Molecular identification and characterization of Trypanosoma infection in cattle in Chittagong Metropolitan area, Bangladesh

Abstract

Trypanosomiasis is an important infectious disease of animals, including cattle. The present study attempted to ascertain the prevalence of trypanosomiasis and relevant risk factors associated with the disease. All the samples for this study were collected from different dairy farms inside Chittagong Metropolitan Area (CMA) under Chittagong district of Bangladesh. The preliminary screening was aided by conventional thin smear technique (Giemsa stain) while modern molecular tools like PCR were used for accurate and reliable identification and characterization. Only three samples (out of 480 samples tested) were found positive through thick blood smear and PCR assay. All these three samples were from Holstein Friesian crossbred cows, and none of the local indigenous breeds were found positive. Data analyses revealed the highest prevalence of trypanosomiasis in the rainy season when compared to summer and winter seasons. Animals older than six years old were found to be infected by trypanosomiasis. PCR assay was applied to all three screened positive samples targeting 18S rRNA gene fragments, which were successfully amplified. Further sequencing of PCR products and phylogenetic analyses revealed that the isolates recovered during this study were closely related to the isolates previously reported from Egypt, Taiwan, Thailand, and Japan.