Effects of tick control by acaricide self-treatment of white-tailed deer on host-seeking tick infection prevalence and entomologic risk for Ixodes scapularis-borne pathogens.
We evaluated the effects of tick control by acaricide self-treatment of white-tailed deer on the infection prevalence and entomologic risk for three Ixodes scapularis-borne bacteria in host-seeking ticks. Ticks were collected from vegetation in areas treated with the "4-Poster" device and from control areas over a 6-year period in five geographically diverse study locations in the Northeastern United States and tested for infection with two known agents of human disease, Borrelia burgdorferi and Anaplasma phagocytophilum, and for a novel relapsing fever-group spirochete related to Borrelia miyamotoi. Overall, 38.2% of adults and 12.5% of nymphs were infected with B. burgdorferi; 8.5% of adults and 4.2% of nymphs were infected with A. phagocytophilum; and 1.9% of adults and 0.8% of nymphs were infected with B. miyamotoi. In most cases, treatment with the 4-Poster device was not associated with changes in the prevalence of infection with any of these three microorganisms among nymphal or adult ticks. However, the density of nymphs infected with B. burgdorferi, and consequently the entomologic risk for Lyme disease, was reduced overall by 68% in treated areas compared to control areas among the five study sites at the end of the study. The frequency of bacterial coinfections in ticks was generally equal to the product of the proportion of ticks infected with a single bacterium, indicating that enzootic maintenance of these pathogens is independent. We conclude that controlling ticks on deer by self-application of acaricide results in an overall decrease in the human risk for exposure to these three bacterial agents, which is due solely to a reduction in tick density.
Hoen
Anne Gatewood
AG
Department of Epidemiology and Public Health, Yale School of Medicine, New Haven, Connecticut. anne.gatewood@childrens.harvard.edu
Rollend
Lindsay G
LG
Papero
Michele A
MA
Carroll
John F
JF
Daniels
Thomas J
TJ
Mather
Thomas N
TN
Schulze
Terry L
TL
Stafford
Kirby C
KC
Fish
Durland
D
D056810:Acaricides / Q000008:administration & dosage*; D000704:Analysis of Variance; D041081:Anaplasma phagocytophilum / Q000235:genetics / Q000302:isolation & purification*; D000821:Animal Feed; D000818:Animals; D001096:Arachnid Vectors / Q000382:microbiology; D001898:Borrelia / Q000235:genetics / Q000302:isolation & purification*; D025065:Borrelia burgdorferi / Q000302:isolation & purification; D003670:Deer / Q000469:parasitology*; D016873:Ehrlichiosis / Q000453:epidemiology / Q000517:prevention & control; D006801:Humans; D018884:Ixodes / Q000254:growth & development / Q000382:microbiology*; D008193:Lyme Disease / Q000453:epidemiology / Q000517:prevention & control; D009511:New England / Q000453:epidemiology; D016133:Polymerase Chain Reaction; D011156:Population Density; D015995:Prevalence; D013983:Tick Control / Q000379:methods; D013984:Tick Infestations / Q000453:epidemiology / Q000517:prevention & control / Q000662:veterinary*
D056810:Acaricides