|Year : 2017 | Volume
| Issue : 2 | Page : 60-65
Malaria elimination in Sri Lanka
Julia Nicole Simac1, Sayema Badar2, Jessica Anne Farber3, Maame Yaa Owusua Brako4, Rafael Angel Lo Giudice-Jimenez5, Steven Saverio Raspa6, Meshack Achore7, Sean Dale MacKnight7
1 Department of Biology, McGill University; Institute for the Study of International Development, McGill University, Montreal, Canada
2 McGill International TB Centre, McGill University, Montreal, Canada
3 Institute for the Study of International Development, McGill University, Montreal, Canada
4 Department of Pharmacology and Therapeutics, Biostatistics and Occupational Health, McGill University, Montreal, Canada
5 Department of Microbiology and Immunology, Biostatistics and Occupational Health, McGill University, Montreal, Canada
6 School of Environment, McGill University, Montreal, Canada
7 Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Canada
|Date of Web Publication||24-Apr-2017|
Julia Nicole Simac
McGill University, 845 Sherbrooke Street West, Montreal, Quebec H3A 0G4
Sri Lanka was declared malaria-free on 5 September 2016 by the World Health Organization. This success was the result of over a century of efforts that combined disease surveillance, vector control and treatment. By 2008, there was zero mortality from indigenous cases, and the country witnessed its last indigenous case in 2012. This process involved long-term, sustained financial support, particularly from the Sri Lankan Government, the World Bank and the Global Fund. Given that malaria is still a global health burden, there is much to be learnt from Sri Lanka's achievement in the ongoing efforts to reach a malaria-free world.
Keywords: Elimination, malaria, Sri Lanka
|How to cite this article:|
Simac JN, Badar S, Farber JA, Brako MY, Giudice-Jimenez RA, Raspa SS, Achore M, MacKnight SD. Malaria elimination in Sri Lanka. J Health Spec 2017;5:60-5
|How to cite this URL:|
Simac JN, Badar S, Farber JA, Brako MY, Giudice-Jimenez RA, Raspa SS, Achore M, MacKnight SD. Malaria elimination in Sri Lanka. J Health Spec [serial online] 2017 [cited 2020 Nov 29];5:60-5. Available from: https://www.thejhs.org/text.asp?2017/5/2/60/205074
| Introduction|| |
Malaria is a mosquito-borne disease caused by the Plasmodium genus of parasites and transmitted by the bite of infected female Anopheles mosquitoes. The disease disproportionately affects marginalised groups in tropical and subtropical areas. The World Health Organization (WHO) estimates that in 2015 there were 214 million clinical cases of malaria worldwide, leading to 438,000 deaths, most of them occurring in Africa in children under the age of five. However, there has been tremendous progress in reducing both malaria incidence and mortality over the last 15 years. While the particular numbers mask regional and country-specific disparities, the overall successes underscore the potential of achieving the WHO's vision of a malaria-free world by 2030.
On 5 September 2016, the WHO officially certified Sri Lanka to be malaria-free. Located south-east of the Indian subcontinent, Sri Lanka is a tropical island nation with a population of roughly 21 million. Malaria transmission is seasonal as cases peak at the end of the country's monsoons. The country receives two monsoon periods every year: Maha season and Yala season. The Maha season brings rainfall to the north and south-eastern dry zones of the Island during the winter, while the Yala season brings rainfall to the south-western wet zone during the summer. The rainfall in the wet zone inundates malaria vector breeding sites, washing them away, and thus, malaria incidence is lowest in the wet zone and most abundant in the dry zone.
Over the past century, malaria has consistently been one of the most devastating health burdens in Sri Lanka. Epidemics have occurred periodically, the worst of which was between 1934 and 1935, killing over 1.5% of the population. Additional major epidemics in the following decades further intensified the public health challenges. Until recently, out of Sri Lanka's 25 districts, only six had low to no risk of malaria.
From July 1983 to May 2009, civil war ravaged the country, with a ceasefire period from 2002 to 2006. This ethnic conflict was between the government and national forces and the Liberation Tigers of Tamil Eelam (LTTE). The conflict led to the displacement of a large portion of the population and created significant barriers for access to health services. While conflict has historically created a breeding ground for epidemic transmission, the case of malaria throughout Sri Lanka's civil war is unique. Between 2000 and 2015, the country saw a reduction from 200,000 to zero indigenous cases. This was due to continued vector control efforts targeted to at-risk populations in conflict regions made possible through partnerships with the Sri Lankan government's Anti-Malaria Campaign (AMC), non-governmental organisations (NGOs), humanitarian organisations, military, LTTE as well as the reduction in foreign nationals entering the country, thereby containing the epidemic within the national borders. Since Sri Lanka is an island, there is reduced possibility for the migration of mosquitoes from the Mainland. It is also one of the few tropical countries where only one principal vector, Anopheles culicifacies, exists. This particular vector does not transmit malaria as efficiently as other Anopheles species and is more susceptible to vector control measures. Sri Lanka's successful elimination of malaria, especially in the face of persistent civil conflict, is a testament to its own resilience as well as its unrelenting efforts.
| Program Rollout|| |
History of malaria elimination
Throughout the early 20th century, malaria epidemics occurred in Sri Lanka every 3–5 years. Following the devastating epidemic of 1934–1935 (refer to [Figure 1], a timeline of incidence and significant events throughout Sri Lanka's malaria elimination process) Sri Lanka instituted an indoor residual spraying (IRS) programme with the pesticide dichlorodiphenyltrichloroethane (DDT), which successfully brought the number of cases down to only 17 in 1963. However, due to a perceived lack of need, the government withdrew funding and scaled back IRS, resulting in regular epidemics in subsequent decades. Following a massive epidemic in 1986–1987 with over 600,000 cases, the AMC decentralised and began operating under the central AMC Directorate, where it reorganised its programmes at the district level and replaced single-vector programmes, such as IRS, with an integrated vector approach.,
|Figure 1: Timeline of incidence and significant events throughout Sri Lanka's malaria elimination process|
Click here to view
Surveillance was an essential part of the elimination effort consisting of tracking each case in the country and allowing for IRS and treatment programmes. Since 1959, Sri Lanka has used passive case detection (PCD), whereby all fever cases brought to public health facilities are clinically investigated for malaria., In the late 1990s, the AMC introduced activated PCD (APCD), whereby fever cases are tested for malaria with microscopy, resulting in a dramatic increase in diagnostic effectiveness and informing better quality IRS and treatment., APCD has since been the most important method of case detection, identifying 89.8% of cases in 1995 and 94.0% of cases in 2005. In 1997, the World Bank International Development Association supported the establishment of active case detection (ACD), whereby mobile malaria clinics travelled to remote populations, often in conflict zones, expanding the range of service access throughout the country. The majority of ACD diagnoses were made by microscopy., In 2009, the AMC hired a private organisation, Tropical and Environmental Diseases and Health Associates (TEDHA), contributing to surveillance efforts, focusing on ACD in conflict zones and high-risk populations, especially pregnant females.
In 2001, the Global Fund introduced rapid diagnostic tests (RDTs) to Sri Lanka, through the AMC Directorate., Sri Lanka uses the CareStart ™ Malaria histidine-rich protein 2/parasite lactate dehydrogenase (HRP2/PLDH) RDT. It includes antibodies to HRP2, which is specific to Plasmodium falciparum, and PLDH, which is responsive to all the species of Plasmodium., The CareStart ™ test kit detects P. falciparum with 88.52% sensitivity and 98.26% specificity; it detects Plasmodium vivax with 90.77% sensitivity and 100% specificity. Unfortunately, RDTs do not reliably detect low-density parasitaemia, which can occur in mildly symptomatic or asymptomatic individuals who act as reservoirs for the parasite and contribute to the spread of disease. To guard against false results, RDT tests are confirmed by microscopy at the regional and national level., RDTs have been used in emergencies, such as after the 2004 tsunami and by ACD mobile clinics in conflict zones., In 2003, RDTs constituted 4% of the 1.2 million malaria tests conducted. Now, their use is almost exclusive to ports of entry to detect imported cases.
After the 1934–1935 epidemic, Sri Lanka instituted an entomological surveillance programme aimed at tracking mosquito breeding patterns to identify the potential location and timing of epidemics., Adult mosquitoes were captured by trained mosquito catchers using cattle-baited traps and window exit traps. Larvae were collected from bodies of water using nets. Genetic tests were employed at regional and national laboratories to assess insecticide resistance. These activities were essential in guiding Sri Lanka's vector control efforts, which consisted mainly of IRS and bed net distribution.
IRS involves spraying insecticide on the inside of dwellings in malarious regions to kill mosquitoes and prevent disease transmission. Sri Lanka has a long history of IRS use, beginning with DDT in 1946. The AMC transitioned to using the pesticide malathion in 1975 following reports of DDT resistance and growing health concerns., The WHO recommendations in 1993 led to a more targeted IRS approach, with priority given to areas of historical transmission, chloroquine-resistant cases (chloroquine being one of the main treatments), a higher proportion P. falciparum and proximity to mosquito breeding sites. Lambda-cyhalothrin, a synthetic pyrethroid pesticide, was introduced in 1994 and malathion was abandoned in 2002 due to increasing resistance in A. culicifacies., The LTTE collaborated with the AMC to deploy IRS in conflict zones; in 2000, 24% of the at-risk population was covered by IRS. As the prevalence of malaria declined and the AMC focused on more targeted spraying, IRS coverage decreased steadily from 64.8% in 1995 to 22.5% in 2005 and to 5.9% in 2010. Larvivorous fish and chemical larviciding were also used as supplementary vector control measures.
Insecticide-treated nets (ITNs) and long-lasting insecticide-treated nets (LLINs) were also crucial to vector control., While ITNs last for about 6 months before requiring re-impregnation with insecticide, LLINs last for approximately 3 years., The Global Fund supported the introduction of ITNs in 1999 and LLINs in 2004. Approximately 300,000 LLINs were distributed from 2005 to 2007, which benefitted from high uptake; a survey conducted in 2008 of 2467 Sinhalese, Tamil and Muslim households found that 90.2% of respondents used their net every night while sleeping. Mosquito nets were most useful in remote regions and conflict zones where regular IRS was impractical.,
Sri Lanka's national health-care system provides free consultation and treatment at public hospitals. From the mid-1990s to 2006, malaria cases were treated with chloroquine and primaquine (0.25 mg/day for adults), with a 5-day regimen in low-transmission areas and a 14-day regimen in high-transmission areas., Primaquine treatment became more prominent after 2006, and sulphadoxine-pyrimethamine was used as a second-line treatment for chloroquine-resistant cases., Due to rising drug resistance and sustained levels of imported malaria cases, artemisinin-based combination therapy was introduced in 2008. Since not all people could reach public hospitals, the use of mobile clinics to offer these treatment services was also crucial.
While the last indigenous malaria-related mortality was in 2008 and the last indigenous case was in 2012, imported cases remain an issue. Screening at ports of entry, predominantly with RDTs, is crucial in detecting incoming cases. Maintained parasitological and entomological surveillance informs targeted IRS in areas of high vector density and those that surround imported cases., Treatment remains free at public health facilities and residents travelling to malaria-endemic countries are provided with complementary prophylaxis.
| Impact|| |
Sri Lanka's efforts led to successful malaria elimination status in 2016. The annual parasite incidence fell from 11.9 cases/1000 people at risk in 1995 to 1/1000 in 2005 and to 0.1 in 2010. This reflected a drop in the number of cases from 264,549 in 1999 to 736 in 2010 and to 175 in 2011, only 124 of which were indigenous., Imported cases continue to raise concern, with 70 imported cases in 2010 and 95 in 2013, affirming the need to maintain surveillance and screening programmes.
Deaths due to malaria declined steadily from 76 in 1995 to 40 in 2005. As the last indigenous case fatality was in 2008, the remaining 25 deaths in 2010 were from imported cases. The malaria-specific mortality rate for all ages experienced an increase from 0.31/1000 people at risk in 1990 to a peak of 0.55/1000 in 1997, subsequently declining steadily to 0.13/1000 in 2010.
| Cost|| |
Given that the elimination campaign has been ongoing since the early 1900s, a precise estimate for the total cost of efforts is unavailable at this point. However, major contributors to Sri Lanka's malaria elimination success were the Sri Lankan Government, the USAID, the UNICEF, the Global Fund and the WHO – first through the global malaria eradication effort and then through the Roll Back Malaria partnership., Of these bodies, the most significant sources of funding were the Sri Lankan government and the Global Fund. All dollar amounts mentioned in this section are in USD.
In 1996, the World Bank contributed $18.8 million to the Sri Lankan health services project, which focused on a range of health issues including malaria. In 1999, the Sri Lankan government partnered with the WHO Roll Back Malaria programme. The Sri Lankan president agreed to provide support for several activities involving the prevention, early diagnosis and treatment of malaria as well as research initiatives pertaining to drug resistance, drug therapy and surveillance. These activities, financed by the World Bank, were rolled out in five pilot districts: Jaffna, Kilinochchi, Mullaitivu, Anuradhapura and Monaragala, where malaria was most deadly. The World Bank also supported the creation of ACD to complement the APCD that was already established.
Financial support from the Global Fund contributed significantly to malaria elimination efforts. Beginning in 2003, Sri Lanka applied for and received funding for its malaria program in Rounds 1 (2002), 4 (2004) and 8 (2008) of funding from the Global Fund., To date, the Global Fund has signed $42,058,140, committed $38,157,830 and disbursed $35,662,201 towards malaria elimination in Sri Lanka. This funding has been used for scaling up IRS, active surveillance through mobile clinics, diagnosis and treatment and LLIN distribution.
Malaria activities in Sri Lanka are financed primarily through domestic sources, representing 58% of total funding ($8.8 million) in 2014. Domestic spending includes funding from the Sri Lankan government for the AMC, solely directed towards malaria-specific initiatives. Only 0.94% of total government spending on health (an estimated $934.1 million) was devoted to malaria in 2014, marking an increase from 0.80% that was spent the year before. With a donation of $3.7 million, the Global Fund accounted for the remaining 42% of the total funding for malaria in 2014., Sources of funding vary widely across districts as the AMC, the Ministry of Health and the Global Fund determine which districts to include in grant proposals. At the district level, the median cost for malaria control was $195,316 in 2014 with a cost per capita ranging from $0.21 to $0.54 and an overall estimated national cost per capita of $0.50. In the light of the difficulty in obtaining data from the AMC, a 2012 study focused on the districts of Anuradhapura and Kurunegala in 2004 and 2009. As the AMC is part of a decentralised health system, detailed programmatic and cost data are kept at district levels, managed by regional malaria officers and overseen by the Regional Director of Health Services. Therefore, evaluating the cost of the anti-malaria programme in these two previously high-burden districts offers a more in-depth look at the cost and allocations of malaria expenditure at the district level. Please refer to [Table 1] for the costs of different vector control interventions implemented in Sri Lanka.
|Table 1: Operating and capital costs of various vector control interventions|
Click here to view
With the last indigenous malaria case in 2012, Sri Lanka now focuses on preventing reintroduction. To ensure sustained elimination, existing surveillance and screening programmes must be maintained., The Sri Lankan National Malaria Strategic Plan (NMSP) estimated that an annual budget of $10 million (from 2015 to 2018) is required to prevent reintroduction. However, assuming a steady economic growth rate of 6.4% including existing human resource and capital costs that the NMSP budget did not consider and basing the projection off of the current strategies rather than proposed activities, the University of California, San Francisco Global Health Group, estimated an annual budget of $14 million (from 2015 to 2020) to prevent reintroduction.
| Reasons for Success|| |
The AMC distinguished itself as the main driver of malaria elimination thanks to a comprehensive approach of vector control, surveillance and case management. The AMC was a centralised body until 1989 when it began project implementation through eight provincial programs headed by the national AMC Directorate. After joining the WHO Roll Back Malaria partnership in the 1990s, the government solidified multiple partnerships with funders such as the World Bank and the Global Fund as well as local and international NGOs, which allowed for the scaling up of its anti-malaria programmes.,
In addition to excellent programming and partnerships, Sri Lanka's strong institutions were critical to its success (Nadira Karunaweera, personal communication, 23 November 2016). The country has an impressive adult literacy rate (91.2% between 2008 and 2012), which contributed to high levels of public compliance to available health-care measures (Nadira Karunaweera, personal communication, 23 November 2016). It also has a national health-care policy that facilitates a strong primary health-care system by offering free health care to all citizens through a network of government hospitals and health-care centres (Nadira Karunaweera, personal communication, 23 November 2016).
Throughout Sri Lanka's civil war, the conflict-marred regions experienced increased parasite incidence as their primary health-care services were disrupted. The AMC recognised the deficit of treatment and prevention measures in these areas, and along with regional malaria teams, NGOs and the military scaled up treatment protocols. The LTTE were themselves impacted by high infection rates and eventually agreed to support control efforts, which was critical in ensuring treatment and prevention for as many people as possible despite ongoing conflict. The AMC as well as the UNICEF, the WHO and the Sri Lankan NGO Sarvodaya worked to distribute ITNs across the country, with the Global Fund supporting the introduction of LLINs later in the conflict., The Sri Lankan Red Cross, the International Committee of the Red Cross, Médecins Sans Frontières, TEDHA and local health workers provided access to diagnostic and treatment services, largely through mobile clinics., By 2005, the annual parasite incidence rates in both conflict and non-conflict areas had stabilised and were well below previous levels., Sustained ACD, treatment and vector control in these areas was a crucial factor in the eventual elimination of malaria.,
The use of DDT in the IRS programme had excellent results, but its subsequent scaling back led to a dramatic resurgence of cases. The shift from malathion to pyrethroid insecticides in 1994, in response to drug resistance in mosquitoes, not only marked the uptake of a more effective insecticide but also increased community acceptance of IRS, as pyrethroids were less pungent and left less residue where they were sprayed. An effective entomological surveillance program was critical in informing targeted IRS for high-risk areas, which became more important as malaria prevalence declined. In addition, the use of ITNs and LLINs was particularly effective in areas inaccessible to IRS teams.,
The development and refinement of both parasitological and entomological surveillance systems allowed for high case detection. More microscopists were able to employ APCD in publicly run health facilities, and ACD could be remotely dispatched to difficult-to-reach areas. In 2009, the AMC developed standard operating procedures for each confirmed or suspected infection, including post-treatment follow-up, household malaria screening and IRS within a 1-km radius of the case. This protocol offered treatment as well as data collection opportunities for ongoing monitoring. In addition, regional malaria control officials, some of whom had doctorate degrees, received research training and used their advanced education to enhance these efforts (Nadira Karunaweera, personal communication, 23 November 2016). Sri Lanka was also one of the first countries to adopt the WHO Global Malaria Eradication Programme's surveillance reporting system and submitting quarterly progress reports. This type of surveillance was critical in tracking the disease to its end and will continue to be essential in ensuring that imported cases do not spur new epidemics.
| Implications for Global Health|| |
If there is one takeaway from the case of Sri Lanka, it is that there is no silver bullet to malaria elimination. Sri Lanka's journey has spanned more than a century and does not owe its success to a singular approach but rather a sustained multidimensional programme that was responsive to changing biomedical and social factors. Given that malaria is still a global concern, there is much that can be learnt from Sri Lanka's success. Namely, countries seeking to mirror Sri Lanka's malaria-free status must recognise the critical interplay of the multiple interventions used and partnerships formed throughout this process.
The coupling of both APCD and ACD allows for broad detection capacity within a country, and the use of RDTs at ports of entry screens for imported cases, which is especially important following elimination., Vector control methods were used appropriately, with targeted IRS in areas of high vector density and in areas surrounding malaria cases., Due to the inconvenience of regular IRS, ITNs and LLINs were relied on more heavily in remote regions and conflict zones. Complementary measures such as larvivorous fish and chemical larviciding played minor roles but highlight the multidimensional and situation-specific uses of various vector control measures., Of course, the success of vector control efforts relied on effective and reliable parasitological and entomological surveillance.
It is critical to build and maintain partnerships with NGOs and other parties to ensure that almost all citizens have access to prevention and treatment measures, regardless of the country's sociopolitical environment., This requires reflexive leadership that is committed to providing unrelenting support for these efforts., Secure sources of funding are required to operate these programs not only throughout the elimination process but also afterwards to avoid relapsing into endemicity. Thus, national governments must be willing to dedicate significant funds alongside their partners.
While Sri Lanka's elimination is impressive, the country must remain vigilant to ensure that the disease is not reintroduced. Community-centred approaches have strengthened biomedical ones, and this synergy was the ultimate driver of success., This resonates with the tenets of public health and has the potential for global impact.
We would like to thank Professor Nadira Karunaweera for her expertise and contributions to this case study. We would also like to thank Dr. Madhukar Pai and Sophie Huddart for their guidance throughout the process.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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