Prawns can carry a virus that can jump to humans. Photo: Unsplash
According to reports, a marine virus has jumped to humans for the first time. As of this writing, the virus has only infected a small group of people in China. It causes symptoms similar to glaucoma and irreversible vision loss. It’s thought that the virus was transmitted after eating raw seafood and handling infected animals. There are, however, signs that it can move from human to human, as well.
“That this virus can infect invertebrates, fish and mammals is pretty remarkable,” Edward Holmes, who works at the University of Sydney, Australia, said. “I can’t think of a virus with such a broad host range.”
The condition the virus causes is called ocular hypertension viral anterior uveitis (POH-VAU). Like glaucoma, it causes high pressure within the eye, damaging the optic nerve. In an attempt to understand how it may be spreading, researchers from the Chinese Academy of Fishery Sciences in Qingdao studied 70 people who have been infected since 2022. They were tested for covert mortality nodavirus, which, until now, has been a virus that affects marine animals. All 70 of the subjects’ tests came back positive.
According to New Science, no virus carried by aquatic animals has been able to make the jump to humans and directly cause illness.
“The individuals were given medication to ease the swelling, but approximately one-third still required surgery, and one person developed irreversible vision loss,” wrote New Science. “To better understand the virus, the researchers infected mice, which developed ‘obvious pathological changes in the cornea, iris and retina’ within a month. They also noticed that mice sharing water were able to transmit the virus to each other.”
While there isn’t any direct evidence of human-to-human transmission, an epidemiological study does hint that it might be possible. Of the 70 people the researchers looked at, a little over half of them had aquatic animals in their homes. When they did the epidemiological study, they found a subgroup of patients who had POH-VAU without any contact with aquatic animals, but did have a “high risk of contracting covert mortality nodavirus, and had hand injuries at the time of handling aquatic animals.” The researchers believe this may be a sign that it can spread within families.
In an analysis of 523 wild and farmed aquatic animals collected from all over the world, they found that covert mortality nodavirus is indeed present around the planet. It was found in 49 species, which included prawns, crabs, fish, sea cucumbers, and barnacles. For them, though, it causes lethargy and a loss of color.
It’s likely that the pathogen is actually far more widespread than we previously thought, but it’s not something most of the population of the world needs to be all that concerned with at the moment. “I think it’s very likely that the virus will be present in other species that we’ve not yet sampled,” Holmes explained. “I don’t think it can be totally excluded that it passed through another species first, perhaps even another mammal… It’s not an epidemic.”
