Third person in US tests positive for H5N1 avian flu, CDC stresses risk is low

A third person in the United States has tested positive for the Avian Influenza (H1N1) virus. While the CDC has assured the risk to the general public remains low, the situation continues to be closely monitored and they are working with states to monitor individuals who have had contact with the animals. This is the second positive case reported in Michigan, the first being in Texas. The three cases are unrelated to each other, but all three patients were dairy workers who had contact with cows infected with the virus.^1,2

Mammals can become infected with the avian influenza virus if they eat contaminated birds or are exposed to environments contaminated with the virus. H5 avian influenza is typically widespread in wild birds and has occurred in poultry and dairy cows in the United States.^1,2

Image credit: Jonatan Rundblad | stock.adobe.com

The latest patient infected with avian influenza reported typical flu-like symptoms, including cough, stuffy nose, sore throat, and watery eyes. This differs from other cases, who reported eye symptoms similar to conjunctivitis. Typical symptoms of H5N1 avian influenza are mild (such as upper respiratory tract symptoms and eye infections), but more severe cases resemble pneumonia and include symptoms such as fever, muscle and body aches, headache, fatigue, and shortness of breath or difficulty breathing, which can lead to hospitalization. Other less common symptoms include diarrhea, nausea, vomiting, and seizures.^1,2

“What the respiratory symptoms tell us more than anything is that this virus, like many viruses, can manifest in multiple ways, so we need to remain vigilant and not fearful,” Nirav Shah, MD, JD, principal deputy director of the US Centers for Disease Control and Prevention, said at a briefing reported by CNN.¹

According to the CDC, the most effective treatment for avian influenza is considered to be influenza antiviral drugs. In addition, one patient infected with avian influenza has been found to be susceptible to influenza antiviral drugs. The CDC emphasizes that seasonal influenza vaccines do not protect individuals against the H5N1 strain.³

Officials said the third patient confirmed to be infected with H5N1 avian influenza is currently receiving treatment at home and is improving. An additional 200 people are under monitoring in Michigan. As of June 4, 2024, a total of 81 dairy cows in nine U.S. states have been infected with avian influenza. Since 2022, there have been a total of three cases of human infection through contact with dairy cows and one case through contact with poultry.^1,3

CDC recommends that individuals continue to take precautions by avoiding contact with wild or captive birds that appear sick or dead and are confirmed or suspected to be infected with the H5N1 virus, avoiding unprotected exposure to infected live or dead animals and contaminated surfaces, consuming raw milk or unpasteurized dairy products or uncooked or undercooked animal products (such as chicken) from animals infected with avian influenza, and traveling to other countries. FDA and USDA have stated that there is no significant safety threat to both commercially available milk and dairy products due to pasteurization requirements for interstate commerce. Additionally, individuals exposed to the virus are encouraged to monitor for signs of illness for 10 days after initial exposure.^2,3

Up-to-date information on cases of H5N1 avian influenza is available through the U.S. Department of Agriculture's Animal and Plant Health Inspection Service and the CDC.

References

1. Gore L. 3rd person in US tests positive for bird flu: what are the symptoms? AL.com. June 4, 2024. Accessed June 5, 2024. https://www.al.com/news/2024/06/3rd-person-in-us-tests-positive-for-bird-flu-what-are-symptoms.html

2. CDC. H5N1 Avian Influenza: A Summary of the Current Situation. CDC.gov. Updated June 4, 2024. Accessed June 5, 2024. https://www.cdc.gov/flu/avianflu/avian-flu-summary.htm

3. Gerlach, A. CDC confirms H5N1 avian influenza outbreak in the United States, but notes public health risk remains low. Pharmacy TimesApril 23, 2024. Accessed June 5, 2024. https://www.pharmacytimes.com/view/cdc-confirms-case-of-h5n1-bird-flu-in-the-united-states-noting-risk-to-public-health-remains-low