Virologist and partners awarded two patents for genetically engineered viruses to protect against African swine fever

Guillmero Risatti
Guillmero Risatti

African swine fever (ASF) virus is a deadly hemorrhagic disease affecting domestic and wild pigs. While historically found in Africa, ASF is currently considered an epidemic in Europe and Asia. In 2007 it was detected in the Republic of Georgia, and from there it spread through the Caucasus to Russia, Ukraine and Belarus. By 2014, it appeared in the European Union, and it was recently found in a wild boar in Belgium. In September 2018, China reported outbreaks of ASF across several pig-producing regions in the country.

“This disease expansion is of great concern to pork producers,” says Guillermo Risatti, associate professor in the Department of Pathobiology and Veterinary Science. “There is a high concern here because we don’t know if it will be an issue down the road for the United States. We hope not, but we have a lot of commercial partners, and products are moved from different countries into the United States, so certainly it could be a potential risk.”

While ASF does not pose a risk to human health, it has a huge impact on pork production. The ASF virus is not related to classical swine fever (CSF) virus, which was eradicated from the United States in 1978. A vaccine for CSF is available, and two years ago a differentiated vaccine was developed by Zoetis, a global animal health company. Both CSF and ASF are considered foreign animal diseases, and Risatti’s research on these viruses is restricted to laboratories at Plum Island Animal Disease Center of New York. In addition, he has recently conducted ASF field studies overseas.

Risatti studies both CSF and ASF, but with the global increase in ASF, he is currently focused on this deadly infection. As a virologist, Risatti does not develop vaccines, but conducts genetic research to identify potential viruses that might serve as vaccine candidates. Currently there is no vaccine available for ASF.

For every successful vaccine, researchers spend years in the laboratory working to understand the biology of the virus and the mechanisms for infection and to identify the genes that cause the infection. Once isolated, these genes are eliminated, then the virus is tested to see if it is still lethal to the animal. If it is not, the modified virus may offer some protection against the wild virus. At that point, the private sector laboratories work with these vaccine viruses attempting to create an effective vaccine.

For more than a decade, Risatti and a team of collaborators have been studying the ASF virus. The group has created several viruses that look promising for protection against ASF.

“This is a very complicated virus, with a complex genome,” he says. “There are many groups around the world trying to develop something against this devastating swine disease. We are collaborating with the USDA Plum Island and a group at the Center for Research into Animal Health in Barcelona, Spain, to create viruses that have the potential to be developed into a vaccine to control this disease.”

In a significant step toward the control of ASF, Risatti has partnered with the USDA Plum Island team on two patents for genetically engineered attenuated African swine fever viruses that can protect pigs against the disease. The Notice of Intent To Grant Exclusive License was published in the Federal Register on October 15. The two patents will be co-owned by UConn and USDA. Zoetis has applied for an exclusive license of these two patents.

Pending the development of a vaccine, pork producers work to control ASF through strict biosecurity and environmental protocols. The disease is spread when people move animals, which is why the disease is more prevalent in backyard farms where pigs are allowed to roam about the countryside.

In addition to his conducting his research, Risatti is section head of diagnostic testing services at the Connecticut Veterinary Medical Diagnostic Laboratory (CVMDL). In testing for a wide range of animal diseases, staff use techniques in microbiology, serology, virology, molecular diagnostics and parasitology. In addition its essential role in monitoring the health of Connecticut’s animal populations, the diagnostic testing services lab provides research opportunities for undergraduate students. Current group projects include work on Lyme disease in horses and developing tests for emerging tick diseases.

“We currently test ticks for four different diseases,” Risatti explains. “We are also collaborating with UConn’s Department of Molecular and Cell Biology to study the microbiome of ticks, examining different bacteria to see if these relate to diseases caused by ticks.”

The lab is working with the Connecticut Agricultural Experiment Station in New Haven to determine what species of Culicoides, a tiny biting fly known as a midge, is causing epizootic hemorrhagic disease (EHDV-6), recently detected in Connecticut deer by CVMDL staff.

“Most of these diseases have probably been around for a while, but the range of these insects is increasing due to climate change,” Risatti points out.

In addition to insect-borne diseases, the CVMDL tracks incidence of rabies. In 2017, most rabies cases 2017 occurred in skunks and raccoons, but it is found sporadically in other species such as bats and feral cats.

“There will always be viral diseases,” Risatti says. “Viruses are everywhere, and we are part of everywhere.”

By Kim Colavito Markesich