A third dairy worker in the US has been diagnosed with H5N1 bird flu, this time experiencing respiratory symptoms, indicating the virus has reached the lungs. This Michigan-based worker is the first in the US to exhibit acute respiratory illness from H5N1 contracted from a cow, unlike the previous two cases that only involved conjunctivitis.
Human influenza typically spreads through respiratory droplets, such as from coughing or sneezing. With the recent mutation of H5N1 infecting the upper respiratory tract, experts worry about a higher risk of human-to-human transmission. Adam Kucharski, co-director of the Centre for Epidemic Preparedness at the London School of Tropical Hygiene and Medicine, noted on social media that these developments could be early signals of a new pandemic pathogen.
H5N1, which has killed millions of animals since resurfacing in 2020, has now spread to 68 cattle herds across nine US states. Experts anticipate a significant rise in human cases in the coming weeks as state health authorities ramp up surveillance efforts. Recently, US authorities introduced financial incentives to encourage farmer cooperation with testing.
In Michigan, the state hardest hit by infected dairy herds, about 220 individuals are being monitored for potential exposure to the virus. Dr. Nirav Shah, deputy director of the CDC, mentioned during a briefing that blood tests are being conducted to determine how many workers have developed antibodies to H5N1, indicating past infections or exposures.
The CDC still considers the risk of H5N1 to humans to be low but urges anyone working directly with cattle or poultry to wear personal protective equipment (PPE) and report any symptoms to health authorities. Meanwhile, the US government is in discussions for a significant investment in mRNA H5N1 vaccines produced by Moderna. An unnamed source involved in these talks revealed that tens of millions of dollars in funding from the US Biomedical Advanced Research and Development Authority (BARDA) could be available soon. The potential deal includes a commitment to stockpile millions of vaccines if trials prove successful.
In conclusion, the appearance of respiratory symptoms in a dairy worker infected with H5N1 marks a concerning development in the virus’s progression. While the CDC maintains that the risk to humans remains low, the mutation’s ability to infect the respiratory tract heightens concerns about possible human-to-human transmission. Ongoing monitoring, increased surveillance, and potential vaccine developments are critical steps in addressing this emerging threat.