Outbreaks of bovine herpesvirus 2 infections in calves causing ear and facial skin lesions.

We describe 3 outbreaks of superficial dermatitis caused by bovine herpesvirus 2 (BoHV-2) in dairy breed calves. Clinically, all of the affected calves were 12-26 d of age, had alopecia and crusts on the face and ears, and were non-pruritic and afebrile. Affected animals recovered spontaneously without any treatment within 2-4 wk after onset of clinical signs based on 1 herd with follow up. Histologic examination of all skin crust or tissue samples identified neutrophilic inflammation, mild hyperkeratosis, multinucleate syncytial cells, and intranuclear inclusion bodies in the syncytial cells. Real-time PCR testing on affected surface crusts or tissue provided evidence of BoHV-2, and testing, where performed, was negative for parapoxvirus including bovine papular stomatitis virus and the ovine form of malignant catarrhal fever tested in EDTA blood samples. Bovine viral diarrhea virus also was negative by ELISA, as well as bovine herpesvirus 1 by immunohistochemistry. Direct electron microscopy of infected tissues in the first outbreak revealed herpesvirus-like particles.

Bilateral Malignant Seminomas in Two Unrelated, Aged Trumpeter Hornbills (Bycanistes buccinator).

Seminomas occur infrequently in birds. Two cases of bilateral malignant seminomas in unrelated trumpeter hornbills (Bycanistes buccinator) are described. Case 1 was a 22-year-old trumpeter hornbill submitted for necropsy because of sudden death at a zoo in California. Postmortem examination revealed multiple masses within the body cavity, 2 of which replaced both testes. Case 2 was a 19-year-old trumpeter hornbill at a zoo in North Carolina that underwent exploratory surgery for a suspected gastrointestinal obstruction. Both testes were diffusely enlarged, compressing and replacing the adjacent kidneys. In both birds, the masses were composed of discrete, round to polyhedral cells, typical of seminomas. Examination of the ancestry of the hornbills showed they were unrelated to each other, suggesting a potential predisposition for these birds to develop seminomas.

Malignant edema in postpartum dairy cattle.

Five cases of postparturient vulvovaginitis and metritis in cattle caused by Clostridium septicum (malignant edema) are described in the current report. The diagnosis was established based on detection of C. septicum by culture and fluorescent antibody test. All animals were Holsteins, and 4 were primiparous (the parity of 1 animal was not reported). All animals developed clinical signs 1-3 days after calving, consisting of swelling of perineal and perivulvar areas, fever, and depression. Perineal, perivulvar, and perivaginal gelatinous and often hemorrhagic edema was consistently observed on gross examination. Longitudinal vulvar, vaginal, cervical, and uterine body tears, covered by fibrinous exudates, were also present. Microscopically, vulvar, vaginal, and uterine mucosae were multifocally necrotic and ulcerated. Large Gram-positive rods, some with subterminal spores, were present within the edematous subcutaneous and submucosal tissues. Clostridium septicum was demonstrated by culture and/or fluorescent antibody test in tissues of most animals. These cases of malignant edema were considered to be produced by C. septicum and predisposed by the trauma occurring during parturition.

Placental teratocarcinoma in a mare with possible metastasis to the foal.

A teratocarcinoma was diagnosed in the amnion of a 5-year-old Arabian mare that delivered a healthy, full-term foal. The foal died at 2.5 months of age as a result of metastasis of an undifferentiated component of the mass. This case is unique because it is the first reported case of placental teratocarcinoma in animals and the malignant component apparently metastasized to the foal resulting in its death.

Determination of the median toxic dose of type C botulinum toxin in lactating dairy cows.

Because of the difficulty in identifying botulinum toxin in cattle, it is hypothesized that cattle are sensitive to levels of toxin below the detection limits of current diagnostic techniques (the mouse protection bioassay and the immunostick enzyme-linked immunosorbent assay [ELISA] for type C botulinum toxin). Using an up-down method for toxicologic testing, the median toxic dose (MTD50) for cattle was determined. Four lactating Holstein cows were dosed at 0.125 or 0.25 ng/kg with Clostridium botulinum type C toxin and failed to develop clinical signs of botulism during the 7-day observation period. Three cows given 0.50 ng/kg of toxin developed clinical signs of botulism. From these results, the MTD50 was calculated at 0.388 ng/kg (3.88 mouse lethal doses/kg) using the trim-logit method. These results suggest that cattle are 12.88 times more sensitive to type C botulinum toxin than a mouse on a per kilogram weight basis. The mouse protection bioassay and the immunostick ELISA for type C botulinum toxin failed to identify the presence of the toxin in the serum, blood, and milk samples taken from all 7 animals.