June 16, 2009

Bird flu viruses can survive nearly two years in bird carcasses placed in landfills, according to a study by the University of Nebraska-Lincoln, and the researchers are investigating ways to shorten that timeframe.

 

The study showed that the virus could be inactivated more quickly through warmer temperatures and non-neutral pH levels.

 

In preparation for a widespread bird flu outbreak, researchers at the university examined how to contain and properly dispose of infected bird carcasses without the virus spreading further. They found that under certain conditions, the virus' inactivation rate could be sped up.

 

So far, disposal options for infected bird carcasses include composting, incinerating or burying the bodies, but carcasses usually end up in municipal solid-waste landfills. But information about post-disposal presence of the virus was limited, researchers said in a study published in the recent issue of "Environmental Science & Technology."

 

The study looked specifically at the H6N2 subtype of bird flu.

 

"There is really no information about survival [of H6N2] in landfills," said Shannon Bartelt-Hunt, an assistant professor of environmental engineering at UNL who worked on the study. "[Research] was being done under the assumption that deactivation [of the virus] was rapid."

 

The research team spiked landfill leachate - basically garbage water found in landfills - with the bird flu virus. They used previous bird flu studies combined with lab tests to determine what factors work best to inactivate the virus in leachate.

 

The study concluded that after 60 days, the virus placed in colder temperatures and neutral pH levels could survive the longest, at nearly two years. However, the virus placed in warmer temperatures (tested at 21 and 37 degrees Celsius) and non-neutral pH levels inactivated the virus more quickly.

 

With this information, landfill operators could take steps to speed up bird flu virus inactivation if there were infected carcasses in their landfill. An additive to the carcasses that would change the pH to acidic or basic could help, as could covering the carcasses to raise temperatures, Bartelt-Hunt said.

 

Still, she said there are more variables that could affect the disease's survival, many specific to the landfill's current environmental conditions that the lab tests didn't cover.

 

Bird flu has numerous subtypes that can cause anything from mild illness to death in birds. While most types of bird flu aren't harmful to humans, the H5N1 subtype has been blamed for numerous deaths, mostly in Asia.