Wild ducks contaminated with mercury are more likely to contract bird flu, according to a study published Wednesday.

Avian flu, which is very common in Asia, re-emerges regularly in Europe and the United States, causing the slaughter of millions of poultry each year.

This study will once again demonstrate the human impact on wildlife and the ease with which viruses spread because of this complex coexistence.

Wild ducks are major spreaders of viruses due to the long distances they travel during their migration.

For this study, published in the Royal Society’s (Great Britain) biological research journal, scientists hunted about 750 different wild duck species in San Francisco Bay (northwest United States).

This bay is located in a wide migration corridor running from Alaska to Patagonia.

Mercury has harmful effects on the immune system.

Experts looked for traces of this heavy metal in the ducks and whether they had bird flu or the presence of antibodies to the virus.

The results were published in the journal procedures Research from the Royal Society B showed that ducks contaminated with mercury were 3.5 times more likely to contract bird flu at some point in the previous 12 months.

The greater the amount of mercury in the animal’s body, the higher the probability of the prevalence of antibodies confirming the presence of the virus.

The study notes that the ducks tested negative for the strain of the deadliest pathogen of the H5N1 virus, which has been detected in multiple outbreaks worldwide and can be transmitted to humans.

Immune problems from mercury

The study’s lead author, Claire Teitelbaum, explained that the presence of mercury “increases the likelihood of contracting any infection, including bird flu.” wild.

San Francisco Bay, he explained, was “a major source of mercury pollution in North America (…) mainly due to gold mining”, which attracted large numbers of adventurers in the 19th and 20th centuries.

Epizootics declined in the northern summer as “many wild birds returned to their nests”. But “we’re likely to see a resurgence of bird flu as it starts to decline,” the expert said.

Human existence has historically changed the natural environment in various ways. Climate change experts and advocates of animal life condemn this impact as being fundamentally negative.

Daniel Becker, a biologist at the University of Oklahoma who was not involved in the research, praised the results, calling them “impressive.”

“Surprisingly little work has been done on the concentration of pollutants in wild animals and their relationship to infectious diseases, particularly viruses that can cross species barriers such as the H5N1 virus.”