As mentioned eighteen hours ago in CDC FluView Week #50: Seasonal Flu Rising - 3 Confirmed & 1 Probable H5 Cases For the Week, the CDC's official H5 case count - which then stood at 61 - was likely to increase before the day was out.
A few hours later, California announced 2 more cases (n=36), and late yesterday, Iowa announced their first case (see statement below).
Iowa HHS Reports First Human Case of Highly Pathogenic Avian Influenza (HPAI) in Iowa, Risk Remains Very Low to Public
Friday, December 20, 2024
News Release
The Iowa Department of Health and Human Services (Iowa HHS) is reporting the first human case of avian influenza A(H5) in the state. The individual was exposed to infected poultry while working with a commercial flock in northwest Iowa. The individual reported mild symptoms, has received appropriate treatment and is recovering. The case was identified through testing at the State Hygienic Laboratory and confirmed by the Centers for Disease Control and Prevention (CDC).
As of December 20, 2024, the CDC has reported 64 confirmed human cases of H5 HPAI across nine states. The majority of the exposures are linked to infected poultry or dairy cows. There is no evidence that human-to-human transmission of influenza A(H5) is occurring in the U.S.
Although human infections are rare, the virus is spread through prolonged exposure around infected flocks and herds, through the eyes, nose or mouth. Any individuals with direct contact who develop flu-like symptoms or an eye infection should contact their doctor. To reduce the risk of infection or spread, people in direct contact with exposed animals should wear proper PPE and avoid direct contact with sick or dead animals, including birds.
“Iowa has monitored the spread of avian influenza closely since it was first detected in poultry in the state in 2022, and our state is prepared with the established knowledge, strong partnerships, and effective tools to mitigate its impact on our community,” said Iowa HHS State Medical Director Dr. Robert Kruse.
There is no concern about the safety of eggs and poultry products or pasteurized milk and dairy products. As a reminder, consumers should always properly handle and cook eggs and poultry products, including cooking to an internal temperature of 165˚F. Pasteurization has continually proven to successfully inactivate bacteria and viruses, like influenza, in milk.
Twelve states have now reported either CDC confirmed (n=10) or probable (n=2) H5 infections. In addition to their confirmed cases, California also has identified 1 probable and Washington has identified 3.
Combined, the number of H5 cases now sits well over 70 (not including serologically identified cases).
Last yesterday the CDC updated their chart (see below) to include 2 new cases from California, and 1 from Wisconsin. Note: it does not include the newest Iowa case.
While we watch these numbers intently, they likely only represent a portion of the human H5 cases out there. We know from experience that surveillance and testing only picks up a fraction of the total number of cases.
The proverbial `tip of the iceberg’ or in the case of the graphic below, the `top of the pyramid’.
Sentinel surveillance systems are important for the monitoring of respiratory viruses in the EU/EEA, but these systems are not designed and are not sufficiently sensitive to identify a newly emerging virus such as avian influenza in the general population early enough for the purpose of implementing control measures in a timely way.Similarly, in 2023's analysis from the UKHSA (see TTD (Time to Detect): Revisited), they estimated there could be dozens or even hundreds of undetected human H5N1 infections before public health surveillance would likely detect them, potentially over a period of weeks or months.
