BEIJING – Confirmed cases of H7N9 avian flu infections have spiked, prompting officials in China to ban live poultry sales ahead of the Chinese New Year. In Hong Kong, public health officials culled 20,000 birds, mostly chickens, at the country's wholesale market.

The World Health Organization (WHO) said there is no evidence of sustained human-to-human transmission, and the organization is not recommending travel or trade restrictions. Cases of H7N9 began in an initial wave from February to May 2013, the agency noted, but a second wave of human cases has been occurring since October. WHO reported 74 cases of H7N9 as of Jan. 21. China's official Xinhua News Agency has reported 96 known infections and 20 deaths from the virus.

The jump in cases is particularly troubling because the increase comes during the busy Chinese New Year. The Associated Press reported that the Chinese are expected to take 3.6 billion trips during the holiday, which officially begins Jan. 31. People will be traveling on crowded trains and buses, often with live chickens, according to AP. Evidence indicates that people become infected following close contact with infected live poultry, primarily in live-bird markets or when slaughtering birds at home.