Scientists illuminate how virus attacks cat kidney, could jump to humans

Virologists from the University of Pittsburgh Center for Vaccine Research reverse-engineered an elusive virus linked to chronic kidney disease in cats and described the mechanism of infection, outlining the potential of the virus to infect people.

A study published Oct. 17 in the Proceedings of the National Academy of Sciences suggests that the feline morbillivirus uses the same mechanism of cell entry and infection as other viruses in the morbillivirus family, such as measles. However, unlike measles, FeMV appears to spread from host to host through urine in a way similar to the zoonotic Nipah virus harbored in bats, which causes annual deadly outbreaks in humans across Southeast Asia.

Two stray cats
The feline morbillivirus was first discovered a decade ago in stray cats in Hong Kong, such as these, and has since been found in domestic cats across Asia and Europe and identified and fully sequenced in the U.S. in 2016.

“Feline morbillivirus stayed under the radar for many years,” said senior author Paul Duprex, PhD, director of the Center for Vaccine Research, in an announcement. “By understanding the genetics of a virus that was challenging to grow in the laboratory, we are now able to shine light on its connection to chronic kidney disease and better understand how we can stop transmission and potential spillover into human populations.”

First discovered in stray cats in Hong Kong a decade ago, FeMV has since been found in domestic cats across Asia and Europe and identified and fully sequenced in the U.S. in 2016 by Dr. Duprex’s research team, then in Boston. While previous studies have linked FeMV infections to chronic kidney disease in cats—one of the leading causes of death in older cats—the new study shows in detail how the virus gets to the kidneys.

Similar to other members of the same viral family, FeMV enters cells by binding to a surface protein receptor called CD150. Measles and other related viruses use CD150 as their primary entry receptor.

By creating a genetically modified version of FeMV containing a fluorescent probe, researchers were able to track the spread of the virus throughout cells and organs, discovering that transmission can be halted by inhibiting a class of protein-cleaving enzymes called cathepsins. Cathepsins are mostly used by Nipah viruses but not the morbilliviruses, suggesting that FeMV is an evolutionary intermediate between the two viral families.

“Learning about the viruses that infect cats is not only important for reducing the rates of kidney failure in our beloved pets, but also helps us understand something new about emerging infectious diseases and how they can spread across different animal species,” Dr. Duprex said.