A chance discovery in Kenya could help millions of farmers who have lost their livestock to east coast fever.
Researchers from the International Livestock Research Institute (ILRI) in Kenya and the Roslin Institute at the University of Edinburgh in Scotland have identified a genetic marker that predicts whether an individual cow is likely to survive infection with East Coast Fever.
In their findings, published in PLOS Genetics last week , the team says the allele they identified (the variant of a particular gene) is not necessarily the specific gene that limits the growth of animal cells when infected with the parasite, thus protecting them from the disease.< /p>
“It doesn’t really matter for breeding,” says David Wragg of Roslin.
“You just have to say, ‘This animal does breed well from ‘because his offspring have the strength disease are likely to survive.”
“Tests have shown that the marker does this very well, with only one out of 20 animals with two copies of the allele succumbing to the disease.”
The scientists said that further research to determine the exact gene(s) responsible and their mechanism of action will allow the scientists to edit the DNA of cattle to make them disease tolerant.
This new information presents an opportunity to develop breeding programs that could develop strains of cattle with resistance to the disease.
Although a vaccine for East Coast Fever exists and usually confers lifelong immunity on cattle, making it a “complex affair” that involves making a kind of “tick smoothie” by crushing hundreds of thousands of infected ticks in an industrial blender, which is time-consuming and expensive up to 20 times more than other common uses commercial livestock vaccines and can cause disease if mishandled.
“There are many manufacturing and distribution issues associated with this vaccine. It is a difficult vaccine to manufacture, difficult and expensive to store and supply. And it has to be administered by an experienced person,” said Vish Nene, co-leader of the ILRI Animal and Human Health Program.
The other option is to regularly dip animals in acaricides—pesticides, killing the ticks—but it’s also labor-intensive and environmentally damaging.
“We’re struggling to control this disease,” says Phil Toye, ILRI’s chief animal health scientist.
“If the cattle are vulnerable, without treatment you can lose 100 percent of your herd in two or three weeks.”