Serologic Evidence for the Exposure of Eastern Coyotes (Canis latrans) in Pennsylvania to the Tick-Borne Pathogens Borreliella burgdorferi and Anaplasma phagocytophilum.

Lyme disease and anaplasmosis are tick-borne bacterial diseases caused by Borreliella and Anaplasma species, respectively. A comprehensive analysis of the exposure of eastern coyotes (Canis latrans) in the northeastern United States to tick-borne pathogens has not been conducted. In this report, we assess the serological status of 128 eastern coyotes harvested in Pennsylvania in 2015 and 2017 for antibodies to Borreliella burgdorferi and Anaplasma phagocytophilum Immunoblot and dot blot approaches were employed to test each plasma sample by using cell lysates and recombinant proteins as detection antigens. The results demonstrate high seropositivity incidences of 64.8% and 72.7% for B. burgdorferi and A. phagocytophilum, respectively. Antibodies to both pathogens were detected in 51.5% of the plasma samples, indicating high potential for coinfection. Antibodies to the B. burgdorferi proteins DbpB, VlsE, DbpA, BBA36, and OspF (BBO39) were detected in 67.2, 63.3, 56.2, 51.6, and 48.4% of the plasma samples, respectively. Antibodies to the A. phagocytophilum P44 and P130 proteins were detected in 72.7 and 60.9% of the plasma samples, respectively.IMPORTANCE The incidence of Lyme disease (Borreliella burgdorferi) and anaplasmosis (Anaplasma phagocytophilum) are increasing in North America and Europe. The causative agents of these debilitating tick-transmitted infections are maintained in nature in an enzootic cycle involving Ixodes ticks and diverse mammals and birds. It has been postulated that predators directly or indirectly influence the dynamics of the enzootic cycle and disease incidence. Here, we demonstrate high seropositivity of eastern coyotes for B. burgdorferi and A. phagocytophilum As coyotes become established in urban and suburban environments, interactions with humans, companion animals, and urban/suburban wildlife will increase. Knowledge of the pathogens that these highly adaptable predators are exposed to or carry, and their potential to influence or participate in enzootic cycles, is central to efforts to reduce the risk of tick-borne diseases in humans and companion animals.

Evaluation of Trapper-Collected Nobuto Filter-Paper Blood Samples for Distemper and Parvovirus Antibody Detection in Coyotes (Canis latrans) and Raccoons (Procyon lotor).

Blood samples are often collected from free-ranging wildlife for antibody detection. However, filter-paper (FP) strips are more cost efficient and easy to collect and store. We evaluated trapper-collected FP strips and body-cavity blood for canine distemper (CDV) and parvovirus (CPV-2) antibody detection in raccoons (Procyon lotor) and coyotes (Canis latrans). From 2008 to 2010, licensed trappers near Madison and Milwaukee, Wisconsin, US collected paired samples from harvested animals. Canine distemper antibodies were detected using virus neutralization and parvovirus antibodies were detected using hemagglutination inhibition. Titers ≥ 1:32 for CDV and ≥ 1:25 for CPV-2 were considered evidence of exposure. Using Cohen's kappa test of agreement, FP strip titers agreed with sera for CDV in coyotes (n = 28, K = 0.772) and raccoons (n = 29, K = 0.858) and for CPV-2 in coyotes (n = 40, K = 0.775) and raccoons (n = 70, K = 0.646). However, raccoons determined to be exposed to CPV-2 from sera were unexposed by FP strips in 35% of the samples. Titer results may be affected by quality and volume of blood samples, interval between collection and processing, small sample sizes, and diagnostic testing procedures. Filter-paper strips can be useful for detecting CDV and CPV-2 exposure in coyotes and raccoons with correct field sample collection and appropriate diagnostic testing procedures.

Immunological and clinical response of coyotes (Canis latrans) to experimental inoculation with Yersinia pestis.

Multiple publications have reported the use of coyotes (Canis latrans) in animal-based surveillance efforts for the detection of Yersinia pestis. Coyotes are likely exposed via flea bite or oral routes and are presumed to be resistant to the development of clinical disease. These historic data have only been useful for the evaluation of the geographic distribution of Y. pestis in the landscape. Because the canid immunologic response to Y. pestis has not been thoroughly characterized, we conducted experimental inoculation of captive-reared, juvenile coyotes (n = 8) with Y. pestis CO92 via oral or intradermal routes. We measured the humoral response to Y. pestis fraction 1 capsular protein (anti-F1) and found a significant difference between inoculation groups in magnitude and duration of antibody production. The anti-F1 titers in animals exposed intradermally peaked at day 10 postinoculation (PI; range = 1∶32 to 1∶128) with titers remaining stable at 1∶32 through week 12. In contrast, orally inoculated animals developed higher titers (range = 1∶256 to 1∶1,024) that remained stable at 1∶256 to 1∶512 through week 6. No clinical signs of disease were observed, and minimal changes were noted in body temperature, white blood cell counts, and acute phase proteins during the 7 days PI. Gross pathology was unremarkable, and minimal changes were noted in histopathology at days 3 and 7 PI. Rechallenge at 14 wk PI via similar dosage and routes resulted in marked differences in antibody response between groups. Animals in the orally inoculated group produced a striking increase in anti-F1 titers (up to 1∶4,096) within 3 days, whereas there was minimal to no increase in antibody response in the intradermal group. Information gathered from this experimental trial may provide additional insight into the spatial and temporal evaluation of coyote plague serology.

Mucosal adjuvants to improve wildlife rabies vaccination.

RABORAL V-RG(®)a is a recombinant vaccine used in oral rabies vaccination (ORV) programs for wildlife in the United States. Vaccination rates for raccoons are substantially lower than vaccination rates for gray foxes and coyotes. Research suggests that the low viscosity of the oral vaccine may preclude animals from receiving an effective dose when biting into the vaccine bait delivery system. We evaluated the possibility of using two benign compounds, chitosan and N,N,N-trimethylated chitosan (TMC), to increase the viscosity of the vaccine and potentially act as adjuvants to improve the immune response in raccoons (Procyon lotor). Forty mildly sedated raccoons were orally vaccinated via needleless syringe with either RABORAL V-RG (n = 12), chitosan+RABORAL V-RG (n = 12), TMC+ RABORAL V-RG (n = 12), or no vaccine (n = 4), on day 0 and again on day 90. We collected sera every 2-4 wk for 4 mo and evaluated rabies virus-neutralizing antibodies (rVNA). Raccoons were considered responders if rVNA titers were ≥ 0.1 IU/mL. Eleven of 12 raccoons vaccinated with TMC+RABORAL V-RG responded after one dose of vaccine, as did eight of 12 vaccinated with RABORAL V-RG, and three of 12 vaccinated with chitosan+ RABORAL V-RG. Our results suggest that the inclusion of an adjuvant, such as TMC, could increase vaccine efficacy to aid in controlling rabies virus spread in wildlife reservoirs.

Antigenic profiling of yersinia pestis infection in the Wyoming coyote (Canis latrans).

Although Yersinia pestis is classified as a "high-virulence" pathogen, some host species are variably susceptible to disease. Coyotes (Canis latrans) exhibit mild, if any, symptoms during infection, but antibody production occurs postinfection. This immune response has been reported to be against the F1 capsule, although little subsequent characterization has been conducted. To further define the nature of coyote humoral immunity to plague, qualitative serology was conducted to assess the antiplague antibody repertoire. Humoral responses to six plasmid-encoded Y. pestis virulence factors were first examined. Of 20 individual immune coyotes, 90% were reactive to at least one other antigen in the panel other than F1. The frequency of reactivity to low calcium response plasmid (pLcr)-encoded Yersinia protein kinase A (YpkA) and Yersinia outer protein D (YopD) was significantly greater than that previously observed in a murine model for plague. Additionally, both V antigen and plasminogen activator were reactive with over half of the serum samples tested. Reactivity to F1 was markedly less frequent in coyotes (35%). Twenty previously tested antibody-negative samples were also examined. While the majority were negative across the panel, 15% were positive for 1-3 non-F1 antigens. In vivo-induced antigen technology employed to identify novel chromosomal genes of Y. pestis that are up-regulated during infection resulted in the identification of five proteins, including a flagellar component (FliP) that was uniquely reactive with the coyote serum compared with immune serum from two other host species. Collectively, these data suggest that humoral immunity to pLcr-encoded antigens and the pesticin plasmid (pPst)-encoded Pla antigen may be relevant to plague resistance in coyotes. The serologic profile of Y. pestis chromosomal antigens up-regulated in vivo specific to C. latrans may provide insight into the differences in the pathogen-host responses during Y. pestis infection.