Anaplasma phagocytophilum from Rodents and Sheep, China

Anaplasma phagocytophilum has been recognized as an animal pathogen and is an emerging human pathogen of public health relevance. From 1994 to 2005, ≈3,000 cases of human granulocytic anaplasmosis were diagnosed in the United States (1), and in more recent years, sporadic and clustered cases have been reported in Europe and the People’s Republic of China (2–5). Human are usually infected by tick bites, although perinatal transmission or transmission through contact with infected animal blood has been reported (1). A broad variety of animal species are known to carry A. phagocytophilum, and humans are incidental dead-end hosts (6). Various A. phagocytophilum strains have been isolated from humans (6), domestic and wild animals, and ticks in the United States and Europe (1,6,7). Prior serologic and molecular evidence suggests that A. phagocytophilum has also infected humans, rodents, and ticks in many Asian countries, including China, Japan, and Korea (8–12). Our objectives were to obtain isolates of A. phagocytophilum in vitro by using the HL60 cell line and to characterize the strains from wild and domestic animals in China.