Four years after Sri Lanka’s worst outbreak of dengue fever, fewer people are dying of the mosquito-borne disease, but health officials caution that more public action is needed to prevent epidemics.
The number of fatalities has been dropping since 2004 when 88 people of the 15,334 known to have contracted dengue died of the illness. In 2008, some 6,431 people were infected and 24 deaths were recorded, according to provisional figures collected by the Healthcare and Nutrition Ministry.
However, health authorities are cautious about the drop in the number of cases reported, saying there could be a resurgence of the potentially fatal illness.
[...] Unlike malaria, the other mosquito-borne disease that once plagued the island’s rural provinces, dengue occurs mainly in urban centres, with the capital Colombo and two neighbouring districts, Gampaha and Kalutara, topping the list. Almost half the country’s 25 districts are designated high-risk areas.
[...] To combat the spread of the dengue mosquito, Aedes Aegypti, health officials are advocating more public vigilance and discouraging the widespread use of insecticides administered without proper supervision. The dengue mosquito is also responsible for spreading chikungunya, characterised by high fever and inflamed joints.
“People should not be encouraged to use insecticides because the danger is that the mosquito will develop resistance to these chemicals,” said Supriya Warusavithana of the World Health Organization (WHO). “The most effective way of preventing the disease is by cutting back mosquito breeding sites.” [Also] the high and frequent dosages required could lead to other diseases. The cost of funding long-term insecticide use could also prove prohibitive.
“The only way to combat dengue is to change the behaviour of people and mobilise community support to eliminate mosquito breeding sites,” said Warusavithana.
The Dengue Control Unit’s main strategy is persuading people to keep homes and neighbourhoods free of breeding sites, where water collects, such as tyres and other receptacles. Home-owners, school-children and tyre traders are being targeted in a campaign to dispose of coconut shells, plastic cups, old tyres and other containers that hold even a few centimetres of water in which the mosquito can lay its eggs.
WHO has been supporting the Communication for Behavioural Impact (COMBI) strategy by providing funds and technical advice. The agency gave US$90,000 for 2008 and 2009 to supplement the government’s budgetary allocation for the dengue control programme.
Although there is a legal provision to fine anyone with breeding sites on their premises, the amounts are small and insufficiently prohibitive. The government is currently drafting tougher laws to bring offenders to book.
Source: IRIN, 08 Jan 2009
Dear Sir/Madam,
As a Scientist working in the field of vector control for the past three decades, I am happy to suggest my views for the benefit of the readers.
1. Aedes aegypti and Aedes albopictus are well known vectors of both chikungunya and dengue.
2. The original home of these mosquitoes are forests and the breeding places are tree holes, tree stumps, tree axils, rock pools, rock holes etc., People who are visiting nearby forests are bitten by these mosquitoes. Those people carry the infections to the local population in villages, towns/cities. The viruses of both chikungunya, dengue are maintained in sylvatic cycle. Currently, the breeding sources are in very close proximity to the human habitation, during non-rainy months defrost water collection trays in refrigerators found to be potential breeding sites reported by us (Srinivasan, R., Mariappan, T. and Jambulingam, P. in Dengue Bulletin, 2007, vol:31, 174-175).
3. Acute domestic water shortage forced people to store in domestic water containers facilitate for breeding of these mosquitoes are well documented as reported in places like Jeddah, Kingdom of Saudi Arabia, UAE, Middle East Countries(Mariappan, T. Environmental Health Perspectives, 2009, vol:117(2)).
4. The dormant eggs of these mosquitoes could survive for 6-8 months in adverse conditions. Thereby, during rainy period these species shoot up in density and facilitate for transmission.
5. The only choice of vector control has to be undertaken by every individual in the globe through source reduction procedures. For that purpose, above 10 years old group of people must be trained in practical hand in hand training to avoid any out break in future.
6. The Govt. organized sector is necessary to be vigilance and they could concentrate more on natural breeding sites as continuous measures without break.
Suggestions are welcome,
With kind regards,
Dr. T. Mariappan,
Scientist, Vector Control Research Centre (ICMR)
IndiraNagar, Puducherry, Pin: 605 006. India.
Phone: +91-413-2272219
E mail: thirumari@yahoo.com
tmappan@gmail.com