While emphasizing that no human-to-human transmission has occurred, global health officials are urging countries to closely track bird flu to detect any potential changes in the virus that may make it more adept at spreading to and among humans.
Earlier this month, the CDC said while the threat avian flu poses to humans remains low, the situation is being taken "very seriously." Experts have heightened calls to ramp up surveillance efforts over the past few weeks amid growing reports of bird flu cases among dairy cows in the U.S., marking the first time the disease has been found in dairy cattle.
An individual in Texas who worked on a dairy farm tested positive for H5N1, health officials confirmed April 1. It was the second human case reported in the U.S. The first occurred in 2022 in an individual who worked with poultry. While human cases are rare, the disease carries a high mortality rate.
"The great concern, of course, is that in … infecting ducks and chickens, but now increasingly mammals, that this virus now evolves and develops the ability to infect humans," Jeremy Farrar, MD, a chief scientist at the World Health Organization, said during a press conference April 18, CNN reported. "We have to watch, more than watch, we have to make sure that if H5N1 did come across to humans with human-to-human transmission that we are in a position to immediately respond with access equitably to vaccines, therapeutics and diagnostics."
According to the Agriculture Department, genetic sequencing of virus samples taken from infected cattle indicates the virus is not more transmissible to humans, though scientists say additional data are needed to make more firm determinations.
HHS recently confirmed vaccines are in development to target the strain that infected the Texas resident. A technical analysis on flu samples from the case indicated the strain closely aligns with two candidate vaccines.