Local transmission of Plasmodium vivax malaria in Singapore
Ooi, P.L.; Goh, K.T.; Lee, K.M.
Annals of the Academy of Medicine Singapore 26(5): 588-592
1997
ISSN/ISBN: 0304-4602 PMID: 9494662 Document Number: 470916
As a result of both the constant influx of travellers and foreign workers from endemic countries and the presence of Anopheles vectors, Singapore remains vulnerable to malaria. In May and June of 1996, a localized outbreak involving 19 cases of vivax malaria was reported in central Singapore's Dairy Farm area. Resident in this area at the time were 120 foreign workers employed by and living within two nurseries. Following the outbreak, both epidemiologic and entomologic surveillance studies were conducted. The 19 cases of Plasmodium vivax involved 2 local residents of Dairy Farm Estate condominium and 17 foreign nursery workers (1 Thai, 5 Bangladeshi, and 13 Indian). The origin of the outbreak was traced to 2 foreign workers infected with Plasmodium vivax who defaulted on chloroquine treatment and relapsed within 7 months of arrival in Singapore. Malaria symptoms included fever (100%), rigors (94.7%), chills (89.5%), headache (78.9%), and sweating (42.1%). Larvae of Anopheles maculatus were found in 7 habitats: 4 seepages, 1 ground puddle, 1 earth drain, and 1 antimalaria drainage well. Transmission was interrupted within a week after the outbreak was alerted through a comprehensive strategy of active case finding, isolation and treatment of infected persons, epidemic vector control measures, and improved drainage to prevent Anopheles maculatus breeding. Malaria should always be considered in the differential diagnosis of foreign workers who present with fever.