The H5N1 flu virus and I go way back.
In 1997, I watched as more than a million chickens were slaughtered in Hong Kong to combat the first major global outbreak of the disease. Eighteen people were sickened by the virus and six died, all of whom had close contact with the birds. They were the first deaths in humans.
Though officials in Hong Kong and at the Centers for Disease Control and Prevention were pretty sure H5N1 was unlikely to spread from person to person (and still are), there were mysteries surrounding this flu strain that had suddenly acquired the ability to infect people. Among them: Some workers in Hong Kong’s poultry markets had antibodies to the virus but didn’t fall ill.
It fell off my radar until late 2005, when birds started dying in biblical numbers in remote eastern Turkey, where residents live in proximity to their animals. When bird flu is detected in an area, best practice is to promptly kill all domesticated fowl to prevent spread of the disease. The government was slow to react and farmers in the area only reluctantly culled their birds, often their main source of income. More than a dozen people were sickened and about a third died, including three of Zeki and Marifet Kocyigit’s four children.
I visited the family in their simple cement home during a frigid January and asked if the children had had contact with the birds. “Of course my children played with our chickens; they are children,” he said.
Shortly thereafter birds started dying of H5N1 in Greece and Nigeria. It was popping up all over Europe and Africa. Scientists determined that the virus was spreading from wild birds landing among domesticated flocks, making it hard to control by culls.
As wild fowl continued to threaten outbreaks in Europe, several countries mandated that chickens be kept indoors if dead wild birds were found in an area. In 2015, a variant of the H5N1 virus came to the United States, sparking outbreaks and culls on Midwest farms — though no human deaths.
Last year it turned up in harbor seals.
“This has been a 20-year process,” said Peter Hotez, an infectious-disease expert at Baylor College of Medicine. “The first red flag was birds dropping from the sky. The second was harbor seals. The third is, now, cattle.”
Cows in at least 51 dairy cattle herds in nine states have tested positive for the flu, though the full extent of the U.S. outbreak is unclear in part due to reluctance by farmers and farmworkers to cooperate with health officials. One human case has been reported — a dairy worker who suffered conjunctivitis.
There are important differences between the Hong Kong outbreak of more than 25 years ago and the current U.S. outbreak. H5N1 today is better understood; health authorities say that in the event of more human cases it should respond to antivirals like Tamiflu, and the CDC says the United States could produce and ship 100 million doses of a vaccine — already developed — within months.
But experts like Hotez still worry. “Surveillance testing has been very fragmented — I don’t think cattle was on anyone’s radar.”
He likens the virus’s appearance in herds to a modest earthquake in San Francisco: “You know something bigger is likely coming, but you don’t know if it’ll be one year or 100.”
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