7/27/2019 Malaria vector unexpectedly found in Sri Lanka’s east

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Malaria vector unexpectedly found in SriLanka’s east

Dilrukshi Handunnetti/IRIN

New wells in Sri Lanka's post-war zones prove to be fertile breeding grounds

for mosquitoes carrying malaria

COLOMBO, 18 October 2013 (IRIN) - Sri Lanka’s main malaria vector,the Anopheles culicifacies mosquito, long thought to prefer nesting in ruralareas, has been found in war-affected peri-urban areas in the country’seast, according to a new medical survey.

Medical researchers were only able to study parts of the north and a singledistrict in the east - both closed off to epidemiological surveillance during

the country's 26-year-long civil war - after fighting ended in 2009.

A 2010 survey in the eastern district of Trincomalee, published recently,showed the country’s main malaria vector in wastewater drains, upending acommonly held belief that malaria vectors prefer to breed in clear, cleanwater more commonly found in rural areas.

Lead researcher, Nayana Gunathilaka of the molecular medicine unit at

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Kelaniya University, in the country’s capital, Colombo, told IRIN there is nowan “urgent” need for detailed entomological surveillance in urban areas,especially war-affected ones, to detect the potential re-emergence of malaria in a country that has primarily dealt with it in the countryside.

Conflict and malaria 

 The researcher said massive destruction and displacement during conflictgenerally increases vulnerability to vector-borne diseases.

Dissanayaka Mudiyanselage Amarabandu, 61, a farmer from TrincomaleeDistrict, told IRIN that staff from the health ministry's anti-malaria campaignbegan conducting community awareness programmes in Padavi Siripuraand Kantale villages following the war.

“ They said we have to be [prepared for malaria] even though the country is

concentrating on dengue eradication.”

 The health ministry conducted a nationwide dengue-prevention week from7 to 13 October. The number of dengue cases reported in 2013, as of theend of September, was near 23,500, about 10,000 fewer infections thanwere reported for the same period last year.

“Early warning”Gunathilaka says the new finding is an “early warning”, noting that thecountry’s North and North Central provinces are particularly vulnerable due

to revived paddy farms and large-scale post-war construction, which hascreated pits, drains, irrigation waterways, lakes, ponds and rain waterreservoirs - all fertile breeding grounds for mosquitoes.

“ The country remains unprepared to face urban malaria, especially as newsettlements are created in the former conflict zones to facilitateresettlement.” He added that there has also been an uptick in reports of imported cases of malaria from visitors.

As of December 2012, when the UN Refugee Agency stopped compiling

statistics on internally displaced persons in Sri Lanka , almost 470,000peoplehad returned to the former conflict zone, joining new settlers in thenorth and east, including migrant workers from other parts of the countryand visiting members of the diaspora, Gunathilaka observed.

Health officials are looking to replicate the 2010 malaria surveillanceelsewhere, especially in former conflict zones that have had scantsurveillance; the next is planned to take place in Northern Province.

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 The recent study in Trincomalee District acknowledges there is an absenceof systematic research, particularly in the former conflict zones of the northand the east, about the link between changing ecological and weatherpatterns and mosquitoes’ breeding grounds. Its authors told IRIN peri-urbanareas outside the former conflict zone may be at risk.

Urban threatOnly 15 percent of the island’s 21 million people are estimated to be livingin cities or peri-urban areas, places where the population is growing at 2percent annually.

“Sri Lanka was previously not considered vulnerable to urban malaria,”Sarath Deniyage, director of the health ministry's anti-malaria campaign,told IRIN. But now it appears Sri Lanka, like its neighbours, is increasinglyfacing the threat of malaria in its cities, he said.

A 2012 review of factors contributing to urban malaria transmission in sub-Saharan Africa - the world’s most malaria-affected region - also wentagainst the “general consensus” that urbanization decreased malariatransmission. It had previously been believed that improved infrastructure,“mosquito-proof” housing, increased access to healthcare and reducedbreeding sites would reduce malaria incidence in cities.

Medical research from 2008 had said that “malaria vectors are known toprefer clean water for breeding, which is difficult to come by in pollutedurban areas…” But last year's review, which covered some 1,200 published

articles on urbanization and malaria dating back to 1984, concluded thedisease persisted in a number of African cities, in some cases more thannearby rural areas.

Poor housing, rural-to-urban migration, unpaved roads and pockets of poorhealthcare access were considered factors in the spread of malaria incities.

Declared malaria-free The Sri Lankan government declared the island malaria-free in 2012; after

going three years without local (as opposed to imported) malaria infections,countries can request malaria-free certification from the World HealthOrganization.

 That year, the government reported its lowest level of reported malariainfections - 23, near all deemed to be infections from outside the country -since 1963. Thus far in 2013, three infections have been reported, allimported cases.

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 There have been no recorded deaths linked to the disease since 1999.

 The country had nearly eliminated malaria once before. In 1963, during theera of global eradication efforts, the country achieved a low of only 17cases, down from 92,000 cases in 1953. But with funding declines and

reduced spraying and surveillance, the country saw a resurgence to 1.5million reported infections in 1967-1968.

Posted by Thavam