Pest of small ruminants: Need to broaden the focus
Peste des Petits Ruminants (PPR), also known as the pest of small ruminants, is a highly contagious, non-zoonotic viral disease of sheep and goats. The disease is recognized in the field by a sudden onset of diarrhoea and fever, discharges from the eyes, nose, and mouth, sores with or without scabs or nodules around the mouth, pneumonia, and significant animal deaths.
At one time, PPR was thought to be restricted to West Africa, but it has since been recognized from the equator line up to the Sahara desert, as well as in Asia and the Middle East. In East Africa, PPR is a real threat to pastoralists because small ruminants are of economic importance. Other areas, like Southern Africa and Central Asia, are under increasing threat of disease spread.
After rinderpest eradication, many veterinarians believe that PPR is a good candidate for global disease eradication, but probably not the next target. The Chief Veterinary Officer of FAO, Dr. Juan Lubroth, cautions against focusing on one pathogen at a time. In fact, he believes that a focus on multiple diseases at once helps break the single-focus pattern set by rinderpest.
Since PPR is not a disease that infects humans, it is believed that the disease may be perceived by governments as less relevant and therefore not imperative to control. To make disease control attractive and cost-effective, PPR control activities could be integrated with other diseases, such as goat pox, sheep pox, brucellosis (Brucella melitensis), and foot-and-mouth disease (FMD).
A collective protection against these diseases could be achieved through a coordinated effort to develop a polyvalent vaccine, that is, a vaccine prepared from cultures or antigens of more than one strain or specie. This approach to control and manage diseases that affect small ruminants could be later used as a working model for the control of other diseases in other animal species.
One of the main challenges with control of PPR in the field is that it overlaps with areas that are also infected or prone to outbreaks of Brucellosis, Contagious Caprine Pleuropneumonia (CCPP), and Rift Valley fever. In view of this situation, any disease control effort will need to be preceded by better information on what diseases are out there as well as how prevalent they are according to season.
Nicoline DeHaan, socioeconomic coordinator at the Animal Production and Health Division (AGA), notes that women are often in charge of small ruminant husbandry and that this fact should be kept in mind when designing and implementing animal health interventions. She adds that to ensure livelihoods, more should be done to protect the livestock keepers' assets.
The progressive control of PPR in Africa, Asia, and Middle East is critical given that goats and sheep are sources of food to many communities and also as the means of economic support or subsistence for numerous rural households. This is one of the main reasons why PPR falls within the remit of One Health, an integrated health approach led by FAO.
FAO is a partner of World Veterinary Year (Vet2011) and has recently adopted a resolution declaring Global Freedom from Rinderpest.