Uncovering the Link: Marine Animal Virus Linked to Unusual Eye Issues in Humans

A newly identified virus typically affecting marine animals has led to alarming glaucoma-like symptoms, including irreversible vision loss, in a handful of individuals in China. This marks the first documented instance of an aquatic virus infecting humans and resulting in serious health complications. The infections are believed to have occurred through consumption of raw seafood or handling aquatic creatures, with some evidence suggesting possible human-to-human transmission.

“It’s astonishing that this virus is capable of infecting invertebrates, fish, and mammals,” says Edward Holmes, a researcher at the University of Sydney. “I cannot recall any virus exhibiting such a broad host range.”

Cases of persistent ocular hypertension viral anterior uveitis (POH-VAU), characterized by inflammation and increased eye pressure leading to optic nerve damage, are escalating in China. To delve into the triggers behind this spike, researchers from the Chinese Academy of Fisheries Sciences in Qingdao evaluated 70 patients diagnosed with the condition between January 2022 and April 2025.

The research team tested these individuals for the latent and lethal nodavirus, which commonly infects various marine species; remarkably, all 70 tests returned positive. “Up to this point, viruses from aquatic animals have not been shown to cause illness in humans directly,” the researchers stated, though they declined to provide further commentary. Despite treatment aimed at reducing inflammation, a significant portion of subjects required surgical intervention, with one case resulting in irreversible vision loss.

In an effort to better understand the virus, the research team infected mice, which exhibited marked pathological changes in the cornea, iris, and retina within a month. They also observed that the virus could spread among mice sharing water.

Of those studied, more than half owned aquatic animals, highlighting a potential source for the infection. However, approximately 16% reported consuming raw seafood or had close ties with high-risk groups.

While there is no definitive proof of human-to-human transmission, an epidemiological study revealed a distinct subgroup of urban POH-VAU patients with no direct contact with aquatic animals or other risk factors, apart from close interactions with family members. These relatives, who are at a heightened risk for the latent nodavirus, have experienced hand injuries during handling of aquatic animals, implying that the virus may transmit within households, potentially via shared utensils.

To gauge the virus’s prevalence, researchers evaluated 523 captive and wild aquatic animals across Asia, the Americas, Europe, Antarctica, and Africa, concluding the global presence of this hidden and deadly nodavirus. They identified it in 49 species, including shrimp, crabs, fish, and barnacles, resulting in symptoms like lethargy and color loss; yet the reasons behind its ocular effects in humans remain unclear.

Holmes emphasized the potential ubiquity of this pathogen: “I suspect it is much more prevalent than currently recognized. I wouldn’t discount the possibility it first passed through another species, possibly a mammal.”

The virus may also propagate among marine organisms consuming infected animals. For instance, researchers found that farmed shrimp often consume frozen brine shrimp or Antarctic krill, potentially resulting in infections. Moreover, the introduction of this virus into warmer waters has led to increased infections in marine life, suggesting that Antarctic species may serve as reservoirs for pathogens without displaying illness themselves.

Researchers warn that the transmission of this elusive and deadly nodavirus from marine life to humans presents new biosecurity threats. Nonetheless, Holmes reiterates the absence of clear evidence for human-to-human transmission, stating, “This is not regarded as a contagious disease.”