Serotypes of foot and mouth disease virus in African buffaloes and cattle in Queen Elizabeth National Park

Abstract

A cross-section study was done in Queen Elizabeth National Park (QENP) to determine the FMDV serotypes circulating in buffaloes and cattle. Serum and oro-pharygeal fluids (probang samples) were collected from African buffaloes (n=36) and cattle (n=114) from August 2011 to June 2012. Serum was screened using Priocheck FMDV NS ELISA and oro-pharyngeal probang samples were screened using Real-Time PCR. Serotype specific antibodies were determined by solid phase blocking ELISA (SPBE) and Virus Neutralization Test (VNT). The VP1 gene of positive PCR probang samples was amplified and genetic relatedness determined by construction of a phylogenetic tree. On Priocheck NS ELISA; 20/114(18%) cattle and 26/36 (72%) buffalo sera were positive. On SPBE; antibodies against serotypes; O (5/7; 71.4%), SAT 2 (1/6; 16.7%) and SAT 3 (2/8; 25%) in cattle and serotype; O 1/22(4.5%), A 1/8 (12.5%), SAT 1 (4/20; 20%), SAT 2 (5/29; 17.2%) and SAT 3 (3/23; 13%) in buffalo were detected. By virus neutralization test only antibodies against serotype; O 3/23 (13%) in cattle were detected, while in buffaloes it was only antibodies against SAT 2 (10/29, 35.4%) and SAT 3 (2/23, 8.6%) were detected. Real-Time PCR detected positive 3/20(15%) in cattle and (16/26) 61.5% in African buffalo. The VP1 gene, responsible for coding the major antigenic determinant of FMD virus, was used to characterize the SAT 2 sequence (UGA 11/13) that was got from buffalo. The phylogenetic analysis showed that it belonged to the East African buffalo lineage and was closely related to the previously isolated SAT 2 FMD sequences Buffalo 6 QE with pair wise identity of 83%, and Buffalo 10 QE with pair wise identity of 82%. The findings confirmed that SAT serotypes are found among African buffaloes in QENP. This study also showed that the circulating FMDV serotype antibodies in buffaloes and cattle were not the same since only antibodies against serotype; O were found in cattle sera while serotype; SAT 1 and SAT 2 in buffaloes by VNT.