Abstract
BACKGROUND AND AIM: Bovine coccidiosis, caused by the protozoa Eimeria, is an important parasitic cattle disease that affects animal health and has economic impact worldwide. This study was conducted to report the first molecular prevalence and genetic diversity of Eimeria spp. in dairy cattle in Khon Kaen province, Thailand, and to identify the risk factors associated with Eimeria spp. infection. MATERIALS AND METHODS: From July 2020 to October 2021, 296 fecal samples were collected from dairy cattle divided into three age groups, including <3-month-old calves, 3-month-old to 1-year-old calves, and >1-year-old cattle. Eimeria spp. were identified by multiplex polymerase chain reaction (PCR) amplifying 18S RNA gene and confirmed by DNA sequencing. Information regarding all associated risk factors was collected using questionnaires and analyzed using logistic regression tests in the Statistical Package for the Social Sciences program. RESULTS: Polymerase chain reaction results showed that 104 (35.13%) of 296 samples were positive for Eimeria spp. The <3-month-old calves (46.51%) had the highest infection rate. Moreover, multiplex PCR identified five species of Eimeria, namely, Eimeria bovis (32.69%), Eimeria zuernii (18.26%), Eimeria alabamensis (5.76%), Eimeria ellipsoidalis (3.84%), and Eimeria cylindrica (2.88%). An association was observed between risk factors and Eimeria spp. incidence (p < 0.05). DNA sequencing revealed the similarity of each Eimeria spp. with 91%-100% nucleotide identity. Phylogenetic tree analysis demonstrated the close relationships of clusters of E. bovis and E. zuernii, E. ellipsoidalis, and E. cylindrica and another cluster of E. alabamensis. CONCLUSION: The results confirm that Eimeria spp. are commonly found in dairy cattle, especially calves. The molecular test could be powerful for species identification. This study also provides epidemiological information for developing future strategies to control bovine coccidiosis.