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

Livestock grazing at the 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 labour 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 & 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.

Findings from this research, which were published in Vaccine in August, 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.

Elizabeth Cook, the lead author of this study and a scientist at ILRI said, ‘We are very happy with the results of the trial which show the vaccine is safe and effective for controlling WA-MCF in cattle. The current limitation to rolling out the vaccine is that it is produced on a small scale for research purposes only. We are looking for a partner to scale up production.’ She added that the market for the vaccine in Kenya and Tanzania is limited and a market scoping study in these areas is needed to understand the incentives and willingness to pay for the vaccine.

Vish Nene, leader of ILRI’s livestock vaccines and diagnostics work said ‘MCF is not an attractive target disease for the large-scale commercial sector. Therefore, we need an unconventional approach to develop a commercial vaccine.’

While some may question both the economic impact of WA-MCF and regional confinement of the disease to sub-Saharan African, it is worth noting that Dieter Schillinger, ILRI’s deputy director general for the bioscience directorate says, ‘MCF is a classical neglected livestock disease that affects the pastoralist community and it is ILRI’s mandate to work on such diseases which can positively contribute towards the livelihoods of those who are affected.’

Read the full findings of the study:

• A randomized vaccine field trial in Kenya demonstrates protection against wildebeest associated malignant catarrhal fever in cattle

Read other related publications:

• The economic impact of malignant catarrhal fever on pastoralist livelihoods
• Maasai perception of the impact and incidence of malignant catarrhal fever (MCF) in southern Kenya
• Field validation of clinical and laboratory diagnosis of wildebeest associated malignant catarrhal fever in cattle

For more information on this study contact Elizabeth Cook