Human H5 bird flu case confirmed in Missouri

Media Contact:
Lisa Cox
Missouri Department of Health and Senior Services

JEFFERSON CITY, MO - The Centers for Disease Control and Prevention (CDC) has confirmed a human case of avian influenza A (H5) ("H5 bird flu") detected by the Missouri Department of Health and Senior Services (DHSS), the first human case detected in Missouri. The risk of sustained transmission or infection among the general public remains low.

The case was identified through DHSS' ongoing influenza surveillance program. The Missouri State Public Health Laboratory was sent a specimen from a patient who was hospitalized on Aug. 22. The adult patient has underlying medical conditions and tested positive for influenza A. The patient has reported no exposure to animals. The patient has recovered and was discharged home. To ensure patient privacy is maintained, no additional patient information will be provided.

As part of the normal influenza surveillance testing program, the Missouri State Public Health Laboratory conducted additional testing to determine the influenza subtype. This resulted in the presumptive detection of the H5 subtype. The specimen was forwarded to CDC for additional testing and was confirmed as H5 subtype of flu, also known as a bird flu, or avian flu. Additional virus characterization is underway at CDC.

H5 is primarily found in wild birds and poultry, and recently in dairy cows and other animals, and can occasionally infect humans through close contact with infected animals or contaminated environments. This is the fifteenth human case of H5 reported in the U.S. since 2022 (fourteenth this year). No H5 infection in dairy cattle has been reported in Missouri; some H5 cases in commercial or backyard flocks and wild birds have been reported.

Nationally, this is the first case of H5 that has been detected as part of the flu surveillance system, rather than the targeted H5-outbreak specific surveillance that has been conducted as part of ongoing animal outbreaks which has identified all the other cases. Missouri's flu surveillance system involves a collaborative partnership between clinical laboratories, Missouri health care providers, local public health agencies and the Missouri State Public Health Laboratory. DHSS continues to closely monitor available data from influenza surveillance systems, and there has been no sign of unusual influenza activity in people, including no increase in emergency room visits for influenza and no increase in laboratory detection of human influenza cases in Missouri.