Mass radical treatment of a group of foreign workers to mitigate the risk of re-establishment of malaria in Sri Lanka.

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.

Technical and operational underpinnings of malaria elimination from Sri Lanka.

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.

The first introduced malaria case reported from Sri Lanka after elimination: implications for preventing the re-introduction of malaria in recently eliminated countries.

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.

Severe Plasmodium vivax malaria, HIV, tuberculosis co-infection in a Sri Lankan traveller: case management and challenges during the prevention of malaria reintroduction phase.

BACKGROUND: The country received malaria-free certification from WHO in September 2016, becoming only the second country in the WHO South East Asia region to be declared malaria-free. Imported malaria cases continue to be reported, with 278 cases reported between 2013 and 2017. The diagnosis of a severe Plasmodium vivax patient co-infected with HIV and tuberculosis is discussed with an overview of the rapid response mounted by the Anti Malaria Campaign (AMC), Sri Lanka. CASE PRESENTATION: A Sri Lankan gem miner who returned from Madagascar on the 6th of April 2018 presented to a private hospital for a malaria diagnostic test on the 21st April, 2 days after the onset of fever. He came on his own for this test due to the awareness he had regarding the risk of imported malaria. As the patient was positive for P. vivax malaria, he was admitted to a government hospital for further management. The patient had features of severe malaria upon admission with a systolic BP < 80 mmHg and thrombocytopaenia (38,000 cells/mm3). Treatment with IV artesunate was initiated immediately and management was carried out rapidly and efficiently by the clinicians with guidance from the staff of the AMC headquarters, which resulted in a rapid recovery of the patient. IV artesunate was followed by a course of artemether plus lumefantrine and the blood smear was negative for malaria by the 2nd day. A 14-day course of primaquine was commenced after excluding a G6PD deficiency. Due to an accidental needle stick injury of a health care worker attending on the patient was tested for HIV and subsequently tuberculosis and was found to be positive for both infections. The patient was discharged on the 1st of May with instructions for follow up visits for malaria. Management of the HIV and tuberculosis infections was attended to by the clinicians and staff of the appropriate disease control programmes (i.e. the national STD/AIDS Control Programme in Sri Lanka and the National Programme for tuberculosis control and chest diseases). CONCLUSIONS: It is important to consider comorbid conditions and immunosuppression when a patient with a benign form of malaria presents with severe manifestations. Measures should be strengthened to prevent importation of diseases, such as malaria and AIDS through migrant workers who return from high-risk countries.

Thrombocytopenia in Malaria: A Red-Herring for Dengue, Delaying the Diagnosis of Imported Malaria.

INTRODUCTION: Fever and thrombocytopenia, often presenting features of malaria, are also the hallmarks of dengue infections. This study examines the degree and duration of thrombocytopenia in imported malaria infections in Sri Lanka and the extent to which this could provide a false trail in favor of a dengue diagnosis. METHODS: The data of all confirmed malaria cases reported in Sri Lanka from 2017 to 2019 were extracted from the national malaria database. These included detailed histories, the time to malaria diagnosis, platelet counts, and in 2019, the trail of diagnostic procedures. RESULTS: Over the 3 years, 158 malaria cases (157 imported and one introduced) were reported. Platelet counts were available in 90.5% (n = 143) of patients among whom 86% (n = 123) showed a thrombocytopenia (<150,000 cells/µl) and in nearly a third (n = 52) a severe thrombocytopenia (<50,000 cells/µl). Only 30% of patients (n = 48) were diagnosed with malaria within 3 days of the onset of symptoms, while in 37% (n = 58) it took 7 or more days. Platelet counts where significantly higher in patients who had symptoms for 7 days or more compared to those who had symptoms for <7 days (χ2 = 6.888, P = 0.009). Dengue fever was suspected first in 30% (n = 16) of the total malaria patients reported in 2019. CONCLUSIONS: Low platelet counts could delay suspecting and testing for malaria. Eliciting a history of travel to a malaria-endemic country could provide an important and discerning clue to suspect and test for malaria in such patients.

Success of malaria chemoprophylaxis for outbound civil and military travellers in prevention of reintroduction of malaria in Sri Lanka.

BACKGROUND: Sri Lanka was certified as malaria-free in September 2016. However, the continuous presence of the malaria vector poses serious risks of reintroduction of the disease. Chemoprophylaxis and advice on malaria preventive behaviour for international travellers is a key strategy adopted to reduce the risk of imported malaria. METHODS: We conducted an efficiency study of malaria chemoprophylaxis for civilian and military travellers who requested travel advice from the Anti Malaria Campaign (AMC) prior to departure. The AMC is the only agency that can issue malaria chemoprophylaxis to travellers and hence this sample is representative of all such individuals seeking travel advice in Sri Lanka. RESULTS: A total of 544 (400 civilians and 144 military) travellers were interviewed prior to departure and after return. The majority travelled to African destinations (516/544 [94.8%]) and were prescribed mefloquine (517/544 [95%]). Chemoprophylaxis was well tolerated and discontinuation due to adverse events was minimal. Regular chemoprophylaxis was reported by 505 (92.8%) participants while overseas. The protective efficacy of chemoprophylaxis was 100% among those who complied with the full course. CONCLUSIONS: The compliance with chemoprophylaxis and its protective efficacy were satisfactory in this study. It is an effective tool in preventing imported malaria to post-elimination Sri Lanka.