Robert B. Moeller

Causes of Caprine Abortion: Diagnostic Assessment of 211 Cases (1991–1998)

In an 8-year period, 1991–1998, 217 accessions of caprine abortions were submitted to the California Veterinary Diagnostic Laboratory System. Of these 217 submissions, 211 were suitable for examination in this study (6 had insufficient data). Infectious agents as the cause of abortions were found in 37% of the cases: bacterial agents were identified in 30.5%, viral agents in 2%, fungal agents in 0.5%, and protozoal agents in 4% of the cases submitted. The most common causes of abortions were Chlamydia psittaci and Coxiella burnetii infection, which accounted for 23% of all goat abortions. Mineral deficiencies were observed in 4%, fetal anomalies accounted for 3%, and leukoencephalomalacia of the brain (probable oxygen deprivation) accounted for 3% of the submissions. No diagnosis was made in 112 of the 211 submissions (53%). No lesions were noted in 104 of the submissions (49%). The other 8 submissions (4%) had histologic lesions suggestive of a bacterial agent; however, no infectious agents were identified in these cases.

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.

Mustelid Herpesvirus-2, a Novel Herpes Infection in Northern Sea Otters (Enhydra Lutris Kenyoni)

Oral ulcerations and plaques with epithelial eosinophilic intranuclear inclusions were observed in northern sea otters (Enhydra lutris kenyoni) that died or were admitted for rehabilitation after the 1989 Exxon Valdez oil spill (EVOS) in Alaska, USA. Transmission electron microscopy demonstrated the presence of herpesviral virions. Additionally, a serologic study from 2004 to 2005 found a high prevalence of exposure to a herpesvirus in live-captured otters. Tissues from 29 otters after the EVOS and nasal swabs from 83 live-captured otters in the Kodiak Archipelago were tested for herpesviral DNA. Analysis identified a novel herpesvirus in the gamma subfamily, most closely related to Mustelid herpesvirus-1 from badgers. Results indicated that this herpesvirus is associated with ulcerative lesions but is also commonly found in secretions of healthy northern sea otters.

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.

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.

Jejunal hematoma in cattle a retrospective case analysis

Sixteen years of adult cattle submissions to the California Animal Health and Food Safety Laboratory System were examined and data captured from cases with anaerobic cultures of intestinal content. Analysis was performed to determine if there were statistical differences between case submission types (nonbloody intestinal content [129 cases], bloody intestinal content [134 cases], and jejunal hematoma [JH; 51 cases]) for the presence of Clostridium perfringens (314 cases), C. perfringens toxinotypes (35 cases), and C. perfringens toxins (51 cases) in the content. Across submission types, significant differences were found in the isolation of C. perfringens between different specimen types (live cow, dead cow, or tissue from a field necropsy) with field samples being the most likely to have C. perfringens detected and live animals the least likely (P = 0.001). In cases of JH, detection of C. perfringens by enzyme-linked immunosorbent assay was more likely when a live or dead animal was submitted (P = 0.023) or when a live animal was submitted (P = 0.019) compared with submission of field necropsy tissues. These differences were not observed when cultures were performed to detect C. perfringens in cases of JH. There were no statistical differences between submission types with regard to any other variables evaluated. Detailed histologic examination of 21 cases of JH suggested disturbance of normal vascular or lymphatic function as the underlying problem in this entity.

Feline Infectious Peritonitis in a Mountain Lion (Puma concolor), California, USA

Feline infectious peritonitis (FIP) is a fatal immune-mediated vasculitis of felids caused by a mutant form of a common feline enteric virus, feline enteric coronavirus. The virus can attack many organ systems and causes a broad range of signs, commonly including weight loss and fever. Regardless of presentation, FIP is ultimately fatal and often presents a diagnostic challenge. In May 2010, a malnourished young adult male mountain lion (Puma concolor) from Kern County, California, USA was euthanized because of concern for public safety, and a postmortem examination was performed. Gross necropsy and histopathologic examination revealed necrotizing, multifocal myocarditis; necrotizing, neutrophilic, and histiocytic myositis and vasculitis of the tunica muscularis layer of the small and large intestines; and embolic, multifocal, interstitial pneumonia. Feline coronavirus antigen was detected in both the heart and intestinal tissue by immunohistochemistry. A PCR for coronavirus performed on kidney tissue was positive, confirming a diagnosis of FIP. Although coronavirus infection has been documented in mountain lions by serology, this is the first confirmed report of FIP.

Systemic Bovine herpesvirus 1 infections in neonatal dairy calves

During a 6-year period, 62 out of 2,980 calves examined (2.08%) between 1–30 days of age had lesions consistent with Bovine herpesvirus 1 infection. The mean and median age of affected calves was 14 days of age. Most cases of infection were in calves 12 and 15 days of age, with 34 calves (54.8%) affected; 14 calves (22.6%) were between 16–21 days of age; 11 calves (17.8%) were between 7–11 days of age; and 3 calves (4.8%) were between 22–30 days of age. In 29 of the calves, the adrenal gland was the only organ affected. In 25 calves, the adrenal gland and at least 1 other tissue had lesions consistent with herpes viral infection. Five animals had no adrenal lesions but had 1 or more additional tissue with lesions consistent with herpesvirus. Three animals had no adrenal gland present for examination but had lesions in other tissues. Organs and number of animals affected by Bovine herpesvirus 1 infection were adrenal gland (54), liver (18), lungs (15), kidney (8), small intestines (7), large intestines (7), rumen/omasum (7), trachea/larynx (3), abomasum (2), heart (1), esophagus (1), thymus (1), and lymph node (1).

Antimicrobial resistance in Salmonella enterica subspecies enterica serovar Dublin from dairy source calves in the central San Joaquin Valley, California (1998-2002)

The present study describes antimicrobial resistance patterns of Salmonella enterica subspecies enterica serovar Dublin (S. Dublin) in clinical submissions from calves and temporal and farm-type trends in antimicrobial resistance patterns of the isolates. A total of 300 isolates of S. Dublin were obtained from fecal or internal organs of calves fewer than 120 days of age originating from 84 dairies and 18 calf ranches from July 1998 to December 2002. The isolates were susceptibility tested to a panel of 10 antimicrobials using the disk diffusion assay. Temporal and farm-type trends in individual antimicrobial inhibition zone sizes were assessed and antimicrobial resistance patterns were described using cluster analysis. Isolates obtained from calf ranches compared with dairies exhibited decreased susceptibility to florfenicol, gentamicin, neomycin, sulfisoxazole, sulfamethoxazole/trimethoprim, and tetracycline. During the years 1998–2002, decreasing susceptibility was seen for ceftiofur, enrofloxacin, and sulfamethoxazole/trimethoprim. There were 20 different antimicrobial resistance patterns in the isolate set, indicating that S. Dublin has the ability to transfer and pick up resistance genes with relative ease. The trends seen in antimicrobial resistance in S. Dublin may likely be linked to antimicrobial drug use in young calves.

Escherichia fergusonii Associated with Pneumonia in a Beef Cow

An adult Angus cow developed hyperthermia, prostration, and respiratory distress, dying 36 hours after the onset of clinical signs. The main finding during postmortem examination was a severe focally extensive pneumonia. Icterus and a chronic mastitis were also noticed. Histologic examination of the lungs detected fibrinonecrotic pneumonia, with large number of oat cells and intralesional Gram-negative bacterial colonies. Samples from lung lesions were collected, and a pure growth of Escherichia fergusonii was obtained. E. fergusonii is a member of Enterobacteriaceae, related to Escherichia coli and Salmonella sp. In veterinary medicine, E. fergusonii has been reported in calves and sheep with clinical cases suggestive of salmonellosis; in a horse and a goat with enteritis and septicemia; and in ostriches with fibrinonecrotic typhlitis. To our knowledge, this report represents the first description of E. fergusonii associated with an acute pneumonia in cattle.