Survey of coyotes, red foxes and wolves from Wyoming, USA, for Echinococcus granulosus s. l.

The paraphyletic group Echinococcus granulosus sensu lato is comprised of parasitic tapeworms of wild and domestic canids such as wolves (Canis lupus) and coyotes (Canis latrans), which serve as definitive hosts, and ungulates, which are the intermediate hosts. Members of this tapeworm group are characterized by both cosmopolitan distribution and zoonotic disease potential. This survey (conducted from 2012 through 2017) was designed to provide insight into the prevalence and distribution of this parasite in wild canids in Wyoming. Echinococcus sp. infections were documented in 14 of 22 gray wolves (63.6%), 1 of 182 coyotes (0.55%) and 0 of 5 red foxes (Vulpes fulva). Echinococcus granulosus s. l. was confirmed in 4 of these 14 specimens obtained from wolves with two parasite specimens corresponding morphologically with E. canadensis (G8/G10). These results suggest that wolves serve as the major definitive host of E. granulosus s. l. in Wyoming, while coyotes do not play an equivalent role. Limited sample size precludes evaluation of the importance of the red fox as a favorable definitive host. Whereas this study documents the occurrence of E. granulosus s. l. in Wyoming, the zoonotic disease risk does not appear to be high. Education remains the key to disease prevention, coupled with good hygienic practices by humans and anthelmintic treatment of domestic dogs exhibiting elevated risk of exposure.

LEPTOSPIRA ANTIBODIES DETECTED IN WILDLIFE IN THE USA AND THE US VIRGIN ISLANDS.

From 2011 to 2017, 4,534 serum samples from 13 wildlife species collected across the US and in one territory (US Virgin Islands) were tested for exposure to Leptospira serovars Bratislava, Canicola, Grippotyphosa, Hardjo, Icterohaemorrhagiae, and Pomona. Of 1,759 canids, 1,043 cervids, 23 small Indian mongooses ( Herpestes auropunctatus), 1,704 raccoons ( Procyon lotor), and five striped skunks ( Mephitis mephitis), 27.0, 44.4, 30.4, 40.8, and 60%, respectively, were antibody positive for any of the six serovars. The most commonly detected serovars across all species were Bratislava and Grippotyphosa. Our results indicate that Leptospira titers are very common in a wide variety of wildlife species. These species may act as important reservoirs in the epidemiological cycle of the pathogen. Additional studies to determine the relationship between serologic evidence and shedding of the pathogen by wildlife are necessary to better understand the risk.

Surveillance for Baylisascaris procyonis in raccoons (Procyon lotor) from Wyoming, USA.

Baylisascaris procyonis is a common roundworm of raccoons that causes severe clinical disease in many vertebrates, including humans. The distribution of B. procyonis in the US is poorly documented in portions of its range and has not been reported from Wyoming. Our objectives were to determine the statewide distribution and prevalence of this parasite in raccoons in Wyoming, using intestinal and fecal examinations. We examined 363 raccoons from 23 Wyoming counties in 2009-11, testing the reliability of two methods (intestinal extrusion and incision) to determine worm burdens. We found 163 raccoons (45%) positive for B. procyonis. The two methods of examination did not differ, although extrusion missed some infections. Neither age nor sex affected apparent prevalence or worm burdens. Prevalence did not differ with land use, yet burden was highest among rural raccoons. Fecal examination revealed that juvenile raccoons had a higher proportion of patent infections than adults, but neither sex nor location were indicators of prevalence. Egg density (eggs per gram of feces) did not differ by sex or age; however, rural raccoons had higher egg densities than urban/suburban animals. Understanding the distribution and prevalence of B. procyonis in Wyoming, especially in and around highly populated areas, is an important step in educating the general public and medical community on the potential risks of raccoon roundworm infection.

Epizootiologic survey of Mycobacterium bovis in wildlife and farm environments in northern Michigan.

Bovine tuberculosis (bovine TB), caused by Mycobacterium bovis, has reemerged in northern Michigan, USA, with detections in white-tailed deer (Odocoileus virginianus) in 1994 and in cattle in 1998. Since then, significant efforts have been directed toward reducing deer densities in the area in the hopes of reducing the bovine TB prevalence rate in deer and eliminating spillover of the disease into cattle. Despite the success of the efforts to reduce deer densities, additional cattle herds have become infected. Other mammals can be infected with M. bovis, and some carnivores and omnivores had been found to be infected with the disease in northern Michigan, USA. We conducted a multiyear surveillance effort to detect bovine TB in wild species of mammals in the Michigan, USA, outbreak area. From 2002 to 2004, tissue samples from 1,031 individual animals of 32 species were collected, processed, and cultured for M. bovis. Only 10 (1.0%) were culture-positive for M. bovis (five raccoons [Procyon lotor], four opossums [Didelphis virginiana], and one grey fox [Urocyon cinereoargenteus]). We also found two raccoons and four opossums to be positive for Mycobacterium avium. We collected 503 environmental samples from cattle farms recently identified as bovine TB positive; none yielded positive M. bovis culture results. Finally, we used infrared cameras to document wildlife use of four barns in the area. Many avian and mammalian species of wildlife were observed, with raccoons being the most commonly observed species. This surveillance study identified no new wildlife species that should be considered significant reservoirs of bovine TB in the outbreak area in northern Michigan, USA. However, the relatively high, apparent bovine TB prevalence rates in some carnivorous and omnivorous species, their relatively long life spans, and their frequent use of barns, suggests that removal of raccoons, opossums, foxes, and coyotes (Canis latrans) should be considered when a newly infected farm is depopulated of cattle.

Population monitoring in support of a rabies vaccination program for skunks in Arizona.

Three population monitoring methods were evaluated in support of a trap/vaccinate/release program for controlling a bat variant of rabies virus in skunks (Mephitis mephitis) in Flagstaff, Arizona (USA). Skunks were the primary species targeted for population monitoring during the program, but feral cats were also monitored as they represented an abundant secondary vector species capable of rabies transmission. Skunks were vaccinated and released, except for a subset tested for rabies. All captured cats were placed in the local animal shelter. Spotlight surveys essentially did not detect skunks, and were not able to detect reductions in the cat population. Catch-per-unit-effort marginally tracked population trends, but a passive track index adapted for an urban setting was most sensitive for detecting changes in skunk and cat populations. Mark-recapture population estimates could not be validly calculated from the data on captures and recaptures due to multiple violations of analytical assumptions.