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NAVLE® Question of the day

MO TU WED TH FR

April 30, 2024

NAVLE

A flock from a turkey farm is presented with a mysterious illness. Numerous dead birds are noted.

Sick turkeys are listless, with drooping wings, unkempt feathers, yellow droppings. Some birds are emaciated.

Necropsy shows a marked thickening of the cecal wall, cecal ulcerations, and yellowish, caseous exudate distending the cecal lumen (cecal core). A typical liver looks like the image below.

What is the diagnosis?

A - Histomoniasis

B - Avian spirochetosis

C - Necrotic enteritis

D - Coronaviral enteritis of turkeys

E - Hemorrhagic enteritis of turkeys

Sorry. You chose "B - Avian spirochetosis" but the correct answer is "A - Histomoniasis"

This is histomoniasis; the combination of characteristic "bull's-eye" lesions on liver and cecal changes are pathognomonic.

Caused by the protozoa Histomonas meleagridis, and transmitted in eggs of cecal nematode Heterakis gallinarum.
Expect a presentation of depression/diarrhea.

Expect to see more sudden death with necrotic enteritis caused by Clostridium perfringens.
Follow this link to see the so-called "Turkish towel" intestinal pseudomembrane of necrotic enteritis.

Signs of avian spirochetosis are highly variable, may be absent: see listlessness, shivering, increased thirst, green/yellow diarrhea with increased urates early on. Caused by a tick-borne Borrelia. Look for characteristic enlarged, mottled spleen with petechial hemorrhages, similar to Marble spleen disease of pheasants.

Expect depression, bloody droppings, substantial mortality with hemorrhagic enteritis of turkeys.
Follow this link to see hemorrhagic intestines. Follow this link to see characteristic enlarged spleen.

Expect diarrheal presentation with coronaviral enteritis of turkeys but NOT the characteristic cecal/liver lesions described on necropsy above.

For a good visual resource key poultry diseases, see the Cornell Atlas of Avian Diseases.

Image courtesy of U.S. Geological Survey National Wildlife Health Center Field Manual of Wildlife Diseases: General Field Procedures and Diseases of Birds.