The outbreak of plague reached Seychelles, The New York Times reported on 11 October.

The development comes within a fortnight of when World Health Organisation (WHO) said on 29 September that an outbreak of plague killed 20 people in Madagascar within a span of one month.

Madagascar’s health ministry confirmed the case on Wednesday when a 34-year-old man tested positive for the plague after he returned to Seychelles, a series of Islands in the Indian ocean, from Madagascar, reportedly. He has been put in isolation at a hospital in Seychelles.

Other than killing people, WHO had confirmed in September that another 84 were infected.

But the more dangerous pneumonic form invades the lungs and can kill a person within 24 hours if not treated. About half of the 104 known cases are pneumonic, the WHO said.

WHO spokesman Tarik Jasarevic told reporters in Geneva that areas affected included the capital Antananarivo and the port cities of Mahajenga and Toamasina.

The UN health agency said it feared that the outbreak could worsen because the season for plague, which is endemic in Madagascar, had only just begun, and runs until April. On average, 400 cases are reported each year.

"The overall risk of further spread at the national level is high," WHO said in a statement.

(With inputs from Reuters and The New York Times.)