Munich (dpa / lby) - The Hellabrunn Zoo in Munich has put six monkeys to sleep because of an incurable disease. The six drills, one of Africa's most endangered primate species, had previously been infected with fox tapeworm eggs. The remaining six conspecifics are being closely observed, as the zoo announced on Wednesday. Other primates in the zoo are not affected, and there is no danger to visitors either.

An examination of all twelve drills (Mandrillus leucophaeus) revealed severe and advanced organ changes in half of the animals. The disease would have resulted in death within a few weeks. The time and cause of the infection initially remained unclear. "We are currently working flat out to find out how the pathogen got to the drills," said zoo director Rasem Baban.

The fox tapeworm is widespread in Central Europe. Transmission is not possible either from monkey to monkey or from monkey to human. According to the information, there is currently no vaccine for animals against the pathogen approved in the EU.