An Outbreak of Plasmodium Falciparum Malaria in the Torres Strait

This report describes the largest outbreak of Plasmodium falciparum malaria in the Torres Strait for more than 25 years. It details factors that may have contributed to the outbreak, the public health response and implications for the broader region. Eight cases of locally-acquired falciparum malaria occurred on Saibai and Dauan islands during March and April 2011. Including imports, there were 17 P. falciparum notifications between February and May 2011. Three cases of pure P. vivax malaria that might have been locally acquired have been omitted from this report. Malaria is endemic on the nearby coast of Papua New Guinea (PNG), and regularly imported to the Torres Strait where a competent vector exists in sufficient numbers to transmit the disease to the local population. The most common malaria vectors in northern Australia and Torres Strait are the Anopheles farauti complex. Factors contributing to the outbreak may include an increase in travel between the outer islands and PNG, inadequate local vector control and late or missed diagnoses of malaria. Outbreak management involved intensive case finding and treatment, vector control and health promotion. Reducing the risk of future outbreaks requires studies of vector behaviour, ecology and management, health promotion, improvements to protective infrastructure, and clinical guideline revision. Further malaria outbreaks are likely in the Torres Strait and elsewhere in northern Australia. It is important to maintain awareness and be prepared to respond rapidly.