CAHFS Connection - November 2024

Avian

Blackhead disease was diagnosed in eight free-range, White turkeys that showed depression and loss of appetite before dying. On necropsy, all birds had severe liver and cecal necrosis, and abundant Heterakis gallinarum in the cecum. Microscopic examination revealed abundant protozoans compatible with Histomonas meleagridis in the cecum and liver.

Ulcerative enteritis was diagnosed in a flock of six-week-old layer pullets experiencing high mortality for the past four days. Twenty dead birds were submitted for necropsy. Markedly enlarged, mottled and friable spleens, mottled and enlarged livers, cecal cores, and multifocal well circumscribed regions of necrosis with hyperemic margins were noted in the jejunum and ileum of several birds. Clostridium colinum was isolated from the spleens and livers, and Clostridium perfringens was isolated from the intestines. Microscopically, ulcerative enteritis, and hepatic and splenic necrosis with colonies of bacilli were observed. C. colinum is the etiologic agent of ulcerative enteritis, commonly known as quail disease. It can affect quail, chickens, turkeys, pheasants and other gallinaceous birds.

Bovine

Necrotic pharyngitis and laryngitis were associated with bovine herpesvirus type 1 (BHV-1), Fusobacterium necrophorum, and Trueperella pyogenes infections in a three-week-old Holstein calf from a calf-ranch that had respiratory signs before death. About 70% of the lungs had necrosis and hemorrhage with pleuritis. There were multifocal, well-demarcated ulcers in the larynx and soft palate on gross examination. BHV-1 was detected by PCR in the lung and larynx. T. pyogenes and F. necrophorum were isolated from the larynx, and T. pyogenes, Streptococcus suis, and mixed bacteria were isolated from the lungs. 

Equine

Cholelithiasis with obstruction of the common bile duct and severe hepatopathy was diagnosed in an 11-year-old bay Warmblood mare with a long-standing history of liver disease and colic. On necropsy, there was a ~ 7cm diameter choledocholith blocking the common bile duct. Grossly, the liver was enlarged and firm, and microscopically it had severe fibrosis, bile duct proliferation, and bile stasis.

Small Ruminant

Mycoplasma mycoides subspecies capri polyarthritis was diagnosed in a one-month-old goat kid submitted after sudden illness and death. At necropsy, the carpi were swollen and contained gray, cloudy fluid. M. mycoides subspecies capri was isolated from multiple joints. The kid was also copper deficient and had moderate coccidiosis.

West Nile virus (WNV) meningoencephalitis was diagnosed in a two-year-old Dorper ewe that had clinical signs for one day. The head was submitted to CAHFS for rabies and polioencephalomalacia evaluation. Histology revealed marked, widespread, lymphohistocytic and neutrophilic meningoencephalitis. Rabies testing was negative and no lesions compatible with polioencephalomalacia were seen. WNV immunohistochemistry was positive. WNV encephalitis is sporadically diagnosed in sheep in California.