New virus spreads: Health experts issue US pandemic warning as H5N1 bird flu virus spreads rapidly across all 50 States

Since March 2024, the outbreak has affected over 1,000 dairy herds nationwide, leading to more than 70 human infections and at least one confirmed death. The Global Virus Network (GVN) is warning that the virus's continued presence in mammals increases the risk of mutations that could enable human-to-human transmission.

They emphasize the urgency of enhanced surveillance, standardized testing, and vaccination strategies for both animals and farmworkers. "Understanding the current landscape of H5N1 infections is critical for effective prevention and response," said Sten H Vermund, MD, PhD, chief medical officer of the GVN and dean of the USF Health College of Public Health at the University of South Florida, USA. "The virus' ability to infect both animals and humans, combined with recent genetic changes, underscores the importance of proactive surveillance and rapid response measures."

Despite the outbreak, the Centers for Disease Control and Prevention (CDC) maintains that the risk to the general public remains low. However, they stress the importance of precautions, especially for those in close contact with infected animals.

According to a journal posted online in the Lancet Regional Health “one mystery is the sporadic H5N1 infections that have occurred in humans with no known contact with infected animals, some of which resulted in severe disease”. It adds: “The first confirmed death in the US is an individual who likely contracted infection from wild birds that died on his property. These sporadic human infections increase the opportunities for a virus with sustained ability of human-to-human transmission.”

While the current public health risk is low, CDC is watching the situation carefully and working with states to monitor people with animal exposures. CDC is using its flu surveillance systems to monitor for H5 bird flu activity in people.