Researchers say CRISPR could help control ASF outbreaks

Researchers at the International Livestock Research Institute (ILRI) say that new vaccine trials against the East African strain of African swine fever (ASF) are yielding promising results.

22 March 2021, at 8:59am

Scientists at the ILRI are using CRISPR Cas9 gene editing and synthetic biology to modify the African swine fever genome to produce attenuated virus for vaccines that could reduce deaths from the pig disease. The method has yielded 10 potential vaccine candidates.

“This is the first test based on a genome to be conducted on genotype IX, which is prevalent in Eastern and Central Africa,” Lucilla Steinaa, leading scientist in the vaccine research on ASF at ILRI. The genetic characterization of all the ASF virus isolates known so far has demonstrated 23 geographically related genotypes with numerous subgroups, according to the Food and Agriculture Organization (FAO).

“There are seven to 10 candidates, on a variety of stages,” Steinaa said. “We have just started the lab experiment, a controlled animal experiment, which I estimate may run until the end of 2022 or thereabouts. By then, we hope to have found a candidate vaccine that can be produced.”

Outbreaks of African swine fever have been detected in 26 African nations, as well as parts of Asia and Europe. An effective vaccine would be a major breakthrough for pig farmers and ensure that global pork supplies remained stable.

“The only reason it’s not yet a catastrophe here is that the pig production is not one of the biggest commodities in Africa,” Steinaa said. “But it’s coming on — fast. Africa is doing a lot more pig rearing year by year. It would be a disaster if they had a big production like, say, Europe.”

Steinaa explained that the vaccines would be helpful for smallholder farmers. Outbreaks of ASF can come with a 100% fatality rate and are highly contagious. For many smallholders, a case of African swine fever can permanently discourage them from pig farming.

“A vaccine would obviously prevent that,” she says. “If it can be availed at a price that is affordable, then this would be the easiest way to maintain production.”

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