sábado, 28 de noviembre de 2009

Tick-borne Agents in Rodents, China | CDC EID

EID Journal Home > Volume 15, Number 12–December 2009

Volume 15, Number 12–December 2009
Tick-borne Agents in Rodents, China, 2004–2006
Lin Zhan,1 Wu-Chun Cao,1 Chen-Yi Chu, Bao-Gui Jiang, Fang Zhang, Wei Liu, J. Stephen Dumler, Xiao-Ming Wu, Shu-Qing Zuo, Pan-He Zhang, Hai-Nan Huang, Qiu-Min Zhao, Na Jia, Hong Yang, Jan H. Richardus, and J. Dik F. Habbema
Author affiliations: Beijing Institute of Microbiology and Epidemiology, Beijing, People's Republic of China (L. Zhan, W.-C. Cao, C.-Y. Chu, B.-G. Jiang, F. Zhang, W. Liu, X.-M. Wu, S.-Q. Zuo, P.-H. Zhang, H.-N. Huang, Q.-M. Zhao, N. Jia, H. Yang); Johns Hopkins University School of Medicine, Baltimore, Maryland, USA (J.S. Dumler); and University Medical Center, Rotterdam, the Netherlands (J.H. Richardus, J.D.F. Habbema)

Suggested citation for this article

A total of 705 rodents from 6 provinces and autonomous regions of mainland People's Republic of China were tested by PCRs for tick-borne agents (Anaplasma phagocytophilum, Borrelia burgdorferi sensu lato, spotted fever group rickettsiae, and Francisella tularensis). Infection rates were 5.5%, 6.7%, 9.1% and 5.0%, respectively. Eighteen (2.6%) rodents of 10 species were positive for 2 or 3 agents. Sequence analysis of PCR products confirmed the presence and genotypes of detected agents. These findings demonstrate that these tick-borne agents cocirculate and that a variety of rodent species may be involved in their enzootic maintenance.

Anaplasma phagocytophilum, Borrelia burgdorferi sensu lato, spotted fever group (SFG) rickettsiae, and Francisella tularensis are the causative agents of human granulocytic anaplasmosis, Lyme disease, spotted fever, and tularemia, respectively. These agents are naturally maintained in animal reservoirs and considered emerging or reemerging pathogens with serious public health implications. Although these agents could infect humans through various routes, ticks play a major role in transmission from animal hosts to humans.

Co-infection with these agents has been found in many tick species including Ixodes scapularis in northeastern United States, I. pacificus and I. spinipalpis in the western United States I. ricinus in Europe, and I. persulcatus in Asia (1). Patients co-infected with 2 tick-borne pathogens usually show more severe clinical signs of longer duration (1). Experimental concurrent infections with A. phagocytophilum and B. burgdorferi may suppress interleukin-2 (IL-2) and interferon-γ production, promote IL-4 response, increase pathogen load, and intensify Lyme arthritis (2–4). Natural infection and co-infection with these 4 agents have been reported in the People's Republic of China in various tick species (5–7) such as I. persulcatus, Dermacentor silvarum, Haemaphysalis concinna, H. longicornis, and H. warburconi, which are known to feed on small mammals as well as humans.

We hypothesize that multiple agents might be present in rodents from tick-infested areas. The purpose of this study was to identify A. phagocytophilum, B. burgdorferi, SFG rickettsiae, and F. tularensis in rodents from mainland China and to better understand the public health role of these emerging and reemerging pathogens.

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Tick-borne Agents in Rodents, China | CDC EID

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