Progress in vaccines against peste des petits ruminants virus

Peste des petits ruminants (PPR) is a highly contagious and economically important viral disease of both domestic (goats and sheep) and wild small ruminants. Due to the devastating effect of this disease on livestock and livelihoods, the Food and Agriculture Organization of the United Nations (FAO) and the World Organization for Animal Health (WOAH) endorsed the Global Strategy for the Control and Eradication of PPR (PPR GCES) and launched the PPR Global Eradication Programme (PPR GEP) to eradicate PPRV by 2030. In order to achieve this goal, a potent, safe and efficacious live-attenuated PPR vaccine with long-lasting immunity is available for immunoprophylaxis. However, the live-attenuated PPR vaccines are thermolabile and require maintenance of an effective cold chain to deliver to the field. In addition, infected animals cannot be differentiated from vaccinated ones (DIVA). To overcome these limitations, some new generation PPR vaccines have been developed: poxvirus vaccine, positive and negative marker vaccine through reverse genetic approach, chimeric vaccine, anti-idiotypic vaccine, subunit vaccine, virus-like particles vaccine, edible vaccine and combined vaccines. Novel recombinant PPR DIVA vaccines were evaluated in goats for safety and efficacy, and all vaccinated animals were clinically protected against an intranasal PPRV challenge. Furthermore, newly developed ELISAs were capable of differentiating between infected and vaccinated animals. Therefore, these DIVA vaccines and the associated tests can facilitate the serological monitoring process and speed up global PPR eradication through vaccination.