At least 72 tigers have died from a viral infection at a zoo in Chiang Mai province, northern Thailand, according to a statement issued Friday by the provincial livestock department. Tests confirmed that the animals were infected with the highly contagious canine distemper virus and also suffered from bacterial respiratory infections. The zoo, known as Tigers Kingdom, has been temporarily closed following the mass deaths.

Somchuan Rattanamungklanon, director of Thailand’s national livestock department, told local media that detecting illness in tigers is more difficult than in domestic animals such as dogs or cats, and by the time symptoms become apparent, it is often too late. The zoo, a popular tourist attraction, allowed visitors to hug and take photos with tigers.

Animal rights group PETA said in a statement to AFP that the tigers lived and died in distressing, confined, and fearful conditions. The organization added that if tourists stayed away, such facilities would quickly become unprofitable and tragedies like this would not occur.