Thai authorities said Tuesday that 72 tigers in two tourist animal parks in northern Thailand died from canine distemper virus (CDV), not bird flu, reassuring the public that the outbreak poses no human health threat.

The tigers, located in Mae Taeng and Mae Rim districts of Chiang Mai province, became ill and died over a ten-day period from Feb. 8 to 18. Autopsies detected genetic material of CDV and some bacterial infection, but no avian influenza virus. Public Health Minister Pattana Promphat confirmed that no human infections have been reported, though officials are monitoring anyone who recently came into contact with the animals.

CDV, which affects dogs and felines, can be particularly severe in tigers, especially in confined environments with stress or inbreeding. The carcasses were necropsied, disinfected, cremated, and buried to prevent further risk, according to Livestock Development Department Director-General Somchuan Rattanamangklanan.

Veterinarian Visit Arsaithamkul, involved in the necropsies, said the exact source of the infection remains unclear, suggesting that shared food sources might be a factor given the parks’ proximity. Both Tiger Kingdom parks remain closed.

Authorities also reminded the public to exercise caution with poultry, amid ongoing concerns about bird flu in the region, citing previous outbreaks in Thailand and neighboring countries.