Search

Abstract Background Sri Lanka, an island nation, has eliminated endemic malaria transmission. Maintaining elimination in the continued presence of vectors requires vigilance in screening people travelling from high malaria-risk areas and a rapid response with focal screening for infections identified in the community. Such screening requires accurate and very rapid assays that enable an immediate response. Both microscopy and rapid diagnostic tests (RDTs) have limitations including sensitivity and speed in screening large numbers, while polymerase chain reaction (PCR) is practical only as laboratory confirmation. This study assessed the utility of ‘Gazelle’, a novel rapid malaria assay based on magneto-optical detection of haemozoin, a by-product of malaria parasite metabolism. Methods Between October 2020 and March 2021, two groups of individuals were screened for malaria by four methods, namely, microscopy, Rapid Diagnostic Test (RDT), Gazelle and PCR. Passive case detection was carried out for confirmation of diagnosis amongst individuals suspected of having malaria. Individuals at high-risk of acquiring malaria, namely persons returning from malaria endemic countries, were screened by active case detection. Results Of the 440 individuals screened for malaria, nine malaria positives were diagnosed by PCR, microscopy and the HRP2 band of RDT, which included five Plasmodium falciparum infections, two Plasmodium ovale, and one each of Plasmodium vivax and Plasmodium malariae. Gazelle correctly detected the P. vivax, P. ovale and P. malariae infections within the 2 min test time, but did not detect two P. falciparum infections giving a sensitivity of 77.8%. Specificity was 100%. Discussion The Gazelle, a portable bench top device proved useful to screen a large number of blood samples for non-falciparum parasites within 5 minutes of sample input. Species differentiation, and improvement in P. falciparum detection, will be important to broaden utility.

Abstract Background Sri Lanka has been free from indigenous malaria since November 2012 and received the WHO certificate for malaria-free status in September 2016. Due to increased global travel, imported malaria cases continue to be reported in the country. Military personnel returning home from international peace-keeping missions in malaria endemic countries represent a key risk group in terms of imported malaria. The present study intended to characterize the potential causes of a malaria outbreak among the Sri Lankan security forces personnel deployed in the Central African Republic (CAR). Methods Data were collected from a cross-sectional survey distributed among Sri Lankan Air Force personnel who had returned from United Nations peace-keeping missions in the CAR region. A pre-tested questionnaire was used for the data collection, and focus group discussions were also conducted. Results One hundred twenty male Air Force personnel were interviewed (out of a group of 122 officers and airmen). All participants were deployed in the CAR for 14 months and were aware of the existence of chemoprophylaxis against malaria. The majority of the subjects (92.5%, 111/120) also knew that prophylaxis should be started prior to departure. However, the regular use of chemoprophylaxis was reported by only 61.7% (74/120) of the sample. Overall, 30.8% of the participants (37/120) had 44 symptomatic episodes of malaria during deployment, and one person succumbed to severe malaria. All cases were associated with noncompliance with chemoprophylaxis. Conclusion Better coordination with overseas healthcare services and the establishment of directly observed chemoprophylaxis may help to avoid similar outbreaks in the future.