2012 SOUTHEASTERN NATURALIST 11(3):529–533

Survey of Zoonotic Pathogens in White-tailed Deer on Bald Head Island, North Carolina

Brandon L. Sherrill1,*, Anthony G. Snider2, Suzanne Kennedy-Stoskopf 3, and Christopher S. DePerno1

Abstract - Odocoileus virginianus (White-tailed Deer) have become overabundant in many urban and suburban areas, which can cause concern about exposure of humans and pets to zoonotic pathogens. Bald Head Island, NC is a small barrier island that has experienced ongoing residential development since the mid-1980s and has a relatively high deer density (15–17 deer/km2). To address concerns expressed by residents, we screened ≈13% of the White-tailed Deer population for potential zoonotic pathogens. We collected blood from 8 deer in January through March 2008 and 5 deer in January 2009. We tested sera for antibodies to Anaplasma phagocytophilum, Borrelia burgdorferi, and six serovars of Leptospira interrogans; and whole blood samples for Bartonella spp. and B. burgdorferi DNA. All sera were negative for antibodies to L. interrogans; two samples were seropositive for A. phagocytophilum, and one was seropositive for B. burgdorferi. Whole blood PCR results were negative for Bartonella spp. and B. burgdorferi. Con- tinued surveillance for wildlife diseases on Bald Head Island is necessary to determine prevalence of specifi c pathogens, their impacts on the White-tailed Deer population, and the risk of exposure to humans and pets.

Introduction Odocoileus virginianus Zimmerman (White-tailed Deer; hereafter also “Deer”) are overabundant in many areas throughout their range and can often negatively impact human populations (e.g., property damage, vehicle collisions, exposure to zoonotic pathogens), particularly in suburban areas with expanding residential development (Butfi loski et al. 1997). Epidemiologic surveillance can be useful in identifying and managing zoonotic pathogens, and Deer can serve as effective sentinels for diseases of economic and public health concern (Wolf et al. 2008). Bartonellosis is a constellation of vector-transmitted (e.g., fl eas, ticks, fl ies) bac- terial infections caused by Bartonella spp., which have the potential to affect humans and a variety of animals, including Deer (Guptil 2010). Leptospirosis is a bacterial zoonotic disease caused by spirochetes of the genus Leptospira that can be transmitted through urine and tissue of infected carrier animals, and through urine-contaminated water (Alder et al. 2011). Lyme disease and human granulocy- totropic anaplasmosis are tick-borne diseases associated, at least indirectly, with

1Department of Forestry and Environmental Resources, Fisheries, Wildlife, and Conser- vation Biology Program, North Carolina State University, Raleigh, NC 27607. 2Depart- ment of Environmental Studies, University North Carolina at Wilmington, Wilmington, NC 28403. 3Environmental Medicine Consortium and Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606. *Corresponding author - [email protected]. 530 Southeastern Naturalist Vol. 11, No.3 White-tailed Deer (Dugan et al. 2006, Lane et al. 1991). Borrelia burgdorferi, the causative agent of Lyme disease, and Anaplasma phagocytophilum, the agent of human granulocytotropic anaplasmosis, have been reported in regions where Ixo- des scapularis Say (formerly Ixodes dammini) (Black-legged Ticks) occur (Dugan et al. 2006, Frank et al. 1998, Magnarelli et al. 2004). White-tailed Deer are impor- tant hosts for the adult stage of Black-legged Ticks, and increased Deer density has been shown to increase reproduction and density of these ticks (Magnarelli et al. 2004, Wilson et al. 1985). Additionally, research from Rhode Island noted that bar- rier islands inhabited by Deer contained spirochete-infected Black-legged Ticks, whereas neither ticks nor pathogens were detected on barrier islands not inhabited by Deer (Anderson et al. 1987). Therefore, increased residential development in areas of high Deer density, especially on barrier islands, could increase exposure of humans and pets to zoonotic pathogens and create a heightened concern among residents (Butfi loski et al. 1997). Bald Head Island, NC (≈33°51'N, ≈77°59'W) is a 6.2-km2 barrier island located at the mouth of the Cape Fear River and is an affl uent golf-course com- munity. Residential development began during the 1980s, and by 2009 there were approximately 220 year-round residents on the island; however, each year, the number of visitors to the island may exceed 100,000. By the early 2000s, the number of Deer on Bald Head Island increased to approximately 80 Deer/ km2. As Deer and human density increased, concerns related to Deer impacts to forested habitat, private property, and public health also increased. In response to public concern, managers began a population-control program (i.e., annual culls) in 2003 to reduce Deer numbers, and by 2008–2009 the estimated Deer popula- tion was between 15–17 Deer/km2 (Sherrill et al. 2010). Therefore, we examined movements and home ranges of female White-tailed Deer on Bald Head Island and collected blood and serum samples to determine exposure of Deer to specifi c pathogens that have implications for Deer and human health.

Methods During January–March 2008 and January 2009, we captured White-tailed

Deer using a CO2-powered dart rifle (Model JM Standard, Dan-Inject, Inc., Børkop, Denmark) or a cartridge-fired dart rifle (Pneu-Dart, Williamsport, PA) to collect blood samples to test for serological evidence of exposure to B. burgdorferi, A. phagocytophilum, and Leptospira interrogans (serovars bratislava, canicola, grippotyphosa, hardjo, icterohemorrhagica, and pomona) and for DNA from Bartonella spp. and B. burgdorferi. We immobilized Deer with an intramuscular injection of 4.4 mg/kg of Telazol® (1:1 tiletamine hy- drochloride and zolazepam hydrochloride; Fort Dodge Animal Health, Fort Dodge, IA) and 2.2 mg/kg of XYLA-JECT® (xylazine hydrochloride, Phoenix Pharmaceutical, Inc., St. Joseph, MO) (Kreeger et al. 2002, Sherrill et al. 2010). We collected blood via jugular venipuncture to obtain a minimum of 10 ml to be centrifuged for serum and 6 ml for whole-blood analysis. Serum samples were centrifuged within 30 minutes after collection, and all samples were frozen. Animal-handling methods used in this project were approved by the 2012 B.L. Sherrill, A.G. Snider, S. Kennedy-Stoskopf , and C.S. DePerno 531 Institutional Animal Care and Use Committee (Approval Number 2007-017) at the University of North Carolina at Wilmington and followed guidelines ap- proved by the American Society of Mammalogist (Gannon et al. 2007). We sent sera to the Connecticut Agricultural Experiment Station to detect total antibodies to strain 2591 and recombinant antigen VlsE1-HIS (VlsE) of B. burg- dorferi, and separate recombinant protein (p) 44 antigen of A. phagocytophilum using a polyvalent enzyme-linked immunosorbent assay (ELISA) (Magnarelli et al. 1999, 2004). Also, indirect fl uorescent antibody (IFA) staining methods were used to detect antibodies to strain NCH-1 of A. phagocytophilum (Magnarelli et al. 1999). We sent serum samples to the Michigan State University Diagnostic Center for Population and Animal Health to test for agglutinating antibodies against Leptospira interrogans (serovars bratislava, canicola, grippotyphosa, hardjo, icterohemorrhagica, and pomona) using a microscopic agglutination test (MAT) (Cole et al. 1973). We sent whole blood samples to North Carolina State University College of Veterinary Medicine to screen for Bartonella spp. and B. burgdorferi using polymerase chain reaction (PCR) analyses (Diniz et al. 2007, Maggi et al. 2010).

Results In 2008 (n = 8), we sampled 1 adult male along with 1 fawn, 1 yearling, and 5 adult females. In 2009 (n = 5), we sampled 1 fawn, 1 yearling, and 3 adult females. All test results for Bartonella spp. and L. interrogans were negative. One adult female in 2009 had an antibody titer of 320 to the p44 recombinant A. phagocytophilum antigen. In 2008, the male was seropositive for both the p44 recombinant antigen and strain NCH-1 of A. phagocytophilum with antibody titers of 256 and 320, respectively. All PCR results from whole-blood samples were negative for B. burgdorferi; however, the male had an antibody titer of 640 for the VlsE-1 recombinant B. burgdorferi antigen. All antibody-positive and -negative sera were retested to assess reproducibility of results.

Discussion In this study, we documented that White-tailed Deer on Bald Head Island were exposed to A. phagocytophilum and B. burgdorferi, which provides valuable information useful in continued disease surveillance. Based on our results, we believe the current risk of human exposure to the select zoonotic pathogens we tested in Deer is probably low. As Deer and/or vector density fluctuates, the vulnerability of wildlife, humans, and pets to various patho- gens may change. Bald Head Island has a relatively high Deer density, and changes in Deer density can impact vector populations (e.g., ticks), thereby influencing the risk of exposure of residents and pets to potential zoonotic diseases. Although Ixodes scapularis is the primary vector of Lyme dis- ease in much of the eastern United States, I. affinis may be more important in the maintenance of enzootic cycles of Lyme borreliosis spirochetes in the coastal regions of the Southeast (Harrison et al. 2010). Ixodes affinis is 532 Southeastern Naturalist Vol. 11, No.3 widely distributed in the coastal plain of North Carolina, and recent research documented a high incidence of Borrelia spp. in I. affinis collected in coastal North Carolina, highlighting the potential importance of I. affinis in the main- tenance of the enzootic transmission cycle of B. burgdorferi in this region (Maggi et al. 2010). Although this was a small-scale study over a short period, we documented the exposure of Deer on Bald Head Island to A. phagocytophilum and B. burgdorferi. Future research should incorporate increased surveillance of White-tailed Deer, determine the density of primary vectors of specifi c pathogens, and provide a measure of relative risk of zoonotic disease exposure to wildlife, humans, and pets on Bald Head Island.

Acknowledgments This project was funded by the Village of Bald Head Island, North Carolina State Uni- versity, and the University of North Carolina at Wilmington. We thank the undergraduate and graduate students from NCSU and UNCW who volunteered on this project. In addi- tion, we thank the staff of the Bald Head Island Conservancy and numerous Bald Head Island residents for their support.

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