Detection of Brucella melitensis Rev–1 vaccinal antibodies in sheep in India

Abstract

In sheep, brucellosis is mainly caused by Brucella melitensis which is an important reproductive disease and is characterized by abortion in the fourth or fifth month of gestation, stillbirths and reproductive failure. The Rev.1 live B. melitensis vaccine is the most widely used vaccine in control programs against brucellosis in small ruminants in different parts of the world. This vaccine however shows a considerable degree of virulence and induces abortions. In India, B. melitensis Rev.1 vaccine for small ruminants is officially not recommended by the Government of India. Present study reports B. melitensis Rev.1 vaccinal antibodies detection in breeding sheep flock due to use of Brucella melitensis Rev1 vaccine. We investigated an organized sheep flock located in the southern part of India, consisting around 1200 sheep of breeds like Rambouillet and Bannur local breed ewes (600), Rambouillet lamb (300), crossbreds of Rambouillet and Dorper (200) and Rams (100) by random sampling of forty six sheep (vaccinated –20 and unvaccinated– 26) in order to detect antibodies against B.melitensis Rev–1 vaccinal strain. Among 20 vaccinated sheep serum samples tested, 19 (95%) and 13 (65%) and 19 (95%) were positive for anti Brucella antibodies by RBPT, SAT and iELISA respectively which is a major drawback of Rev–1 vaccine. This study further emphasized the need to initiate the control strategy in terms of suitable vaccines against B. melitensis in India in order to prevent import of Rev–1 vaccine by the farmers