Racing to contain an avian flu outbreak, about 400 workers culled 112,000 birds at two Kumamoto chicken farms from Sunday night through Monday.

After bagging up the live chickens, the workers, dressed in white protective suits, surgical masks and rubber boots, gassed them with carbon dioxide and buried them at the two farms, one in the town of Taragi and the other in the village of Sagara.

Two hundred Ground Self-Defense Force personnel, dispatched from the 8th Division based in the city of Kumamoto, joined the culling effort and delivered caustic lime to disinfect the farms.

At least 1,100 chickens at the Taragi farm were apparently struck by an H5-type avian flu virus between Friday and Sunday morning.

The Kumamoto Prefectural Government ordered 56,000 chickens culled at the Taragi farm and the same number at another nearby run by the same operator in Sagara.

Seventy chickens were found dead at the Taragi farm on Friday and another 200 on Saturday, a Kumamoto Prefectural Government official said. The farmer reported the deaths to the prefectural government on Saturday.

“I’m not worried much about (possible) spread of secondary infection because we received a report (from the farm operator) at a relatively early stage,” Tottori University professor Toshihiro Ito was quoted by Kyodo News as saying to reporters.

Ito chaired a panel on avian flu for the agriculture ministry.

For now at least there is no perceived threat to human health. The agriculture ministry notes that no case of bird-to-human infection has ever been recorded in Japan.

But the outbreak has raised the alarm among chicken farmers in neighboring Kagoshima and Miyazaki prefectures, the top two domestic chicken producers in terms of value, respectively.

Local authorities have begun disinfecting vehicles at 11 checkpoints around the two farms, agriculture ministry officials in Tokyo said.

The Kumamoto Prefectural Government has banned the transportation of any eggs and all 43,000 chickens kept within 3 km of the farms, the officials said.

Chicken ranchers between 3 km and 10 km from the farms are forbidden from transporting their chickens and eggs outside the areas, although moving them within the region is still acceptable, the agriculture ministry said.

Meanwhile, the Consumer affairs agency on Monday posted a Food Safety Commission notice on its website offering assurances that there is virtually no chance of human infection occurring through ingesting chicken meat or eggs. The commission notes that cross-species infection is rare in Japan and stomach acid quickly destroys the flu virus. An agriculture ministry official at the animal hygiene section declined to comment on where the virus may have originated, though noted that migratory birds from overseas were a possible source. The ministry is now testing samples of the virus taken from the Taragi farm to determine its exact type. It will take two or three days to get the results, the official told The Japan Times. The last bird flu outbreak in Japan occurred in the city of Chiba in March 2011. It is the first outbreak ever at a chicken farm in Kumamoto Prefecture.