China has reported the world’s third case of human infection with the avian influenza virus A(H3N8). This was reported by the World Health Organization (WHO) on Tuesday evening. This is not the H5N1 lineage 2.3.3.4b, which is currently rampant among wild birds and poultry around the world and has also been detected in various mammals.
The most recent H3N8 case infected a 56-year-old from the Chinese province of Guangdong. She came to the hospital on March 3 with severe pneumonia and died there on March 16. The woman with previous illnesses had contact with poultry at a market where this virus was also detected. Other people with whom the woman had contact would not have been infected. The other two human H3N8 cases were reported from China in April and May 2022, according to the WHO. One person became seriously ill, a second had only mild symptoms.
Individuals are usually infected with bird flu viruses after contact with poultry or wild birds. Many do not even notice the infection or have only mild symptoms, while others develop serious respiratory diseases. Health experts warn of the danger that the virus will adapt to humans and then be transmitted from person to person.
WHO: Little risk of spread in humans
With regard to the H3N8 case now reported from China, the WHO writes that this bird flu virus is often found in dogs, horses, pigs and other animals worldwide. Unlike H5N1, it causes hardly any or only mild symptoms in poultry and wild birds. “According to the information available, the virus does not appear to have the ability to spread easily from person to person,” the WHO said. “The risk of the virus spreading among people at the national, regional and international levels is assessed as low.”
A more detailed risk analysis from May 2022 is still valid, said a WHO spokeswoman. It said: “While further infection in humans with A(H3N8) viruses cannot be ruled out, the risk is low. The likelihood of sustained human-to-human transmission is also low, based on the limited information available to date stand.”
According to the Friedrich Loeffler Institute (FLI), the German research center for animal health, as of March 6 there were a single-digit number of human infections worldwide with the H5N1 lineage 2.3.3.4b, which is currently rampant worldwide. This lineage is also known to infect and kill mammals such as mink, seals, foxes, raccoons, martens and bears.
Human infections and deaths with other H5N1 strains of bird flu have been known for many years. Since 2003, a total of 873 cases in humans from 22 countries have been reported to the WHO in connection with H5N1. More than half were fatal. The WHO has only registered a few cases since 2020, six last year and three this year (as of March 3, 2023).
