Two more people in mainland China have tested positive for the H5N6 bird flu virus, officials said, bringing the number of reported cases to eight this month. The recent rise in human cases has led to calls for increased surveillance.
Hong Kong’s health ministry said in a statement that it had received notice of two additional cases of people in Sichuan and Zhejiang provinces. Both cases occurred earlier this month, but local officials did not immediately disclose.
The first case, a 68-year-old man from Langzhong in Sichuan province, became ill on January 3 and was taken to a local hospital the following day, where he remains in critical condition. It is unknown how he was injured.
The second case concerns a 55-year-old woman from Hangzhou, Zhejiang Province, who became ill on January 6 after being slaughtered. She was admitted to the district hospital on January 9 and remains in critical condition.
Since the first confirmed case in 2014, only 67 people have been infected with H5N6 bird flu, but more than half have been reported in the past six months. Eight cases have been reported so far this year, including two deaths.
According to the World Health Organization, H5N6 bird flu is known to cause serious illness in people of all ages, killing nearly half of those infected. There have been no confirmed cases of human-to-human transmission, but a woman who tested positive last year denied contact with live poultry.
“The increasing trend of human infection with the avian flu virus has become a major public health problem that cannot be ignored,” researchers said in a study published by the CDC in China in September. The study revealed several mutations in two recent cases of H5N6 avian influenza.
Thijs Kuiken, professor of comparative pathology at the Erasmus University Medical Center in Rotterdam, expressed his concern about the growing number of cases. “This alternative may be more contagious (to humans)…or there is currently more of this virus in poultry and therefore more people are infected,” Koiken told Reuters in October.
Earlier that month, a WHO spokesperson said the risk of human-to-human transmission remained low because H5N6 had not acquired the ability to continuously transfer between humans. However, the spokesperson added that more surveillance is “urgently needed” to better understand the growing number of human cases.