Influenza D was first isolated from a diseased pig, it was later found that cattle are the primary reservoir.
The executive committee of the International Committee of Taxonomy of Viruses approved naming a new virus, influenza D, as the South Dakota State University researchers who discovered it proposed, according to professor Feng Li.
The committee officially announced a new genus, Orthomyxovirdae, with a single species, Influenza D virus, because of its distinctness from other influenza types—A, B and C.
Though SDSU alumnus Ben Hause isolated the virus from a diseased pig in 2011, he later found that cattle were the primary reservoir for influenza D. Hause identified and characterized the new virus as part of his doctoral research under Li's tutelage.
This is the first influenza virus identified in cattle, Li explained. "This contribution was made in South Dakota and our theory has been confirmed independently by other research groups."
Li and Radhey Kaushik, professor and assistant head of the biology and microbiology department, secured a National Institutes of Health grant for nearly $400,000 to study the biology, genetics and evolution of the new virus.
"From a science viewpoint, it's very exciting to work with a brand-new virus," said Li, who has joint appointments in the biology and microbiology and veterinary and biomedical sciences departments.
Volker Brözel, head of the Department of Biology and Microbiology, said, "This is a great example of how our researchers add to scientific knowledge and seek solutions to challenges impacting both human and animal health."
In particular, these researchers have actively engaged graduate and undergraduate students, he pointed out. "Being associated with the discovery of a new virus genus is a huge boost for their future career paths in medicine, academia and private industry."
Ultimately, the goal is to determine whether influenza D, which has 50 percent similarity to human influenza C, can cause problems in humans, according to Kaushik. However, he noted, "the virus has not been shown to be pathogenic in humans. No one should be afraid of this."
The research group showed that influenza D is spread only through direct contact and proved a guinea pig can be used as an animal model to study the virus. Influenza D antibodies have been identified in blood samples from sheep and goats, but the virus does not affect poultry.
Studies are underway to compare the virulence among the bovine and swine influenza D strains and human influenza C using the guinea pig model.
"If the virus can undergo reassortment in combination with a closely related human influenza virus, it may be able to form a new strain that could pose more of a threat to humans," Kaushik explained. Li noted, "We have much to learn about this new virus."