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Five ways we’re battling the threat of Rift Valley Fever

Rift Valley Fever (RVF) hit the headlines recently following an outbreak in Kenya earlier this year, which killed five people. It is the most significant outbreak of the disease for more than a decade.

The zoonotic disease, which is carried by mosquitoes, affects livestock in endemic areas, such as Africa where it was first discovered. It can be passed to humans through the blood, body fluids or tissues of an infected animal.

Cases of the disease have been reported in Africa, Saudi Arabia and Yemen, but RVF has been classified by the United Nations (UN) as among the most likely viruses to trigger a global pandemic. And warning signals have been sounded by academics across the developed world. 

But industry has recognised the threat RVF poses. We look at five ways the global community is innovating to battle against the disease. 

1. New vaccine development

Animal vaccines exist for RVF, but, there is none for people. However, a new vaccine is on the horizon, which may be able to be used in both livestock and humans.

A group of scientists at the Jenner Institute in the UK have developed a potential vaccine that could work in both people and animals, using the same technology that is being harnessed to develop several other human vaccines against diseases such as malaria, HIV and more recently Ebola. 

Such is the value of the team’s work, they have already recently received two awards from the UK Vaccine R&D Network to support the One Health programme, in which the same GMP manufactured batch of ChAdOx1-GnGc vaccine will be tested in parallel in humans and livestock in East Africa.

If successful, this vaccine development will potentially represent a genuine world first. 

2. Understanding mosquito behaviour

Mosquito behaviour could hold the key to better controlling the disease in endemic regions. 

A new study, published this year, shows how environmental changes can actually remove mosquito populations for specific areas permanently. 

Researchers at the University of Cambridge, University of Surrey and the International Livestock Research Institute (ILRI), examined the effect of air temperature and the seasonality pools of water, on mosquitos. 

Results were able to calculate how low water levels and temperatures in the area must be for the mosquito populations to die out, which will stop the spread of RVF.

Crucially, this knowledge can help inform policy makers about the risk of disease when making environmental changes. For example, if building a dam could increase water levels in an area to level where RVF could thrive. 

3. Forecasting and climate

In 2015, the Kenya Meteorological Department, predicting a high possibility of El-Niño rainfall and Rift Valley Fever (RVF) epidemic in Eastern Africa, launched a surveillance programme to better understand the association between rainfall and RVF . 

They collected data on RVF-associated syndromes in cattle, sheep, goats, and camels from 1100 farmers over a two year period.

Through a better understanding of the local ecological responses to rainfall, and the associated spread of RVF, researchers and scientists have been able to develop forecasting models and early warning systems for RVF by using satellite images and weather or climate forecasting data .

It is hoped that such early warning systems, could be used to trigger detection of animal cases at an early stage of an outbreak, enabling authorities to implement measures to avert impending epidemics.

4. Experimental larvicide techniques 

One of the most effective methods of mosquito control already being employed around the globe is a technique called ‘larviciding’ . When the risk of mosquitos rises, such as after heavy rains, a larvicide can be added to the water. This then kills mosquito larvae that attempt to grow there.

It is currently being used experimentally to help control the spread of RVF where a sudden increase in a body of water, such as flooding, may take place. 

The technology is also being considered for trial in California where larvicides could be applied by drone to control other serious mosquito-borne diseases .

5. A One Health approach 

Many organizations believe that infectious and zoonotic diseases can only be tackled using a One Health approach. A project in South Africa aims to do just that, bringing together government, universities, and livestock game ranchers to unlock key pieces of information about the disease. 

EcoHealth Alliance, a US NGO, is leading the project with a number of partners. 

The work has brought together three expert groups: scientists pioneering climate-based prediction tools; researchers at the forefront of developing diagnostic tests for RFV; and experts who have worked through outbreaks on the ground, to discover ways to directly manage mosquitos.

As global temperatures rise, as a result of climate change, mosquitos and the diseases they harbour are spreading. But it’s hoped these many measures will help protect us now and for the future.