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Bird Flu Viruses Can Survive 600 Days

by 5m Editor
28 May 2009, at 9:54am

US - Work at the University of Nebraska Lincoln provides evidence that the H6N2 sub-type of the avian influenza virus can remain infectious up to 600 days in municipal landfills – the chosen disposal option for the culls of the 2002 bird flu outbreak in Virginia.

Amid concerns about a pandemic of H1N1 flu, researchers from Nebraska report for the first time that poultry carcasses infected with another threat – the 'bird flu' virus – can remain infectious in municipal landfills for almost two years, according to PhysOrg. The report is scheduled for the 15 June issue of American Chemical Society's journal, Environmental Science & Technology.

Shannon L. Bartelt-Hunt and colleagues note that avian influenza, specifically the H5N1 strain, is an ongoing public health concern. Hundreds of millions of chickens and ducks infected with the virus have died or been culled from flocks worldwide in efforts to control the disease. More than four million poultry died or were culled in a 2002 outbreak in Virginia, and the carcasses were disposed of in municipal landfills. Until now, few studies have directly assessed the safety of landfill disposal.

"The objectives of this study were to assess the survival of avian influenza in landfill leachate and the influence of environmental factors," says the report. The data showed that the virus survived in landfill leachate – liquid that drains from a landfill – for at least 30 days and up to 600 days. The two factors that most reduced influenza virus survival times were elevated temperature and acidic or alkaline pH, according to PhysOrg.

"Data obtained from this study indicate that landfilling is an appropriate method for disposal of carcasses infected with avian influenza," says the study, noting that landfills are designed to hold material for much longer periods of time.

Abstract

An integral component in preventing an avian influenza pandemic is containment and disposal of infected bird (poultry) carcasses. Disposal of carcasses in Subtitle D municipal solid waste (MSW) landfills may be an advantageous option due to their large capacities and facility distribution in the US.

In this study, the survival of H6N2 avian influenza virus (AIV) was measured in a methanogenic landfill leachate and water as a function of temperature, conductivity and pH.

Elevated temperature and non-neutral pH resulted in the quickest inactivation times for AIV in both media, whereas conductivity did not have a significant influence on AIV survival. Media effects were significant and AIV inactivation in leachate was consistently the same or faster than AIV inactivation in water.

Based on an initial titre of 105 TCID50/mL, calculated inactivation times ranged from 30 days to greater than 600 days, indicating that AIV will remain infectious during and after waste disposal.

Disposal of infected carcasses in a MSW landfill may be an appropriate option as inactivation times are within the design life of required barrier systems at Subtitle D landfills.

Reference

Graiver D.A., C.L. Topliff, C.L. Kelling and S.L. Bartelt-Hunt. 2009. Survival of the avian influenza virus (H6N2) after land disposal. Environ. Sci. Technol., 2009, 43 (11): 4063–4067.

Further Reading

- You can visit the Avian Flu page by clicking here.