A new study has found that the bird flu virus can survive for up to two years in the carcasses of buried birds.
Dr. Shannon Bartelt-Hunt, an environmental engineer at the University of Nebraska-Lincoln, says that the findings of the study indicate that waste managers need to be particularly careful with how they dispose and manage landfills containing infected birds.
"There are a lot of birds at landfills. If you think of landfills as reservoirs, you could have birds as vectors. Other animals could be vectors. Landfill personnel could be potentially exposed," ABC Online quoted Dr. Bartelt-Hunt as saying.
Bird flu is an H5N1 form of the influenza virus that mainly infects birds, including chicken, ducks and turkeys.
Whenever any bird gets infected with the virus, farmers usually kill the entire flock to subdue an outbreak.
Thus far, hundreds of millions of birds have been killed by the flu, or by efforts to control it.
Even though there are options for disposal like composting and burning, most carcasses often end up in landfills.
For the current study, Bartelt-Hunt and colleagues filled Petri dishes with leachate-the liquid that drains from landfills, adding avian influenza to each dish.
The researchers then tested the mixtures at four different temperatures levels, three pH levels, and three levels of conductivity to test for the presence of heavy metals.
After 60 days, they were able to estimate how long the virus would remain infectious based on how quickly it was breaking down.
Reporting their findings in the journal Environmental Science and Technology, the researchers said that at colder temperatures and neutral pH levels, the virus was likely to survive the longest-sometimes for up to nearly two years.
"The assumption was that once it's in the landfill, there's no more question about whether it's infectious. This is suggestive that carcasses will likely remain infectious when they're placed in a landfill and for a period of time after that," says Bartelt-Hunt.
The new work suggests that the bodies should get covered quickly to raise their temperature, or to make the landfill more acidic or basic to deactivate the virus as quicly as possible.
"In general, waste disposal is one of those things that's just 'out of sight, out of mind'. Once it gets there, people tend to think it's just gone and they don't have to worry about it ... It's hard to say if waste disposal is this huge unknown red flag out there, but I think having some consistent guidelines is important," says Bartelt-Hunt.