Scientists test an experimental vaccine against malignant catarrhal fever at ILRI’s Kapiti Research Station

 

Livestock grazing at Kapiti Research Station (Photo credit: ILRI/Paul Karaimu)

The annual migration of wildebeest between the Serengeti and Maasai Mara parks in Tanzania and Kenya is one of the seven new wonders of the world. Thousands of tourists from all over the world gather to see this spectacle. However, for one group, the Maasai pastoralists, this is an unfavourable time. Many of these livestock keepers are forced to move their cattle away from the seasonal migration of wildebeests to prevent their animals getting malignant catarrhal fever (MCF). MCF is a fatal disease of cattle and sheep which occurs following infection with a herpesvirus.  Alcelaphine herpesvirus 1 (AlHV-1) found in the wildebeests is transmitted to cattle during the wildebeest calving season. Sheep-associated MCF is common outside of Africa.

There is currently no vaccine or treatment available for MCF. This causes a dilemma for the Maasai pastoralists. If they move their cattle to avoid the wildebeests, they incur costs from lost opportunities to consume and sell milk and meat, and the labor input needed to move the cattle. If they stay in the wildebeest grazing zones, they are at risk of losing approximately 10% of animals from their herds, which represents a significant loss to their livelihoods.

In 2014, a severe outbreak of wildebeest-associated MCF (WA-MCF) at the International Livestock Research Institute (ILRI) Kapiti Research Station combined with requests from cattle keepers around the Athi-Kaputiei Plains and the Maasai Mara highlighted the economic impacts of the disease and the need for an effective control measure.

Scientists from ILRI, UK, US, Australia and Tanzania have been working together since 2016 to test an experimental vaccine for the disease. The project was carried out under the CGIAR Research Program on Livestock and has also been supported jointly by ILRI, the Scottish Government Rural and Environment Science and Analytical Services Divisions (RESAS) and the Global Alliance for Livestock Veterinary Medicines (GALVmed) with funding from the Bill and Melinda Gates Foundation (BMGF) and UK Aid

Researchers from these institutions tested an attenuated vaccine strain of MCF (AlHV-1 C500) at the Kapiti Research Station located in Machakos County, Kenya. The 13,000-hectare research station has approximately 2,500 cattle, 1,200 sheep and 250 goats coexisting with wildlife including wildebeests, giraffe and zebra as well as lions, hyenas and cheetahs. The unique mix of livestock and wildlife at the research facility enables scientists to test the dynamics of disease transmission at the wildlife-livestock interface, which is a critical step towards understanding the ecology of livestock diseases.

The findings published in the Journal of Vaccine provide proof-of-principle that WA-MCF can be controlled through vaccination with the attenuated virus. The vaccine was shown to offer a safe and effective method of protecting cattle against WA-MCF with a vaccine efficacy of 80%. The attenuated vaccine strain of AlHV-1 C500 which was isolated from a Kenyan MCF case, was produced at the Moredun Research Institute (UK), The experimental vaccine was tested in a blinded randomized placebo-controlled trial with 73 cattle in each group. Vaccinated and control animals were grazed as one herd together with wildebeest. . . .