Epidemiological survey of Anaplasma marginale in cattle and buffalo in Sri Lanka

Abstract

Bovine anaplasmosis caused by Anaplasma marginale represents a serious threat to cattle farming worldwide, especially in the tropics and subtropics. In the present study, archived DNA samples from the blood of cattle (n=437) in the Nuwara Eliya, Galle, Ampara, Polonnaruwa, and Jaffna districts and buffalo (n=327) in the Galle, Polonnaruwa, Mannar, and Mullaitivu districts in Sri Lanka, were screened for A. marginale using a major surface protein 5 (msp5) gene-based PCR assay. The findings showed that 32.7 and 57.5% of cattle and buffalo, respectively, were A. marginale-positive. The rate of positivity differed significantly among geographical regions. In conclusion, the high rates of A. marginale infection in cattle and buffalo highlight the importance of effective control measures in Sri Lanka.

Keywords: Anaplasma marginale; PCR; Sri Lanka; buffalo; cattle.

Fig. 1.

Geographical distribution of Anaplasmamarginale in Sri Lanka. Anaplasma marginale-positive rates in cattle and buffalo in the surveyed districts, which are located in different provinces, are shown. Note that the A. marginale-positivity is higher in North-Central and Northern provinces, with the exception of Jaffna district in Northern province, compared with Central, Eastern and Southern provinces.

Fig. 2.

Phylogenetic analysis of the Anaplasmamarginale msp5 gene. The newly determined A. marginale msp5 sequences (highlighted in boldface type) from cattle and buffalo in Sri Lanka, together with those from other countries, were used to construct a maximum likelihood phylogeny. Note that the Sri Lankan msp5 gene sequences from cattle and buffalo are located in clade 1.