Authorities are closing live poultry markets in multiple Chinese cities and provinces, in an effort to stop the spread of the deadly H7N9 strain of the avian flu virus. "Officials in the southern Chinese city of Guangzhou – population 17 million – found more than 30 percent of the city's poultry markets are contaminated with the H7N9 strain of bird flu," as NPR's Rob Schmitz reports from Shanghai. The large city is a "major transportation hub for migrant workers," according to the South China Morning Post , raising fears of further spread of the deadly strain. China has seen an uptick of cases of H7N9. "State media has reported 130 human cases of bird flu in January, resulting in 24 deaths," Rob says. In Sichuan province, authorities say they have closed "280 live poultry trading and slaughtering venues in Suining city," according to the state-run Xinhua news agency . It adds that authorities have also halted poultry live trading in Zhejiang province since Saturday evening.