Researchers call for vigilance in a new study describing an obscure family of viruses that cause Ebola-like symptoms in certain monkeys, warning that one of these viruses could soon make the leap to humans.
Simian hemorrhagic fever, an arterivirus that is already endemic in wild African primates and primarily affects macaque monkeys, may have the potential to become the next monkeypox or even the next HIV in the future, say researchers. researchers.
Although human infections with these viruses have never been reported, experts warn that we should keep an eye on them now.
“This animal virus has figured out how to gain access to human cells, multiply and escape some of the important immunological mechanisms that we would expect to protect us from an animal virus. That’s pretty rare,” Sara Sawyer, professor of molecular, cellular, and developmental biology at the University of Colorado Boulder, and lead author of the research, he said in a press release.
“We should pay attention to it.”
The study, published last week in the scientific journal Cellexamines how simian hemorrhagic fever (SHFV) uses a specific cell receptor to infect target cells, a receptor that also exists on human cells.
Arteriviruses have been studied in pigs and horses, but versions that target nonhuman primates are less well known. SHFV causes a fatal disease among macaque colonies, with symptoms of internal bleeding and fever similar to Ebola. SHFV often kills infected macaques.
The researchers found that SHFV uses a specific cell receptor called CD163 to infect monkeys. Research shows that primates with differences in this receptor are sometimes less susceptible to SHFV infection, demonstrating the importance of this receptor.
The researchers realized that all the proteins required for SHFV to replicate within the host body were also present in human cells, although they are expressed differently within humans.
To test whether the virus could infect a human, they ran a series of lab experiments with a variety of simian DNA, including human DNA, and found that SHFV could enter human cells using the human version of CD163.
The study called this the “first hurdle to successful spread to humans.”
The researchers added SHFV to several human cell lines and found that SHFV could even replicate using human proteins, which goes far beyond simply being able to enter cells.
The CD163 receptor is present exclusively on myeloid cells such as monocytes and macrophages, which are types of white blood cells. White blood cells play a very important role in our health as they help protect our body against infection. If these cells are affected by a virus, the consequences can be dire.
So does this mean that SHFV is going to wipe out the humans next, causing death and destruction?
Not yet. It is important to remember that there have been no cases of this virus passing from animals to humans. There is no pandemic on the horizon at this time, the authors emphasize.
But they say it’s concerning that this virus appears to have many of the tools needed to start infecting humans.
“The similarities are profound between this virus and the simian viruses that gave rise to the HIV pandemic,” Cody Warren, assistant professor at The Ohio State University College of Veterinary Medicine and first author of the study, said in the statement.
HIV’s predecessor was the simian immunodeficiency virus (SIV), which first crossed from African monkeys to apes sometime between 1884 and 1924, according to Encyclopedia Britannica. As the virus mutated, it eventually became the devastating virus we now know as HIV.
When HIV/AIDS began to reach pandemic levels among humans, there was no treatment or accurate testing. As of 2022, more than 40 million people worldwide have died from HIV/AIDS, the statement noted, and 2,000 people die from the disease worldwide every day.
This cautionary tale means that if we take the threat of SHFV seriously now and do more research to study it, we may be able to avert disaster if the virus ever crosses over to humans.
“If we knew earlier about the biology of SIVs and the risks they posed, could we have been more effective in fighting the HIV pandemic sooner?” Warren said. “I think we could have done it.”
There is no guarantee that SHFV will ever become a threat to humans, as some viruses with the lab-proven ability to jump to humans simply have never done so. But even if it’s not this virus, more pandemics are coming in the future and more research is needed to monitor threats, the researchers say.
“COVID is just the latest in a long series of animal-to-human indirect events, some of which have become global catastrophes,” Sawyer said. “Our hope is that by raising awareness about the viruses we need to be aware of, we can get ahead of this so that if human infections start to happen, we can address it quickly.”