Investigation of koi herpesvirus latency in koi.

Koi herpesvirus (KHV) has recently been classified as a member of the family of Alloherpesviridae within the order of Herpesvirales. One of the unique features of Herpesviridae is latent infection following a primary infection. However, KHV latency has not been recognized. To determine if latency occurs in clinically normal fish from facilities with a history of KHV infection or exposure, the presence of the KHV genome was investigated in healthy koi by PCR and Southern blotting. KHV DNA, but not infectious virus or mRNAs from lytic infection, was detected in white blood cells from investigated koi. Virus shedding was examined via tissue culture and reverse transcription-PCR (RT-PCR) testing of gill mucus and feces from six koi every other day for 1 month. No infectious virus or KHV DNA was detected in fecal secretion or gill swabs, suggesting that neither acute nor persistent infection was present. To determine if KHV latent infections can be reactivated, six koi were subjected to a temperature stress regime. KHV DNA and infectious virus were detected in both gill and fecal swabs by day 8 following temperature stress. KHV DNA was also detectable in brain, spleen, gills, heart, eye, intestine, kidney, liver, and pancreas in euthanized koi 1 month post-temperature stress. Our study suggests that KHV may become latent in leukocytes and other tissues, that it can be reactivated from latency by temperature stress, and that it may be more widespread in the koi population than previously suspected.

Prevalence of Baylisascaris procyonis in raccoons (Procyon lotor) in Portland, Oregon, USA.

We investigated the prevalence of Baylisascaris procyonis in raccoons living in the metropolitan area of Portland, Oregon, USA, in order to assess the potential public health risk involved in the transmission of B. procyonis to humans and companion animals. Sixty-nine euthanized raccoons were collected from Portland wildlife-control agencies. Infection with B. procyonis was determined through the harvesting of adult worms from raccoon intestines during necropsy and by fecal analysis using modified double-centrifugation technique with a sugar-flotation solution. Fifty-eight percent of sampled raccoons were found to be infected with B. procyonis. Juveniles represented a greater percentage (64%) of raccoons captured by wildlife-control agents and were found to have the highest prevalence (70%) and heavier adult worm burdens (mean=35 worms). No gender bias was evident. This is one of the few studies of Baylisascaris prevalence in the Pacific Northwest, and it demonstrates that there is a high prevalence of B. procyonis in raccoons inhabiting the Portland area. This factor should be considered in raccoon relocation and management. The data also suggest that juvenile raccoons are the major potential source of B. procyonis contamination in the Portland community and may merit special attention to minimize their interaction with humans.

Pigmented tumors in fallow deer ( Dama dama): 11 cases.

Pigmented tumors have been reported infrequently in captive deer. We document herein the clinical progression and gross and histopathologic features of pigmented tumors diagnosed as melanoma and pigmented schwannoma in 11 white fallow deer ( Dama dama). Affected animals were part of a captive herd maintained at a drive-through park in southern Oregon and were 5-17 y of age during the study period (2004-2013). Primary lesion locations included periocular, perineal, and neck tissues, with cutaneous and internal metastases later identified at autopsy in some cases of malignant melanoma. Diagnoses included 7 malignant melanomas, 2 benign melanomas, and 2 pigmented schwannomas. Diagnosis of melanoma was based on typical histomorphologic features, and final diagnosis of pigmented schwannomas was based on histomorphologic features with negative staining for melan A and positive staining for laminin. Metastasis was found in 3 of 7 cases diagnosed as malignant melanoma; 2 had extensive pulmonary involvement and resulted in euthanasia of the animal; 1 animal developed eyelid and ear lesions that also resulted in euthanasia.

West Nile virus infection in two alpacas.

A male alpaca acutely developed signs of anorexia and fever. Within 2 days, neurologic signs (head tremors and asymmetric ataxia) developed. West Nile virus (WNV) infection was considered a primary differential diagnosis on the basis of 6 previous cases on nearby alpaca farms on which animals had similar clinical signs. Four days after the male alpaca became ill, a female alpaca from the same farm developed similar neurologic signs. In addition to anti-inflammatory and supportive treatments, both alpacas received a transfusion of llama plasma with antibodies against WNV Seven days after the onset of clinical signs, the female alpaca had made a full recovery; however, the more severely affected male died. West Nile virus infection was confirmed post mortem by use of reverse transcriptase-polymerase chain reaction assay and immunohistochemical staining.

A review of episodes of zinc phosphide toxicosis in wild geese (Branta spp.) in Oregon (2004-2011).

Epizootic mortality in several geese species, including cackling geese (Branta hutchinsii) and Canada geese (Branta canadensis), has been recognized in the Willamette Valley of Oregon for over a decade. Birds are generally found dead on a body of water or are occasionally observed displaying neurologic clinical signs such as an inability to raise or control the head prior to death. Investigation of these epizootic mortality events has revealed the etiology to be accidental poisoning with the rodenticide zinc phosphide (Zn(3)P(2)). Gross and histologic changes are restricted to acute pulmonary congestion and edema, sometimes accompanied by distension of the upper alimentary tract by fresh grass. Geese are unusually susceptible to this pesticide; when combined with an epidemiologic confluence of depredation of specific agricultural crops by rodents and seasonal avian migration pathways, epizootic toxicosis may occur. Diagnosis requires a high index of suspicion, appropriate sample collection and handling, plus specific test calibration for this toxicant. Interagency cooperation, education of farmers regarding pesticide use, and enforcement of regulations has been successful in greatly decreasing these mortality events since 2009.

Experimental deerpox infection in black-tailed deer (Odocoileus hemionus columbianus).

The pathogenic potential of deerpox virus was investigated via an experimental study utilizing seven black-tailed deer fawns (Odocoileus hemionus) between June and August of 2007. Successful transmission was achieved via intracutaneous and intravenous routes, and by commingling an uninoculated animal with experimentally infected fawns. One fawn became depressed and reluctant to eat but systemic clinical signs in the other fawns were confined to mild transient pyrexia. Typical multifocal poxviral cutaneous lesions of erythema, papules, pustules, ulceration, and crusting were observed. Two locally extensive ulcerative lesions also developed at inoculation sites. Oral lesions were seen in one commingled fawn, with some palatine epithelial cells containing intracytoplasmic inclusions. Microscopic cutaneous lesions included epithelial cell hyperplasia with hydropic change, intraepithelial pustules, erosions, folliculitis, and dense leukocytic dermal infiltrates. Transmission was confirmed by one or more of virus isolation, polymerase chain reaction or serum neutralization tests. Significant internal lesions were not seen at necropsy.