antibiotic treatment of the tick vector amblyomma americanum reduced reproductive fitness抗生素治疗的蜱虫向量科学家americanum减少生殖健康.pdf

Antibiotic Treatment of the Tick Vector Amblyomma americanum Reduced Reproductive Fitness 1,2 1 1 Jianmin Zhong , Algimantas Jasinskas , Alan G. Barbour * 1 Department of Microbiology and Molecular Genetics, Department of Medicine and Pacific-Southwest Center for Biodefense and Emerging Infections, University of California Irvine, Irvine, California, United States of America, 2 Department of Biological Sciences, Humboldt State University, Arcata, California, United States of America Background. The lone star tick Amblyomma americanum is a common pest and vector of infectious diseases for humans and other mammals in the southern and eastern United States. A Coxiella sp. bacterial endosymbiont was highly prevalent in both laboratory-reared and field-collected A. americanum. The Coxiella sp. was demonstrated in all stages of tick and in greatest densities in nymphs and adult females, while a Rickettsia sp. was less prevalent and in lower densities when present. Methodology/Principal Findings. We manipulated the numbers of both bacterial species in laboratory-reared A. americanum by injecting engorged nymphs or engorged, mated females with single doses of an antibiotic (rifampin or tetracycline) or buffer alone. Burdens of the bacteria after molting or after oviposition were estimated by quantitative polymerase chain reaction with primers and probes specific for each bacterial species or, as an internal standard, the host tick. Post-molt adult ticks that had been treated with rifampin or tetracycline had lower numbers of the Coxiella sp. and Rickettsia sp. and generally weighed less than ticks that received buffer alone. Similarly, after oviposition, females treated previously with either antibiotic had lower burdens o