Just in case you needed another reason to be wary of getting too close to bats, researchers have accidentally discovered that a species of microbat in Texas is carrying a new herpes virus, and it can infect human cells.
Bats are already known to carry several diseases that affect humans, and although it's rare, they can trigger outbreaks if they come into contact with humans or animals. In fact, bats are known to be carriers of Ebola, and have been implicated by some researchers in the 2014 Guinea outbreak - although virologists have debated this claim. Now it turns out that some species of the winged mammals are also carrying a new type of herpes.
Researchers from the Icahn School of Medicine and J. Craig Venter Institute found the new virus by accident while studying tumour cells taken from the wing of an adult microbat (Myotis velifer incautus) found in a Texas cave.
They were sequencing the genome of this tumour to better understand the bats' immune response, but noticed that a lot of the genes sequenced weren't bat genes at all - they were related to a herpes virus.
After further investigation, the researchers discovered that it was an entirely new herpes virus – one that had never been fully sequenced before.
The new virus, which has been described in mSphere, has been called bat gammaherpesvirus 8 (BGHV8). "This is the first replicating bat gammaherpesvirus that's been isolated. Most labs just have bits and pieces of a virus," lead researcher, Reed Shabman, told Sci-News.
BGHV8 didn't just thrive when tested in specialised cells that replicate viruses, known as Vero cells, it was also able to infect human cells. "Within 18 hours, the Vero cells were dead. BGHV8 cells also were able to infect isolated human lung and human liver cells," Shabman said.
Before you freak out, that doesn't necessarily mean the virus is capable of infecting humans in real-world situations, or, even if it could, that it poses a threat to us.
Herpesviridae, or the herpes virus family, is a huge family of viruses. Not only are there eight species of herpes that infect humans, there are also individual herpes viruses for nearly every mammal species studied as well. But most of these herpes viruses are common and harmless, or have limited toxicity.
For example, cold sores are caused by herpes simplex, and despite causing discomfort and blisters, don't do long-lasting damage. And over 90 percent of adults will have had the Epstein-Barr virus at some point in their lives, usually without them noticing.
Not only are most herpes viruses pretty harmless, but animal-to-human transmission of herpes is very rare. There have only been 17 cases of bat-to-human rabies in the US from 1997-2006, and rabies is significantly easier to transmit. The likelihood of being affected by BGHV8, or any other animal herpes, is exceptionally low, so researching how this virus affects humans won't be a high priority for now.
But, more importantly, the discovery of the virus stresses the need to better understand how the winged animals spread disease to humans. Currently, 75 percent of emerging infectious diseases are zoonoses - diseases that are transferred from an animal to a human. And unfortunately for bat-lovers, some of the most significant emerging viruses are bat-borne.
Bats have been implicated in everything from the Ebola virus and Severe Acute Respiratory Syndrome (SARS), to the incredibly deadly Hendra virus. If they bite or scratch you, they can also give you rabies, and the Australian equivalent, Australian bat lyssavirus.
But despite scientists knowing over 66 viruses that bats carry, it's hard to pick which animal viruses will transfer to humans until someone gets the disease, and then the race is on to try and find a cure or vaccine.
Regardless of the risk, we can't go down the mosquito route and contemplate wiping bats out, as this paper by Charles Calisher points out:
"Irrespective of the negative public perception of bats, they are critical elements of all terrestrial biotic communities. They help control insects, reseed cut forests, and pollinate plants that provide food for humans and other species, and their guano is used as a fertiliser and for manufacturing soaps, gasohol, and antibiotics."
So looks like we'll have to work out how to stop these viruses and other diseases when they emerge. Which is why research like this is so important.
"A big question is why bats are repeatedly associated with infections that transfer to humans," said Christopher Basler, a microbiologist involved with the study. "We have very few tools to study bats' immune response to viruses. This natural bat virus is actually going to prove to be useful in understanding and probing how bats respond to natural infections and microorganisms that can cause disease."
In the meantime, it's probably best to stay away from bats and their excretions, just to be on the safe side.
Editor's note, 8 March 2016: We've updated the story to reflect the fact that there's no scientific consensus on how the 2014 Ebola outbreak started. Bats in the area have been confirmed as carriers of the disease, but scientists don't have the tools to isolate the origin of the outbreak.
It's also important to note that many bats species are endangered, and all bats are crucial parts of our ecosystem that need to be protected. It wasn't our intention to stigmatise bats with this story, simply highlight their role in carrying disease. We've updated our image (original) accordingly.