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.
Forty-two people who arrived from Madagascar recently are being monitored for signs of fever or coughs, Dr. Gedeon said, including members of a basketball team who participated in an international tournament in late September.
Madagascar is struggling to contain a plague outbreak that began in August. The outbreak has killed at least 50 people so far, and 500 confirmed cases have been reported, according to the World Health Organization and Madagascar’s health ministry.
Schools have been closed, and large public gatherings like sporting events and music festivals have been banned.
The W.H.O., Doctors of the World, Doctors Without Borders and other medical aid groups are sending experts to help Madagascar fight the outbreak.
The Centers for Disease Control and Prevention issued a Level 2 alert on Wednesday, suggesting “enhanced precautions” for Americans headed for Madagascar.
Although the risk to travelers “appears to be very low,” the C.D.C. said, visitors should wear insect repellent to prevent flea bites and should avoid people with coughs or pneumonia and sick or dead animals.
The case in the Seychelles is the first instance of the current outbreak spreading to another country. Officials are worried it may gain momentum, like the 2014 Ebola outbreak, which killed more than 11,000 people.
Plague is endemic in Madagascar, and the country typically has about 400 cases a year. But the disease is normally confined to the rural central highlands. Most cases there are spread by fleas that bite rats, which increase in number after the rice harvest.
This outbreak alarms health officials because it has reached several Malagasy cities, including the capital, Antananarivo, and because most cases are of the pneumonic form, which is spread by coughing. The infection attacks the lungs and can kill within days.
Pneumonic plague does not pass between people as easily as measles or the flu. Like tuberculosis, the cause is bacterial, and it can be transmitted between people in prolonged close contact, such as members of a single household, or those in prisons, schools or hospitals.