Borrelia burgdorferi not detected in widespread Ixodes scapularis (Acari: Ixodidae) collected from white-tailed deer in Tennessee.

Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, 37996, USA.
Journal of Medical Entomology (Impact Factor: 1.82). 11/2012; 49(6):1473-80. DOI: 10.1603/ME11255
Source: PubMed

ABSTRACT Lyme disease (LD), caused by the bacterium Borrelia burgdorferi and transmitted in the eastern United States by blacklegged ticks, Ixodes scapularis Say, is classified as nonendemic in Tennessee and surrounding states in the Southeast. Low incidence of LD in these states has been attributed, in part, to vector ticks being scarce or absent; however, tick survey data for many counties are incomplete or out of date. To improve our knowledge of the distribution, abundance, and Borrelia spp. prevalence of I. scapularis, we collected ticks from 1,018 hunter-harvested white-tailed deer (Odocoileus virginianus (Zimmerman)) from 71 of 95 Tennessee counties in fall 2007 and 2008. In total, 160 deer (15.7%) from 35 counties were infested with adult I. scapularis; 30 of these counties were new distributional records for this tick. The mean number of I. scapularis collected per infested deer was 5.4 +/- 0.6 SE. Of the 883 I. scapularis we removed from deer, none were positive for B. burgdorferi and one tested positive for B. miyamotoi. Deer are not reservoir hosts for B. burgdorferi; nevertheless, past surveys in northern LD-endemic states have readily detected B. burgdoreferi in ticks collected from deer. We conclude that I. scapularis is far more widespread in Tennessee than previously reported. The absence of detectable B. burgdorferi infection among these ticks suggests that the LD risk posed by I. scapularis in the surveyed areas of Tennessee is much lower than in LD-endemic areas of the Northeast and upper Midwest.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Borrelia miyamotoi is a newly described emerging pathogen transmitted to people by Ixodes species ticks and found in temperate regions of North America, Europe, and Asia. There is limited understanding of large scale entomological risk patterns of B. miyamotoi and of Borreila burgdorferi sensu stricto (ss), the agent of Lyme disease, in western North America. In this study, B. miyamotoi, a relapsing fever spirochete, was detected in adult (n = 70) and nymphal (n = 36) Ixodes pacificus ticks collected from 24 of 48 California counties that were surveyed over a 13 year period. Statewide prevalence of B. burgdorferi sensu lato (sl), which includes B. burgdorferi ss, and B. miyamotoi were similar in adult I. pacificus (0.6% and 0.8%, respectively). In contrast, the prevalence of B. burgdorferi sl was almost 2.5 times higher than B. miyamotoi in nymphal I. pacificus (3.2% versus 1.4%). These results suggest similar risk of exposure to B. burgdorferi sl and B. miyamotoi from adult I. pacificus tick bites in California, but a higher risk of contracting B. burgdorferi sl than B. miyamotoi from nymphal tick bites. While regional risk of exposure to these two spirochetes varies, the highest risk for both species is found in north and central coastal California and the Sierra Nevada foothill region, and the lowest risk is in southern California; nevertheless, tick-bite avoidance measures should be implemented in all regions of California. This is the first study to comprehensively evaluate entomologic risk for B. miyamotoi and B. burgdorferi for both adult and nymphal I. pacificus, an important human biting tick in western North America.
    PLoS ONE 10/2014; 9(10):e110853. · 3.53 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background In the northeastern and midwestern regions of the United States Ixodes scapularis Say transmits the causal agents of anaplasmosis (Anaplasma phagocytophilum), babesiosis (Babesia microti), and borreliosis (Borrelia burgdorferi and B. miyamotoi). In the southeastern United States, none of those pathogens are considered endemic and two other tick-borne diseases (TBDs) (ehrlicihosis and rickettiosis) are more common. Our objective was to determine baseline presence and absence data for three non-endemic bacterial agents (Anaplasma, Borrelia and Babesia) and two commonly reported bacterial agents (Ehrlichia, and Rickettsia) in southern I. scapularis (n = 47) collected from 15 hunter-harvested white-tailed deer (Odocoileus virginianus) in western Tennessee. FindingsOf the 47 ticks, 27 tested PCR positive for non-pathogenic Rickettsia species, two for Ehrlichia ewingii, one for Ehrlichia sp. ¿Panola Mountain¿, and one for Anaplasma phagocytophilum variant 1 strain. None of these ticks were positive for Babesia or Borrelia (including B. burgdorferi).Conclusions Finding human pathogens in host-fed I. scapularis merits additional studies surveying pathogen prevalence in questing ticks. Collection of questing I. scapularis in their peak activity months should be undertaken to determine the overall encounter rates and relative risk of pathogenic Ehrlichia in southern I. scapularis. Ehrlichia sequences were homologous to previous human isolates, but neither Babesia nor B. burgdorferi were identified in these ticks. With the identification of pathogenic bacteria in this relatively small collection of I. scapularis from western Tennessee, the study of the absence of Lyme disease in the south should be refocused to evaluate the role of pathogenic Ehrlichia in southern I. scapularis.
    Parasites & Vectors 10/2014; 7(1):473. · 3.25 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background/Question/Methods Ticks transmit more pathogen species than any other group of blood-feeding arthropods worldwide, affecting humans, livestock and companion animals. The major impact of tick-borne pathogens on the general public in North America and Europe first became evident with the detection of Borrelia burgdorferi as the causative agent of Lyme disease in the 1980’s. The Ixodes species, e.g., Ixodes scapularis, are competent vectors for B. burgdorferi. Lyme disease is the most prevalent arthropod-borne disease in the US and Europe. Recently the number of reports of infected humans has increased, making Lyme disease acquire a new category as an emergent infectious disease. Lyme disease risk maps have been developed in the US, mainly focusing in the Northeast and Midwest regions of the country. The causative agent, vector, and mammalian reservoirs are distributed throughout the region between the US and Mexico. Nevertheless, no major studies of risk for Lyme disease or evaluation of climate change effects on the spatial or temporal distribution of the vector Ixodes have been conducted in these areas. Maps for present and future suitable habitat distribution (2050; under climate change) in the USA-Mexico border were developed for Ixodes scapularis using a maximum entropy algorithm by correlating the known distribution of the species with climatic variables. Maps were evaluated using the AUC in a ROC plot. Results/Conclusions Our findings indicate that I. scapularis is potentially widely distributed in the Texas-northeast Mexico region with a higher probability of occurrence along the Gulf of Mexico coast and with a stable area of distribution of approximately 592,240 Km2 that will remain stable for the most part until 2050. Additionally, B. burgdorferi infection was documented in I. scapularis from the US-Mexico border region. Projections of the models for vector distribution and disease risk highlight the relevance of the US-Mexico border as a region of shared ecological risk for Lyme disease. Forecasting based on climate trends provides a tool to adapt strategies in the near future to mitigate the impact of Lyme disease related to its distribution and risk for transmission to human populations in the eastern sector of the Mexico-US region.
    99th ESA Annual Convention 2014; 08/2014


Available from
Dec 13, 2014