A neglected, but devastating, livestock disease that poses a threat to ruminants in Europe could be fought with better-coordinated vaccine strategies, Pirbright scientists have said.
Peste des petits ruminants (PPR), also known as goat plague, is a highly contagious disease caused by PPR virus (PPRV) that infects sheep and goats, and can have a mortality rate of up to 90%. Cattle and pigs can be affected, too, but tend not to develop clinical signs.
Such is its pervasiveness, the Food and Agriculture Organization of the United Nations and the World Organisation for Animal Health have targeted it for eradication by 2030.
Related disease rinderpest was eradicated in 2011, a process scientists from The Pirbright Institute played a major part in.
Pirbright’s head of vaccine differentiation Satya Parida said: “As long as rinderpest was there, PPR did not spread much because it gave cross-protection to ovine species, such as sheep and goats. But when rinderpest was eradicated, PPR spread rapidly.“
Another contributory factor to the spread is said to be a lack of coordinated vaccine strategies, meaning PPR poses a “real risk” to Europe via contaminated vehicles returning after transporting animals in north Africa.
To help improve understanding about the virus‘ progression, Pirbright researchers analysed the spread of PPRV from eastern Africa to the Maghreb region of northern Africa.
Analysis revealed one particular lineage of the virus spread along known animal movement routes from eastern Africa and in to northern Africa. The presence of the same virus in subsequent outbreaks in Algeria, Morocco and Tunisia suggests a continual regional circulation, despite mass vaccination efforts in Morocco following the 2008 outbreak, scientists said.
Prof Parida has travelled to a number of countries, including Spain and Greece, following outbreaks of PPRV in Thrace, in western Turkey, to deliver workshops to raise awareness and enhance understanding.
“Existing vaccines provide lifelong immunity; however, they do not enable Differentiate Infection from Vaccinated Animals [DIVA], which is essential for seromonitoring – particularly in the last phase of the ongoing eradication programme,” said Prof Parida
“To address this issue, we are developing a live attenuated DIVA vaccine at Pirbright using a technique called reverse genetics, where we can recover vaccine virus from a full-length copy of the virus DNA.”
- Read the full story in the 29 May issue of Veterinary Times.