Veterinary Parasitology 170 (2010) 193–196 Contents lists available at ScienceDirect Veterinary Parasitology journal homepage: www.elsevier.com/locate/vetpar Seroprevalence of Babesia infections of dairy cows in northern Thailand Hiroshi Iseki a , Lijia Zhou a , Chulmin Kim a , Tawin Inpankaew b , Chainirun Sununta c , Naoaki Yokoyama a , Xuenan Xuan a , Sathaporn Jittapalapong b , Ikuo Igarashi a,∗ a National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan b Department of Parasitology, Kasetsart University, Bangkok, Thailand c Chiang Rai Provincial Office, Department of Livestock Development, Chiang Rai, Thailand article info Article history: Received 3 November 2009 Received in revised form 18 February 2010 Accepted 24 February 2010 Keywords: Babesia bovis Babesia bigemina Indirect fluorescent-antibody test (IFAT) Dairy cows Enzyme-linked immunosorbent assay (ELISA) Western blot Thailand abstract The present study was conducted to demonstrate the epidemiological distribution of bovine babesiosis in the northern regions of Thailand. A total of 700 serum samples of dairy cows in the northern provinces (Chiang Rai, Chiang Mai, Lumpang, and Mae Hong Sorn) were tested for antibodies against Babesia bovis and B. bigemina. Species-specific enzyme-linked (rRAP-1/CTs) were performed. According to the results, 517 (73.8%) and 484 (69.1%) were positive for B. bovis and B. bigemina, respectively. In addition, 370 (52.9%) were positive for mixed infections by both ELISAs. On the other hand, all samples were also examined by the indirect fluorescent-antibody test (IFAT) with B. bovis- and B. bigemina-infected blood smears. According to the IFAT, 482 (68.8%) and 531 (75.8%) were positive for these infections, respectively. The overall concordances between the ELISA and IFAT techniques were 93.6% and 90.7% for B. bovis and B. bigemina infections, respectively. These results indicated that babesia infections are widespread in the northern parts of Thailand. To our knowledge, this is the first report describing the epidemiology of Babesia infections using rRAP-1/CT-based ELISAs in these areas. © 2010 Elsevier B.V. All rights reserved. 1. Introduction Bovine babesiosis is known as one of the most eco- nomically important diseases in tropical and subtropical regions (McCosker, 1981). This tick-borne disease is mainly caused by two intraerythrocytic protozoan parasites, Babesia bovis and B. bigemina. The clinical signs induced by these parasites are characterized by fever, anemia, and hemoglobinuria in the infected cattle (de Vos and Potgieter, 1994). However, the disease caused by B. bovis is more severe than that by B. bigemina (Ristic, 1981). Acute infec- tions are usually diagnosed by a microscopic examination of blood smears, whereas subclinical infections have been identified serologically (Weiland and Reiter, 1988). There- fore, differential diagnosis between B. bovis and B. bigemina ∗ Corresponding author. Tel.: +81 155 49 5641; fax: +81 155 49 5643. E-mail address: igarcpmi@obihiro.ac.jp (I. Igarashi). infections will lead to a better understanding of their epi- demiology, and the species-specific distribution in the field will provide useful information to establish a control pro- gram of these diseases (de Vos and Potgieter, 1994). Thailand is a developing agricultural country located in Southeast Asia. In this country, livestock development, par- ticularly for dairy cows, has been hampered by persistently low production of milk and meat due to many infectious pathogens, including Babesia. In 1990, 428 cattle sera of 12 provinces in Thailand were tested for the antibodies of bovine babesiosis by the IFAT (Nishikawa et al., 1990). The prevalence of antibodies to B. bovis and B. bigemina was 74.5% (Nishikawa et al., 1990); however, there are only a few reports of bovine babesiosis in Thailand. Therefore, further reliable information is needed to reduce losses to animal owners due to these diseases. The objective of the present study is to determine the prevalence of Babesia infections among dairy cows in northern provinces of Thailand using the IFAT and 0304-4017/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.vetpar.2010.02.038