Submitted to: Journal of Veterinary Medical Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/20/2012
Publication Date: 5/5/2012
Citation: Lee, B.H., Kim, W.H., Jeong, J., Yoo, J., Kwon, Y.K., Jung, B.Y., Kwon, J.H., Lillehoj, H.S., Min, W. 2012. Prevalence and cross-immunity of Eimeria species on Korean chicken farms. Journal of Veterinary Medical Science. 72-985-989. Interpretive Summary: Coccidiosis is an important intestinal infectious disease affecting global economy. Comprehensive epidemiology survey of poultry farms is critical to design a logical control strategy against this infection. In this paper, Korean scientists from the Gyeonsang National University reports a survey of Eimeria strain prevalence in South Korea in collaboration with a scientist at ARS. Based on microscopic examination and molecular diagnostic examination on the fecal samples collected from 356 farms in southern part of Korea, multiple species of chicken Eimeria were identified. For example, PCR amplification of the internal transcribed spacer 1 (ITS-1) region with species-specific primers, two major species were E. acervulina and E. tenella. The information presented in this report will help poultry scientists and veterinarians to develop logical disease control strategy against avian protozoan infections prevalent in poultry farms.
Technical Abstract: The epidemiology of Eimeria species in poultry flocks is important to increase the effectiveness of vaccinations and prophylactic strategies on chicken farms. In this study, fecal samples from 356 chicken farms were collected randomly and examined for the prevalence of Eimeria species. Through microscopic examination, it was determined that 78.7% of the tested farms contained Eimeria-infected animals. All seven Eimeria species were detected by PCR amplification of the internal transcribed spacer 1 (ITS-1) region with species-specific primers. E. acervulina and E. tenella were the most prevalent, followed by E. brunetti and E. praecox (87.5%, 62.5%, 59.3%, and 37.5% of farms, respectively). Each of E. maxima, E. mitis, and E. necatrix was identified in 31.3% of farms. Multiple Eimeria species (mean = 3.4) were observed in individual positive fecal samples. Since E. maxima generates antigenic variants, cross-immunity was investigated for four isolates of E. maxima from poultry farms in different regions of Korea. The extent of cross-protection varied from 54.3% to 100% against the heterologous isolates. The results obtained from this large-scale survey will be a useful reference for controlling coccidiosis within the poultry industry.