Hong Kong reported its third fatal case of the H7N9 bird flu virus on Wednesday, as a 75-year-old man died in hospital. In common with two other Hong Kong residents who contracted bird flu, the victim had recently visited the southern Chinese city of Shenzhen.

Chinese state-controlled Xinhua News Agency also reported on Tuesday that three members of the same family in the eastern city of Hangzhou had been infected, one after another. Zhejiang province, where Hangzhou is the capital, is worst affected by H7N9, with almost half of the nation’s 110 cases this year occurring there.

Although Xinhua confirmed limited human-to-human transmission of the virus on Monday, the World Health Organization has said that there is no evidence so far of sustained transmission.

“So far there have not been any cases in which one person transmits the flu to another, and the latter transmits the virus to a third person,” Li Lanjuan, an academician at the Chinese Academy of Engineering and a specialist in H7N9 prevention, told Xinhua.

On Wednesday, China’s Ministry of Agriculture said that poultry farmers had lost an estimated $3.3 billion due to H7N9 infections, as sales and prices of poultry products have slumped severely. Chickens have been culled and live poultry markets have been closed as a protective measure.