Bird flu virus: Preparing for tomorrow despite minimal risk today

Highly pathogenic H5N1 avian influenza A virus (HPAI H5N1) remains a low risk to the general public. U.S. public health experts believe available treatments and vaccines, along with those in development, can prevent severe disease.

Despite this reassurance, the National Institutes of Health (NIH) continues to monitor the virus closely, evaluating potential changes.

In a commentary published in the New England Journal of Medicine, Dr. Jeanne M. Marrazzo and Dr. Michael G. Ison from the National Institute of Allergy and Infectious Diseases (NIAID) emphasize the importance of balancing vigilance with normalcy regarding HPAI H5N1.

“People should find a balance between enhanced vigilance and ‘business as usual’ with respect to HPAI H5N1,” the experts stated.

Global spread of bird flu virus

Since 1996, HPAI H5N1 has circulated across at least 23 countries. By late 2021, the virus spread from Europe to North America, infecting wild birds and poultry farms.

In 2022, it devastated birds and marine mammals in South America. Alarmingly, in March 2024, U.S. Department of Agriculture (USDA) scientists detected HPAI H5N1 in dairy cows, spreading to herds across 16 states. Over the past 30 days, the virus has been identified in dairy herds in three U.S. states.

Human infections remain rare but concerning. In 2024, 66 confirmed and 7 probable cases were reported in the U.S., along with one case in Canada.

These cases were linked to two types of the virus – one circulating in birds (D1.1) and another in dairy cows (B3.13).

Keys to controlling bird flu virus outbreak

Drs. Marrazzo and Ison outline four essential strategies to manage the current HPAI H5N1 outbreak:

Promote collaboration across disciplines

Effective control requires timely collaboration among experts in human and veterinary medicine, public health, health care, and occupational safety.

Building trust with communities and ensuring individuals seek care for symptoms, such as conjunctivitis, are equally critical. Fortunately, most U.S. cases have been mild, resolving without treatment.

Enhance disease surveillance

The Canadian HPAI H5N1 patient who developed respiratory failure highlights the urgency of vigilant disease surveillance. Genetic mutations in the virus found in this patient highlight the need for complete genomic sequencing of viral samples.

Dr. Marrazzo and Dr. Ison emphasize that this data should be shared quickly to identify and track viral changes, which might signal an increased risk of human-to-human transmission.

“Without information pertaining to where and when isolates were collected, the data cannot be linked phylogenetically to other reported sequences,” the authors noted. This early detection helps pinpoint mutations that may enhance the virus’s ability to infect human respiratory systems.

Advance medical countermeasures

Developing and testing vaccines and therapies remain vital. Fortunately, current vaccine candidates effectively neutralize circulating virus strains, and antivirals have shown promise in mitigating transmission and illness severity.

Minimizing bird flu virus exposure

Reducing contact with the bird flu virus is essential to limit its spread and protect individuals, especially those at higher risk of exposure.

Workers who handle poultry or cows, such as farmers or animal handlers, are particularly vulnerable because the virus can spread through infected animals or their environments.

To stay safe, these workers should follow guidelines from the CDC (Centers for Disease Control and Prevention) and USDA. This includes wearing personal protective equipment (PPE), such as gloves, masks, and protective clothing, to create a barrier against the virus.

Additionally, understanding occupational risks is vital. Workers should learn how the virus spreads, recognize potential symptoms of infection, and follow safe handling practices.

These precautions not only protect individual workers but also help prevent the virus from spreading further, potentially affecting others or reaching broader populations. By taking these steps, the risk of infection can be significantly reduced.

Ongoing challenges of bird flu

The four strategies outlined by Dr. Marrazzo and Dr. Ison aim to enhance our understanding of the H5N1 virus’s spread, evolution, and impact.

By integrating robust collaborations, effective surveillance, medical advancements, and preventive practices, public health experts hope to control the virus and answer key questions about its behavior.

While HPAI H5N1 presents ongoing challenges, the collective effort of scientists, health officials, and communities ensures we remain prepared for any future developments.

The study is published in the journal New England Journal of Medicine.

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