In May 2024 the US CDC announced that a second human case of highly pathogenic avian influenza (HPAI) A (H5) virus infection had been identified in Michigan, the third human case associated with an “ongoing multistate outbreak” of A(H5N1) in dairy cows. The CDC states that none of these three cases is associated with the others, but the latest case is a dairy farm worker with exposure to infected cows. However, this case is the first human case in the US to report “more typical symptoms” of acute respiratory illness associated with influenza virus infection. Despite assurance that it “continues to closely monitor available data”, questions are being raised about the adequacy of the response so far.
Case details
The case originated from a different farm than the previous case in Michigan and is in a dairy worker with exposure to H5N1-infected cows. The patient reported upper respiratory tract symptoms and was given antiviral treatment and encouraged to isolate. The patient’s symptoms “are resolving” and household contacts have not developed symptoms, nor have other workers at the same farm. Of specimens collected from the patient, one was positive for influenza A(H5) virus when tested at the state health department laboratory. Genetic analysis is underway to assess if changes have taken place within the virus to change the current risk assessment.
Health risk remains low
The CDC states that the case “does not change” the current human health risk assessment for the US public, as all three cases had direct contact with infected cows.
“Risk depends on exposure.”
Therefore, the risk to members of the public who have not had exposure to infected animals “remains low”. However, the recommended precautions remain in place.
Concerns about the response
Since the outbreak emerged in the US, experts have voiced concerns about the public health response and capacity or willingness to increase surveillance. In April, Dr James Lawler of the University of Nebraska Medical Centre’s Global Centre for Health Security told MedPage Today that “we really need to be moving quickly” to understand “what’s happening in the animal population and also what’s happening in the human population”.
“I don’t think we’ve been testing adequately to be able to get a real picture of that.”
For Time in May 2024, Dr Michael Mina, Chief Science Officer of eMed, and Janika Schmitt, Fellow at the Institute for Progress, identified a “complicating factor” in the US’ ability to control outbreaks: the responsibility is “divided between three federal agencies”. The US Department for Agriculture (USDA) manages livestock, the US Food and Drug Administration (FDA) manages food safety, and the CDC manages human health and surveillance. A lack of coordination here would be disastrous, and Dr Mina and Schmitt call for “regular and widespread testing”.
“We must stop flying blind.”
However, they suggest that there is “good news”.
“We have the tools to prevent an H5N1 pandemic at hand. But we must be willing to use them, and fast.”
Do you think the US is responding appropriately to control the situation? Join us to discuss the threat of avian influenza at the Congress in Barcelona this April, and don’t forget to subscribe to our newsletters for more updates.
