Detection and study of genetic diversity of selected vector-borne protozoa and rickettsia in buffaloes in Thailand by biomolecular method

Abstract

This study aimed to determine the occurrence, geographical distribution and genetic diversity of tick and mosquito-borne protozoa and rickettsia in buffaloes by the PCR – sequencing approach. A total of 456 blood samples were collected in provinces of Thailand including Mukdahan, Uthai Thani, Lampang, Amnat Charoen, Nong Bua Lamphu, Phatthalung, Surin and Chachoengsao. DNA was extracted from buffalo blood and screened for the presence of pathogens, followed by sequencing. The results indicated that the overall prevalence of rickettsia, protozoa, and malaria were 41%, 25.4%, and 12.9% respectively. Double and triple infection of buffaloes with pathogens were observed in 19.1% of the samples. A significant association between A. marginale infection and the buffalo gender was seen by Pearson’s Chi-squared test. Nucleotide identity matrixes and phylogenetic trees of A. marginale and T. orientalis indicated that those isolates had high similarity and close relationships with each other. Nucleotide diversity values suggested that low levels of polymorphism and genetic diversity of A. marginale and T. orientalis were observed between different isolates owing to the highly conserved property. However, cytochrome b in P. bubalis population showed a higher number of segregating sites and nucleotide diversity. The present study revealed the infection of A. platys in buffaloes for the first time and extended the endemic area of malaria parasites to other unexplored provinces.