Nearly 750 wild ducks were shot and killed in California’s San Francisco Bay for a study on the link between mercury pollution and bird flu.
Researchers tested the ducks for mercury contamination and whether they were infected with bird flu or had antibodies for the virus in their system.
The results, published in the journal Proceedings of the Royal Society B on Wednesday, showed that wild ducks contaminated with mercury were up to 3.5 times more likely to have had bird flu.
Claire Teitelbaum, ecologist and the study’s lead author, said mercury contamination “can suppress the immune system, and that might make infection with anything (including influenza) more likely”.
The San Francisco Bay is a “significant hotspot for mercury contamination in North America… largely from historical gold mining, where mercury was part of that process,” Teitelbaum told news agency AFP.
Researchers increasingly sound the alarm that climate change, deforestation, animal farming and other human-induced factors raise
the likelihood of viruses crossing over from animals to humans.
Teitelbaum said that “there are just so many ways in which humans have historically altered and are continuing to alter the natural environment.”