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.

Surveillance of Wildlife Diseases: Lessons from the West Nile Virus Outbreak.

The West Nile virus outbreak of 1999 revealed many weaknesses in this country's ability to respond to disease threats that cross species lines. There were issues of poor communication among human, domestic animal, and wildlife health agencies that delayed diagnosis; a lack of diagnostic capacity of wildlife agencies at the state level; the exclusion of captive wildlife from any surveillance efforts; an inability to visualize the geospatial relationship between the human and avian outbreaks in a timely manner; and marked disparities of funding levels across agencies. Wildlife has played an important role in recent emerging infectious diseases, and it is clear that a One Health approach will be necessary to respond to future threats. The question is, are we any better prepared to recognize and respond to a wildlife-related emerging infectious disease than we were 14 years ago? Have the lessons of WNV been learned?

Acute lead toxicosis via ingestion of spent ammunition in a free-ranging cougar (Puma concolor).

Lead toxicity has long been documented and acknowledged as a significant health issue of water birds and avian scavengers. However, few instances of toxic effects to higher mammalian carnivores have been documented. Here we present an acute case of lead toxicity in a free-ranging cougar (Puma concolor) in Oregon.

Cylicospirura species (Nematoda: Spirocercidae) and stomach nodules in cougars (Puma concolor) and bobcats (Lynx rufus) in Oregon.

The stomachs and proximal duodena of 160 cougars (Puma concolor) and 17 bobcats (Lynx rufus), obtained throughout Oregon during 7 yr, were examined for Cylicospirura spp. and associated lesions. Prevalence in cougars was 73%, with a range in intensity of 1-562 worms. The mean diameter of nodules was 1.2 cm (SD=0.5), and many extended through the submucosa to the muscularis. About 83% of cougars had nodules; most nodules contained worms, but 14% of the smaller nodules (<0.2 cm) contained porcupine (Erethizon dorsatum) quills. A mean of 12.4 worms/nodule (SD=34.1) was observed, with a maximum of 340 worms/nodule. Prevalence in bobcats was 53%, with an intensity of 1-25 worms. About 65% of bobcats had nodules, which were slightly smaller than those in cougars but appeared to involve similar layers of gastrointestinal tissue. One to 25 Cylicospirura sp. were found in all but two small nodules in bobcats. Cougars killed for livestock damage or safety concerns had a significantly higher median worm intensity than did those that died of other causes. Also, the median worm intensity of older cougars was higher than that of younger lions. There were more males than females killed for livestock damage or safety concerns. The cylicospirurid from cougars was Cylicospirura subaequalis, and that of bobcats was Cylicospirura felineus. These two similar species were separated morphologically by differences in tooth and sex organ morphology. They were also differentiated by DNA sequence analysis of the mitochondrial cytochrome c oxidase subunit 1 gene (cox1). Worm sequences from cougars differed from those from bobcats by 11%, whereas essentially no difference was found among worms from the same host. Phylogenetic analysis showed that within the order Spirurida, both cylicospirurids were most closely related to Spirocerca lupi, based on this gene sequence.

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.

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.

DNA-based identification of a hepatic trematode in an elk calf.

Liver fluke infection was identified as a probable cause of clinical disease in an approximately 6-mo-old elk (Cervus elaphus) in coastal Oregon. Clinical pathology and necropsy findings are described. The alcohol-fixed flukes that were submitted for identification were similar in size to Fasciola hepatica, but their shape resembled Fascioloides magna in that they lacked a distinctive anterior cone. A few structures consistent with the eggs of F. magna were observed in liver lesions, suggesting that at least some of the worms were sexually maturing. Due to difficulties in morphologic identification associated with improper fixation technique, DNA analysis was used to compare small subunit (SSU) and internal transcribed spacer 2 ribosomal RNA gene sequences of the recovered parasites with those of F. hepatica and F. magna, confirming these small, but sexually mature flukes were F. magna. This is the first publication of the SSU gene sequence for F. magna. Phylogenetic analysis showed that it is related to, but is an outlier, to the genus Fasciola. Due to the high mortality rate associated with this disease outbreak, the overall significance of trematodiasis in the herd is unclear.

Factors associated with pathogen seroprevalence and infection in Rocky Mountain cougars.

Serological and genetic material collected over 15 years (1990-2004) from 207 cougars (Puma concolor) in four populations in the Rocky Mountains were examined for evidence of current or prior exposure to feline immunodeficiency virus (FIV), feline parvovirus (FPV), feline coronavirus (FCoV), feline calicivirus (FCV), canine distemper virus (CDV), feline herpesvirus (FHV), and Yersinia pestis. Serologic data were analyzed for annual variation in seroconversions to assess whether these pathogens are epidemic or endemic in cougars, and to determine whether family membership, age, sex, or location influence risk of exposure. FIV and FPV were clearly endemic in the studied populations, whereas exposure to FCoV, FCV, CDV, and Y. pestis was more sporadic. No evidence was found for FHV. Age was the most consistent predictor of increased exposure risk, often with no other important factors emerging. Evidence for transmission within family groups was limited to FIV and FCoV, whereas some indication for host sex affecting exposure probability was found for FIV and Y. pestis. Overall, cougar populations exhibited few differences in terms of pathogen presence and prevalence, suggesting the presence of similar risk factors throughout the study region.

Serologic survey for viral and bacterial infections in western populations of Canada lynx (Lynx canadensis).

A serologic survey for exposure to pathogens in Canada lynx (Lynx canadensis) in western North America was conducted. Samples from 215 lynx from six study areas were tested for antibodies to feline parvovirus (FPV), feline coronavirus, canine distemper virus, feline calicivirus, feline herpesvirus, Yersinia pestis, and Francisella tularensis. A subset of samples was tested for feline immunodeficiency virus; all were negative. For all other pathogens, evidence for exposure was found in at least one location. Serologic evidence for FPV was found in all six areas but was more common in southern populations. Also, more males than females showed evidence of exposure to FPV. Overall, prevalences were low and did not exceed 8% for any of the pathogens tested. This suggests that free-ranging lynx rarely encounter common feline pathogens.