LANZHOU -- Northwest China's Gansu province has reported three H7N9 bird flu cases, the province's first human infections this year, authorities said Tuesday.

On April 7, the city of Jiuquan reported Gansu's first human H7N9infection. The patient has recovered and has been discharged from hospital, according to a report by the provincial government.

Another two cases were reported this month in the cities of Jiuquan and Zhangye. Two women are receiving treatment at local hospitals, with one in a serious condition, the report said.

All three patients had been involved in the live poultry trade before becoming infected

Gansu has increased supervision of poultry markets.

In April, Jilin Province and Tibet Autonomous Region also reported their first human H7N9 infections for 2017.

The first human infection of the H7N9 bird flu strain was reported in China in March 2013. Infections are most likely to occur in winter and spring.

Experts recommend avoiding contact with birds, and only buying certified poultry.