Experimental Infection of White-Tailed Deer with Anaplasma phagocytophilum, Etiologic Agent of Human Granulocytic Anaplasmosis

Southeastern Cooperative Wildlife Disease Study, Wildlife Health Building, College of Veterinary Medicine, The University of Georgia, Athens, GA 30602-7393.
Journal of Clinical Microbiology (Impact Factor: 3.99). 09/2005; 43(8):3595-601. DOI: 10.1128/JCM.43.8.3595-3601.2005
Source: PubMed


Serologic and molecular evidence of Anaplasma phagocytophilum has been demonstrated in white-tailed deer (WTD; Odocoileus virginianus), and deer are an important host for the tick vector Ixodes scapularis. In this study, we describe experimental infection of WTD with A. phagocytophilum. We inoculated four WTD with a human isolate of A. phagocytophilum propagated in tick cells. Two additional deer served as negative controls. All inoculated deer developed antibodies (titers, > or =64) to A. phagocytophilum, as determined by an indirect fluorescent antibody test, between 14 and 24 days postinfection [p.i.]), and two deer maintained reciprocal titers of > or =64 through the end of the 66-day study. Although morulae were not observed in granulocytes and A. phagocytophilum was not reisolated via tick cell culture of blood, 16S reverse transcriptase nested PCR (RT-nPCR) results indicated that A. phagocytophilum circulated in peripheral blood of three deer through at least 17 days p.i. and was present in two deer at 38 days p.i. Femoral bone marrow from one deer was RT-nPCR positive for A. phagocytophilum at 66 days p.i. There was no indication of clinical disease. These data confirm that WTD are susceptible to infection with a human isolate of A. phagocytophilum and verify that WTD produce detectable antibodies upon exposure to the organism. Because adults are the predominant life stage of I. scapularis found on deer and because adult I. scapularis ticks do not transmit A. phagocytophilum transovarially, it is unlikely that WTD are a significant source of A. phagocytophilum for immature ticks even though deer have a high probability of natural infection. However, the susceptibility and immunologic response of WTD to A. phagocytophilum render them suitable candidates as natural sentinels for this zoonotic tick-borne organism.

1 Follower
11 Reads
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In the second half of the 1990’s the moose population on the island Öland declined drastically and the hunters decided to completely stop hunting for moose for a number of years. When the hunting commenced the hunters found the slaughter weights to be lower than expected and the number of calves were also low. The hunters then contacted the Swedish National Veterinary Institute who then initiated a project which this report is a part of. Samples from a total of 40 moose was collected, 32 out of 33 sampled moose were positive for antibodies against Anaplasma phagocytophilum and 4 out of 36 samples were positive by PCR for Ananplasma phagocytophilum. Out of these three were calves and one was a female yearling. Reported slaughter weights for calves were low and the number of observed calves per adult female were half compared to the mainland. This survey indicates that infection with Anaplasma phagocytophilum constitutes a contributing cause for the low number of observed calves in the moose population on the island of Öland.
  • [Show abstract] [Hide abstract]
    ABSTRACT: We present analytical studies of output intensity fluctuations of systems having PMD, PDL and CD. Analytical expressions for autocorrelation functions are derived. Results applied to different modulation formats lead to analytical evaluations of eye diagrams.
    Holey Fibers and Photonic Crystals/Polarization Mode Dispersion/Photonics Time/Frequency Measurement and Control, 2003 Digest of the LEOS Summer Topical Meetings; 08/2003
  • [Show abstract] [Hide abstract]
    ABSTRACT: Anaplasma phagocytophilum, the causative agent of human granulocytotropic anaplasmosis, can infect white-tailed deer (WTD; Odocoileus virginianus), and this species is a crucial host for adult Ixodes scapularis, the primary vector of A. phagocytophilum. The goal of this study was to determine the geographic distribution of A. phagocytophilum among WTD across a 19 state region and to evaluate the utility of WTD as natural sentinels. Serologic testing using the indirect fluorescent antibody (IFA) assay was conducted on WTD serum samples and molecular and xenodiagnostic tests were performed to confirm serologic results. The surveillance system was assessed through examination of vital attributes including WTD age and gender associations with serologic status, sample size adequacy for accurate infection status classification, and presence of the vector, I. scapularis. Six hundred thirty-three of 2,666 (24%) WTD in 17 states tested positive for antibodies (>or=128) when tested by IFA assay. Testing for p44 and/or 16S rRNA gene targets identified 73 (16%) PCR positive WTD among 458 animals tested, all of which originated from seropositive populations. Attempts to culture A. phagocytophilum from WTD were unsuccessful; however, xenodiagnostic mice inoculated with blood from 3 WTD became infected. Seroprevalence did not differ by deer age or gender; however, WTD<or=0.75 years old had a higher prevalence of PCR positivity. Using seroprevalence data, a sample size of 6-9 animals per population was projected to be adequate for identifying seropositive populations. The presence of I. scapularis was significantly associated with A. phagocytophilum antibodies in WTD. Collectively, the results of this study demonstrate that WTD would be suitable natural sentinels for this emerging zoonotic pathogen.
    Vector Borne and Zoonotic Diseases 02/2006; 6(2):192-207. DOI:10.1089/vbz.2006.6.192 · 2.30 Impact Factor
Show more


11 Reads
Available from