COLOMBO (AlertNet) - Dengue fever, a potentially fatal disease that has infected more than 70,000 people and killed over 500 in Sri Lanka since January 2009, has shown the first signs of abating in two years as the government steps up a campaign that includes fines against people and businesses that fail to remove mosquito breeding areas.
The fall in cases comes despite extensive flooding this year, which can encourage dengue-carrying mosquitoes to breed in standing water.
Dengue, a severe, flu-like illness, is transmitted by the bite of a mosquito infected with any one of four dengue viruses. There is no specific treatment, and dengue haemorrhagic fever is a potentially lethal complication that causes abdominal pain, vomiting and bleeding.
In Sri Lanka, infections and deaths from dengue fell considerably in the first seven weeks of 2011, compared to a year ago, according to data from the health ministry’s epidemiology unit.
Up to Feb. 24, only 1,606 infections and 15 deaths were reported, compared with more than 4,700 infections and 50 deaths in January 2010 alone. While the country so far has seen only early indications of success, the unit’s chief epidemiologist, Dr Sudath Peiris, is relieved that concerted efforts to curb the spread of the disease are starting to pay off.
In 2009, dengue prevalence reached dangerously high levels, with 35,000 infections and 346 deaths. That represented a six-fold increase in infections over the previous year, and a big surge in deaths from just 28 in 2008. The figures for 2009 were the highest recorded in over a decade.
In 2010, there was a marginal drop in the number of infections to 34,000, but deaths fell faster to 241 as more people sought medical help.
In the middle of last year, faced with the rising trend in infections, the government agreed to take swift action to destroy the carrier mosquito’s breeding areas.
Last May, it sent out a circular to all regional health offices advising them on how to curb the spread of disease after major flooding. During the recent flash floods in January and February, officials visited affected communities to warn them about health risks.
“We had teams on the ground instructing people on how to dispose of garbage, looking into the sanitary facilities and (conditions for) vulnerable groups like pregnant woman and infants,” said Sinnathmabi Sharamuham, the regional medical head for Batticaloa District, which was hit hard by the floods.
Other steps have included releasing into standing water bacteria that kill mosquito larvae, and carrying out public information campaigns to educate Sri Lankans about the fever, targeting vulnerable communities in particular.
The government has initiated dengue awareness weeks, and private businesses have joined in by funding public service announcements.
FINES AND COURT CASES
But epidemiologist Peiris is convinced it is punitive action that has turned the tide. Some of the more drastic anti-dengue measures introduced by the government in June include legal action and financial penalties.
People dumping garbage in unauthorised locations have been fined. Armed forces personnel and police have also been deployed to clean up public spaces used by mosquitoes as breeding grounds.
“The moment people realised they risked fines and possible jail time, they became more serious about keeping the environment they live in clean,” Peiris said.
A manager of a private bank in the north central town of Anuradhapura was recently fined 15,000 rupees (around $130) because police found stagnant water near air conditioning units and old tyres dumped on the premises - an ideal breeding ground for mosquitoes.
In another incident, a top official of a national nongovernmental organisation has been summoned to appear in court in Mount Laviniya, a suburb of the capital Colombo, for installing water systems in houses in Rathmalana, built for survivors of the 2004 tsunami, that allowed spillage from tanks to remain stagnant on the concrete floor.
Dengue fever has spread fastest in Sri Lanka’s crowded urban areas. The three districts of the Western Province - the most densely populated on the island - recorded more than 11,000 infections and over 100 deaths last year.
“This is an urban phenomena - the mosquito is breeding because of the way people live,” Peiris said.
Research on the spread of the fever by the epidemiology unit found it has been exacerbated by building design, mainly in towns and cities.
“This is a mosquito that will lay eggs in the smallest available space with water,” explained Peiris. “I can walk into any house or office, and show (you) a dozen such places any time.” They include containers of water unchanged for days, open drains, rain gutters and waste water pits.
According to the head of the health ministry’s epidemiology unit, Dr Pabha Palihawadena, educational programmes – especially those targeting young children - have proven effective in reducing such hazards. In some schools, dengue prevention material has been incorporated into the curriculum.
“Now I know where the mosquito lives,” said 10-year-old Thurulu Navodaya, a student in Ma-eliya, a rural village in Kurunegala District, about 150 km ( 94 miles) from Colombo. “I make sure that we clean all those places now.”
CLIMATE RISK REQUIRES VIGILANCE
While Sri Lanka’s anti-dengue campaign is showing promising early results, Peiris warned that recent extreme rainfall - with eastern regions receiving a year’s worth of rain between December and February - suggests continued vigilance is vital, both now and in the longer term.
Two studies published in the journal Nature in February found that more frequent heavy rainfall is linked to greenhouse gas emissions, suggesting a clearer human fingerprint on a recent spate of floods around the world.
Scientists agree that greenhouse gas emissions are warming the planet and expect this will lead in future to more evaporation of water, moister air and heavier rainfall. Health officials have warned that climate change could raise the risk of dengue in some tropical and sub-tropical regions where it is already a problem, and expand its reach into new areas.
“Climate change can change the way epidemics spread, (so) despite infections going down (in Sri Lanka), we should not lose focus and be complacent,” Peiris said.
Amantha Perera is a freelance writer based in Sri Lanka. This story is part of a series supported by the Climate and Development Knowledge Network.