The first case of introduced malaria in Sri Lanka after elimination: Approach by the Anti Malaria Campaign to prevent re-establishment of malaria

Abstract

INTRODUCTION & OBJECTIVES: Apart from imported malaria infections Sri Lanka has been free of malaria cases for the past six years after elimination until December 26th 2018, when the first introduced case was reported. This manuscript describes the probable index case and the introduced case of malaria, and actions taken to curtail the spread of transmission. METHODS: Detailed case investigations of the probable index and introduced cases were carried out and appropriate responses were mounted by the Anti Malaria Campaign (AMC). Genome sequencing was performed on parasites obtained from the two cases to determine relatedness of the two parasite isolates. RESULTS: An Indian employed at a construction site in Moneragala district, developed a Plasmodium vivax infection 23 days after arriving in Sri Lanka. Thirteen days later a Sri Lankan with no travel history to a malaria endemic country was diagnosed with P.vivax malaria following his visit to the same site. Multi-locus genome sequencing show that P. vivax strains obtained from these cases share 100% genetic identity at five loci of three polymorphic genes (CSP, MSPI and MSP3a genes), suggesting that both patients were infected with the same P.vivax strain. AMC mounted a rapid response including parasitological and entomological surveillance, active case detection, appropriate vector control measures and raising public and clinician awareness at relevant sites. CONCLUSION: An outbreak and the re-introduction of malaria to Sri Lanka from an index and introduced cases were prevented by prompt interventions which illustrate a very effective surveillance and response system.