Third Person in US Tests Positive for H5N1 Bird Flu, CDC Emphasizes Risk Remains Low

A third person has tested positive for avian influenza (flu, HPAI) H5N1 virus in the United States. The CDC assures that the risk to the general public still remains low; however, the situation remains carefully watched and collaborations with states are being made to monitor individuals with animal exposures. This positive case was the second to be reported in Michigan, and the first positive case was in Texas. The 3 cases are not associated with each other; however, all 3 patients were dairy farm workers who were exposed to cows infected with the virus.^1,2

Mammals can be infected with bird flu viruses when they either eat tainted birds or are exposed to environments that have been contaminated with viruses. H5 bird flu is typically widespread in wild birds and is causing outbreaks in poultry and United States dairy cows.^1,2

The most recent patient to be infected with bird flu reported symptoms that are similar to the typical flu—such as cough, congestion, sore throat, and watery eyes—unlike the other cases, which reported eye symptoms that were more like pink eye. Typical symptoms of H5N1 bird flu can be mild (eg, upper respiratory symptoms or eye infection), with more more severe cases similar to pneumonia—with symptoms including fever, muscle or body aches, headaches, fatigue, and shortness of breath or difficulty breathing, potentially leading to hospitalization. Other less common symptoms include diarrhea, nausea, vomiting, or seizures.^1,2

“What the respiratory symptoms tell us, more than anything, is that this virus, like many viruses, can present in more than 1 way, and for that reason, we should remain alert, not be alarmed,” said Nirav Shah, MD, JD, the principal deputy director of the US Centers for Disease Control and Prevention, in a briefing reported by CNN.¹

According to the CDC, flu antiviral medications are considered to be the most effective treatment against bird flu. Additionally, 1 of the patients infected with bird flu were confirmed to be susceptible to flu antiviral drugs. The CDC emphasizes that seasonal flu vaccines are not able to protect individuals against H5N1.³

This third confirmed patient with H5N1 bird flu is currently being treated at home with improving symptoms, according to officials. Additionally, another 200 people are being monitored in Michigan. As of June 4, 2024, a total of 81 dairy cow herds within 9 US states were affected by bird flu. Since 2022, there have been a total of 3 cases in humans following exposures to dairy cows, and 1 following exposure to poultry.^1,3

The CDC recommends that individuals can continue to practice protective actions by avoiding contact with wild birds and wild or domestic birds that appear ill or have died and are confirmed or suspected to have the H5N1 virus; avoid unprotected exposure to infected live or dead animals and contaminated surfaces; consuming raw or unpasteurized milk products and uncooked or undercooked animal products (eg, poultry meat) from animals with bird flu; and traveling to other countries. Both the FDA and United States Department of Agriculture note that there is no significant safety threat to both commercial milk and dairy products due to interstate commerce pasteurization requirements. Further, individuals with exposure to the virus are recommended to monitor for potential signs of illness for 10 days following the initial exposure event.^2,3

Updates on H5N1 bird flu cases can be found through the USDA Animal and Plant Health Inspection Service as well as the CDC.

References

1. Gore L. 3rd person in U.S. tests positive for bird flu: What are 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 Bird Flu: Current Situation Summary. 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 Case of H5N1 Bird Flu in the United States, Noting Risk to Public Health Remains Low. Pharmacy Times. April 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