Browsing by Author "Ranaweera, D."

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The first introduced malaria case reported from Sri Lanka after elimination: implications for preventing the re-introduction of malaria in recently eliminated countries
(BioMed Central, 2019) Karunasena, V. M.; Marasinghe, M.; Koo, C.; Amarasinghe, S.; Senaratne, A.S.; Hasantha, R.; Hewavitharana, M.; Hapuarachchi, H.C.; Herath, H.D.B.; Wickremasinghe, R.; Mendis, K.N.; Fernando, D.; Ranaweera, D.
BACKGROUND:There has been no local transmission of malaria in Sri Lanka for 6 years following elimination of the disease in 2012. Malaria vectors are prevalent in parts of the country, and imported malaria cases continue to be reported. The country is therefore at risk of malaria being re-established. The first case of introduced vivax malaria in the country is reported here, and the surveillance and response system that contained the further spread of this infection is described.METHODS:Diagnosis of malaria was based on microscopy and rapid diagnostic tests. Entomological surveillance for anophelines used standard techniques for larval and adult surveys. Genotyping of parasite isolates was done using a multi-locus direct sequencing approach, combined with cloning and restriction fragment length polymorphism analyses. Treatment of vivax malaria infections was according to the national malaria treatment guidelines.RESULTS:An imported vivax malaria case was detected in a foreign migrant followed by a Plasmodium vivax infection in a Sri Lankan national who visited the residence of the former. The link between the two cases was established by tracing the occurrence of events and by demonstrating genetic identity between the parasite isolates. Effective surveillance was conducted, and a prompt response was mounted by the Anti Malaria Campaign. No further transmission occurred as a result.CONCLUSIONS:Evidence points to the case of malaria in the Sri Lankan national being an introduced malaria case transmitted locally from an infection in the foreign migrant labourer, which was the index case. Case detection, treatment and investigation, followed by prompt action prevented further transmission of these infections. Entomological surveillance and vector control at the site of transmission were critically important to prevent further transmission. The case is a reminder that the risk of re-establishment of the disease in the country is high, and that the surveillance and response system needs to be sustained in this form at least until the Southeast Asian region is free of malaria. Several countries that are on track to eliminate malaria in the coming years are in a similar situation of receptivity and vulnerability. Regional elimination of malaria must therefore be considered a priority if the gains of global malaria elimination are to be sustained.
Mass radical treatment of a group of foreign workers to mitigate the risk of re-establishment of malaria in Sri Lanka
(BioMed Central., 2020) Marasinghe, M.M.; Karunasena, V.M.; Seneratne, A.S.; Herath, H.D.B.; Fernando, D.; Wickremasinghe, R.; Mendis, K.N.; Ranaweera, D.
BACKGROUND: Following malaria elimination, Sri Lanka was free from indigenous transmission for six consecutive years, until the first introduced case was reported in December 2018. The source of transmission (index case) was a member of a group of 32 migrant workers from India and the location of transmission was their residence reporting a high prevalence of the primary vector for malaria. Despite extensive vector control the situation was highly susceptible to onward transmission if another of the group developed malaria. Therefore, Mass Radical Treatment (MRT) of the group of workers for Plasmodium vivax malaria was undertaken to mitigate this risk. METHOD: The workers were screened for malaria by microscopy and RDT, their haemoglobin level assessed, and tested for Glucose 6 phosphate dehydrogenase deficiency (G6PD) using the Care Start RDT and Brewers test prior to treatment with chloroquine (CQ) 25 mg/kg body weight (over three days) and primaquine (PQ) (0.25 mg/kg/day bodyweight for 14 days) following informed consent. All were monitored for adverse events. RESULTS: None of the foreign workers were parasitaemic at baseline screening and their haemoglobin levels ranged from 9.7-14.7 g/dl. All 31 individuals (excluding the index case treated previously) were treated with the recommended dose of CQ. The G6PD test results were inconclusive in 45% of the RDT results and were discrepant between the two tests in 31% of the remaining test events. Seven workers who tested G6PD deficient in either test were excluded from PQ and the rest, 24 workers, received PQ. No serious adverse events occurred. CONCLUSIONS: Mass treatment may be an option in prevention of reintroduction settings for groups of migrants who are likely to be carrying latent malaria infections, and resident in areas of high receptivity. However, in the case of Plasmodium vivax and Plasmodium ovale, a more reliable and affordable point-of-care test for G6PD activity would be required. Most countries which are eliminating malaria now are in the tropical zone and face considerable and similar risks of malaria re-introduction due to massive labour migration between them and neighbouring countries. Regional elimination of malaria should be the focus of global strategy if malaria elimination from countries is to be worthwhile and sustainable. KEYWORDS: G6PD; Malaria; Mass radical treatment; Migrant labour; Prevention of reintroduction.
RB1 screening of retinoblastoma patients in Sri Lanka using targeted next generation sequencing (NGS) and gene ratio analysis copy enumeration PCR (GRACE-PCR)
(BioMed Central, 2023) Kugalingam, N.; de Silva, D.; Abeysekera, H.; Nanayakkara, S.; Tirimanne, S.; Ranaweera, D.; Suravajhala, P.; Chandrasekharan, V.
BACKGROUND: Retinoblastoma (RB) a tumour affecting those under 5 years, has a prevalence of 1 in 20,000, with around twenty new diagnoses per year in Sri Lanka. Unilateral and bilateral RB presents around 24 and 15 months respectively. Approximately 10% are familial. Systematic genetic testing for germline pathogenic variants of RB1, the only gene associated with an inherited risk of RB, is unavailable in Sri Lanka. Genetic testing optimizes management of affected children and at-risk siblings. This study aimed to develop accessible genetic testing to identify children with a germline pathogenic variant of RB1 in Sri Lanka. METHODS: Targeted next generation sequencing (NGS) for detecting pathogenic sequence variants and Gene Ratio Analysis Copy Enumeration PCR (GRACE-PCR) for detecting RB1 copy number variations (CNVs) were performed for 49 consecutive RB patients treated between 2016 and 2020 at the designated RB care unit, Lady Ridgway hospital, Colombo. Patients (bilateral RB (n = 18; 37%), unilateral n = 31) were recruited following ethical clearance and informed consent. RESULTS: There were 26 (53%) females. Mean age at diagnosis was 18 months. Thirty-five patients (71%) had undergone enucleation. Germline pathogenic variants of RB1 identified in 22/49 (45%) patients including 18 (37%; 12 bilateral and 6 unilateral) detected by targeted NGS (2 missense, 7 stop gained, 1 splice donor, 8 frameshift variants). Six were previously undescribed, likely pathogenic frameshift variants. Four bilateral RB patients had GRACE-PCR detected CNVs including one whole RB1, two intragenic deletions (exon 12/13; exon 11 and 23) and a partial duplication of exon 27. The only familial case (affected mother and child) shared the duplication. Only 2 of 4 CNVs and 10 of 18 pathogenic variants were confirmed by whole exome sequencing and Sanger sequencing respectively, due to funding limitations. CONCLUSIONS: The study identified pathogenic or likely pathogenic germline RB1 sequence variants and copy number variants in 16/18 (89%) bilateral and 6/31(19%) unilateral cases, which is comparable to worldwide data (10-15% unilateral, 80-85% bilateral). Targeted NGS combined with GRACE-PCR significantly reduce the cost of RB1 testing in Sri Lanka, and may widen access for genetic diagnosis of RB patients in other low and middle income countries.
Technical and operational underpinnings of malaria elimination from Sri Lanka
(BioMed Central, 2019) Premaratne, R.; Wickremasinghe, R.; Ranaweera, D.; Gunasekera, W.M.K.T.A.W.; Hevawitharana, M.; Pieris, L.; Fernando, D.; Mendis, K.
Malaria was eliminated from Sri Lanka in 2012, and the country received WHO-certification in 2016. The objective of this paper is to describe the epidemiology of malaria elimination in Sri Lanka, and the key technical and operational features of the elimination effort, which may have been central to achieving the goal, even prior to schedule, and despite an ongoing war in parts of the country. Analysis of information and data from the Anti Malaria Campaign (AMC) of Sri Lanka during and before the elimination phase, and the experiences of the author(s) who directed and/or implemented the elimination programme or supported it form the basis of this paper. The key epidemiological features of malaria on the path to elimination included a steady reduction of case incidence from 1999 onwards, and the simultaneous elimination of both Plasmodium falciparum and Plasmodium vivax. Against the backdrop of a good health infrastructure the AMC, a specialized programme within the Ministry of Health operated through a decentralized provincial health system to implement accepted strategies for the elimination of malaria. Careful planning combined with expertise on malaria control at the Central level with dedicated staff at all levels at the Centre and on the ground in all districts, for several years, was the foundation of this success. The stringent implementation of anti-relapse treatment for P. vivax through a strong collaboration with the military in whose cadres most of the malaria cases were clustered in the last few years of transmission would have supported the relatively rapid elimination of P. vivax. A robust case and entomological surveillance and investigation system described here enabled a highly focused approach to delivering interventions leading to the interruption of transmission.