Researchers at The Pirbright Institute have developed “reliable, rapid and simple to use” field tests for Indian strains of bluetongue virus (BTV).
Bluetongue is a viral disease transmitted by biting midges (Culicoides) that infects cattle, goats, sheep and wild animals such as deer, although sheep tend to be the most severely affected.
In India, BTV impacts directly on subsistence level sheep farmers in southern states and is a key limiting factor in development.
There are currently 27 different types of bluetongue virus, or serotypes. Each serotype can vary depending on the area it was isolated from.
These serotype variations – or topotypes – can be split into two groups: eastern and western. According to Pirbright, there are several serotypes circulating in India belonging to both, which makes vaccination against the virus especially difficult as a vaccine for one topotype usually does not protect against the other.
Also, tests that can accurately diagnose these different types of BTV have previously been confined to the laboratory, causing inevitable delays in diagnosing which strains are circulating and causing disease.
Joint research by Peter Mertens and his group at The Pirbright Institute and scientists from the LLR University of Veterinary and Animal Sciences (LUVAS) in India has produced two new tests able to tell the difference between both the serotypes and the topotypes circulating in India.
The technique used by the researchers – called loop-mediated isothermal amplification (LAMP) – is a portable test that can be used in the field and is “rapid and easy to use”. The study, published in Transboundary and Emerging Diseases, was funded by the Biotechnology and Biological Sciences Research Council.
According to the team, the new test is similar to one for African horse sickness recently developed by another team of scientists at Pirbright.