It all starts with symptoms that resemble those of glaucoma: abnormally high pressure in the eye, inflammation, pain. Except that for the 70 patients included in a recent Chinese study, the cause had nothing to do with viruses already known in ophthalmology. All were found to be carriers of “covert mortality nodavirus” (CMNV), a pathogen previously only identified in shrimp, crabs, fish and other aquatic animals – never in humans.
This new disease was named POH‑VAU, to “persistent ocular hypertensive viral anterior uveitis”, viral anterior uveitis with persistent ocular hypertension. It affects the front part of the eye and can, in the most serious cases, irreversibly damage the optic nerve, leading to loss of vision. In the cohort studied, approximately a third of patients required surgery to control intraocular pressure, and one of them permanently lost part of their vision.
What makes this discovery particularly striking is that it constitutes a documented first in the history of viral zoonoses. “To date, no aquatic virus has been demonstrated to be capable of infecting humans and directly causing disease.”summarize the authors in their study published at the end of March 2026 in the journal Nature Microbiology. The work, spotted by New Scientist, describes a transition from species to species, from marine fauna to humans.
How did these people become infected with this virus? The exposure survey shows that approximately 71% of cases concerned individuals in frequent and unprotected contact with aquatic animals: aquarists, fishermen, fishmonger employees or cooks handling fish and shellfish with bare hands, as well as people regularly consuming raw seafood products. The authors also mention possible transmissions within households via the sharing of utensils or contaminated surfaces, even if these scenarios remain difficult to document precisely.
A virus present everywhere in the oceans
To measure the scale of the problem, the team from the Chinese Academy of Fisheries Sciences in Qingdao widened the focus. It tested 523 wild or farmed aquatic animals, collected from six continents (Asia, North and South America, Europe, Africa and Antarctica). Result: CMNV is detected everywhere, in 49 different species – shrimp, crabs, fish, sea cucumbers, barnacles, etc. In these animals, the virus causes lethargy and discoloration, and can thus cause significant economic losses in aquaculture, without being systematically fatal.
“I don’t know of any viruses with such a wide host range.underlines virologist Edward Holmes, of the University of Sydney. It does not exclude that the pathogen also circulates in species that have not yet been studied, nor that it could have passed through another mammal before reaching humans. CMNV was already known for its ability to infect many aquatic invertebrates; the fact that it is now associated with a human disease makes it a textbook case of a general virus to be closely monitored.
Should we therefore speak of a major health threat? Researchers remain cautious. While a few cases suggest that human-to-human transmission via close contact or contaminated objects is conceivable, no direct evidence of person-to-person contagion has yet been provided. Edward Holmes himself insists: “It’s not an epidemic,” but a warning signal about the risks of new passages of aquatic viruses towards humans in a context of globalization and climate change.
This discovery above all requires us to review our perception of the risks linked to raw seafood products and the handling of aquatic animals without protection. Wear gloves when gutting fish, avoid cutting your hands when preparing shellfish, limit the consumption of raw seafood or even better monitor the health chain of these products. Chinese health authorities, like several international teams, are now calling for strengthening surveillance of this virus, which has long been confined to farms but which has just proven that it can also find its way… into our eyes.
