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Detecting avian influenza could save millions of birds each year

The development of a method to detect infectious bird flu in wetlands marks a significant advancement in our understanding and management of avian influenza, especially the highly pathogenic avian influenza (HPAI). 

The research, led by Laura Hubbard and her team at the U.S. Geological Survey, highlights the importance of rigorous monitoring of wild bird populations. 

The study is especially relevant in the context of recent outbreaks that have led to the deaths of millions of poultry and the subsequent rise in the cost of eggs and poultry products.

Deadly virus

The study focused on wetlands, a critical habitat for waterfowl, which are known to be a significant reservoir for the avian influenza virus. 

While many strains of this virus do not cause disease, highly pathogenic avian influenza can be deadly, making its detection and management crucial. 

Detecting the virus in natural environments

One of the primary challenges in controlling the spread of bird flu has been the difficulty in detecting the virus in natural environments like wetlands, where the concentration of infectious viruses is typically low. 

The new method developed by Hubbard’s team addresses this issue by using a multistep process to concentrate and identify the virus in environmental samples.

Contaminated wetland sites

The effectiveness of this new method was demonstrated in a study conducted in the spring of 2022, where the team collected surface water samples from four wetlands and a lake in Iowa. The results were telling: infectious bird flu virus strains were found in all four wetland sites in April, but not in the lake. 

Notably, the detection rates for viral RNA using standard diagnostic protocols were significantly lower (11.1%) compared to the rates when the samples were inoculated into eggs for virus isolation (66.7%). This discrepancy underlines the need for improved RNA detection techniques to avoid false negatives.

Interestingly, most of the viral strains detected in the water samples were of low pathogenicity. However, the detection of highly pathogenic avian influenza in one sample was particularly noteworthy, marking the first time this strain has been identified in a U.S. waterway. 

Environmental factors

Subsequent testing five weeks later did not detect the virus at the same sites, despite previous research indicating that the virus could persist for months in such environments. 

The researchers suggest that environmental factors, such as the presence of fewer waterfowl and warmer water temperatures, might influence the survival of the virus.

Potential risks

This research underscores the potential risks that bird flu poses not only to wild and domestic birds but also to other animals and humans, especially those using these waterways for recreational purposes. 

The detection of both highly pathogenic avian influenza and other strains in the wetlands highlights the importance of regular monitoring and early detection of the virus. 

Such measures are vital for mitigating the transmission of the virus, which can have significant economic implications, as evidenced by the recent increase in poultry and egg prices.

Controlling the spread of avian influenza 

The innovative method developed by Hubbard and her team offers a more effective way to monitor and understand the transmission of bird flu in natural environments. 

This advancement is critical in our ongoing efforts to manage and control the spread of avian influenza, thereby protecting not only our poultry industry but also public health and natural ecosystems.

More research is needed

“Further research is needed to improve the collective understanding of AIV in the environment, including persistence and potential for transmission via water to birds and mammals, supporting early detection of HPAI viruses and other AIVs, and mitigation to reduce the spread of disease into domestic poultry and potentially to other wildlife,” wrote the study authors. 

“This information also has potential human health implications, especially in public use waterways, where people may have direct exposure to AIV with primary or secondary contact.”

The study is published in the journal Environmental Science & Technology Letters

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