Targeted FMD Vaccines for Eastern Africa: The AgResults Foot and Mouth Disease Vaccine Challenge Project

Abstract

As one of the most infectious livestock diseases in the world, foot and mouth disease (FMD) presents a constant global threat to animal trade and national economies. FMD remains a severe constraint on development and poverty reduction throughout the developing world due to many reasons, including the cost of control measures, closure of access to valuable global FMD-free markets for livestock products, production losses through reduced milk yield, reduced live weight gain, and the inability of infected livestock to perform traction. FMD virus infects a variety of cloven-hoofed animals, including cattle, sheep, goats, swine, all wild ruminants, and suidae, with high morbidity in adult animals. High mortality can occur in young animals due to myocarditis. FMD is endemic in Africa, most of Asia, the Middle East, and parts of South America. The global clustering of FMD viruses has been divided into seven virus pools, where multiple serotypes occur but within which are topotypes that remain mostly confined to that pool. Three pools cover Europe, the Middle East, and Asia; three pools cover Africa; and one pool covers the Americas. The highly infectious nature of FMDV, the existence of numerous continually circulating serotypes and associated topotypes, the potential for wildlife reservoirs, and the frequent emergence of new strains that are poorly matched to existing vaccines all serve to compound the difficulties faced by the governments of endemic countries to effectively control and reduce the burden of the disease at the national and regional levels. This clustering of viruses suggests that if vaccination is to be a major tool for control, each pool could benefit from the use of tailored or more specific vaccines relevant to the topotypes present in that pool, rather than a continued reliance on the currently more widely available vaccines. It should also be noted that, currently, there are varying degrees of effort to identify improved vaccines in different regions. There are relatively few targeted for use in Africa, while the developed world’s vaccine banks have a good stock of vaccines destined for emergency outbreak use in FMDV-free countries. The AgResults Foot and Mouth Disease (FMD) Vaccine Challenge Project (the “Project”) is an eight-year, US $17.68 million prize competition that supports the development and uptake of high-quality quadrivalent FMD vaccines tailored to meet the needs of Eastern Africa (EA). The Project targets the following Pool Four countries: Burundi, Ethiopia, Kenya, Rwanda, Tanzania and Uganda. The Project is being run in two phases: a development phase, which will encourage the production of regionally relevant vaccines, and a cost-share phase, designed to help to reduce the price of these vaccines in the marketplace to the end users, which is hoped will encourage broader uptake. Manufacturers can submit quadrivalent FMD vaccines containing serotypes A, O, SAT1, and SAT2, which will be assessed as relevant for use in the region through a unique component of the Project requiring the screening of vaccines against the Eastern Africa Foot and Mouth Disease Virus Reference Antigen Panel assembled by the World Reference Laboratory for FMD (WRLFMD), at the Pirbright Institute, UK, in collaboration with the OIE/FAO FMD Reference Laboratory Network. To be eligible for the Project, sera from vaccinated cattle will be used to evaluate serological responses of FMD vaccines for their suitability for use in Eastern African countries. If they pass a determined cut-off threshold, they will be confirmed as relevant for use in the region and will be entered into the Project’s cost-share phase.

Correlation between 146S Antigen Content in Foot-and-Mouth Disease Inactivated Vaccines and Immunogenicity Level and Vaccine Potency Alternative Test Methods

“…FMD has drawn global attention due to its high infectivity rate, high mortality rate among young livestock, and wide host range [33,34]. In response, China has classified it as a Category I animal disease and mandated immunization.…”

Outbreaks of Foot-and-Mouth Disease in Burundi, East Africa, in 2016, Caused by Different Serotypes

“…In order to be successful, such a regional approach should be tailored to the prevailing animal husbandry and trade practices and associated transboundary animal movements [ 59 ], as movement of infected animals is the most important factor in the spread of FMD in endemically infected regions [ 57 , 58 , 60 ]. The vaccination strategy should take the multiple serotypes, topotypes, and genetic variants circulating in this part of East Africa into account [ 61 ].…”

The Immunogenicity of a Foot-and-Mouth Disease Virus Serotype O Vaccine in Commercial and Subsistence Cattle Herds in Zambia

“…The post-vaccination VNT titres to heterologous viruses associated with post-vaccination cross-protection have been evaluated. Using VNT, an indicator of likely heterologous cross-protection is considered to be a log 10 reciprocal titre of 1.5 (1:32) after a single-dose vaccination with serum collected 21 days later [ 21 , 22 ].…”