“However, the altered ecology of H5N1 has opened the door to new evolutionary pathways.”
The concern is that cattle being found with the disease means that potentially humans could be exposed before the infected animals are caught.
This is because, as it stands, the only testing being done on cows is after they have died, the paper notes.
The doctor continued: “What keeps scientists up at night is the possibility of unseen chains of transmission silently spreading through farm worker barracks, swine barns, or developing countries, evolving under the radar because testing criteria are narrow, government authorities are feared, or resources are thin.”
The rapid evolution of HN51 is scaring virologists as the mortality rate for H5N1 humans is high, with a more than half of cases fatal from January 1, 2003, to July 19, 2024.
But, this may be an overestimate as some people may have no symptoms at all or only mild symptoms.
In addition, the latest outbreak has resulted in a milder illness, with those infected reporting flu-like symptoms before fully recovering.
“The severity of a future H5N1 pandemic remains unclear. Recent human infections with H5N1 have a substantially lower case fatality rate compared to prior H5N1 outbreaks in Asia, where half of the people with reported infections died.
“The lack of severity in US cases may be due to infection through the eye, rather than through viral pneumonia in the lung,” the researchers noted in the new study.
