Map of China showing areas that have reported cases of bird flu infection and fatalities since the start of January.

Human bird-flu infections may rise in Asia as people handle more poultry for next week’s Lunar New Year celebrations, according to a United Nations veterinarian who tracks the virus in birds.

Health authorities in China, South Korea and Vietnam have stepped up surveillance of H5N1 avian influenza among poultry ahead of the festival, which starts Jan. 26.

Production of chickens and ducks swells as much as three times in the run-up to the holiday, making outbreaks more likely, said Jeff Gilbert of the UN’s Food and Agriculture Organization in Hanoi, Vietnam.

“It’s a little bit more of a tinderbox,” Gilbert said in a telephone interview Tuesday. “If it’s going to happen, it’s more likely to happen now than in another two or three months.”

A flu pandemic of avian or other origin could kill 71 million people worldwide and lead to a “major global recession” costing more than $3 trillion, according to a worst-case scenario outlined by the World Bank in October.

Indonesia, which leads the world in human deaths from bird flu, reported two more fatalities Wednesday. China has reported three human deaths from the virus this year and Vietnam has reported one case in a girl who recovered. Last week Nepal reported its first outbreak of the virus among poultry.

In Vietnam, the nation with the most outbreaks of H5N1 in birds since late 2003, cases in poultry surged in the lead-up to the Lunar New Year every year from 2004 to 2007, FAO figures show. The number of outbreaks in the country has dropped roughly by half in the past two years, and no new infections in fowl have been reported so far this year to the Paris-based World Organization for Animal Health.

Health authorities have been monitoring H5N1 for more than a decade for any sign that it’s becoming as contagious as seasonal flu. While millions of birds have been infected, fewer than 400 people are reported to have contracted the illness, of which almost 250 have died, according to the Geneva-based World Health Organization.