China has reported two new cases of H5N6 bird flu in humans

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 the number of human cases has led to calls for increased surveillance.

The Hong Kong Ministry of Health said in a statement that it had received notification of two additional cases of people in Sichuan and Zhejiang provinces. Both cases occurred earlier this month, but local officials did not immediately disclose them.

The first case, a 68-year-old man from Langzhong in Sichuan Province, fell ill on January 3 and was taken to a local hospital the next day, where he remains in critical condition. It is not known how he was injured.

The second case is a 55-year-old woman from Hangzhou, Zhejiang Province, who fell 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 avian influenza, but more than half have been reported in the past six months. Eight cases have been reported so far this year, including two deaths.

Click here for a list of all human cases to date.

According to the World Health Organization, the H5N6 virus 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 the woman who tested positive for the virus last year denied coming into contact with live birds.

“The increasing trend of human infection with avian influenza 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 bird flu.

Thijs Kuiken, professor of comparative pathology at Erasmus University Medical Center in Rotterdam, expressed 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, so more people are infected,” Quicken 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 transmit between humans. However, the spokesperson added that there is an “urgent need for more monitoring” to better understand the growing number of human cases.