Molecular detection of piroplasms in domestic donkeys in Xinjiang, China.

Abstract

BACKGROUND: Piroplasmosis is a common and prevalent tick-borne disease that affects equids. OBJECTIVES: To determine the infection and molecular characteristics of the piroplasms in donkeys from Xinjiang, northwestern China, we undertook a cross sectional study by collecting representative samples across several counties within the region. METHODS: A total of 344 blood samples were collected from adult domestic donkeys from 13 counties in Xinjiang. PCR was conducted to test for T. equi and B. caballi in the blood samples based on the equine merozoite antigen-1 (Ema-1) gene and the 48 kDa rhoptry protein (BC48) gene, respectively. RESULTS: Sixteen blood samples tested positive for piroplasms and the overall infection rate was 4.7% (16/344). Seven of the 13 counties were positive for piroplasms. Among the 16 piroplasm-positive samples, 15 were singly infected with T. equi with an infection rate of 4.4% (15/344), and coinfection with T. equi and B. caballi was detected in one sample (0.3%, 1/344) from Wushi. Four T. equi sequence genotypes were identified and grouped into different branches of the evolutionary trees. CONCLUSION: These findings suggest that the infection rate of piroplasms is low in domestic donkeys in southern Xinjiang and that T. equi genotypes have a regional distribution.