A Dutch cruise ship with near­ly 150 peo­ple aboard, in­clud­ing 17 Amer­i­cans, was wait­ing for help off the coast of Cape Verde in the At­lantic Ocean on Mon­day af­ter a sus­pect­ed out­break of the rare han­tavirus killed three pas­sen­gers and left at least three oth­ers se­ri­ous­ly ill, the World Health Or­ga­ni­za­tion and the ship’s op­er­a­tor said.

The MV Hondius, which was on a week­s­long po­lar cruise from Ar­genti­na to Antarc­ti­ca and then sev­er­al iso­lat­ed is­lands in the South At­lantic, had re­quest­ed help from lo­cal health au­thor­i­ties on Sun­day af­ter mak­ing its way to the is­land of Cape Verde off the coast of West Africa, but no one has yet been al­lowed to dis­em­bark, the com­pa­ny op­er­at­ing the cruise said.

There are 88 pas­sen­gers — in­clud­ing one who has died — and 61 crew mem­bers, two of whom are sick, on­board, the op­er­a­tor said Mon­day. The pas­sen­gers in­clude 17 Amer­i­cans, 19 from the U.K. and 13 from Spain, among oth­er na­tion­al­i­ties.