Malaria acquired in the Torres Strait.

Two cases of Plasmodium vivax malaria acquired in the Torres Strait during 1997 are reported. The source of infection could not be firmly established but two possibilities are discussed. Anopheline mosquitoes are present in the Torres Strait, and malaria is frequently imported from Papua New Guinea (PNG), thus transmission by local mosquitoes poses an ongoing threat. However, in this particular location, Badu Island, no recent importation of malaria was identified and mosquito surveillance demonstrated low numbers of anopheline species at the time and for the preceding two years. These cases could also feasibly be explained by a variant of 'baggage malaria' in which mosquitoes already infected with the malaria parasite were imported from PNG in one of the small boats that regularly make this journey. These cases serve as a reminder to health care providers in northern Australia to consider the diagnosis of malaria in patients presenting with a febrile illness.