Swarming insects causing distress at World Exposition in Osaka

The small flies have been found on walls and the pillars of the wooden Grand Ring encircling many of the pavilions, with people forced to fight them off to avoid swallowing them.

"It shocked me when they landed on the bread I was eating. There are so many of them around and it's disgusting," said Toma Masatani, a 23-year-old graduate school student visiting the expo with friends from Saitama, near Tokyo.

While the midges at the expo do not bite, dead ones can cause asthma and other allergic reactions if inhaled.

"Wearing a face mask is advisable for those with asthma," said Koichiro Kawai, a professor emeritus at Hiroshima University specializing in the species. He added that electronic insect killers and insecticides are effective in getting rid of them.

The insects are believed to be emerging from the Water Plaza in the southern part of the venue, where seawater is stored. Noting they are possibly of marine origin, Kawai said they could persist until the end of autumn.

The expo organizer is taking action, spraying insecticide in locations where the midges are spotted, treating areas where rainwater tends to accumulate with a growth inhibitor and installing insect repellent lights.

Osaka Gov. Hirofumi Yoshimura has also sought cooperation from insecticide maker Earth Corp. to counter the midges.

"We will fulfill our role of contributing to the expo's success by utilizing the knowledge and technology we have cultivated," the company said.

As written before, World Expo in Osaka tops 1 mil. visitors in first 13 days.