A four-year-old in central China’s Henan Province has contracted the H3N8 variant of the influenza virus, which was previously only known to be present in dogs, horses, and seals.
The case, which was announced on April 26 by authorities in the city of Zhumadian, involved a boy who developed symptoms on April 5 and was later hospitalized. He was diagnosed with H3N8 on April 24 — the first known human infection — and is reportedly in critical condition.
According to the U.S. Centers for Disease Control and Prevention (CDC), H3N8 is one of two strains known to cause dog flu in the U.S, and affects canines across the country.
The Chinese Health Commission said that while chickens and crows were raised in the boy’s home and that the area was populated by wild ducks, he was probably not infected via birds, according to an initial assessment.
The U.S. CDC said the case was likely “an accidental cross-species transmission” and that there was “a low risk of large-scale transmission.”
China reported 21 human cases of the H5N6 bird flu to the World Health Organization. Though such cases are rare, they often cause serious symptoms, with six of the registered cases resulting in death.