Cholera

chicken (Gallus gallus)

Clinical Description

In the chronic form of fowl cholera, birds that survive the acute infection or birds exposed to a low virulence strain of Pasteurella multocida, often develop swelling of the wattles, sinuses, foot pads, sternal bursa, and joints. This chicken has a large abscess on the right wattle as a result of localized infection.

Edema ear-wattles

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gross image

  • swelling: ear
  • swelling: face
  • swelling: wattles

ear, head, wattles

Fowl Cholera

chicken (Gallus gallus)

Clinical Description

Swollen wattles and inflammation of the face are frequently found in susceptible broiler breeders infected with fowl cholera. This photo also shows edema of the ears and surrounding facial tissue.

Edema wattles2

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gross image

  • edema: skin
  • swelling: wattles

wattles

Fowl Cholera

chicken (Gallus gallus)

Clinical Description

Swollen wattles are found frequently in susceptible broiler breeders infected with fowl cholera.

swollen wattles

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clinical sign

swelling (wattles)

  • swelling: wattles

wattles

Fowl Cholera

chicken (Gallus gallus)

Clinical Description

Severely swollen wattles resulting from a localized chronic fowl cholera infection. This swelling is caused by a developing abscess.

Wattle-Sample

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gross image

  • swelling: wattles

wattles

Fowl Cholera

chicken (Gallus gallus)

Clinical Description

Purulent exudate may be found within the facial swellings associated with chronic fowl cholera. Here, the wattle was lanced and a swab sample was taken for bacterial culture, resulting in the isolation of Pasteurella multocida.

CoelomicCavity1

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normal

heart, liver

Normal Reference

chicken (Gallus gallus)

Clinical Description

With the bird in dorsal recumbency, the walls of the right atrium and ventricle are positioned on top. After death, the atria often expand with blood and can appear quite enlarged. The great vessels can be seen entering the base of the heart. The heart muscle should be reddish-brown in color. A variable amount of fat will be present in the coronary grooves. If the bird is emaciated, this fat may be absent or have undergone serous atrophy, resulting in a gelatinous, wet appearance. Look for any external lesions on the epicardial surface of the heart or on the surrounding fat.

CoelomicCavity3

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normal

heart

Normal Reference

chicken (Gallus gallus)

Clinical Description

With the bird in dorsal recumbency, the walls of the right atrium and ventricle are positioned on top. After death, the atria often expand with blood and can appear quite enlarged. The great vessels can be seen entering the base of the heart. The heart muscle should be reddish-brown in color. A variable amount of fat will be present in the coronary grooves. If the bird is emaciated, this fat may be absent or have undergone serous atrophy, resulting in a gelatinous, wet appearance. Look for any external lesions on the epicardial surface of the heart or on the surrounding fat.

Heart1

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normal

heart

Normal Reference

chicken (Gallus gallus)

Clinical Description

The heart muscle should be reddish-brown in color. A variable amount of fat will be present in the coronary grooves. If the bird is emaciated, this fat may be absent or have undergone serous atrophy, resulting in a gelatinous, wet appearance. Look for any external lesions on the epicardial surface of the heart or on the surrounding fat.

Heart3

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normal

heart

Normal Reference

chicken (Gallus gallus)

Clinical Description

View of the left side of the heart.

Heart7

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normal

heart

Normal Reference

chicken (Gallus gallus)

Clinical Description

View of the apex of the heart.

Heart11

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normal

heart

Normal Reference

chicken (Gallus gallus)

Clinical Description

The bottom 1/3 of the apex of the heart has been removed. This view allows the thickness of the ventricular walls and septum to be assessed. The right ventricular free wall should be approximately 1/3 to 1/2 the thickness of the intraventricular septum and the left ventricular free wall. In the normal heart, the lumina of the ventricles should be small and there should be negligible space between the walls of the ventriculae and the septum. In cardiac diseases, such as pulmonary hypertension or congenital defects, this space will be widened.

Heart8

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normal

heart, right atrioventricular valve

Normal Reference

chicken (Gallus gallus)

Clinical Description

In this view, the chambers of the right atrium and ventricle have been opened by making a cut up the right ventricular free wall. Once opened, the right atrioventricular valve and endocardium are exposed. The septal leaf of the right valve is normally very muscular.

Heart9

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normal

heart, left atrioventricular valve

Normal Reference

chicken (Gallus gallus)

Clinical Description

In this view, the chambers of the left atrium and ventricle have been opened by making a cut up the left ventricular free wall. The left atrioventricular valve is normally thin and smooth.

Heart10

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normal

aortic valve, heart

Normal Reference

chicken (Gallus gallus)

Clinical Description

The aorta has been opened by inserting scissors under the left atrioventricular valve and cutting upward. The normal lumen of the aorta, as seen here, is creamy white and the leaflets of the aortic valve are uniform and very thin.

18_liver

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normal

liver

Normal Reference

chicken (Gallus gallus)

Clinical Description

The liver is separated into a right and left lobe, as seen here, attached at the base. The right hepatic lobe is slightly larger than the left and the liver margins should come to a thin crisp edge.

liver2

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normal

liver

Normal Reference

chicken (Gallus gallus)

Clinical Description

In domestic birds, the left lobe has a fissure running along its surface, dividing it into 2 parts.

liver1

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normal

liver

Normal Reference

chicken (Gallus gallus)

Clinical Description

The liver is separated into a right and left lobe, as seen here, attached at the base. The right hepatic lobe is slightly larger than the left and the liver margins should come to a thin crisp edge.

liver3

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normal

liver

Normal Reference

chicken (Gallus gallus)

Clinical Description

The overall size of the liver is variable, often extending beyond the edge of the sternum. To identify hepatomegaly, look at the liver margins. Blunted or thickened margins are a sign of an enlarged liver.

liver4

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normal

liver

Normal Reference

chicken (Gallus gallus)

Clinical Description

Healthy hepatic parenchyma should be somewhat firm on palpation and have a smooth and glistening appearance. The color of the liver can vary depending on the nutritional state of the bird. Generally, the liver is reddish-brown but it can be light brown or even slightly yellow, depending on the fat content in the diet. However, a very yellow liver is an abnormal finding, except in chicks between 1 to 5 days of age.

liver5

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normal

liver

Normal Reference

chicken (Gallus gallus)

Clinical Description

Healthy hepatic parenchyma should be somewhat firm on palpation and have a smooth and glistening appearance. The color of the liver can vary depending on the nutritional state of the bird. Generally, the liver is reddish-brown but it can be light brown or even slightly yellow, depending on the fat content in the diet. However, a very yellow liver is an abnormal finding, except in chicks between 1 to 5 days of age.

gallbladder1

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normal

gallbladder

Normal Reference

chicken (Gallus gallus)

Clinical Description

The gallbladder is located on the visceral surface of the right hepatic lobe. It is normally dark green in color, due to the bile located within the lumen of this thin-walled structure. During autolysis, bile pigments may leak out of the gallbladder, staining the adjacent hepatic tissues yellow to green. This bile inbibition is a normal part of autolysis and should not be confused with a lesion. Similar staining can also occur in the ascending duodenum, adjacent to the area where the bile and pancreatic ducts empty. The size of the gallbladder is variable and may be enlarged in birds that are off-feed.

gallbladder2

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normal

gallbladder

Normal Reference

chicken (Gallus gallus)

Clinical Description

The gallbladder is located on the visceral surface of the right hepatic lobe. It is normally dark green in color, due to the bile located within the lumen of this thin-walled structure. During autolysis, bile pigments may leak out of the gallbladder, staining the adjacent hepatic tissues yellow to green. This bile inbibition is a normal part of autolysis and should not be confused with a lesion. Similar staining can also occur in the ascending duodenum, adjacent to the area where the bile and pancreatic ducts empty. The size of the gallbladder is variable and may be enlarged in birds that are off-feed.

liver6

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normal

liver

Normal Reference

chicken (Gallus gallus)

Clinical Description

View of the liver on cross section. As seen here, the color and texture should be uniform. Focal or regional changes may indicate a lesion. It’s normal for a small amount of blood to ooze from the cut surface of the liver.

39_lungs

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normal

lungs

Normal Reference

chicken (Gallus gallus)

Clinical Description

The lungs are tightly adhered to the dorsal rib cage. Their color should be bright pink in a fresh bird but will become increasinly more congested, wet, and dark red with autolysis, as seen here. To assess the lungs, do not over-interpret their color but rather, use a combination of visual inspection and palpation to assess the health of this tissue.

19_air_sacs

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normal

air sacs

Normal Reference

chicken (Gallus gallus)

Clinical Description

The air sacs are thin membranes distributed throughout the body. In a fresh healthy bird, air sacs should be transparent but, as seen here, the membranes will become slightly cloudy after death. In over-conditioned birds, fat may be present on the air sac membranes. Inflammation of the air sacs can result in thickened membranes, opacities, or fibrin deposition. Fluid, foam, or exudate can accumulate between the air sac membranes.

CoelomicCavity2

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normal

proventriculus, ventriculus (gizzard)

Normal Reference

chicken (Gallus gallus)

Clinical Description

The proventriculus is the glandular stomach that lies between the esophagus and the gizzard. It is lined with mucosal glands that secrete digestive enzymes important in food break down. On close inspection, these glands can be seen through the serosal surface, giving it a “honeycomb-like” texture. On palpation the proventriculus should feel turgid and, its surface should be shiny tan. Look for abnormalities such as hemorrhagic lesions or neoplastic infiltrates on its surface.

Proventriculus1

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normal

proventriculus, ventriculus (gizzard)

Normal Reference

chicken (Gallus gallus)

Clinical Description

The serosa of the proventriculus is normally shiny, tan, and has a fine vascular pattern. In a fresh bird, on close inspection, the glands can be visualized through the mucosa. The muscular wall of the proventriculus should feel uniformly turgid. Flaccidity or dilatation of the organ might indicate an improper diet or feeding program, infection, or neuromuscular dysfunction. The external features of the ventriculus, or gizzard, should consist of alternating bands of dark red and light red smooth muscles, forming a roughly circular shape. These muscles may be covered by a thick layer of fat, as seen here. On palpation, the gizzard should be extremely firm. Thinning or laxity in the muscles may indicate inflammation, an improper diet or feeding program, or neuromuscular problems.

Proventriculus3

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normal

proventriculus

Normal Reference

chicken (Gallus gallus)

Clinical Description

The proventriculus in situ.

Pancreas3

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normal

proventriculus, ventriculus (gizzard)

Normal Reference

chicken (Gallus gallus)

Clinical Description

The serosa of the proventriculus is normally shiny, tan, and has a fine vascular pattern. In a fresh bird, on close inspection, the glands can be visualized through the mucosa. The muscular wall of the proventriculus should feel uniformly turgid. Flaccidity or dilatation of the organ might indicate an improper diet or feeding program, infection, or neuromuscular dysfunction. The external features of the ventriculus, or gizzard, should consist of alternating bands of dark red and light red smooth muscles, forming a roughly circular shape. These muscles may be covered by a thick layer of fat. On palpation, the gizzard should be extremely firm. Thinning or laxity in the muscles may indicate inflammation, an improper diet or feeding program, or neuromuscular problems.

Proventriculus6

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normal

proventriculus, ventriculus (gizzard)

Normal Reference

chicken (Gallus gallus)

Clinical Description

View of the serosal surface of the proventriculus and gizzard (ventriculus).

Proventriculus9

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normal

proventriculus

Normal Reference

chicken (Gallus gallus)

Clinical Description

Close-up of the glands of the proventriculus as seen through the outer wall.

Proventriculus10

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normal

proventriculus

Normal Reference

chicken (Gallus gallus)

Clinical Description

View of the glands of the proventriculus as seen from the mucosal surface.

Proventriculus11

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normal

proventriculus

Normal Reference

chicken (Gallus gallus)

Clinical Description

Close-up view of the glands of the proventriculus as seen from the mucosal surface.

28_proventriculos

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normal

proventriculus

Normal Reference

chicken (Gallus gallus)

Clinical Description

The contents of the proventriculus can vary from mucoid and creamy to more formed pieces of ingesta, depending on how recently the bird ate.

Proventriculus8

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normal

proventriculus, ventriculus (gizzard)

Normal Reference

chicken (Gallus gallus)

Clinical Description

View of the serosal surface of the proventriculus and gizzard (ventriculus).

Ventriculus5

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normal

ventriculus (gizzard)

Normal Reference

chicken (Gallus gallus)

Clinical Description

The external features of the ventriculus, or gizzard, should consist of alternating bands of dark red and light red smooth muscles, forming a roughly circular shape. These muscles may be covered by a thick layer of fat, as seen here.

Proventriculus7

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normal

proventriculus, ventriculus (gizzard)

Normal Reference

chicken (Gallus gallus)

Clinical Description

View of the left side of the proventriculus and gizzard.

31_gizzard_contents

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normal

ventriculus (gizzard)

Normal Reference

chicken (Gallus gallus)

Clinical Description

The consistency of the gizzard contents will vary depending on the stage of digestion. Generally, it contains fibers and portions of seeds. Additionally, small pebbles, ingested to facilitate the break up of food, may also be present.

Ventriculus6

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normal

ventriculus (gizzard)

Normal Reference

chicken (Gallus gallus)

Clinical Description

The mucosa of the gizzard is covered by a sturdy layer of protein called koilin, which aids in food digestion. The koilin layer should be smooth and uniform. The color may vary from white, to yellow, to green depending on the diet and the degree of bile staining.

Ventriculus7

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normal

ventriculus (gizzard)

Normal Reference

chicken (Gallus gallus)

Clinical Description

Close-up view of the koilin layer of the gizzard (ventriculus).

Spleen1

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normal

spleen

Normal Reference

chicken (Gallus gallus)

Clinical Description

The spleen is located dorsal to the gizzard.

Spleen4

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normal

spleen

Normal Reference

chicken (Gallus gallus)

Clinical Description

On very close inspection, the spleen as a slight stippled pattern.

29_spleen

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normal

spleen

Normal Reference

chicken (Gallus gallus)

Clinical Description

On very close inspection, the spleen as a slight stippled pattern.

Spleen5

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normal

spleen

Normal Reference

chicken (Gallus gallus)

Clinical Description

On very close inspection, the spleen as a slight stippled pattern.

Spleen6

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normal

spleen

Normal Reference

chicken (Gallus gallus)

Clinical Description

View of the cut section of the spleen. On cross section, the spleen may appear slightly granular due to the variations in red and white pulp.

Duodenum1

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normal

duodenum

Normal Reference

chicken (Gallus gallus)

Clinical Description

The duodenum has a descending and ascending loop, arranged in a U-shape. The loops are held together by a thin strip of mesentery and surround the pancreas. The appearance of the intestine can vary greatly depending on the post-mortem condition of the bird. In a fresh bird, the serosa of a healthy intestine is usually pink, smooth, and glistening. As the post-mortem interval increases, the intestinal walls will become congested, as seen here, and eventually, even a healthy loop of bowel may appear dark red. However, if the serosa has a dull granular appearance, this can be evidence of inflammation. The normal appearance of the pancreas is pale red or slightly yellow. On close inspection, its glandular nature is evident. Swelling of the pancreas can be recognized if the organ extends beyond its normal location between the loops of the duodenum.

Duodenum4

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normal

duodenum

Normal Reference

chicken (Gallus gallus)

Clinical Description

The walls of the duodenum should be smooth and uniform and offer little resistance to incision. In the proximal duodenum, the ingesta is normally mucoid and pale tan to yellow. Distal to the bile ducts, the ingesta becomes more green in color.

Duodenum3

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normal

duodenum, pancreas

Normal Reference

chicken (Gallus gallus)

Clinical Description

The duodenum has a descending and ascending loop, arranged in a U-shape. The loops are held together by a thin strip of mesentery and surround the pancreas. The appearance of the intestine can vary greatly depending on the post-mortem condition of the bird. In a fresh bird, the serosa of a healthy intestine is usually pink, smooth, and glistening. As the post-mortem interval increases, the intestinal walls will become congested, as seen here, and eventually, even a healthy loop of bowel may appear dark red. However, if the serosa has a dull granular appearance, this can be evidence of inflammation. The normal appearance of the pancreas is pale red or slightly yellow. On close inspection, its glandular nature is evident. Swelling of the pancreas can be recognized if the organ extends beyond its normal location between the loops of the duodenum.

Duodenum2

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duodenum

Normal Reference

chicken (Gallus gallus)

Clinical Description

The duodenum has a descending and ascending loop, arranged in a U-shape. The loops are held together by a thin strip of mesentery and surround the pancreas. The appearance of the intestine can vary greatly depending on the post-mortem condition of the bird. In a fresh bird, the serosa of a healthy intestine is usually pink, smooth, and glistening. As the post-mortem interval increases, the intestinal walls will become congested, as seen here, and eventually, even a healthy loop of bowel may appear dark red. However, if the serosa has a dull granular appearance, this can be evidence of inflammation. The normal appearance of the pancreas is pale red or slightly yellow. On close inspection, its glandular nature is evident. Swelling of the pancreas can be recognized if the organ extends beyond its normal location between the loops of the duodenum.

Pancreas4

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normal

pancreas

Normal Reference

chicken (Gallus gallus)

Clinical Description

The normal appearance of the pancreas is pale red or slightly yellow. On close inspection, its glandular nature is evident. Swelling of the pancreas can be recognized if the organ extends beyond its normal location between the loops of the duodenum.

24_pancreas_texture

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normal

pancreas

Normal Reference

chicken (Gallus gallus)

Clinical Description

On close inspection, the pancreas has a fine glandular texture.

MeckelsDiverticulum1

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normal

Mekel's diverticulum

Normal Reference

chicken (Gallus gallus)

Clinical Description

After 10 days of age, the only remnant of the yolk sac is a small tag of scar tissue, called Meckel’s diverticulum. This tag, located on the antimesenteric side of the intestine, contains lymphoid tissue and is part of the GALT, or Gut Associated Lymphoid Tissue. Meckel’s diverticulum is also an important anatomical landmark, as it is located at the junction between the jejunum and the ileum. Being able to differentiate the jejunum from the ileum is important to generating differentials for intestinal diseases. Some infections, such as coccidiosis, have a predilection for the jejunum and other diseases target the ileum.

MeckelsDiverticulum2

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Mekel's diverticulum

Normal Reference

chicken (Gallus gallus)

Clinical Description

After 10 days of age, the only remnant of the yolk sac is a small tag of scar tissue, called Meckel’s diverticulum. This tag, located on the antimesenteric side of the intestine, contains lymphoid tissue and is part of the GALT, or Gut Associated Lymphoid Tissue. Meckel’s diverticulum is also an important anatomical landmark, as it is located at the junction between the jejunum and the ileum. Being able to differentiate the jejunum from the ileum is important to generating differentials for intestinal diseases. Some infections, such as coccidiosis, have a predilection for the jejunum and other diseases target the ileum.

Cecum1

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ceca

Normal Reference

chicken (Gallus gallus)

Clinical Description

At the junction between the ileum and the descending colon, are two blind-ended sacs known as the ceca. In domestic poultry, the cecae are large structures that bend over themselves, with their apices pointing caudally. The walls should be thin and semi-translucent, allowing the greenish-colored intestinal contents to be visualized within. If the walls are opaque, thin or irregular, infection should be suspected.

Ileum1

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ceca

Normal Reference

chicken (Gallus gallus)

Clinical Description

At the junction between the ileum and the descending colon, are two blind-ended sacs known as the ceca. In domestic poultry, the cecae are large structures that bend over themselves, with their apices pointing caudally. The walls should be thin and semi-translucent, allowing the greenish-colored intestinal contents to be visualized within. If the walls are opaque, thin or irregular, infection should be suspected.

CecalTonsil1

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cecal tonsil

Normal Reference

chicken (Gallus gallus)

Clinical Description

At the base of the ceca, near the junction of the ileum and the descending colon, are 2 important lymphoid structures called cecal tonsils. The tissue here bulges outward slightly as it is thicker and slightly more granular.

CecalTonsil2

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cecal tonsil

Normal Reference

chicken (Gallus gallus)

Clinical Description

At the base of the ceca, near the junction of the ileum and the descending colon, are 2 important lymphoid structures called cecal tonsils. The tissue here bulges outward slightly as it is thicker and slightly more granular.

CecalTonsil3

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cecal tonsil

Normal Reference

chicken (Gallus gallus)

Clinical Description

As demonstrated here, the cecal tonsils should be opened and the mucosa examined closely. This is a common location for lesions to be detected. In inflammatory or neoplastic diseases, the tonsils may be come enlarged and mottled red and tan. In some viral infections, the lymphoid tissue may become necrotic, causing the tonsils to become red.

33_cecaltonsil_mucosa

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cecal tonsil

Normal Reference

chicken (Gallus gallus)

Clinical Description

The cecal tonsil has been opened to show the mucosa. It’s important to examine this area closely for lesions. In inflammatory or neoplastic disease, the cecal tonsils may become enlarged and mottled red and tan. In some viral infections, this lymphoid tissue may become necrotic, causing the tonsils to become red.

CecalTonsil4

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cecal tonsil

Normal Reference

chicken (Gallus gallus)

Clinical Description

As demonstrated here, the cecal tonsils should be opened and the mucosa examined closely. This is a common location for lesions to be detected. In inflammatory or neoplastic diseases, the tonsils may be come enlarged and mottled red and tan. In some viral infections, the lymphoid tissue may become necrotic, causing the tonsils to become red.

Cecum2

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normal

ceca, ileum

Normal Reference

chicken (Gallus gallus)

Clinical Description

The serosa of the ileum should be shiny, tan, and smooth, with no thickening or bulges. Be careful not to over-interpret the color of the intestinal walls as post-mortem congestion and autolysis can quickly turn the intestinal walls red or black. Because the intestinal walls are semi-translucent, look for areas of proliferation or mucosal exudate which can sometimes be visualized through the intestinal wall. At the junction between the ileum and the descending colon, are two blind-ended sacs known as the ceca. In domestic poultry, the cecae are large structures that bend over themselves, with their apices pointing caudally. The walls should be thin and semi-translucent, allowing the greenish-colored intestinal contents to be visualized within. If the walls are opaque, thin or irregular, infection should be suspected.

34_intestinal_lumen

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intestine

Normal Reference

chicken (Gallus gallus)

Clinical Description

The quality of intestinal ingesta can yield important clues about the functional status of the intestines. If the ingesta is normal, as seen here, regardless of the appearance of the intestinal wall, the intestines were likely functioning normal at the time of death. If the content is abnormal, intestinal dysfunction is present. Keep in mind that as the ingesta moves though the intestines, its color and consistency will change. In the jejunum, pictured here, the ingesta becomes slightly thicker and yellow tan in color.

colon1

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ceca

Normal Reference

chicken (Gallus gallus)

Clinical Description

Distal to the ceca, the intestines continue as a short straight tube known as the descending colon. These walls should be smooth and uniform. Look for any dilatations which may indicate an obstruction due to a mechanical blockage, a scar, or another disease process.

35_cloaca

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cloaca

Normal Reference

chicken (Gallus gallus)

Clinical Description

The cloaca is the common chamber for the gastrointestinal, urinary, and reproductive tracts. Here the cloaca has been opened. By the time ingesta enters the cloaca, it should have the normal color and consistency of feces and will be mixed with urates from the urinary system.

Cloaca1

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normal

bursa of Fabricius, cloaca

Normal Reference

chicken (Gallus gallus)

Clinical Description

On the dorsal wall of the cloaca is a diverticulum called the Bursa of Fabricius. This structure is an important lymphoid organ. The shape of the bursa varies with species. In the chicken, it is roughly pear shaped. In ducks, geese and turkeys it is more spindle shaped. The size varies with the age of the bird. It typically reaches its maximum size between 4 to 12 weeks of age, at which time it can weigh up to 4 grams. Normally, the bursa begins to involute when the bird is approximately 3 months of age. By the time the bird reaches sexual maturity, it may no longer be evident on gross examination.

Cloaca2

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bursa of Fabricius

Normal Reference

chicken (Gallus gallus)

Clinical Description

On the dorsal wall of the cloaca is a diverticulum called the Bursa of Fabricius. This structure is an important lymphoid organ. The shape of the bursa varies with species. In the chicken, it is roughly pear shaped. In ducks, geese and turkeys it is more spindle shaped. The size varies with the age of the bird. It typically reaches its maximum size between 4 to 12 weeks of age, at which time it can weigh up to 4 grams. Normally, the bursa begins to involute when the bird is approximately 3 months of age. By the time the bird reaches sexual maturity, it may no longer be evident on gross examination.

Bursa2

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bursa of Fabricius

Normal Reference

chicken (Gallus gallus)

Clinical Description

On the dorsal wall of the cloaca is a diverticulum called the Bursa of Fabricius. This structure is an important lymphoid organ. The shape of the bursa varies with species. In the chicken, it is roughly pear shaped. In ducks, geese and turkeys it is more spindle shaped. The size varies with the age of the bird. It typically reaches its maximum size between 4 to 12 weeks of age, at which time it can weigh up to 4 grams. Normally, the bursa begins to involute when the bird is approximately 3 months of age. By the time the bird reaches sexual maturity, it may no longer be evident on gross examination.

Bursa1

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bursa of Fabricius

Normal Reference

chicken (Gallus gallus)

Clinical Description

On the dorsal wall of the cloaca is a diverticulum called the Bursa of Fabricius. This structure is an important lymphoid organ. The shape of the bursa varies with species. In the chicken, it is roughly pear shaped. In ducks, geese and turkeys it is more spindle shaped. The size varies with the age of the bird. It typically reaches its maximum size between 4 to 12 weeks of age, at which time it can weigh up to 4 grams. Normally, the bursa begins to involute when the bird is approximately 3 months of age. By the time the bird reaches sexual maturity, it may no longer be evident on gross examination.

36_bursa

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bursa of Fabricius

Normal Reference

chicken (Gallus gallus)

Clinical Description

The bursa of Fabricius has been opened to show its mucosal surface. The normal mucosa consists of many folds of tissue, which are pale white to pink or tan and slightly firm on palpation.

Vent1

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vent

Normal Reference

chicken (Gallus gallus)

Clinical Description

The vent, located just beneath the tail, is the external orifice of the urinary, genital and gastrointestinal systems. The normal vent is free of fecal and urate staining, swelling, redness, or evidence of trauma.

37_ovary

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ovary

Normal Reference

chicken (Gallus gallus)

Clinical Description

This image shows the normal ovary of a sexually immature female, approximately 10 weeks of age. Here, the ovary is small and inactive.

Ribs1

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rib bone

Normal Reference

chicken (Gallus gallus)

Clinical Description

View of the dorsal aspect of the ribs. Note that the ventral ribs have been removed from the field.

38b_kidney_chain

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kidney

Normal Reference

chicken (Gallus gallus)

Clinical Description

The kidneys consist of a right and left chain, with each chain being made up of 3 lobes. The lobes are tightly embedded in the bone of the synsacrum. They are normally red to dark mahogany brown in color and have a slightly granular texture.

38a_kidney_texture

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kidney

Normal Reference

chicken (Gallus gallus)

Clinical Description

This image shows a detailed view of the normal texture of the kidneys.

40_ishradic_nerve

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peripheral nerves

Normal Reference

chicken (Gallus gallus)

Clinical Description

The nerves should have a creamy-white color and a slightly striated texture on close inspection. This image shows a normal ishiadic plexus in the caudal coelomic cavity.

ThyroidGlandLeft2

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thyroid gland

Normal Reference

chicken (Gallus gallus)

Clinical Description

The thyroid glands should be smooth, oval, and reddish-brown in color. On very close inspection, the thyroid glands have a very fine granular appearance.

07_beak_articulation

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beak

Normal Reference

chicken (Gallus gallus)

Clinical Description

A properly formed beak, shown here, is bilaterally symmetrical and the upper and lower halves should form a smooth line where they articulate.

beak2

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beak

Normal Reference

chicken (Gallus gallus)

Clinical Description

A properly formed beak is bilaterally symmetrical and the upper and lower halves should form a smooth line where they articulate. Nutritional imbalances may result in beak malformations. The color of the beak depends on the bird’s coloration, with lighter birds typically having yellow beaks. However, beak color can also be influenced by physiologic factors. For example, yellow pigment in the beak may be lost as the chicken produces more eggs.

choana1

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oropharynx

Normal Reference

chicken (Gallus gallus)

Clinical Description

The oropharynx should be examined for any lesions. Note that birds do not have a soft palate or a discrete boundary between the oral cavity and the pharynx. The color of the oral mucosa will vary with lighter birds tending to have a pink mucosa while darker birds will have more pigment. Look for ulcers, erosions, opacities, diptheritic nodules, or other lesions.

tongue1

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tongue

Normal Reference

chicken (Gallus gallus)

Clinical Description

A bird’s tongue is supported by the hyobranchial apparatus, making it somewhat inflexible.

09_oral_mucosa

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oropharynx

Normal Reference

chicken (Gallus gallus)

Clinical Description

The color of the oral mucosa will vary with the overall coloration of the bird. However, the mucosa should be free of ulcers, erosions, opacities, diptheritic nodules, and other lesions.

tongue3

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tongue

Normal Reference

chicken (Gallus gallus)

Clinical Description

The dorsal surface of the chicken tongue should be smooth and pink. There is a row of large papillae near the caudal attachment of the tongue. Inspect the tongue for any lesions such as ulcers or nodules.

08_tongue

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tongue

Normal Reference

chicken (Gallus gallus)

Clinical Description

The dorsal surface of the chicken’s tongue is smooth and there is a row of large papillae near the caudal attachment. When inspecting the tongue, look for ulcers and erosions.

choana2

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choana

Normal Reference

chicken (Gallus gallus)

Clinical Description

On the roof of the oropharynx is a fissure, called the choana, which opens into the nasal cavity. Inspect the area around the choana for ulcers. The choana is also a good place to find respiratory exudate. Birds do not form liquid pus and inspusated exudate tends to accumulate in the choanal orifice. If exudate is present, you can collect a swab sample from the choana. The choana is surrounded by ridges and rows of sharp well-demarcated papillae that point caudally. A variety of diseases can damage the papillae, resulting in blunting.

13_infundibular_cleft

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infundibular cleft

Normal Reference

chicken (Gallus gallus)

Clinical Description

Just caudal to the choana is the infundibular cleft. This is the opening to the Eustachian tube and it is surrounded by ridges and rows of sharp well-demarcated papilla that point caudally.

pharynx1

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oropharynx, tongue

Normal Reference

chicken (Gallus gallus)

Clinical Description

The tongue, esophagus, and trachea have been removed as one unit. This view allows the structures of the structures of the caudal oral cavity and pharynx to be examined more closely.

pharynx3

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oropharynx

Normal Reference

chicken (Gallus gallus)

Clinical Description

The tongue, esophagus, and trachea have been removed as one unit. This view allows the structures of the caudal oral cavity and pharynx to be examined more closely.

crop1

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esophagus

Normal Reference

chicken (Gallus gallus)

Clinical Description

The esophagus runs down the length of the neck and, in domestic species, is interrupted by a diverticulum called the crop. The esophagus continues down the neck and empties into the proventriculus. The esophagus and crop are thin-walled and located just below the skin. Their outer surfaces should be pale tan and smooth.

crop2

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esophagus

Normal Reference

chicken (Gallus gallus)

Clinical Description

The esophagus runs down the length of the neck and, in domestic species, is interrupted by a diverticulum called the crop. The esophagus continues down the neck and empties into the proventriculus. The esophagus and crop are thin-walled and located just below the skin. Their outer surfaces should be pale tan and smooth.

crop3

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crop, esophagus

Normal Reference

chicken (Gallus gallus)

Clinical Description

The mucosal surface of the esophagus should be smooth and glistening. The cranial portion contains many glands and the caudal portion has numerous longitudinal folds. The color along the entire length should be pale tan to pink. The presence of proliferative lesions may indicate a viral infection or a dietary imbalance. You can gently wash away any food material from the walls of the crop with some water but do not scrape the mucosa. Food material should wash away easily while fibrin and exudate will stick to the mucosa. Look for ulcers and erosions, which appear as red or pale depressions in the mucosa.

26_esophagus_folds

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esophagus

Normal Reference

chicken (Gallus gallus)

Clinical Description

The caudal portion of the normal esophagus has numerous longitudinal folds, as seen here.

crop4

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crop

Normal Reference

chicken (Gallus gallus)

Clinical Description

You can gently wash away any food material from the walls of the crop with some water but do not scrape the mucosa. Food material should wash away easily while fibrin and exudate will stick to the mucosa. Look for ulcers and erosions, which appear as red or pale depressions in the mucosa.

crop5

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crop

Normal Reference

chicken (Gallus gallus)

Clinical Description

You can gently wash away any food material from the walls of the crop with some water but do not scrape the mucosa. Food material should wash away easily while fibrin and exudate will stick to the mucosa. Look for ulcers and erosions, which appear as red or pale depressions in the mucosa.

Trachea3

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trachea

Normal Reference

chicken (Gallus gallus)

Clinical Description

The trachea should be uniform in color, ranging from pale pink to tan or white and the external surface should be smooth. Upper respiratory disease may produce tracheal lesions that are sometimes visible on the outer surface. Look for discoloration, nodules, or irregularities in the tracheal cartilages.

palate2

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trachea

Normal Reference

chicken (Gallus gallus)

Clinical Description

The trachea is a thin tube completely encircled by small cartilagenous rings. The trachea should be uniform in color, ranging from pale tan to white and the external surface should be smooth. Look for discoloration, nodules, or irregularities in the tracheal cartilages.

21_trachea_cartilage

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trachea

Normal Reference

chicken (Gallus gallus)

Clinical Description

The trachea is a thin tube completely encircled by cartilagenous rings. The trachea should be uniform in color, ranging from pale pink to tan or white and the external surface should be smooth. Upper respiratory disease may produce tracheal lesions that are sometimes visible on the outer surface. Look for discoloration, nodules, or irregularities in the tracheal cartilages.

Syrinx1

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syrinx, trachea

Normal Reference

chicken (Gallus gallus)

Clinical Description

At the terminal end of the trachea lies the syrinx, a flattened area at the junction of the trachea and the primary bronchi. The syrinx is responsible for generating vocal sounds.

20_syrinx

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syrinx

Normal Reference

chicken (Gallus gallus)

Clinical Description

Since the diameter of the syrinx is significantly smaller than that of the trachea, examine this area closely for occlusions caused by exudate, fungal mats, or parasites.

Syrinx2

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syrinx

Normal Reference

chicken (Gallus gallus)

Clinical Description

Since the diameter of the syrinx is significantly smaller than that of the trachea, examine this area closely for occlusions caused by exudate, fungal mats, or parasites.

Trachea4

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trachea

Normal Reference

chicken (Gallus gallus)

Clinical Description

View of the inside lumen of the trachea.

Jugular1

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jugular vein

Normal Reference

chicken (Gallus gallus)

Clinical Description

The left jugular vein of the bird, seen here, is much larger than the right.

Jugular2

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jugular vein

Normal Reference

chicken (Gallus gallus)

Clinical Description

The left jugular vein of the bird, seen here, is much larger than the left. The vagal and glossopharyngeal nerves are closely associated with the veins.

22_jugular_and_nerve

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peripheral nerves

Normal Reference

chicken (Gallus gallus)

Clinical Description

The vagal and glossopharyngeal nerves run parallel with the jugular veins.

ThyroidGlandLeft1

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thyroid gland

Normal Reference

chicken (Gallus gallus)

Clinical Description

The thyroid glands are located on each side of the neck, medial to the jugular vein and cranial to the origin of the subclavian and common carotid arteries.

23_thyroid_parathyroid

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thyroid gland

Normal Reference

chicken (Gallus gallus)

Clinical Description

The glands should be smooth, oval, and reddish-brown in color. On very close inspection, the thyroid glands have a very fine granular appearance.

ThyroidGlandRight2

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thyroid gland

Normal Reference

chicken (Gallus gallus)

Clinical Description

Just caudal to the thyroid glands are the small pale pink parathyroid glands. The right parathyroid gland, seen here, lies directly adjacent to the right thyroid gland. The left parathyroid gland is slightly separated from the left thyroid gland.

Thymus1

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thymus gland

Normal Reference

chicken (Gallus gallus)

Clinical Description

The thymus is a bilateral chain of structures, located in the lateral neck region. each side is composed of 4 to 7 lobes. In chickens less than 17 weeks of age, the thymus should be visible but normally regresses around the time of sexual maturity.

Thymus2

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thymus gland

Normal Reference

chicken (Gallus gallus)

Clinical Description

The lobes of the thymus, normally present only in immature birds, are pale tan to pink in color.

VIT E-SELENIUM - 019A.jpg

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brain

Normal Reference

chicken (Gallus gallus)

Clinical Description

The avian brain has a smooth surface, with no gyri or sulci. Its cortex should appear smooth and glistening and the right and left sides should be symmetrical.

44_brain

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brain, cerebrum

Normal Reference

chicken (Gallus gallus)

Clinical Description

This image shows a detailed view of the surface of the normal cerebrum.

PectoralMuscles1

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pectoral muscles

Normal Reference

chicken (Gallus gallus)

Clinical Description

The 3 muscles involved in flight in the bird, called the pectoral muscles, lie on either side of the keel bone. These muscles are very large, making them ideal for body muscle assessment. The muscles should be smooth and have a relatively uniform texture.

PectoralMuscles2

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pectoral muscles

Normal Reference

chicken (Gallus gallus)

Clinical Description

The pectoral muscles can be removed from the keel and ribs in order to examine them more closely. Look for areas of necrosis, inflammation, or hemorrhage.

PectoralMuscles3

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pectoral muscles

Normal Reference

chicken (Gallus gallus)

Clinical Description

With the muscles removed, look for areas of necrosis, inflammation, or hemorrhage. A series of parallel cuts through the muscle bellies can facilitate this assessment.

eyes1

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comb, eyelid, wattles

Normal Reference

chicken (Gallus gallus)

Clinical Description

The eyelids should be free of swelling or exudate from ocular discharge.

eyes2

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eyelid

Normal Reference

chicken (Gallus gallus)

Clinical Description

The eyelids should be free of swelling or exudate from ocular discharge.

10_eye_insitu

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eye

Normal Reference

chicken (Gallus gallus)

Clinical Description

The cornea should be clear and convex and the sclera white. Iris color will vary with the breed and color of the bird however, look for abnormalities of the iris such as redness, anterior synechia, or exudate in the anterior chamber. The shape of the iris and pupil should be uniform and round.

12_conjunctiva

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conjunctiva

Normal Reference

chicken (Gallus gallus)

Clinical Description

The conjunctiva is a mucous membrane. It should be light pink in color and free of any redness, swelling, or exudate.

15_eye_front

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eye

Normal Reference

chicken (Gallus gallus)

Clinical Description

The eye has been removed from the skull showing the full extent of the orbit.

11_ear

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ear

Normal Reference

chicken (Gallus gallus)

Clinical Description

The ears in the bird are simple ostea, with no external pinna. The openings should be free of swelling, exudate, or other material.

beak1

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comb, wattles

Normal Reference

chicken (Gallus gallus)

Clinical Description

The comb and wattles are outgrowths of skin that are highly vascularized, making them a useful way to assess the bird's overall health. They are normally bright red but their color will quickly fade after death. However, they should remain firm and uniform on palpation. look for abnormalities such as edema, petechiae, necrosis, cyanosis, papules and ulcers.

14_sinus

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infraorbital sinus

Normal Reference

chicken (Gallus gallus)

Clinical Description

The infraorbital sinuses are triangular-shaped cavities, located rostroventral to the eyes. The sinuses are air-filled lumens, with one opening into the nasal cavity and the other into the caudal nasal cavity.

06_leg_conformation

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Leg

Normal Reference

chicken (Gallus gallus)

Clinical Description

As seen here, the legs bones of the should be straight and symmetrical.

limb1

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leg bones

Normal Reference

chicken (Gallus gallus)

Clinical Description

The leg bones should be straight and symmetrical. Palpate the bones for fractures and calluses and the joints for swelling or effusion. Flex and extend all the joints to assess range of motion, keeping in mind the effects of rigor mortis.

integument1

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skin

Normal Reference

chicken (Gallus gallus)

Clinical Description

The skin on the limbs is covered by scales that are normally dry, flat, and slightly overlapping. Some parasites live beneath the scales of the legs. Some infectious diseases can cause keratinous outgrowths from this skin.

integument2

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skin

Normal Reference

chicken (Gallus gallus)

Clinical Description

The skin on the limbs is covered by scales that are normally dry, flat, and slightly overlapping. Some parasites live beneath the scales of the legs. Some infectious diseases can cause keratinous outgrowths from this skin.

integument3

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digits, foot pads

Normal Reference

chicken (Gallus gallus)

Clinical Description

Digital pads cover the plantar surface of the birds’ feet. These pads are composed of thick skin and adipose tissue. In the center of the foot, there is a large central metatarsal pad. The pads should be soft, free of scabs, swellings, edema, hemorrhages, or other lesions.

pad2

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foot pads

Normal Reference

chicken (Gallus gallus)

Clinical Description

In the center of the foot, there is a large central metatarsal pad. The pads should be soft, free of scabs, swellings, edema, hemorrhages, or other lesions.

01_claw

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claws

Normal Reference

chicken (Gallus gallus)

Clinical Description

In birds housed on the floor, claws will normally come to a blunt tapered end, as seen here. Claws may be somewhat sharper in birds housed in cages. Curling or fraying claws are abnormal findings.

feathers1

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feathers

Normal Reference

chicken (Gallus gallus)

Clinical Description

Birds have several types of feathers distributed across various regions of their body including down, body feathers, and flight feathers. Look for abnormalities in feather conformation such as warping or malformed barbs and barbules. Make note of any body regions that are missing feathers. Feathers are normally distributed along tracks on the body, called pterylae. These tracks are interspersed with featherless tracts called apteria. Keep in mind, that not all feather loss is abnormal. Seasonal feather molting is a normal physiologic process. Additionally, females who are incubating eggs may have an area on their abdomen lacking feathers, called the brood patch. In non-pathologic feather loss, the skin will appear healthy. In cases of pathologic feather loss, such as excessive feather picking by the bird, or its cage mates, the skin will be traumatized.

04_down_feather

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feathers

Normal Reference

chicken (Gallus gallus)

Clinical Description

This image shows a typical “down” feather.

integument4

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skin

Normal Reference

chicken (Gallus gallus)

Clinical Description

The skin in the chicken is normally very thin and the amount of pigment varies from pink to black, depending on the coloration of the bird. The skin should be free of exudate and have little or no scale. Look for any lesions or evidence of ectoparasites.

05_apteria

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feathers

Normal Reference

chicken (Gallus gallus)

Clinical Description

Feathers are normally distributed along tracks on the body, known as pterylae, seen here. These tracks are interspersed with featherless areas called apteria. Patches of feather loss may be due to normal physiologic processes, such as seasonal molting. Pathologic feather loss can result from trauma and infection and is associated with skin lesions.

feathers2

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feathers

Normal Reference

chicken (Gallus gallus)

Clinical Description

Pay attention to the feather sheath, the area where the feather emerges from the follicle. Swelling in this location can be indicative of several types of infection.

feathers3

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feathers

Normal Reference

chicken (Gallus gallus)

Clinical Description

Pay attention to the feather sheath, the area where the feather emerges from the follicle. Swelling in this location can be indicative of several types of infection.

Uropygealgland1

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uropygeal gland

Normal Reference

chicken (Gallus gallus)

Clinical Description

The uropygial, or preen gland, is located dorsal to the base of the tail. This cutaneous gland secretes an oily substance that birds spread over their feathers during preening. These secretions help maintain normal healthy feathers.

Uropygealgland2

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uropygeal gland

Normal Reference

chicken (Gallus gallus)

Clinical Description

The body of the gland is located subcutaneously and its two lobes can sometimes be visualized beneath the skin, as seen here. The gland’s duct exits externally through a small papilla. Infected glands may result in swelling and reddening of the surrounding skin.

42_cartilage

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cartilage

Normal Reference

chicken (Gallus gallus)

Clinical Description

Cartilage should be smooth, shiny, and white with a slightly blue tinge, as seen here. Look for degenerative changes and roughed, discolored areas.

43_bone_marrow

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leg bones

Normal Reference

chicken (Gallus gallus)

Clinical Description

In a young bird, cut the long bone of the leg lengthwise to examine the epiphysis. Nutrient or mineral deficiencies can lead to poor mineralization of the bone. Look for widening of the epiphyseal plate or generalized hypoplasia of the bone.

Avian Influenza

Avian Influenza

Avian Influenza

Etiology

Avian Influenza (AI) [also known as Fowl Plague] is a viral infection affecting wild and domestic birds. These influenza viruses occur naturally in the intestinal tract of many species of wild birds with no disease outcome. However, pathogenic forms of the Avian Influenza virus can result in a highly contagious respiratory infection. Many species of birds are susceptible to AI including chickens, turkeys, guinea fowl, and other domestic birds, as well as a some wild avian species. AI viruses are classified into two general types based on their pathogenicity for chickens: Low Pathogenic (LP) and Highly Pathogenic (HP) types.

AI is caused by viruses that are members of the family Orthomyxoviridae, and the genus Influenzavirus, Type A. Influenza viruses Type B and C are pathogenic for humans but not for birds. Virus classification is based on antigenic differences in the nucleoprotein (NP) and matrix proteins (M1). Further subtyping of the AI virus is made based on the presence of 2 glycoproteins on the surface of the virus, hemagglutinin (HA) and neuraminidase (NA). Each AI virus has 1 of 16 different HA subtype glycoproteins and 1 of 9 different NA subtype glycoproteins (e.g. H5N1).

The HA and NA protein subtypes confer differences in viral pathogenicity. In LP strains, the HA protein can be cleaved by proteases present only in the respiratory and digestive tracts. In HP strains, proteases in most cells of the body can cleave the protein, resulting in a much wider tissue tropism than mildly pathogenic strains.

The HA protein is the major antigen that elicits antibodies which protect against clinical signs and death. Such antibodies are HA subtype specific. The antigenicity of influenza viruses may change gradually by point mutation (antigenic drift) or drastically by genetic reassortment (antigenic shift). Immunological pressure on HA and NA is thought to drive antigenic drift.

AI subtype classification requires viral isolation and characterization. Further subtyping is based on the antigenicity of the two surface glycoproteins, HA and NA. Classification cannot be made through clinical observations alone because the severity of the infection depends not only on the subtype of the virus but also the host species, the age of the bird, the host's immune status, and the presence of any secondary infections or environmental stress.

Due to the significant economic and public health implications of an AI outbreak, the World Organization for Animal Health (OIE) requires notification of any bird that is diagnosed with low pathogenic notifiable AI (LPNAI) or highly pathogenic notifiable AI (HPNAI). For the purposes of international trade the OIE defines notifiable avian influenza (NAI) as an infection of poultry caused by any influenza A virus of the H5 or H7 subtypes or by any AI virus with an intravenous pathogenicity index (IVPI) greater than 1.2 or, as an alternative, if the virus produces at least 75% mortality after inoculation.

HPNAI viruses have an IVPI greater than 1.2 in 6-week-old chickens or, as an alternative, cause at least 75% mortality in 4 to 8-week-old chickens infected intravenously. H5 and H7 virus isolates that do not have an IVPI of 1.2 or greater, nor produce 75% mortality under experimental conditions, but have an amino acid sequence at the cleavage site of the hemagglutinin that is similar to that observed for other HPNAI isolates, should be considered as HPNAI. LPNAI are all influenza A viruses of H5 and H7 subtype that do not display features of HPNAI viruses.

To date, all highly pathogenic strains of AI have been of the H5 or H7 subtypes. Although most H5 and H7 subtypes are in fact low pathogenic strains, since AI is unstable, there is a potential for LPNAI to mutate into HPNAI. Therefore all H5 and H7 subtypes require reporting to the OIE in order to facilitate global virus control measures. Within the United States, these pathotypes are considered exotic diseases and, in addition to being reported to the OIE, they should also be reported to the State and Federal veterinary authorities.

Host range

The AI viruses have been shown to naturally infect a wide variety of wild and domestic birds. The viruses have been isolated from more than 90 avian species however, in free-living birds most natural infections do not produce recognizable disease. The practice of housing birds in captivity and the development of commercial poultry systems have altered the normal epidemiology of the virus, resulting in clinically significant disease within domestic poultry.

In chickens, AI is capable of producing significant disease and economic losses. Ducks and other waterfowl are susceptible to the Asian HPAI H5N1 currently circulating in Asia, but have innate resistance to most other strains of Avian Influenza. Migratory waterfowl can act as carriers and transport viruses between geographic areas, helping to spread AI viruses to other susceptible animals.
In general, mammals are poorly susceptible to AI. However, several infections of highly pathogenic notifiable Avian Influenza (HPNAI) viruses have been reported since 1997 in humans, pigs and other mammals. Most of these cases have been linked to close contact with infected poultry. Although chicken-to-human infections have been rare, the virus is highly unstable and can alter pathotypes by passage in various animal species. The recombination of avian and human influenza viruses in pigs may be a potential source for sporadic pandemics of human influenza.

Epidemiology

AI viruses are distributed worldwide and identified frequently from clinically normal migratory waterfowl, imported birds, and species in live-bird markets. Data shows migratory waterfowl are the reservoir for AI viruses. Migratory birds introduce LPNAI viruses into poultry and, once introduced, the virus adapts to poultry and spreads from flock-to-flock, mostly by human activity. Most outbreaks of HPNAI in poultry arise from mutations in a LPNAI strain.

AI is excreted from the nares, mouth, and cloaca of infected birds. Spread occurs rapidly among birds housed on the floor but is slower in caged birds. Spread is primarily through contaminated feces and aerosol from the respiratory tract. The ingestion of contaminated feed and drinking water is another common source of transmission. The virus may also be transmitted indirectly by fomites such as contaminated equipment, personnel, clothing, foot wear, artificial insemination, and other human activity.

The incubation for AI is usually 1-7 days and depends on the strain, the dose, the species, and the age of the bird. The typical incubation period for an individual bird is approximately 3 days. It may take up to 14 days for an entire flock to become ill.
The morbidity of LPNAI is variable and the mortality is usually low, unless secondary infections are present or the birds are housed under poor management conditions. The morbidity and mortality of HPNAI may be near 100% within 2-12 days after the onset of the first signs of illness.

Clinical Signs

The severity of clinical signs depends on factors such as age, sex, species, concurrent infections, environment, as well as the pathogenicity of the virus.

Low pathogenic AI in wild birds usually produces no clinical signs. In domestic poultry, clinical signs reflect abnormalities in the respiratory, digestive, urinary, and reproductive organs. Generalized signs include depression, decreased activity, huddling, ruffled feathers, decreased feed and water consumption and occasionally greenish diarrhea. Respiratory manifestations include mild to severe coughing, sneezing, rales, rattles, excessive lacrimation, matted eyelids, and nasal discharge. Increased broodiness and a 5-30% decrease in egg production are observed in laying hens and breeders. Turkeys, infected with swine flu, may experience a much larger drop in egg production. Eggs may be thin-shelled and misshapen, but production will usually return to near-normal levels following recovery. Some viral strains may be associated with egg yolk peritonitis.

Some strains of highly pathogenic AI replicate poorly in wild birds and domestic ducks, producing few clinical signs. Ducks, quail, and turkeys may have mild sinusitis. Recent HPAI Asian H5N1 strains have produced more severe clinical signs in ducks and some wild birds.

In chickens, highly pathogenic AI produces clinical signs that reflect widespread viral replication and damage to multiple body systems. The disease may be fulminate, with some birds found dead without exhibiting any clinical signs. Birds that survive 3-7 days post infection may exhibit depression, ruffled feathers, decreased feed and water consumption, and a precipitous drop or total cessation of egg production. Diarrhea is often present. Early in the course of the disease, the feces may be bright green and watery. As the disease progresses, the droppings may become totally white. Birds may show cyanosis and edema of the skin, particularly of the combs, wattles, and periocular areas. Occasionally, edema and ecchymoses of the shanks and feet may also be observed. In some cases neurologic disease develops. Nervous deficits can include head and neck tremor, inability to stand, torticollis, loss of perching reflex and opisthotonus. Respiratory signs are less prominent in HPNAI than with LPNAI but may include coughing, sneezing (with blood tinged discharge), and rales. Most birds will die within 1-2 days following the onset of illness but some birds may survive for as long as a week. Recovery is uncommon.

Post-mortem Lesions

Lesions are variable in distribution and severity, depending greatly on host species, pathogenicity, and secondary infections.
Domestic ducks with LPNAI may have sinusitis, conjunctivitis, and other mild respiratory lesions. In chickens, lesions are more pronounced and are distributed throughout the upper respiratory tract and include catarrhal, fibrinous, serofibrinous, mucopurulent, or fibrinopurulent exudates. The tracheal mucosa may be edematous with congestion and hemorrhages. The infraorbital sinuses may be swollen and mucoid to mucopurulent nasal discharge may be present. Catarrhal to fibrinous inflammation may be observed in the coelomic cavity. The ovaries may be hemorrhagic with ova involution and degeneration. Eggs may be misshapen and fragile. The coelomic cavity may contain ovules or be filled with egg yolk, from ruptured ova, resulting in egg yolk peritonitis. This peritonitis may cause air sacculitis and diffuse coelomic cavity inflammation in birds that survive for 7-10 days post infection. Catarrhal to fibrinous enteritis may also be observed in the ceca and in the intestines.

Birds infected with HPNAI that die peracutely may not show any gross lesions. In chickens infected with the acute to subacute form, significant gross lesions are usually observed. At gross necropsy, one of the most frequent external findings is edema, manifested by swelling of the head (combs, wattles and periocular regions), upper neck, and feet. This edema may be accompanied by petechial and ecchymotic hemorrhages. Additionally, areas of nonfeathered skin such as the wattles and combs, are commonly cyanotic and have dark areas, caused by ecchymotic hemorrhages and necrotic foci. Internally, generalized hemorrhages and edema can be found in the muscles, especially the pectoral muscles, as well as the tissues of the hocks and feet. With most strains of HPNAI, pinpoint petechial hemorrhages are frequently observed along the abdominal fat, pericardium, serosal surfaces and peritoneum. Visceral organs may also be marked by hemorrhages. The glands of the proventriculus may have hemorrhagic lesions, particularly at the junction with the ventriculus (gizzard). The lining of the ventriculus may peel easily, frequently revealing underlying hemorrhages, erosions, and ulcers. The intestinal mucosa may have hemorrhagic areas, especially in the lymphoid tissue of the cecal tonsils and Peyer's patches in the small intestine.

In laying birds, the ovary may be hemorrhagic or degenerated with darkened areas of necrosis. In birds that survive, the peritoneal cavity is frequently filled with yolk from ruptured ova, causing severe airsacculitis and inflammation. The eggs are frequently soft and fragile due to decreased calcium deposition.

The trachea may appear normal, with the exception of excessive mucous accumulation, or it may be severely affected, with extensive hemorrhagic tracheitis. The lungs may be deep red in color, due to congestion and hemorrhage, and may exude edematous fluid when cut. The bursa of Fabricius and thymus are usually atrophic. The kidneys may be swollen, severely congested, and may by plugged with white urate deposits in the tubules. Necrotic foci may be present in the pancreas, spleen, heart, and occasionally the liver and kidneys.

Differential Diagnosis

AI should be differentiated from other respiratory diseases such as: Newcastle disease, infectious bronchitis, infectious laryngotracheitis, avian pneumovirus, and infectious coryza, among others. Other diseases that cause sudden death and septicemias, such as fowl cholera, should also be considered. Particular attention should be given to differentiating AI from mycoplasmosis, chlamydiosis and fowl cholera in young turkeys.

Diagnosis

In cases where HPAI is suspected, it is important to submit clinical samples to a recognized laboratory capable of carrying out AI diagnosis. Currently, there are a number of laboratories in the United States and around the world that have the capabilities to perform molecular testing, such as reverse transcriptase-polymerase chain reaction (RT-PCR) or a simplified faster real time reverse transcriptase polymerase chain reaction (rRT-PCR), to detect the presence of AI from clinical samples. The validated testing procedures performed at these laboratories are very sensitive, accurate, and rapid.

Cases involving respiratory signs and drop in egg production should be investigated for LPNAI. A presumptive diagnosis can be made in the field if compatible clinical signs and gross lesions are accompanied by a positive influenza type A test result, via commercial antigen capture immunoassay. However, because this test does not distinguish between LPAI and LPNAI, and may produce false-positive results, additional laboratory testing will be needed.

HPNAI should be suspected in any flock experiencing peracute death, high mortality, severe depression, inappetence, and a drastic decline in egg production. The presence of compatible gross lesions and the detection of Type A influenza antigen in oropharyngeal or tracheal swabs, supports a field diagnosis of HPNAI. However, these findings should be followed by more specific tests to identify and characterize the virus's antigenic and pathogenic type.

For HPNAI or LPNAI testing, collect and submit tracheal or cloacal swab samples as well as tissue samples taken from several internal organs such as the trachea, lung, spleen, cecal tonsils, or brain. Specimens should be collected from several birds, as it is not unusual for many specimens to fail to yield virus. If large numbers of birds are dead, you can submit up to 5 swab samples in one tube but do not mix swabs taken from different sites.

Blood for serum testing should be collected from several birds using standard serum tubes. If the specimens can be delivered to a laboratory within 24 hours, they should be placed on cold packs for shipping. If delivery will take longer, quick freeze the specimens in dry ice or liquid nitrogen, but do not allow the samples to thaw during transit. Freezing and storage at standard freezer temperature (-20 degrees C) is not recommended.

In the laboratory, virus isolation is usually performed by inoculation of embryonated chicken eggs with organ homogenizates or with tracheal or cloacal swabs. The AI virus is detected if the allantoic fluid of inoculated eggs hemagglutinates chicken red blood cells. The virus can be sub-typed using specific sera against all known HA and NA proteins. Specific hemagglutination inhibition is the basis of the serologic test for influenza antibodies. The ELISA (enzyme-linked immunosorbent assay) and AGID (agar gel immunodiffusion) tests can be used for determining the presence of antibody in the sera.

Any suspected case of Notifiable Avian Influenza (NAI) in the United States should be immediately reported to the State Veterinarian for the State where the case is suspected. A current list of animal health officials (State Veterinarians) contact information is available at http://www.usaha.org/members.shtml#agency . For suspected cases of NAI in other countries, notification should be given to the Chief Veterinary Officer (or OIE Country Delegate) of the country or territory where the case is suspected. A current list of Chief Veterinary Officers is available at http://www.oie.int/eng/OIE/PM/en_PM.htm?e1d1 .

Given the changes in the zoonotic potential recently seen with the emergence of human infections with the HPAI Asian H5N1 strain, it is recommended to treat any future HPAI as a potentially zoonotic disease. Seek the advice of the Public Health authorities in dealing with any outbreak action. A current list of Public Health authorities in the US is available at: www.astho.org or at http://www.statepublichealth.org/. Information on Public Health authorities outside the US is available at: http://www.who.int/countries/en/

Prevention and Control

The recommended strategy for controlling NAI is eradication. This requires 5 components including: 1) inclusion and exclusion biosecurity practices, 2) increasing host resistance through vaccination, 3) diagnostics and surveillance, 4) elimination of infected animals from the flock, and 5) educating personnel in AI control strategies.
1) Implementing biosecurity practices includes controlling human traffic, quarantining birds before introduction, proper cleaning and disinfection of facilities, keeping healthy birds away from contact with sick birds and wild birds, and incubating eggs only from clean flocks. Strict quarantine measures not only reduce the possibility of introducing Avian Influenza to a farm but also to a region or country.
2) Inactivated vaccines have been shown to be effective but are fairly expensive. Recombinant fowl poxvirus, carrying an inserted H5 gene, have shown similar efficacy in chickens. However, no vaccine will provide absolute prevention against infections or control environmental contamination. Other major drawbacks to current vaccines for controlling NAI include the labor associated with administering vaccine injections to individual birds and the need to match the vaccine to the field hemagglutination subtype in order to confer protection.
3) Diagnostics and surveillance play a critical role in controlling NAI. In the field, appropriate diagnostic samples should be collected and submitted to an accredited laboratory, capable of carrying out AI diagnosis. If NAI is suspected, field samples are inoculated into embryonated eggs, and after incubation for several days, allantoic fluid from inoculated eggs are tested for hemagglutinating activity. Upon detection of any hemaglutinating virus, a presumptive diagnosis of NAI is made and an immediate quarantine of the farms under testing should be made. This quarantine is designed to limit the movement of birds, equipment, and personnel to prevent potential viral dissemination. Agents that show hemagglutinating activity are then further identified in the laboratory by a number of techniques including the newer rapid rRT-PCR .
4) If NAI infection is confirmed by laboratory testing, all birds within the flock should be culled, utilizing humane euthanasia techniques, and disposed of properly. This depopulation effort requires the use of proper personal protective equipment (PPE) in accordance with national or international standards.
5) Finally, it is important to have personnel trained in animal disease control measures before a potential outbreak event. The success of disease control activities requires advanced preparation and familiarity with proper biosecurity and emergency management protocols
Due to the significant economic and public health implications of an AI outbreak, all cases of LPNAI and HPNAI must be reported to the State and federal veterinary authorities in order to facilitate global virus control measures.

Selected References

  1. Charlton, B. R. (ed). 2006. Avian Disease Manual, 6th ed. American Association of Avian Pathologists (AAAP), 953 College Station Road, Athens, Georgia 30602-4875.
  2. Swayne, D.E. 2008. Avian Influenza. In Foreign Animal Diseases, 7th ed. United States Animal Health Association. C. Brown and A. Torres (ed.).. Boca Publications Group, Inc. Boca Raton, FL. (http://www.usaha.org/pubs/fad.pdf)
  3. Swayne, D.E. and D.A. Halvorson. 2008. Influenza. In Diseases of Poultry, 12th ed. Y.M. Saif. et al. (ed.). Blackwell Publishing, Ames, Iowa.
  4. World Organization for Animal Health (OIE) website. 2008. www.oie.int

Thank you to the following individuals for reviewing these materials:

Dennis Senne
Alfonso Torres
Alejandro Banda
Benjamin Lucio-Martinez
Jose Bruzual
Jaime Ruiz
John Coakley

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Fowl Cholera

Fowl Cholera

Fowl Cholera (Pasteurella multocida)

Etiology

Fowl cholera (FC) is a highly contagious disease of domestic and wild birds. The disease is caused by Pasteurella multocida, a gram-negative, non-spore-forming, rod shaped bacteria. There are 16 somatic serotypes of Pasteurella multocida, of which 1, 3, and 3x4 are the most common. The pathogenicity of Pasteurella multocida strains is quite variable and the degree of expression of clinical signs varies by host species as well as variations within the host's immune system.

Host Range

Outbreaks of FC occur most frequently in turkeys, chickens, ducks, and geese. The disease is particularly severe in turkeys. Other bird species raised in captivity, as well as wild avian species, may also develop clinical disease. Some domestic mammals are also susceptible.

Epidemiology

FC is spread via horizontal transmission through contact with infected birds, contaminated equipment, personnel, etc. Pasteurella multocida can enter through mucous membranes, including oral, nasal, and conjunctival, as well as through cutaneous wounds. Chronically infected carriers play a major role in the spread of this disease and infected birds can remain carriers for life. The prevalence of Pasteurella multocida among wild birds, rodents, and other domesticated and non-domesticated species is likely responsible for the introduction of the infection into most domesticated poultry flocks.

FC is widely distributed, with periodic enzootic outbreaks occurring in most countries throughout the world. The disease usually manifests as a septicemia, sometimes with high morbidity and high mortality. However, a more chronic and asymptomatic form of the disease can also occur. Young adults are most susceptible to FC infection and physiologic stresses, such as egg lay cycles and seasonal changes, influence susceptibility. FC is more prevalent in the cooler seasons of the year.

Clinical Signs

Signs vary depending on the course of the disease. In the acute form of FC, infected birds may develop fever, ruffled feathers, anorexia, increased respiratory rate, and cyanosis. Cyanosis is often easiest to appreciate on the non-feathered skin of the comb and wattles. Mucoid discharge from the mouth and diarrhea may also occur. Diarrhea often begins as watery and whitish in color, progressing to a greenish color with mucus. In the acute form, signs may be absent and birds may be found dead in their nests. Birds that survive the acute septicemia may later die of dehydration and emaciation. Some birds may survive but remain chronically infected.

In the chronic form of FC, birds that survive acute infection or birds exposed to a low virulence strain, generally exhibit localized infections. The wattles, sinuses, foot pads, sternal bursa, and leg and wing joints may become swollen. Exudative pharyngeal and conjunctival lesions may be present. Sometimes tracheal rales and dyspnea may occur secondary to respiratory tract infections. Infected birds may also exhibit torticollis from middle ear infections and meningeal involvement. The chronic form of FC may last 3 to 4 weeks and may sometimes persist for years.

Post-mortem Lesions

In the acute form of FC, lesions associated with vascular disturbances are common. The veins of the abdominal viscera, especially the duodenum, may be markedly hyperemic. Petechiael and ecchymotic hemorrhages are frequently found throughout the viscera, most commonly the lungs, intestines, heart, and abdominal fat. Excessive fluid may be found in the pericardium and coelomic cavity. In infections with virulent strains of Pasteurella multocida, there may be liver enlargement and coagulative necrosis. Other findings may include pneumonia, especially in turkeys, and excessive mucous along the digestive tract. Lesions of the ovaries may include flaccid follicles, hyperemia, and egg-yolk peritonitis from ruptured ova.

In the chronic form of FC, localized infections may be found throughout the body including the hock joints, foot pads, oviduct, and coelomic cavity. Suppurative lesions are frequently found in the respiratory tract and pneumatic bones. Pneumonia is especially common in turkeys. Caseous exudate and fibrin may also infiltrate the calvarial bones, middle ear, meninges, and air spaces.

Differential Diagnosis

Fowl cholera must be differentiated from erysipelas, acute colibacillosis, Avibacterium gallinarum and complicated Mycoplasma gallisepticum in turkeys and other birds that may have both diseases. Erysipelas is caused by a gram-positive rod. Cholera can be differentiated from other septicemic diseases by isolation of P. multocida. Related organisms that cause cholera-like diseases in poultry include P. gallinarum, P. haemolytica, and P. anatipestifer.

Diagnosis

Culture samples can be taken from the liver, lungs, spleen, wattles or affected joints at necropsy. Additionally, impression smears of the liver and heart blood can also be obtained. Gram-stained impression smears may reveal bipolar, gram-negative rods suggestive of P. multocida. Use of Wright's stain or methylene blue readily demonstrates the bipolar morphology of P. multocida. Rabbits, hamsters, or mice can be inoculated for pure culture. P. multocida grows readily on blood agar but does not grow on MacConkey agar. Isolates should be tested for antibiotic sensitivity and resistance.

Prevention and Control

The elimination of reservoirs of Pasteurella multocida (such as rats, mice, cats, raccoons, skunks, etc.) in contact with domesticated and commercial poultry is one of the most effective management procedures to control the disease.

Both live and inactivated Pasteurella multocida vaccines are available for use in chickens. Three live products are available in the United States; the Clemson University CU low virulent strain; M-9, a mutant of CU of very low virulence; and PM-1, a mutant of CU intermediate in virulence between CU and M-9. Inactivated bacterins are primarily trivalent whole cell products containing the most common serotypes. Autogenous vaccines are also commonly used. A combination of inactivated and live vaccines can reduce the incidence of fowl cholera in susceptible broiler breeder flocks. Since FC is primarily a disease of older birds, broilers are not commonly vaccinated.

Selected References

  1. Brogden, K.A., K.R. Rhoades, and K.L. Heddleston. 1978. A new serotype of Pasteurella multocida associated with fowl cholera. Avian Dis 22:185-90.
  2. Charlton, B. R. (ed). 2006. Avian Disease Manual, 6th ed. American Association of Avian Pathologists (AAAP), 953 College Station Road, Athens, Georgia 30602-4875.
  3. Glisson. J.R., C.L. Hofacre, and J.P. Christensen. 2008. Pasteurellosis and other respiratory bacterial infections. In Diseases of Poultry, 12th ed. Y.M. Saif. et al. (ed.). Blackwell Publishing, Ames, Iowa.
  4. Glisson, JR. 1998. Bacterial respiratory disease of poultry. Poult Sci Aug;77(8):1139-42. Review.
  5. Harper, M., J.D. Boyce and B. Adler. 2006. Pasteurella multocida pathogenesis: 125 years after Pasteur. FEMS Microbiol Lett. Dec;265(1):1-10. Review.
  6. World Organization for Animal Health (OIE) website. 2008. www.oie.int

Thank you to the following individuals for reviewing these materials:

Charles Hofacre
Jaime Ruiz
Jose Bruzual

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Marek's Disease

Marek's Disease

Marek's Disease

Etiology

Marek's disease (MD) is a transmissible neoplastic disease, primarily affecting chickens. The disease is caused by a cell-associated herpesvirus, containing double-stranded DNA. There are three serotypes of MDV but oncogenicity is only associated with serotype 1 MDVs. Within this serotype however, there are many strains of MDV, whose pathogenicity varies widely. Subsequently, clinical signs in infected chickens vary from asymptomatic infection to neurologic disease, skin disease, and ocular lesions.

Host Range

Marek's disease is primarily a disease of commercial chickens, but it can also affect turkeys. MD often occurs in 2-5 month-old (sexually immature) chickens but can also occur after the onset of egg production. This form of the disease is referred to as

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  • Avian Encephalomyelitis
  • Erythroblastosis
  • Genetic Grey Eye
  • Histomoniasis
  • Lymphoid leukosis
  • Myeloblastosis
  • Myelocytomatosis
  • Newcastle Disease
  • Ovarian Carcinoma
  • Reticuloendotheliosis
  • Riboflavin Deficiency
  • Tuberculosis