Development of multispecies validated serology protocols for complex ecosystems, focused on East Africa, in support of Global PPR eradication

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Peste des petits ruminants virus (PPRV) causes severe disease in sheep and goats, hampering sustainable livestock production and significantly contributing to human poverty and food insecurity in >70 countries majority of which are ODA where it occurs. Consequently, the Food and Agriculture Organisation is coordinating an international effort to eradicate PPRV globally by 2030. PPRV infections also occur in wildlife, which has resulted in severe disease and mass mortalities in Asia and Middle East, including in rare and endangered species underlining significant impacts of this virus upon biodiversity. In Africa, research has shown that wildlife (specifically hoofed mammals like buffalo and gazelle) can become infected with PPRV but do not exhibit clinical disease. Therefore, determining infection rates where healthy animals are infected relies on detecting anti-PPRV antibodies in the animals' serum, i.e. blood testing. Better understanding of PPRV epidemiology in wildlife is critical for the success of the Global PPRV Eradication Program, for example, whether PPRV spills over into wildlife from infected livestock or whether wildlife can spread and maintain PPRV in an asymptomatic state. To answer this question in the GCRF PPR we collected sera from buffalo and Grant's gazelle using randomized sampling in order to obtain an indicationof the true PPRV seroprevalence across the Greater Serengei ecosystem, a complex PPRV-endemic ecosystem, inclusive of both National Park and mixed wildlife livestock areas like the Ngorongoro. In mixed systems the PPR has significant impacts in small ruminants and associated livelihoods and infects multiple host species. Our initial analysis of the wildlife sera from the GCRF and earlier studies under BBSRC ANIHWA indicated that current serological tests (such as ELISA) may not perform adequately with samples from atypical wild hosts compared tosheep and goats. This current project seeks to address the clear need, highlighted by our GCRF study and now by global policy-makers at FAO, to examine availableserological tests in wildlife species, to compare their performance, determine cut-offs for endemic countries. To achieve this, our project brings together expertise from Europe (Royal Veterinary College, ; University of Glasgow, Pirbright Institute, UK; IAEA FAO Joint Division Seibersdorf, Germany, , CIRAD, France) and our ODA partners in Tanzania (SACIDs SUA, Tanzania Wildlife Research Institute, Kenya Wildlife Service). Two novel diagnostic tests, which have clear practical advantages over other existing tests, and which have been developed and published by European partner labs, will be shared and evaluated against a panel of sera at an especially convened workshop of all partner laboratories at IAEA in Austria. These sera will include aliquots from ELISA and VNT tested sera to be provided by Pirbright. These tests will then be transferred to partner laboratories and the regional centre in SACIDs SUA. Training, test set-up and testing of the sera will be done at SACIDS SUA to achieve the second and key objective of establishing a regional PPR research laboratory in eastern Africa. Analysis of the GCRF sera with the new testing protocol provide accurate epidemiological information on PPRV infection rates in wildlife within the Greater Serengeti ecosystem to inform effective routes to PPRV control and eradication. We will publish new test protocols for PPRV in atypical hosts and engage with OIE and FAO to promote these as a standard in the Global PPRV eradication programme. The main outcome of this project will be improved capacity in PPR research and surveillance, in a critical region for PPR persistence, enable use of atypical hosts as sentinels of infection and, inform on the potential risk of disease in wildlife and other hosts to the Global Eradication strategy