Plasmodium falciparum, P. vivax, P. ovale and P. malariae.
In recent years, P knowlesi, a parasite of Old World monkeys has been identified as the fifth major human malaria parasite. It is an emerging infection in SE Asia and is capable of causing serious life threatening complications and death in a minority of cases.
1 to 4 weeks (months for non-falciparum Plasmodium)
Until parasites cleared from blood.
Transmission via bite of infected female Anopheles mosquito. Vertical transmission and by blood transfusion or organ transplant also possible.
Approximately 100-300 cases per annum in Singapore (80% vivax); almost all are imported.
One hundred and seventy laboratory-confirmed cases were reported in 2009, an increase of 13.2% compared to the 152 cases reported in 2008. 16.8% of the cases were reportedly acquired locally, an increase of 16.1% compared to the previous year. There were six cases of simian malaria involving five locals and one foreigner. Three of the local residents acquired their infection while trekking in Malaysia at separate occasions while two were infected during jungle trainings at Brunei.
Endemic in SE Asia, particularly rural areas.
Chloroquine-resistant falciparum malaria is widespread in the region; occasional cases of chloroquine-resistant vivax have also been reported.