Serosurveillance for Yersinia pestis and Francisella tularensis in Wildlife From Across the United States

Plague (Yersinia pestis) and tularemia (Francisella tularensis) are bacterial pathogens that are characterized both by their ability to infect a wide-range of vertebrate hosts and by their potential for zoonotic disease transmission. Both are found in the United States, where human cases often involve arthropod vectors; however, infections can come through multiple transmission routes and the dynamics that maintain both plague and tularemia across the landscape are ecologically complex and difficult to isolate. In an attempt to better understand plague and tularemia presence in the environment, a large scale study was initiated by USDA/APHIS/WS to collect samples from probable host species across broad portions of the US. The wildlife sampled for this study was unprecedented in both scope and geographic scale. Samples were collected year round, from January 2005-December 2010, in cooperation with state and other federal agencies, from 47 US states that had previously documented plague or tularemia activity. Multiple Nobuto strips were collected from each animal, with extra strips archived in the National Nobuto Sample Archive, created and housed at the USDA, Animal and Plant Health Inspection Service (APHIS), Wildlife Services (WS), National Wildlife Research Center (NWRC) in Fort Collins, Colorado. Overall, plague seroprevalence across all regions and species was 8.60%, although region specific plague exposure is often much higher, with some well-sampled counties in Wyoming and New Mexico having coyote exposure rates of 35% and 37% respectively. The data suggest a substantial amount of plague activity across large spatial scales, with carnivores in particular being continually exposed or re-exposed. The degree to which carnivores and omnivorous species are being exposed (Tables 2,3) suggests that prey consumption is driving the plague exposure reported here, although flea-borne transmission occurs as well and cannot be ruled out. On the other hand, F. tularensis was very rarely detected, with an average overall seroprevalence of 0.6%. Any seropositive animals that were detected were often spread out over space and time. Retrospective cluster analyses on plague data lined up with known plague epizootics in prairie dogs. These data provide unique insight into plague and tularemia exposure in wildlife from across the US and demonstrate that sampling a small number of wide-ranging carnivores can provide a broad snapshot of disease activity. Field Evaluation of Raboral V-RG as an Oral Rabies Vaccine in Striped Skunk (Mephitis mephitis) Joanne Maki, Merial Limited Ernest Oertli, Texas Department of State Health Services Bruce Leland, USDA-APHIS, Texas Wildlife Services Abstract Skunk variant rabies is believed to be the last terrestrial rabies variant in Texas. Oral rabies vaccination (ORV) programs implemented in the State over the past 17 years appear to have eliminated both the domestic dog/coyote and Texas gray fox variants.Skunk variant rabies is believed to be the last terrestrial rabies variant in Texas. Oral rabies vaccination (ORV) programs implemented in the State over the past 17 years appear to have eliminated both the domestic dog/coyote and Texas gray fox variants.