An epidemiological survey of equine piroplasmosis in donkeys and horses in Malawi

Equine piroplasmosis (EP) is a tick-borne disease caused by Theileria equi, Theileria haneyi, and Babesia caballi in equids, such as horses, donkeys, mules, and zebras. A comprehensive understanding of the epidemiology of T. equi and B. caballi is vital for EP management. The present study surveyed T. equi and B. caballi infections in donkeys and horses in Malawi. Blood samples were collected from 185 equines, including 178 donkeys in Lilongwe (n = 136) and Dedza (n = 42) districts, and seven horses in Lilongwe district. The blood samples were used to measure hematocrit values and prepare thin smears and blood spots on FTA cards. Microscopic examination of the blood smears detected T. equi in 91 equines (49.2 %), including 88 donkeys (49.4 %) and three horses (42.9 %), while B. caballi was not detected. Screening of DNA samples extracted from FTA cards with species-specific PCR assays detected T. equi in 156 (84.3 %) equines, including 152 (85.4 %) donkeys and four (57.1 %) horses, whereas all animals were negative for B. caballi. We found that the mean hematocrit value of infected donkeys (28.1 %) was significantly lower (P value = 0.0004) than that of uninfected donkeys (31.9 %). Additional analysis of T. equi-positive DNAs with the genotype-specific PCR assays detected all five genotypes (A, B, C, D, and E) in donkeys and four genotypes (A, B, C, and D) in horses. In summary, the present study, the first to report the T. equi infection in Malawi, suggests the need for EP control due to its potential clinical significance.