Importance of active case detection in a malaria elimination programme

Background: With the aim of eliminating malaria from Sri Lanka by 2014, the Anti-Malaria Campaign of Sri Lanka (AMC) sought the support of Tropical and Environmental Disease and Health Associates Private Limited (TEDHA), a private sector organization. In 2009, TEDHA was assigned 43 government hospitals in the district of Mannar in the Northern Province and in districts of Trincomalee, Batticaloa and Ampara in the Eastern Province to carry out malaria surveillance to complement the surveillance activities of the AMC. Passive case detection (PCD), activated passive case detection (APCD) and active case detection (ACD) for malaria have been routinely carried out in Sri Lanka. Methods: The active case detection programme of TEDHA involves screening of populations irrespective of the presence of fever or any other signs or symptoms of malaria to detect infections and residual parasite carriers. ACD is done by TEDHA in a) high risk populations through mobile malaria clinics including armed forces personnel and b) pregnant females who visit antenatal clinics for asymptomatic malaria infections during the first trimester of pregnancy. Populations are selected in consultation with the Regional Malaria Officer of the AMC thus avoiding any overlap with the population screened by the government. Results: TEDHA screened 387,309 individuals in the four districts for malaria by ACD including high risk groups and pregnant women between January 2010 and December 2012. During this period seven individuals were diagnosed with Plasmodium vivax infections and one individual was detected with a mixed infection of P. vivax and Plasmodium falciparum. All eight cases were detected by ACD carried out by mobile malaria clinics among high risk groups in the Mannar district. Conclusion: The progress made by Sri Lanka in the malaria elimination drive is largely due to increased surveillance and judicious use of control methods which has resulted in zero indigenous malaria cases being reported since October 2012. ACD played a major role in interrupting malaria transmission in the country.