August 12, 2024

 

US researchers develop genetic tools to combat ASF threat

A team of researchers from the Department of Entomology at Texas A&M College of Agriculture and Life Sciences, US is leading efforts to develop a next-generation surveillance method to protect the US pork industry from the African swine fever (ASF) virus, National Hog Farmer reported.

 

This innovative project is supported by a four-year, US$800,000 grant from the USDA National Institute of Food and Agriculture.

 

The team, led by Gabriel Hamer, PhD, professor in the Department of Entomology, includes Pete Teel, PhD, AgriLife Research entomologist and Regents Professor, and Job Lopez, PhD, associate professor from the Baylor College of Medicine. The research team also collaborates with scientists from the National Agricultural Research Organisation and Makerere University in Uganda.

 

Hamer stated that the project's primary goal is to develop tools that can quantify contact between domestic swine and soft-bodied ticks, which are known vectors of ASF. The ultimate mission is to prevent the establishment of ASF in the US.

 

"The US is the third-largest consumer of pork products and represents 20% of global production, so this effort has enormous ramifications across the industry, individual producers, and people shopping at grocery stores," Hamer said.

 

The spread of ASF in Africa, Europe, Asia, and the Caribbean underscores the virus's potential threat. The virus causes severe illness and mortality in domestic swine, posing a significant risk to the US swine industry.

 

In 2018, an ASF outbreak in China led to the loss of millions of swine due to mortality and culling, with direct financial losses estimated at US$10 billion. The reduced production capacity resulted in higher pork prices in the US as exports increased to meet Chinese demand.

 

The reemergence of ASF in the Caribbean in 2021, after a 40-year absence, has put the US pork industry on high alert, emphasising the need for preparedness in disease prevention.

 

While ASF could enter the US through various pathways, researchers are primarily concerned about feral swine and soft-bodied ticks potentially serving as reservoirs for the disease.

 

John Tomecek, PhD, Texas A&M AgriLife Extension Service wildlife specialist and associate professor in the Department of Rangeland, Wildlife, and Fisheries Management, estimates that Texas alone has up to 4 million feral hogs. At least 35 US states now report feral hog populations.

 

To identify tick/swine contact rates in wild and domestic swine populations, the team will employ two scientific approaches. They will use bloodmeal analysis, a tool that involves collecting ticks in the wild and analysing DNA from their abdomens to identify previous vertebrate hosts.

 

Researchers also plan to further develop a blood test to detect antibodies in swine blood samples that respond to tick salivary proteins injected during feeding. An improved assay will distinguish swine exposure to soft ticks and other tick types, aiding in risk assessments of tick-borne ASF transmission.

 

In Uganda, where ASF is established, scientists will conduct experiments with swine to evaluate the surveillance tools' performance. Ongoing research in Uganda tracks ASF transmission and its impact on swine production. Evidence of past tick feeding, and further screening of swine will inform researchers about tick feeding frequency and potential virus spread.

 

Hamer noted that many emerging viral pathogens fail to establish themselves because the "stars do not align," leading to their extinction before becoming a problem. The new tools will help researchers assess conditions that might allow ASF to establish itself.

 

"Developing assays that measure contact between ticks and swine that serve as hosts for ASF will help us understand the risk of different introduction and establishment pathways for African swine fever virus in the US," Hamer said. "This is proactive, forward-thinking research, and the ultimate goal is to protect the US pork industry against an outbreak's potential impact on farmers and consumers."

 

-      National Hog Farmer