An H3N8 strain of bird flu has been detected in humans for the first time, in China’s central province of Henan.
The four-year-old boy infected had been in contact with chickens and crows raised at his home, according to reports from China’s National Health Commission.
Avian influenza or bird flu as it is commonly known is a highly contagious viral disease with the first reports of human cases in the 1990s.
Some strains of the bird flu, such as with H3N8 now, have been passed to humans but this is currently very rare, and usually occurs after very close contact with infected birds or animals.
H3N8 viruses circulate widely in birds and in horses and have also been detected in dogs in North America.
“We often see a virus spread to a human and then not spread any further so a single case is not a cause of great concern,” said Sir Peter Horby, professor of emerging infectious diseases and global health, University of Oxford.
“There is no reason to think it will go any further,” said Prof Paul Digard from the Roslin Institute, University of Edinburgh, adding that Chinese authorities had not reported any illness in the immediate contacts of the infected boy.
1st human case of H3N8 bird flu reported in 4-year-old boy in China
A 4-year-old boy in China has become the first human case of the H3N8 strain of bird flu, according to news reports.
The boy, who lives in Henan province, was exposed to chickens and crows at his home, which could have transmitted the virus, according to news reports. The boy was infected with an avian version of the H3N8 virus, though strains of this virus can also infect horses (known as equine influenza virus) and dogs (known as canine influenza virus).
And now it has made the leap to humans, though the risk of it spreading from human to human is low, according to a Reuters report.
Though avian flu viruses originated in birds and don’t easily spread to other animals, in rare cases, strains have adapted to infect other animals — such as dogs and horses — as well as humans, Live Science previously reported. Bird flu strains that have hopped to humans include: H5N1, H7N9, H5N6, H5N8 and now H3N8.
Medical experts have advised residents to avoid contact with sick and dead poultry and live poultry in daily life and to pay close attention to their dietary hygiene as well, the statement noted.
The NHC also said Chinese Center for Disease Control and Prevention tested close contacts of the child.
“Henan Province carried out medical observation and sampling tests on the close contacts of the child, and no abnormality was found,” the statement said.
Rare human case of bird flu
China is among 135 countries affected by the type A influenza pathogen, according to the U.S. Centers for Disease Control and Prevention. In the United States alone, more than 33 million cases of the bird flu have been detected so far this year. The outbreak among poultry in the U.S. is the largest since 2015, according to the Associated Press.
Birds can catch the highly pathogenic illness when they come into contact with the “saliva, nasal secretions or feces” of an infected bird, the CDC says. Since the latest outbreak, farms have had to kill millions of poultry to limit the disease’s spread.
Experts say although the H3N8 virus originates from birds, cases have been detected across an array of species throughout the world.
Human cases of the avian flu are rare, but they are possible when enough viral components get into the eyes, nose or mouth. Direct or indirect exposure to infected live or dead poultry, like at live bird markets, pose as the primary risks for human infections, according to the World Health Organization. Once a person is infected, symptoms range from conjunctivitis, fever, diarrhea and vomiting to severe respiratory illness and neurological changes.
Health officials have urged the public to avoid contact with sick and dead birds, and say it is still safe to eat properly handled poultry cooked to an internal temperature of 165 degrees Fahrenheit.
What We Know About H3N8 Bird Flu Strain
Ian MacKay, a virologist at the University of Queensland, Australia, told CNET: “These early infections should always be responded to thoroughly and comprehensively with sensitive testing of contacts to ensure no other spread occurred or is ongoing.”
In 2012, the H3N8 flu was associated with the deaths of harbour seals in New England the previous year, with researchers saying the virus may have evolved from a type that had been circulating in birds.
In previous years scientists have also said H3N8 has carried out host-jumps from equine populations to dogs, sometimes causing severe illness.
China is among the world’s biggest poultry producers along with the United States. Large populations of farmed birds can create an ideal environment for avian viruses to spread and evolve.
“The increase in human cases in China this year is of concern. It’s a virus that causes high mortality,” Thijs Kuiken, professor of comparative pathology at Erasmus University Medical Centre in Rotterdam, told Reuters. The agency reported on October 26 that at least six people had died.
Bird flu can also be devastating for bird populations. The U.S. is currently experiencing a bird flu epidemic of the H5N1 strain that has resulted in nearly 27 million chickens and turkeys having to be killed in 30 states, according to CNET. The infections have also spread to bald eagles, causing dozens of deaths in that species.