First Human Case of H3N8 Bird Flu Found in China

April 28, 2022:

China has recorded the first human infection with the H3N8 strain of brain flu, though the risk of transmission among people remains low.

The case was found in a 4-year-old boy from the central province of Henan, the country’s National Health Commission said in a statement on Tuesday. He had a fever and other symptoms on April 5 and was hospitalized 5 days later.

The child had been in contact with chickens and crows raised at his home, the health authority said. The variant is also common in horses and dogs and was found in seals in 2011.

Until now, no human cases of H3N8 had been reported. Analyses suggest that the strain in this case is a reassortment, meaning it has genes from viruses that have been found in poultry and wild birds before, according to Reuters.

“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,” Peter Hornby, MD, a professor of emerging infectious diseases and global health at the University of Oxford, told The Guardian.

China’s Health Commission said the variant isn’t yet able to infect humans very well, based on an early study. The risk of a large-scale epidemic appears low, the health authority said.

But infectious disease experts have called for more surveillance of bird flu strains worldwide due to the record number of outbreaks across the U.S., U.K., and Europe this year, The Guardian reported.

Scientists think that a previous strain of H3N8, which is a subtype of influenza A, was behind the 1889 influenza pandemic, also known as the Russian flu. The virus needs to be tracked more closely, Erik Karlsson, deputy head of the Virology Unit at the Institut Pasteur in Cambodia, told Reuters.

Although rare, infections in humans can lead to mutations that could allow viruses to easily spread among mammals, he said.

“We need to be concerned about all spillover events.”

Last year, China reported the first human case of H10N3, according to Reuters. A 41-year-old man in China’s eastern province of Jiangsu was hospitalized and diagnosed with the strain, though the health commission didn’t provide details on how he became infected. He was discharged from the hospital, and an investigation of his close contacts found no other cases.

The country’s large populations of farmed and wild birds across many species can provide an environment for avian viruses to mix and mutate, Reuters reported. Some strains sporadically infect people, typically those who work with poultry.

In February 2021, Russia reported the first case of H5N8 spreading from poultry to humans, according to Live Science. Although there wasn’t evidence of human-to-human spread, seven poultry plant workers became infected with the strain.

The last major outbreak of the bird flu among humans occurred in 2016 and 2017, Reuters reported, when more than 300 people in China died due to the H7N9 strain. WebMD