As the Labor Day holiday on May 1 draws near, people who have booked tour packages to the Yangtze River Delta regions are becoming uneasy about an outbreak of H7N9 bird flu.

To date, no travel warning has been issued, but the daily update of H7N9 cases in the delta regions made a number of tour planners back down, which may hurt confidence in tourism in East China, especially Shanghai, where the first human case was reported and the flu is most serious.

By 4 pm Sunday, Shanghai had reported 24 H7N9 cases, nine of them fatal. Among the people infected was the husband of an H7N9 patient who had died. Health officials said there was insufficient evidence to determine that the man had caught the disease from his wife.