Story of malaria elimination in Sri Lanka
The Fight Being a tropical country, the island of Sri Lanka has been endemic for malaria, probably, over the past few millennia. They successfully ended the endemic in 2012 - two years ahead of the target year set out by their government.
Being a tropical country, the island of Sri Lanka has been endemic for malaria, probably, over the past few millennia. Ancient historical chronicles which have been documented over 2000 years ago refer to episodes of fever and pestilence at almost regular time intervals in the history of Sri Lanka. Current historians also attribute devastation caused by malaria as a reason for shifting ancient capitals of Sri Lanka from Dry Zone (in the northern and eastern parts of the island) to Wet Zone (South-western part of the island) of the country.
During the period of western colonization from 1505 onwards, malaria has played a decisive role in wars between locals and invaders. Historians of all three invading nations (Portuguese, Dutch and British) those accompanied such expeditions have related to a “Jungle Fever” that killed hundreds of their soldiers. Robert Knox, who in Sri Lanka as an “open prisoner” for nineteen years also mentions about this fever which killed his father and nearly killed him.
British Rule and Malaria Control
After occupying the entire island in 1815, the British further experienced several hardships due to malaria in developing the new infrastructure such as highways and railways to manage its new colony. Having experienced several outbreaks of malaria in the 19th Century, then British Government started its first organized unit for the control of malaria in 1911 which later evolved into the Anti-Malaria Campaign of the country.
Island’s first malariologist was appointed in 1921. Six years later, a ‘special division’ was created, with a sanitary engineer and a medical entomologist. Vector control measures during this period consisted mainly of anti-larval measures, such as oiling of breeding sites, spraying with Paris Green (copper(II) acetoarsenite), introduction of larvivorous fish and environmental engineering such as draining and filling.
A major epidemic occurred in the island in 1935, reportedly affecting more than 3 million people and leading to at least 82 000 deaths. Soon afterwards, control activities were extended, with theuse of pyrethrum insecticide sprays and suppressive drug therapy; entomological surveillance was begun, including observation of breeding sites to forecast seasonal epidemics, with collection of larvae and adult mosquitoes.
First Near-Elimination of Malaria
Indoor residual spraying (IRS) was introduced with the establishment of the first mobile unit in November 1945 and this was among the first such initiatives in Asia. It was extended to all endemic and potentially endemic areas in the country. Both DDT and benzene hexachloride were initially used for this purpose. With the use of IRS, drastic reductions were seen in the numbers of cases from 1947 onwards. Further, radical cure of positive cases was started in the 1950s using different regimes of primaquine after having treated with amodiaquine. In 1958 Sri Lanka joined WHO’s Global Malaria Eradication Programme.
The story of malaria control in Sri Lanka Provides a classic example of resurgence of malaria following near elimination in 1960s. Between 1947 and 1956, when indoor residual spraying (IRS) was initiated, the incidence declined drastically. The number of cases continued to decline until 1963, when only 17 cases were documented in the whole country of which 11 were imported. A major epidemic occurred 4 years later with the number of cases reported reaching 538 000 in 1969. Consequently, the programme reverted to a strategy of malaria control.
Control of this “second epidemic” of the 20th century, which lasted nearly 45 years was complicated by many factors both directly and indirectly related to malaria control. Emergence of vector resistance to DDT followed by to Malathion, emergence of parasites resistant to commonly used drugs, mass migration of people to endemic areas as part of major irrigation projects, ethnic conflict and economic down turn were among the main such factors. As a result, there were more than 600 000 cases of malaria in 1986–87 peak while in 1999 the number of confirmed cases of malaria was 264 549. Despite this, the mortality was minimal due to the wide access to quality treatment and infections being predominantly due to Plasmodium vivax.
In this backdrop, Anti-Malaria Campaign (AMC) of Sri Lanka changed its strategies going beyond the single vector-control methods towards integrated vector management (IVM). IVM consisted of carefully selected interventions, including vector control in major irrigation and agriculture projects, rigorous entomological surveillance leading to targeted spraying in high-risk areas, new classes of insecticides for IRS, insecticide-treated nets and larval control, and this process was supplemented by strengthened parasitological surveillance for active case detection combined with rapid response.
Use of Long Lasting Insecticide-treated Nets (LLIN) had a great impact on protecting vulnerable populations from malaria in this phase, especially, those lived in conflict affected areas. In many areas where effective IRS was not possible, LLINs provided 3 years of protection to most vulnerable groups.
Active case detection was introduced in Sri Lanka in the 1990s as a complementary strategy directed towards high-risk areas and for population groups that are hard to reach or have poor access to diagnosis and treatment. Parasitological surveillance was strengthened and investigations were carried out in respect of each passively detected or actively detected case, including mass blood surveys to identify additional cases.
As a result of the adoption of above strategies, the incidence of malaria in Sri Lanka decreased, from 264 549 cases in 1999, to 124 indigenous cases in 2011 during which Sri Lanka prepared to eliminate malaria from her borders for the second time.
Reporting of cases and deaths has been enhanced by instituting reporting within 24 hours, with measures to increase reporting from private clinics and physicians. Case review meetings, led by the Anti-Malaria Campaign (AMC) with regional malaria officers, allow feedback and discussion of best practices.
Effective treatment of P. falciparum and P. vivax cases was also an important strategy in elimination of malaria. New Artemisinin-based Combination Therapies (ACTs) were introduced for the treatment of P. falciparum cases, combined with primaquine to eliminate gametocytes. Chloroquine for 3 days together with primaquine for 14 days continues to be used for the treatment of P. vivax. Revised treatment guidelines were also issued to comply with new strategies of elimination.
All above activities of the Anti-Malaria Campaign came under the technical scrutiny of an independent group of professionals having vast experience in different aspects of malaria control and treatment. This Technical Support Group (TSG) advised the Director General of Health Services and the Director/Anti-Malaria Campaign on technical matters and was helpful in maintaining the technical acuity of the control and elimination processes despite the rapid turnover of permanent technical and managerial staff of the Campaign. Further, core subgroup of the TSG serves as a Case Review Committee as well to verify and decide on all reported cases of malaria independently.
Control of Malaria in Conflict-affected Areas
There were several partners, both local and international, who supported the Government of Sri Lanka to control and eliminate malaria. World Health Organization (WHO) continuously provided its support over the past many decades. Malaria control activities further enhanced when the government entered in to partnership with Roll Back Malaria to receive its advocacy and technical support. Across the country, malaria vector control, surveillance, and treatment interventions were intensified. In subsequent years, further expansion of these interventions were made possible by grants from the Global Fund to Fight AIDS, Tuberculosis and Malaria (GFATM). In 2008, the last case of indigenous malaria-related death was reported in Sri Lanka.
Government’s partnership with locally operating NGOs was an important factor which contributed to the successful control of malaria in conflict affected areas during the civil war. By 2000, Sri Lanka’s eight conflict affected districts accounted for most malaria infections. Integrated vector control and treatment interventions were scaled up in the conflict affected districts by the AMC and the regional malaria teams, often in partnership with non-governmental organizations and the military. The rebels, Liberation Tigers of Tamil Eelam (LTTE), to a great extent, supported the government’s efforts to control malaria in areas under their control which was a unique gesture not seen in many large scale conflict situations,. The Sri Lanka Red Cross, the International Committee of the Red Cross (ICRC), and Médecins Sans Frontières (MSF), and Sarvodaya (a local NGO) are among the leading organizations that were in partnership with the government of Sri Lanka during this period.
With the ending of civil war in 2009, effective coverage of interventions was extended to cover the entire island paving way to the elimination of malaria from the island. Anti-Malaria Campaign and its regional teams got themselves re-oriented for the elimination of the disease according to the WHO guidelines for malaria elimination. The National Strategic Plan was developed with the aim of achieving malaria elimination within a time-bound framework to reach zero local transmission by 2014. However, several key factors among many other factors such as the government commitment, dedication of health workers, highly technical and professional approach combined with the extremely effective surveillance system paved the way to reach the objectives two years ahead of the target year with the last case of locally transmitted case of malaria reported in 2012.