peste des petits ruminants

peste des petits ruminants is a highly contagious viral disease affecting primarily goats and sheep. It is caused by the Peste-des-petits-ruminants virus, a member of the genus Morbillivirus within the family Paramyxoviridae. The disease poses a significant threat to food security and the livelihoods of smallholder farmers across many developing regions, leading to substantial economic losses. International efforts coordinated by the World Organisation for Animal Health and the Food and Agriculture Organization aim for its global eradication by 2030.

Overview

First described in 1942 in Côte d'Ivoire, peste des petits ruminants has since spread across vast regions. The disease is clinically similar to rinderpest in cattle, which was successfully eradicated in 2011. Its severe impact on small ruminants, which are often the primary livestock asset for rural communities, has elevated it to a priority for international animal health agencies. The Global Strategy for the Control and Eradication of PPR provides a framework for coordinated action, involving numerous national veterinary services and research institutions like the Pirbright Institute.

Etiology and transmission

The causative agent, the Peste-des-petits-ruminants virus, is an enveloped, single-stranded RNA virus closely related to the viruses causing rinderpest, canine distemper, and measles. Transmission occurs primarily through direct contact with infected animals, their bodily secretions, and contaminated fomites. The virus can be spread via aerosols, contaminated feed, water, and equipment, and through the movement of live animals. Wildlife species, such as certain antelope and wild sheep in regions like the Serengeti, can also act as reservoirs, complicating control efforts.

Clinical signs and diagnosis

The incubation period typically ranges from four to six days, after which animals develop a high fever, depression, and serous nasal discharge. This progresses to erosive lesions in the mouth, conjunctivitis, severe diarrhea, and bronchopneumonia. The course of the disease is often acute, with mortality rates reaching 90% in naive herds. Diagnosis is based on clinical signs in an endemic area but must be confirmed in the laboratory. Key diagnostic tests include antigen-capture ELISA, RT-PCR for viral RNA detection, and virus isolation. Differential diagnosis must rule out other diseases like foot-and-mouth disease and contagious caprine pleuropneumonia.

Prevention and control

The cornerstone of prevention is vaccination using live-attenuated vaccines, such as the Nigeria 75/1 vaccine strain, which provides long-lasting immunity. Control strategies emphasize strict biosecurity, movement restrictions, quarantine of new animals, and prompt culling of infected herds. International support for vaccination campaigns is often channeled through the Food and Agriculture Organization and regional bodies like the African Union. Successful control requires strong national veterinary services, effective surveillance networks, and community engagement, as demonstrated in parts of Morocco and Türkiye.

Epidemiology and impact

Peste des petits ruminants is endemic throughout much of Africa, the Middle East, and Asia, including countries from Senegal to Mongolia. Its spread has been facilitated by transboundary animal movement, trade, and pastoralist migrations. The economic impact is profound, with estimated global losses exceeding US$2 billion annually due to mortality, reduced productivity, and trade restrictions. The disease severely undermines the Sustainable Development Goals related to poverty and hunger. Ongoing research at institutions like the International Livestock Research Institute focuses on understanding virus evolution and improving vaccine thermostability for use in remote areas.

Category:Animal diseases Category:Viral diseases Category:Sheep and goat diseases