ISSN: 1391 - 0531
Sunday, October 29, 2006
Vol. 41 - No 22

After the deluge, beware of dengue

By Malik Gunatilleke

Health authorities fear that the present wet weather could lead to a dengue epidemic by December.

Dr. Padmal De Silva, Medical Officer of Epidemiology and Statistics in the Public Health Unit (PHU) of the Colombo Municipal Council (CMC), said the heavy rains experienced throughout the island are likely to cause a sudden increase in dengue cases towards the end of the year.

“We are using biological techniques to destroy the dengue larvae but we need a more hands-on approach where the public makes an effort to clear their own neighbourhoods,” he said.

From January to October this year 630 dengue cases have been reported as against 645 cases during the corresponding period last year.

In 2004, which was known as the major dengue epidemic year in Sri Lanka, 1,030 cases of dengue were reported to the PHU while over 15,000 cases were reported island-wide.

The dengue disease usually reaches its peak in the two-week period after a rainy spell, when stagnant water collects and creates prime breeding grounds for these mosquitoes.

The PHU is currently using a system called COMBI (Communication for Behavioural Impact) which is recommended by the World Health Organization (WHO) as the best way to fight the dengue disease.

The COMBI method aims to get people to spend 30 minutes a week to clean their premises and the area surrounding their homes.

“This method is more about educating the public on the disease and its spread and also getting the public involved in the process of clearing breeding sites. It is fairly simple to eradicate this menace but the level of public cooperation has not been satisfactory,” he said.

Countries such as Singapore and Cuba carried out the more successful campaigns on the elimination of dengue, by using public awareness as a weapon but Sri Lanka’s situation poses many problems in using this method.

The PHU of the CMC currently has seven Medical Officers, around 45 Public Health Inspectors and the same number of Health Instructors, while there are over 1.25 million people in Colombo and over 250,000 residences.

“Clearly the CMC is not in a position where we can send leaflets to each and every home, nor clear the entire city of breeding grounds, but by carrying out a more efficient and long running dengue awareness campaign, we can bring round people to our cause,” Dr. De Silva said.

The fact that 50% of reported dengue cases are of school children is also a major concern with the health authorities and has caused them to organize large-scale dengue elimination programmes in schools as well.

Dr. De Silva said the PHU ran a programme where school children were employed to clear mosquito breeding grounds in and around their schools within a 500-metre radius.

“Programmes like this have helped bring school children cases down to 30% but the education authorities are not cooperating with us now since students are not allowed to leave their school premises during school hours,” he said.

He also said the PHU had the authority to prosecute any civilians who did not adhere to warnings concerning the cleanliness of their homes.

If any homes harbouring mosquito breeding grounds or even potential ones are reported to the PHU, a notice requesting the owners to clear their premises is issued and an inspection done after three days. If the breeding grounds are not cleared within a week legal action is taken by the PHU.

“Currently the fine for the offence varies from Rs, 1,000 to Rs. 5,000, but the Government is considering raising the fine to Rs. 25,000,” Dr. De Silva said.

Dr. P. Kariyawasam, Chief Medical Officer of the PHU told The Sunday Times that dengue cases in Colombo were on the rise and even though statistics show an improvement from the past three years, the uncertain weather patterns could cause a major dengue epidemic in December, within the municipal limits.

“We usually get many reports of dengue cases during October but this time we have been able to keep the number of cases under control,” he said.

Points to remember

Dengue mosquitoes are predominantly found in urban areas and are known to be day biters.

Dengue mosquitoes breed in pools of stagnant, clear water that collect in ditches, tins, pots, coconut shells, etc. Studies show that discarded rubber tyres are the dengue mosquito’s favourite breeding ground.

Their peak biting times are between 7 a.m. and at 7 p.m. so school children and people getting back home after work are especially vulnerable.

The dengue mosquito has a biting radius of 250 metres and is known as a relatively lazy mosquito. However it is a compulsive biter and would follow one person for long periods of time.

The dengue mosquito is an outdoor mosquito and most dengue victims are infected outside their homes.

Dengue mosquitoes are most active two weeks after heavy rains.

Dengue mosquitoes do not move too far away from their breeding grounds so most victims are bitten by mosquitoes breeding in their own gardens.

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Copyright 2006 Wijeya Newspapers Ltd.Colombo. Sri Lanka.