What scientists know — and don’t know — about the Langya virus

If you’re coming to grips with the fact that 2022 is the year of infectious microbes — so far, it’s given us an outbreak of monkeypox, our first case of polio in nearly a decade, and not to mention the ever-revolving door of Covid-19 variants — brace yourselves.

An international team of scientists encountered a novel virus, called “Langya”, that has infected 35 people in China’s northeastern provinces of Shandong and Henan. In a commentary published in the New England Journal of Medicine on August 4, the virus was first discovered in a 53-year-old farmer seeking treatment for a fever in late 2018. It was later found in 34 other people but was only formally identified last week.

Following the route of many viruses like Ebola, monkeypox, and Covid-19, it's believed the Langya virus jumped from wild animals before infecting humans. Transmission from one human to another doesn’t appear to be its modus operandi, but health authorities are currently monitoring how the virus is spreading.

Feeling worried? Don’t be, Colleen Kraft, an infectious disease specialist at Emory University School of Medicine, who was not involved in the study that announced the virus, tells Inverse. While we don’t yet have the fully-fleshed picture of how the virus spreads — a crucial detail in determining how bad and far-reaching the infection could get — what we do know is hopefully reassuring.

What is the Langya virus?

Cross-referencing the Langya virus’s genome against others, the researchers found it belongs to the same viral family as the Nipah and Hendra viruses, collectively known as the henipaviruses. These viruses, which are also passed from animals to humans (bats in the former and horses in the latter), are considered highly virulent. Nipah has an estimated case fatality rate of 40 to 75 percent, while Hendra rarely infects humans but when it does, it has an estimated case fatality rate of 57 percent. Unfortunately, we don’t have vaccines against henipaviruses.

So far, the Langya virus isn’t considered to be the bad wolf of the henipaviral bunch. There have been no reported deaths among the 35 people infected, Linfa Wang, the commentary’s co-author and director of the Emerging Infectious Diseases Program at Duke-NUS Medical School in Singapore, told China’s state-run Global Times. According to Wang, cases have “not been fatal or very serious.”

According to the study, in 26 of the 35 people infected with the novel virus, researchers did not detect any other pathogen that could have been causing their symptoms. The most common symptoms among this group were fever, fatigue, cough, weight loss, muscle pain, headache, nausea, and vomiting. However, some did experience more concerning symptoms like low blood count and impaired liver and kidney functions.

What we still don’t know

The million dollar question: How exactly is the virus transmitted and does it jump from one human to another in a similar way to how Covid-19 or the flu does?

Looking for the virus in about 25 different species of wild animals, the researchers found the Langya virus RNA predominantly among shrews (about 27 percent among all shrews surveyed). This suggests the mole-like animal is what scientists call a natural reservoir — an organism or environmental habitat viruses and other pathogens like to hang out in.

The researchers also found that about five percent of dogs and two percent of goats surveyed also carried the viruses, indicating one potential intermediary in the transmission chain is domesticated animals.

While the evidence points to zoonotic spillover — when diseases jump from animals to humans — it doesn’t suggest human to human, which is how Covid-19 and monkeypox are currently spreading. This is good news if true.

“It is possible that these 35 patients all got [the Langya virus] from the animal vector and not from each other,” says Kraft. “In this case, if you’re not handling the shrew in this location of the world, you’re unlikely to ever come across this virus.”

Should you be worried about the Langya virus?

There’s still so much scientists don’t know about the Langya virus. But the fact it’s been going on for the past few years and without many cases, Kraft says panic isn’t necessary.

“If it’s not human-to-human transmission, I don’t ever worry about it coming and infecting anybody else,” she says, mentioning that health authorities are keeping their eyes peeled for any potential cases in China and abroad.

"At this stage, [the Langya virus] doesn't look like a repeat of Covid-19 at all,” Francois Balloux, a professor of computational biology systems at University College London who was not involved in the study, tweeted on Aug. 9. “[But] it is yet another reminder of the looming threat caused by the many pathogens circulating in populations of wild and domestic animals that have the potential to infect humans."