A report on the high prevalence of Anaplasma sp. in buffaloes from two provinces in Pakistan

Abstract

The present study was designed to use a PCR-RFLP protocol for the molecular detection of Anaplasma sp. and to compare its prevalence in blood samples from buffaloes (Bubalus bubalis) from 2 provinces of Pakistan and to determine the risk factors associated with the spread of Anaplasma infection. A total of 281 blood samples were collected from adults and calves of buffaloes from 4 sampling sites in Southern Punjab (Bahawalnagar, Burewala, Layyah, and Multan districts) and 2 in Khyber Pukhtoon Khwa (Peshawer and Kohat districts) from randomly selected herds. Data on the characteristics of the animals (gender, age, tick presence or absence, prior treatment for Anaplasma infection) and the herd (location, size, dogs associated with the herds, tick burden of dogs associated with the herds) were collected through questionnaires. One hundred and sixteen blood samples (41% of total) produced the 577-base pairs DNA fragment specific for the 16S rRNA gene of Anaplasma sp. by PCR amplification. Twenty of the 116 Anaplasma sp.-positive PCR products were confirmed to be Anaplasma marginale upon restriction with BssNa1, specific to cut A. marginale sequences. ANOVA results revealed a highly significant association between sampling sites and prevalence of Anaplasma sp. (P<0.001) indicating that Anaplasma sp. prevalence was variable among all 6 sampling sites. Risk factor analysis indicated that the association of dogs with the herd was the only significant (P=0.029) risk factor associated with the spread of Anaplasma sp. in buffaloes while sex, age, presence of ticks on animals or herd size showed no association with Anaplasma infection.

Keywords: 16S rRNA; Anaplasma marginale; Anaplasma sp.; Buffaloes; PCR-RFLP; Risk factors.