Experience, rigour, determination: How Sri Lanka eradicated malaria

In 1977, Sri Lanka switched to malathion, considered less harmful to humans than DDT.

Written by Nirupama Subramanian | Updated: September 12, 2016 5:34 am
malaria-759 A Sri Lankan worker fumigates buildings in Colombo. AP Photo

The World Health Organisation (WHO) declared Sri Lanka malaria-free last week. Victory over the disease came after more than seven decades, during which the country also went through a crippling civil war. The long years of accumulated technical experience was bolstered by a solid public health system that provided an efficient network of reporting, information-gathering and surveillance, and almost full literacy, which made it easier for health workers to educate and mobilise the 22 million population against the disease.

In the 1990s, Sri Lanka was fighting two big wars at the same time. One, the war in the North and East against the Liberation Tigers; the other, less well known, against the Anopheles culicifacies and the disease it spread. The two were not entirely unconnected.

In 1991, the number of malaria cases was nearly 400,000. In 1995, when the civil war broke out again after a 100-day ceasefire, 142,000 cases of malaria were reported which, in 1999, rose to over 260,000. The patients were mostly male. Soldiers serving in the North-east were identified as vulnerable — and because they travelled back to their homes in southern Sri Lanka, a high-risk group. In 1998, 115 people died of malaria. This is about the time the government launched itself into its second war.

The 2002-06 ceasefire helped the government’s campaign, which was backed by international funding — and by 2007, the incidence of the disease had come down dramatically to under 200. That year, when the fighting began again, saw a minor spike in the number of cases.

At the end of the war in 2009, the Sri Lankan Ministry of Health launched a malaria elimination programme, funded in part by the Global Fund to fight AIDS, Tuberculosis and Malaria. It set itself two goals: to make the country free of p. falciparum strain of malaria by 2012, and of p. vivax by 2014.

In 2010, Sri Lanka reported over 730 cases, which included both indigenous and imported cases. But in 2013, 2014, and 2015, there were only 95, 49 and 36 cases — in all cases, the infection was acquired abroad. The country had achieved three years with zero incidence of indigenously contracted malaria, making it eligible for the WHO certificate.

asasassas

According to Dr Hemantha Herath, Deputy Director of the anti-malaria programme, the success owed to a multi-dimensional approach: an effective vector control programme, a three-pronged parasite surveillance programme, and “patient management”, or treatment of the disease.

Sri Lanka’s efforts at vector control go back to when it experienced its first malaria epidemic in 1934-35. DDT spraying was introduced in the 1940s, and this remained the main method of vector control. Entomological surveillance — the study of vector species, its distribution, density and susceptibility or resistance to insecticides — a labour intensive exercise, began around the same time. Reporting malaria cases was made a legal requirement.

In 1963, as a result of these efforts, only 17 malaria cases were reported. Sri Lanka dropped its guard. Spraying was discontinued. And by 1969, malaria was back. There were 500,000 cases, and the mosquitoes had developed DDT resistance.

In 1977, Sri Lanka switched to malathion, considered less harmful to humans than DDT. But it would be another two decades, until the introduction of a new insecticide group called Pyrethroid, before Sri Lanka would have better ammunition against malaria, and its fight against the disease would begin in right earnest.

“It was highly effective. Because of less smell and less residual staining of surfaces, 99% of households allowed spraying. Insecticide coverage increased,” Herath said.

Alongside, the government also distributed insecticide-treated mosquito nets. Before money poured in from the Global Fund — Sri Lanka received over $ 30 million in three tranches — the nets were made locally, and programme workers went house to house, treating the nets with insecticide, Herath said.

In 1984, a year after the ethnic question tuned into violent confrontation, chloroquine-resistant p. falciparum was discovered in the country for the first time. During 1989-91, there was a big outbreak of malaria, followed by spikes in 1995 and 1999.

Despite running a parallel state in the North for several years, the LTTE cooperated to a large extent in government health initiatives. For 3 years in the mid-1990s, the LTTE would declare a four-day unilateral ceasefire to enable an anti-polio immunisation campaign. In the same way, the Tigers did not obstruct the government’s anti-malaria efforts, implemented through local officials. The reporting was effective, if not 100%.

But there were security restrictions on sending insecticides and drugs to areas under LTTE control. There were restrictions on sending in vehicles, as the LTTE was known to confiscate anything it needed for the war. Also, health workers from the South did not want to travel to the conflict areas. Result: while local health officers continued to report cases, control and surveillance measures were not as effective.

Parasite surveillance consisted of three procedures: passive detection, in which anyone going to hospital or a health centre with symptoms of malaria had to get their blood tested; active detection, in which health workers in mobile malaria units went from house to house doing blood tests on pre-identified high-risk groups; activated passive detection, in which a blood test was done on anyone coming into a health centre for reason.

In the elimination phase from 2008, each case was reported to the anti-malaria control headquarters in Colombo within 24 hours by email. Details of confirmed cases had to be relayed back. The standard operating procedure for nearly a month-long follow-up included treatment with medicines, screening of family and places were the patient had stayed or visited, insecticide spraying in the neighbourhood, and keeping a watch on mosquito density in the area.

“Each case was investigated, treatment given, and followed up. Earlier we used to have only numbers, now we had all the details,” Herath said. He credited a technical support group of administrators, senior doctors, and professors of medicine with institutional memory of the battle against the disease, for coming up with the right strategies.

The country’s public health system, with its extensive network of free primary medical centres and health workers, was the spinal cord of the programme, which ensured no person was left out. Herath estimates that apart from the 3,000 health workers directly involved in the anti-malaria campaign, all other village-level public health workers, including midwives, too were actively engaged in educating people and mobilising opinion.

The army pitched in by not sending home soldiers who fell ill while posted in the North and East, in case it was malaria. They were treated in the camp, and given leave to go home only after they were better. This checked transmission and played a big role in eliminating the disease, Herath said.

Sri Lanka now hopes that India is able to eliminate malaria too, as there is every danger of it returning to the island through infected tourists, business travellers and Buddhist pilgrims. One suggestion from Herath, from Sri Lanka’s own experience, is that as India eliminates malaria from parts of the country, it must not reduce flow of resources to that area. “We shall be hoping and praying for India’s success, and we will be providing all support in detecting cases that may come to us from India,” he said.

 

nirupama.subramanian@expressindia.com