The outbreak of plague in Madagascar has spread to the Seychelles, a nearby chain of islands in the Indian Ocean, the country’s health ministry said Wednesday.

According to the ministry, a 34-year-old man who fell ill after returning from Madagascar on Friday has tested positive for pneumonic plague. He is now in isolation at Seychelles Hospital and is receiving antibiotics.

Fifteen people who had contact with him after his return also have been given antibiotics as a precaution and are under surveillance, the ministry said.

His partner appears to be ill and is being tested for plague, as is the child who lives with them.

Dr. Jude Gedeon, public health commissioner of the Seychelles, asked citizens not to panic. Air Seychelles has canceled all flights to Madagascar, and citizens have been advised not to travel there.