Most of the poultry farms in Japan that have been hit by avian flu since last year had flaws in preventing wildlife from accessing their chicken coops, government officials said Saturday.
The farm ministry's inspection of affected chicken farms found that 90% of the surveyed farms had problems keeping poultry separated from wild birds and other animals. The defects included holes in roofs and walls of the coops.
The Ministry of Agriculture, Forestry and Fisheries has confirmed an avian flu outbreak at 39 farms so far this season, resulting in the culling of about 6.2 million birds, a record number for one season.
The ministry's survey team inspected 30 of the affected farms and discovered flaws in preventive measures at 27 of them.
At the remaining three farms, there were cases where poultry houses had no visible defect or damage but there were signs rodents had entered them, potentially infecting chicken feed, the officials said.
At 19 farms, sufficient disinfection measures were not taken by people working there, they said.
As for the extent of the latest outbreak, the National Agriculture and Food Research Organization has said birds infected by the highly pathogenic type of strain confirmed this season tend to survive longer compared with strains found in past outbreaks, causing infections to spread more widely before farm operators can discover the first signs of infections.
Makoto Ozawa, associate professor of veterinary medicine at Kagoshima University, says the latest type of avian flu strain appears to be more difficult to prevent.
"Looking at how infections have spread this season, (the outbreak) may be more than farms can deal with on their own," he said.
"The latest strain needs to be analyzed more closely to come up with a stronger response," he added.