A. phagocytophilum Infection in Ticks | CDC EID

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Volume 17, Number 5–May 2011
Letter
Anaplasma phagocytophilum Infection in Ticks, China–Russia Border
Jia-Fu Jiang, Bao-Gui Jiang, Ji-Hong Yu, Wen-Yi Zhang, Hong-Wei Gao, Lin Zhan, Yi Sun, Xiao-Ai Zhang, Pan-He Zhang, Wei Liu, Xiao-Ming Wu, Rong-Man Xu, and Wu-Chun Cao

Author affiliations: State Key Laboratory of Pathogen and Biosecurity, Beijing, People's Republic of China; and Institute of Microbiology and Epidemiology, Beijing


Suggested citation for this article


To the Editor: Anaplasma phagocytophilum, an emerging human pathogen of public health importance, is transmitted to humans most commonly by tick bites (1). The agent has been detected in various species of Ixodes ticks around the world (2) and in Dermacentor silvarum ticks in northeastern People's Republic of China (3), where 3 A. phagocytophilum strains were isolated from wild and domestic animals (4). In the Asiatic region of Russia adjacent to China, A. phagocytophilum was identified in Ixodes persulcatus ticks, and A. bovis in Haemaphysalis concinna ticks (5). Human granulocytic anaplasmosis was reported in the southern area of the Russian Far East that borders China (6). The objectives of this study were to investigate the prevalence of A. phagocytophilum in ticks collected from the China–Russia border and to characterize the agent by molecular biology techniques.

During May–June 2009, host-seeking ticks were collected by flagging vegetation of grassland or woodland along the China–Russia border. Attached ticks were collected from sheep and goats in Hunchun, and from dogs in Suifenhe (Table). All ticks were identified by morphologic features to the species level and the developmental stage by 2 entomologists (Y. Sun and R.-M. Xu). DNA was extracted from tick samples by using Tissue DNA Extract kit (Tiangen Biotechnique Inc., Beijing, China), following the instructions of the manufacturer. Nested PCR was performed to amplify partial citrate synthase gene (gltA) of A. phagocytophilum as previously described (7). To avoid possible contamination, DNA extraction, the reagent setup, amplification, and agarose gel electrophoresis were performed in separate rooms, and negative control samples (distilled water) were included in each amplification.

A. phagocytophilum was detected in 83 of 2,429 adult ticks, with an overall prevalence of 3.42% (Table). The infection rates in the 14 survey sites ranged from 0 to 5.96%, and were significantly different (χ2 = 24.43, df = 13; p = 0.027). Except for H. japonica, ticks from 4 species, including H. concinna, H. longicornis, I. persulcatus, and D. silvarum were found to be naturally infected. The difference in infection rates among tick species was statistically significant (χ2 = 13.03, df = 4; p = 0.011). Of 367 attached H. longicornis ticks obtained from domestic animals in Hunchun and Suifenhe, 12 (3.27%) were infected with A. phagocytophilum (Table). Nymphal ticks were only collected from vegetation in Hunchun, and 30 pools (10 in each pool) of 1,190 H. concinna nymphs were positive with an estimated minimum prevalence of 2.52%.

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A. phagocytophilum Infection in Ticks | CDC EID


Suggested Citation for this Article
Jiang J-F, Jiang B-G, Yu J-H, Zhang W-Y, Gao H-W, Zhan L, et al. Anaplasma phagocytophilum infection in ticks, China–Russia border [letter]. Emerg Infect Dis [serial on the Internet]. 2011 May [date cited]. http://www.cdc.gov/EID/content/17/5/932.htm


DOI: 10.3201/eid1705.101630


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Wu-Chun Cao, Beijing Institute of Microbiology and Epidemiology, China, Department of Epidemiology, 20 Dongda St, FengTai District, Beijing 100071, People's Republic of China; email: caowc@nic.bmi.ac.cn