[Molecular epidemiological investigation on Theileria in yellow cattle from Xiangxi Autonomous Prefecture of Hunan Province].

OBJECTIVE: To investigate the prevalence and genetic variation of Theileria in yellow cattle in Xiangxi Autonomous Prefecture of Hunan Province. METHODS: A total of 184 blood specimens were collected from Fenghuang, Huanyuan and Baojing counties of Xiangxi Autonomous Prefecture during the period from August 2018 through August 2019, and were detect using PCR assay with the specific 18S ribosomal rRNA (18S rRNA) gene targeting Theileria. The gene sequences of positive specimens were aligned with the sequences recorded in GenBank, and a phylogenetic tree was created with Plasmodium ovale 18S rRNA as an outgroup. RESULTS: A total of 143 blood samples were positive for Theileria, with a mean detection rate of 77.7%. Theileria was prevalent in the blood samples from yellow cattle in all three counties, with detection rates of 85.0% in Fenghuang County, 88.3% in Huayuan County and 61.0% in Baojing County, respectively. There was no significant difference in the detection rate of Theileria between Xiangxi yellow cattle and normal yellow cattle (77.2% vs. 79.5%; χ2 = 0.08, P > 0.05), while the detection of Theileria was significantly lower in the housed yellow cattle than in free-range cattle (68.9% vs. 89.7%; χ2 = 22.36, P < 0.01). A total of 18 PCR positive samples were randomly selected for sequencing and analysis, and all samples showed more than 99.0% homology with T. luwenshuni isolates. Phylogenetic analysis showed that the 18 positive samples were clustered into the same branch with T. luwenshuni, but were far away from other isolates. CONCLUSIONS: The prevalence of Theileria is high in yellow cattle from Xiangxi Autonomous Prefecture of Hunan Province, and T. luwenshuni may be the dominant parasite species.

[Genetic analysis of mitochondrial pcox1 and ribosomal 18S rRNA genes in Eurytrema pancreaticum isolates from goats in Huaihua City, Hunan Province].

OBJECTIVE: To investigate the genetic variation of Eurytrema pancreaticum isolated from goats in Huaihua City, Hunan Province. METHODS: The partial sequence of mitochondrial cytochrome I (pcox1) and ribosomal 18S rRNA genes were amplified using a PCR assay in E. pancreaticum isolates from goats in Huaihua City, Hunan Province, and the PCR amplification products were sequenced. Then, the gene sequences were subjected to genetic variation and phylogenetic analyses. RESULTS: The sequences of the pcox1 and 18S rRNA genes were 430 bp and 1 857 bp in length in 18 E. pancreaticum isolates from goats in Huaihua City, Hunan Province, and there were 14 and 35 variation sites in pcox1 and 18S rRNA gene sequences, with intra-species genetic variations of 0 to 1.4% and 0 to 0.8%, respectively. The sequences of pcox1 and 18S rRNA genes had 99.0% to 99.8% and 99.5% to 99.8% homologies with those from E. pancreaticum Chinese strain recorded in the GenBank database. Consistent phylogenetic analysis results were found based on pcox1 and 18S rRNA genes. The 18 E. pancreaticum isolates from goats in Huaihua City were clustered into a clade with the known E. pancreaticum isolates registered in GenBank, and the clade with these 18 E. pancreaticum isolates was close to the clades with Eurytrema species and far from the clades with other trematodes. CONCLUSIONS: The E. pancreaticum isolates from goats have a low genetic variation in Huaihua City, Hunan Province. Mitochondrial pcox1 and ribosomal 18S rRNA genes may serve as molecular markers for the studies on the genetic variation in goat-derived E. pancreaticum.