CAHFS Connection - February 2026

Managing Editor: Kerry Ballinger 
Design Editor: Lucy Gomes 
Contributors: Cassie Powers, Emma Torii, Francisco Uzal, Javier Asin Ros, Mark Anderson, Melissa Macias Rioseco, Patricia Blanchard, Todd Cornish

Avian

Intestinal coccidiosis and Marek’s Disease were diagnosed in a <1-year-old White Langshan rooster with a history of weight loss and ill-thrift. On gross evaluation, the small intestine and cecum were diffusely dilated and had thickened walls. Microscopically, necrotizing enteritis with myriad intralesional coccidia was observed (Fig 1).  Clinical disease associated with intestinal coccidiosis is variable and can include ill thrift, weight loss, poor weight gain, and death. This animal also had concurrent Marek's disease.

Fungal tracheitis was diagnosed in a 5-yr-old, female Budgerigar submitted for necropsy with a 5-day history of respiratory signs and lethargy. The distal trachea and syrinx were occluded by exudate containing intralesional fungal hyphae. Fungal infections of the respiratory tract in birds are most commonly due to Aspergillus sp. infection, which usually occurs by inhaling spores from moldy food or bedding and/or due to poorly ventilated cages. Aspergillus sp. often causes opportunistic respiratory infections in birds. Immunocompromised, stressed or debilitated animals are usually predisposed to this condition. Two other birds from the same facility were noted to have respiratory signs, although it is unclear if the submitted bird was representative of the other birds.

Bovine

Bluetongue virus (BTV) was detected by PCR in the spleen from a 16-month-old female American bison that had diarrhea and was in very poor body condition. The bison was dehydrated and had epicardial hemorrhages, thymic atrophy, and fat necrosis. Microscopic exam revealed mild vasculitis and interstitial nephritis. Copper (1.4ppm, normal 25-100ppm) and selenium (0.095ppm, normal 0.25-0.5ppm) deficiencies were identified.

Severe gastrointestinal parasitism, and copper and selenium deficiency were diagnosed in a 1-year-old bison heifer that died with history of sudden weight loss and diarrhea. On necropsy, the carcass had minimal and atrophied fat stores. On microscopic evaluation, significant enterocolitis was observed with 1,450 Trichostrongyle spp. eggs per gram of feces by modified McMaster’s test (Fig. 2); this is considered a high egg count. Liver copper levels were severely deficient (1.8ppm, normal 25-100ppm). A high parasitic load and copper deficiency can cause fatal disease in bison leading to marked weight loss, reduced growth, and diarrhea. Additionally, moderate multifocal, myocardial degeneration and necrosis was observed (Fig. 3). Liver selenium was moderately deficient (0.11ppm, normal 0.25-0.5ppm). Selenium deficiency often leads to myocardial necrosis causing sudden heart failure and death. This condition is commonly referred to as white muscle disease or nutritional myopathy.

Equine

Septicemia and cyathostomiasis were diagnosed in a 23-year-old Miniature Horse gelding with a history of Cushing's disease, ocular abnormalities, and bloody urine. Both kidneys had multifocal nephritis with bacterial colonies (Fig. 4a). Actinobacillus sp. was isolated from the kidney. Streptococcus equi ssp. zooepidemicus was isolated from the ureter, lung and liver. Additionally, in the mucosa of the cecum and right ventral colon were numerous 5 mm to 10 mm in diameter tan to yellow plaques (Fig. 4b) with intralesional nematodes and bacterial colonies. Small strongyle eggs were detected in feces by fecal flotation. These parasites cause damage as larvae burrow into or emerge from the gut wall, leading to visible lesions.

Cranial nuchal bursitis (“poll evil”) was diagnosed in a euthanized, 21-year-old male Belgian draft horse with a history of a draining tract close to the poll, and poor feet condition. On necropsy, the cranial nuchal bursa was filled with dense pus and there was a fistula through which the material oozed to the exterior. Staphylococcus pseudointermedius, Streptococcus equi ssp. zooepidemicus, and Clostridium septicum were isolated either from the bursa or from the fistula. In addition, a pituitary pars intermedia adenoma and chronic laminitis in the right front hoof were observed. Poll evil refers to bursitis of the cranial and/or caudal nuchal bursae and may be sterile or secondary to bacterial infection. It often fistulizes with drainage of the contents. Brucella abortus is frequently isolated from this lesion in endemic areas. In this case, other common bacteria associated with this condition were isolated. This horse likely had pituitary pars intermedia dysfunction, which may predispose to secondary infections, laminitis and other metabolic abnormalities.

Small Ruminants

Cache valley fever virus (CVFV) induced fetal deformities were diagnosed in a term ovine fetus. On gross evaluation the animal had scoliosis, severe hydrocephalus, arthrogryposis and a fibrinous peritonitis (Fig. 5). CVFV antibodies were detected in fetal serum. Cache Valley Fever (CVF) causes abortions, malformed fetuses, infertility and congenital abnormalities in sheep and goats. Classic deformities include malformations in the musculoskeletal system and central nervous system as was seen in this fetus.  However, this disease does not always cause clinical signs. If two or more offspring are born, one may be alive and healthy while the other is stillborn. Malformations are common but not always present in an aborted fetus or stillborn.

Abortion in ewes and does caused by Campylobacter jejuni was diagnosed at multiple CAHFS branches recently. This included a sheep flock of 2,600 ewes with four to five abortions per day; a sheep flock of 300 ewes with 20-30 abortions over three weeks; a sheep flock with a history of two abortions within a 10-day period; a single goat kid abortion from a dam with drooling, slow walking, inappetence and locked jaw; and a late-term aborted goat fetus for which no clinical history was available. Gross lesions ranged from no lesions to classic hepatic necrosis, body cavity effusions, and subtle placental lesions. Histologically, a variety of lesions were observed including placentitis, hepatitis, bronchopneumonia, abomasitis, conjunctivitis, enteritis, and/or leptomeningitis. One of the sheep flocks had been vaccinated against Campylobacter, but vaccination history was not provided for the other cases. C. jejuni was isolated from placenta, liver, and/or abomasal fluid in all cases.

Wildlife

Feline parvovirus was the cause of death in a 4-month-old Northern racoon. The raccoon was at a rehabilitation center for two months and had minimal weight gain during the stay before being found dead. On necropsy, fibrinonecrotizing enterocolitis suggestive of parvovirus infection, was found. Raccoons can be infected by both feline and canine parvoviruses, as well as by a racoon parvovirus. In this case, feline parvovirus was sequenced from the feces. Interestingly, the raccoon had received a booster vaccination against both canine and feline parvovirus a week prior to death. It is unclear if this raccoon was infected with a wild type feline parvovirus or if the infection was due to reversion of the vaccine strain to a virulent form. The raccoon also had systemic salmonellosis and dental lesions suggestive of in-utero distemper infection, although the latter could not be confirmed due to the chronicity of the lesions.

Holiday Schedule

President’s Day: Monday, February 16, 2026 – Closed

Employment Opportunities

None at this time.