HANGZHOU - Three new human H7N9 cases were reported on Sunday in East China's Zhejiang province and Guangdong in the south.

Zhejiang has seen new human H7N9 cases for 17 consecutive days since January 9. The new cases brought the number of infections in the province to 46 so far this year, said the provincial health and family planning commission.

The new patients in Zhejiang, two men aged 40 and 65, are being treated in hospitals in Hangzhou city.

The new case in Guangdong, an 82-year-old man, is in a critical condition, according to the health and family planning commission of Guangdong.

Human cases of H7N9 have been reported in Shanghai, Beijing, Jiangsu province in the east and Fujian in the southeast.

Liang Weifeng, deputy head of the department of infectious diseases at the First Hospital of Zhejiang Province, said that H7N9 virus survives at low temperatures and tends to become more active during fall, winter and spring.

With Spring Festival being peak season for poultry sales and consumption, some poultry markets in Zhejiang have been suspended to prevent the spread of infection.

Liang predicts that the number of new cases will drop sharply after the suspending of poultry markets.

According to Li Lanjuan, academician at the Chinese Academy of Engineering and a specialist in H7N9 prevention, in April 2013, when the virus was as active as it is now, the infection was kept under control by closure of poultry markets.

The H7N9 virus was active in China last spring, and reemerged in November.