The World Health Organization (WHO) yesterday shared more details from Cambodia about its latest fatal H5N1 avian flu case, including that it involves the older 2.3.2.1c clade but noting that the virus that infected the girl is a novel reassortant that include internal genes from the newer 2.3.4.4b clade.
Investigators found that poultry died in the girl's Prey Vent province village and that her family was given some of them to eat and that the girl was exposed to the chicken while preparing food. Her symptoms began on August 11, and, when her condition worsened, she was hospitalized about a week later in Phnom Penh and treated with oseltamivir (Tamiflu). She died on August 20.
Sequencing of the patient's virus sample at the Pasteur Institute in Cambodia found that the hemagglutinin gene from the 2.3.2.1c clade that has been circulating in Cambodia and Southeast Asia since 2013. The internal genes, however, belonged to the newer 2.3.4.4b, which is circulating globally. "This novel reassortant influenza A(H5N1) virus has been detected in human cases reported in Cambodia since late 2023," the WHO said.
Cambodian health officials have tracked and monitored the girl's contacts, and no related cases have been found. The country has reported an uptick in human H5N1 infections since 2023, reporting 6 cases last year and 10 this year, of which 2 were fatal.
Reassortant circulating in poultry, found in earlier human cases
In April, animal health officials in Vietnam and the United Nations Food and Agriculture Organization (FAO) warned of the new reassortant circulating in chickens and muscovy ducks.
The scientists said the virus has been circulating in the Greater Mekong subregion since 2022. Also, they noted that the reassortant had been linked to recent human cases and that the development shows the adaptive capacity of the virus and the risk of new, potentially more virulent strains.