Virus found in Florida resident may be widespread throughout the Southeast

UF researchers discover the first active case of Keystone virus in a human

By Evan Barton

A virus first found in Tampa Bay-area mosquitoes that can cause a rash and mild fever has been identified in humans for the first time, according to UF researchers who published their findings in the journal Clinical Infectious Diseases.

“Keystone virus,” named after the location in Tampa Bay where it was initially identified in 1964, has been found in animal populations along coastal regions stretching from Texas to the Chesapeake Bay. A live case of the virus in a human had never been detected, until now, although human infection has long been suspected.

In the case reported by John Lednicky, Ph.D., a research professor in the college’s department of environmental and global health, and colleagues, a teenage boy went into an urgent care clinic in North Central Florida with a rash and fever symptoms in August 2016. Because of concerns about Zika, laboratory samples were collected from the patient; however, all tests were negative for Zika or related viruses.

Unexpectedly, UF researchers did find Keystone virus. Although the patient did not report symptoms of encephalitis, researchers report that the virus grew well in Neuro-2A cell cultures, suggesting that Keystone virus can infect brain cells, and may pose a risk for brain infections.

“This virus is part of a group commonly known as the California serogroup of viruses,” said Lednicky, a member of the UF Emerging Pathogens Institute. “These viruses are known to cause encephalitis in several species, including humans.”

Glenn Morris, M.D., M.P.H., director of the UF Emerging Pathogens Institute and corresponding author of the report, emphasized the need for additional research into the prevalence of vector-borne diseases in the United States.

“All sorts of viruses are being transmitted by mosquitoes, yet we don’t fully understand the rate of disease transmission,” he said. “Additional research into the spread of vector-borne diseases will help us shine a light on the pathogens that are of greatest concern to both human and animal health.”