Scientists have found that some species of bacteria and other microorganisms can be toxic to aquatic animals and humans.
A study published Monday in the journal Science found that the bacterium Cryptococcus aureus can cause severe liver damage in fish and can also cause cancer.
The study examined data from about 1,600 individuals in seven freshwater aquaria and eight marine aquariums.
Among the findings: The organisms can cause liver and kidney damage, severe burns and tumors in fish.
Cryptococcus can cause infections in fish in up to 10% of the water, but in most cases, they’re confined to the fish’s gills and aren’t harmful to humans.
The organisms also can spread to the brain and heart.
And they can cause infection in humans, too.
Researchers also found that Cryptococci can cause a variety of respiratory problems in people, including asthma, lung infections, pneumonia and acute respiratory syndrome, or ARDS, according to the study.
“We see that the microorganisms, if ingested, can affect the gastrointestinal tract, respiratory system and brain, and they can also affect the immune system,” study author and microbiologist Michael C. Sorensen, an assistant professor of aquatic sciences at Oregon State University, said in a statement.
Sorensens work focuses on how aquatic organisms interact with their environment and the human immune system.
According to the National Institutes of Health, Cryptococcal infections have been linked to the development of asthma and COPD, among other respiratory problems.
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This article originally appeared on Live Science.