A bacterium known to cause "black disease" is most likely to have killed dozens of gaurs in Kui Buri National Park in Prachuap Khiri Khan province, officials say.
Tuangthong Patchimasiri, senior veterinary researcher of the National Institute of Animal Health, said that laboratory tests detected the bacteria Clostridium novyi from samples taken from 15 gaurs, which can lead to black disease and cause immediate death.
A total 24 gaur carcasses, 14 male, eight female and two calves, were found in the national park between late November and early December last year.
According to the test results, 99.5% of the contents of the gaurs' stomachs was grass and only 0.5% comprised double-leafed plants, going against a previous assumption that the animals had died after eating leaves from maiyalarb yak, or giant sensitive plants.
Other bacterial strains such as Clostridium perfringens were also found in some samples, but they were ruled out as the cause of death.
Ms Tuangthong said that Clostridium novyi has never been detected in the country before, but judging from international studies, the bacteria can lead to death in cattle, sheep and horses, adding that researchers are carrying out tissue cultivation and will conduct tests on mice to confirm their findings.
"We expect to get the results within three months to confirm that the bacterial strain killed those gaurs," she said.
No arsenic or other hazardous chemical substances were detected in the samples, except a small amount of nitrate, which was found in all the samples.
Meanwhile, the Department of Pollution Control released the results if its laboratory tests on soil and water samples collected from the areas where the gaurs were found dead.
According to the department, there were no heavy metals, cyanide or pesticides detected.
