Black cats may be considered bad luck in many Western societies, however, one such sooty feline has brought good fortune to a team of scientists, playing a pivotal role in discovering a new virus capable of infecting humans. It's now the second novel pathogen Pepper has hunted down.
Pepper, doing what cats do, had caught and killed an Everglades short-tailed shrew (Blarina peninsulae), a small venomous mammal endemic to the state of Florida. Pepper's owner John Lednicky – a virologist from the University of Florida College of Public Health and Health Professions – then took the shrew into the lab to check it out.
While this might sound like an odd activity, it's certainly not strange in science (I once had a vertebrates professor enthusiastically encourage us to pull over and have a "poke around" in any roadkill we happened to pass by on the road – and he's now one of Australia's leading researchers into highly pathogenic avian influenza). Lednicky has been studying mule deerpox virus transmission for some time, and the shrew offered a surprise research opportunity related to his team's work.
“This was an opportunistic study,” Lednicky said. “If you come across a dead animal, why not test it instead of just burying it? There is a lot of information that can be gained.”
What the researchers found was that the shrew was hosting a previously unidentified pathogen from the Orthoreovirus genus. The mammalian viruses in this group are known to infect many hosts, including humans. While most of the time infection will result in mild upper respiratory or intestinal issues, severe cases can result in central nervous system (CNS) disease, pneumonia and more.
Their full impact on humans is not well understood, but they've also been linked to encephalitis, meningitis and gastroenteritis in children. And like the flu, two different types of orthoreovirus can infect a host cell, which can lead to genetic mingling, creating new bugs.
“There are many different mammalian orthoreoviruses and not enough is known about this recently identified virus to be concerned,” said lead author Emily DeRuyter, a University of Florida researcher. “Mammalian orthoreoviruses were originally considered to be ‘orphan’ viruses, present in mammals including humans, but not associated with diseases. More recently, they have been implicated in respiratory, central nervous system and gastrointestinal diseases.”
Last year, a mouse offering to his owner led to Pepper's first novel virus find, now known as Gainesville rodent jeilongvirus 1. This was the first time any jeilongvirus – a paramyxovirus associated with respiratory infections – had been identified on US soil.
“[Jeilongvirus] grows equally well in rodent, human, and nonhuman primate cells, making it a great candidate for a spillover event,” Lednicky said in October.
Pepper, meanwhile, was not affected by either novel viruses and is no doubt back on patrol at his Gainesville home. And the team has since published the complete genomic coding sequences for the new virus – Gainesville shrew mammalian orthoreovirus type 3 strain UF-1.
“Cats, in general, evolved to eat rodents, and are not sickened by the viruses carried by rodents,” Lednicky said following Pepper's mouse catch. “But we have to do tests to see whether the virus affects pets, and humans.”
And yes, it must also be said that domestic and feral cats have been disastrous to the world's biodiversity, having contributed to the extinction of 40 bird and 21 mammal species – 26% of the extinctions in these groups – since the 1600s. Though, given his contribution to advancing science, we won't paint Pepper as a villain, in this story at least.
“We know that there are many unknown viruses that are present all around us and I feel like a sleuth tracking them down,” DeRuyter said.
“The bottom line is we need to pay attention to orthoreoviruses, and know how to rapidly detect them,” Lednicky added.
The research was published in the journal Microbiology.
Source: University of Florida