Bird flu is once again making many of us nervous. Earlier this week, health officials announced a human case of highly pathogenic H5N1 avian influenza in Texas, which may have been contracted from infected cows in the area. Recent livestock and human cases are indeed concerning, but for now, the risk to the public from avian influenza appears to remain low.
Texas health officials reported the human case on Sunday comfirmed Released Monday by the Centers for Disease Control and Prevention. The individual was identified only as a farmworker who tested positive for the H5N1 influenza virus and had recent exposure to cattle suspected of being infected with H5N1. However, so far, the only symptom the person has reported is red eyes, which could be a sign of conjunctivitis or pinkeye. This is the second human case of H5N1 avian influenza reported in the United States, following a 2022 case involving a prison worker who was handling potentially infected poultry.
Amesh Adalja, a senior scholar at the Johns Hopkins University Center for Health Security, said the potential dangers of H5N1 and other HPAI-like strains of avian influenza are very real.
“Avian influenza viruses have been ranked as the highest pandemic threat because of their ability to cause severe disease and because avian influenza viruses have caused influenza pandemics. For example, the 1918 influenza pandemic was caused by an avian virus,” Adalja said in a statement told Gizmodo in an email. “These viruses are often highly virulent, and the population has little immunity against them. This is significantly different from seasonal influenza viruses, which have herd immunity, vaccination programs, and generally have lower virulence.”
The H5N1 strain of avian influenza has been circulating for decades, causing large and deadly outbreaks in wild bird and even poultry populations. However, in the past few years, reports of sea lions, mink, dolphins and other mammals being infected with the H5N1 virus have been increasing.Last week, local and federal health officials announced first Cases of H5N1 have been found in cows on several dairy farms in Texas and Kansas.So far, cases in cattle have been detected five states, Although there has been a series of cases detected The condition appeared in goats on a Minnesota farm earlier this month.
These livestock cases are unprecedented. Unlike other mammalian cases, the threat of further transmission to humans is more likely given the animals’ close contact with farm workers. Currently, there are many unanswered questions about the nature of these outbreaks. Officials have found dead or infected birds near these farms, at least explaining how the cases began. But it’s unclear whether this strain has spread among cows.
“The key question is understanding how cows become infected,” Adalja said.
While this is concerning, the news we’ve learned so far isn’t all bad. Preliminary genetic analysis of strains collected from cattle has not found any obvious mutations that would make the virus apparently more likely to infect or make mammals sick, including humans. The strains also don’t appear to have undergone genetic changes that make them resistant to existing antiviral drugs, according to the CDC. The CDC says that while seasonal flu vaccines do not provide protection against H5N1, we do have the technology to produce vaccines against these strains on short notice if needed.
“The genetic evidence does not suggest that the virus has changed in a way that makes human-to-human transmission more likely,” Adalja said.
Other aspects of the situation were not immediately known. Recent human cases of avian H5N1 are rare but often fatal, with mortality rates as high as 50%. But it is uncertain whether strains adapted to spread among humans will maintain this level of virulence. At the same time, the covid-19 pandemic has shown that a fast-spreading virus can still kill and harm many people, even if it is not fatal on an individual level.
All of this suggests that H5N1 is a real problem that must be understood and contained as quickly as possible. The longer it circulates among cattle or other mammals, the more likely it is that some strains will acquire the right combination of mutations to turn it into a serious disease in humans. Even if these recent outbreaks are stamped out in time, scientists and health agencies must remain vigilant in case bird flu one day triggers a pandemic again.
For now, though, H5N1 won’t necessarily be the next virus everyone has to worry about.
“Influenza remains the greatest epidemic threat we face. However, it currently appears that these cattle illnesses are not a harbinger of a major public health threat to humans,” Adalja said.