NEW YORK (AP) – The mysterious death of a man in Mexico who contracted a form of bird flu is unrelated to different types of outbreaks on U.S. dairy farms, experts say.
Here’s a look at the case and the different strains of bird flu.
WHAT HAPPENED IN THE MEXICO BIRD FLU CASE?
In Mexico, a 59-year-old man who was bedridden due to chronic health problems experienced fever, shortness of breath and diarrhea in April. He died a week later, and the World Health Organization reported this this week.
The World Health Organization said that the H5N2 version of bird flu was seen in a human for the first time.
WHAT IS HAPPENING WITH BIRD FLU IN THE USA?
H5N1, a variant of bird flu, has been infecting poultry for the past few years, leading to the culling of millions of birds. It is also spreading among all the different animal species in the world.
This year, influenza was detected on dairy farms in the United States. Dozens of herds have been infected, most recently in Iowa and Minnesota.
The cow outbreak has been linked to three reported illnesses in farm workers, one in Texas and two in Michigan. Each had only mild symptoms.
WHAT DO THE LETTERS AND NUMBERS IN BIRD FLU NAMES MEAN?
Because so-called influenza A viruses are the only viruses linked to flu outbreaks in humans, their occurrence in animals and humans is concerning. These viruses are divided into subtypes based on the types of proteins found on their surfaces: hemagglutinin (H) and neuraminidase (N).
Scientists say there are 18 different “H” subtypes and 11 different “N” subtypes, and they occur in many combinations. H1N1 and H3N2 are common causes of seasonal flu in humans. There are many versions also seen in animals.
The version of H5N1 that has recently worried some US scientists has historically been seen primarily in birds, but has also spread to a wide range of mammals in recent years.
WHAT IS H5N2?
H5N2 has long been detected in Mexican poultry, and farms are vaccinating against it.
He is also no stranger to the United States. An H5N2 outbreak struck a flock of 7,000 chickens in south central Texas in 2004; For the first time in two decades, a bird flu dangerous to poultry has emerged in the United States.
H5N2 was also responsible for waves of outbreaks on commercial poultry farms in the United States in 2014 and 2015.
HOW DANGEROUS IS H5N2?
Over the years, H5N2 has fluctuated between a slight threat to birds and a serious threat, but it was not considered a very serious threat to humans.
A decade ago, researchers used mice and ferrets to study the strain that was affecting poultry in the United States at the time and concluded that it was less likely to spread and less lethal than H5N1. Officials also said there was no evidence that the virus was spreading among humans.
Rare cases of animal infection are reported every year, so it is not unexpected for a person to be diagnosed with H5N2.
“If you’re a glass-half-full kind of person, you might say: ‘The system is doing exactly what it’s supposed to do: detecting and documenting these rare human infections that we stumbled upon in the dark years ago.’ ” said Matthew Ferrari, director of the Penn State Center for Infectious Disease Dynamics.
Indeed, Mexican Health Minister Jorge Alcocer said that the man’s death was actually caused by kidney and respiratory failure, not the virus.
Some experts said that it was remarkable that it was not known how the man who caught H5N2 was caught.
St. “The fact that no contact with an infected bird has been reported raises the possibility that it contracted the infection from someone else who visited it, but it is too early to draw these conclusions,” said Richard Webby, an influenza researcher at St. Jude. Children’s Research Hospital in Memphis.
WHAT ABOUT OTHER TYPES OF BIRD FLU?
At this point, H5N2 is still considered a minor threat compared to other strains of bird flu. Most human illnesses are attributed to H7N9, H5N6 and H5N1 avian influenza viruses.
From early 2013 to October 2017, five H7N9 outbreaks were blamed on China, killing more than 600 people. At least 18 people have died during the H5N6 outbreak in China in 2021, according to the U.S. Centers for Disease Control and Prevention.
H5N1 was first identified in 1959, but it didn’t really start to worry health officials until the Hong Kong outbreak in 1997, which caused serious human illness and death.
H5N1 cases have continued ever since, and the vast majority involve direct contact between humans and infected animals. According to WHO statistics, more than 460 human deaths have been identified globally since 2003; This suggests that the virus could kill half of the people reported to be infected.
Like other viruses, H5N1 evolved over time, giving rise to newer versions of itself. Over the past few years, the dominant version of the virus has spread rapidly among a wide range of animals, but the number of human deaths has slowed.
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Associated Press writer María Verza in Mexico City contributed to this story.
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The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Science and Education Media Group. AP is solely responsible for all content.