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Thursday Nov 07, 2024
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By Dr. Pradeep Kariyawasam
It was heartening hear that the health authorities are now focusing on creating Dengue Free Zones (DFZ) in the country as a preventive measure to curb the spread of this dreaded disease.
I have been for a long time a proponent of this idea as without a sustained effort involving everyone to create mosquito non-breeding zones that need a lot of manpower, dengue prevention is a dead topic until a vaccine is produced.
There are talks about introducing sterile mosquitoes or the bacteria Wolbachia where eggs will not hatch and the dengue mosquito numbers will be reduced with time. But it will not happen overnight. Meanwhile we have an emergency at hand to deal with.
It is a well-known fact that Colombo and suburbs are the main hotspots for dengue outbreaks whenever it happened. Of the 100,000 hospitalisations the Western Province accounts for 43%. Colombo city has an all-time record number of patients in six months! These are only hospitalisations. With large numbers of fever patients not showing the typical dengue fever symptoms, the total numbers could be a fourfold figure.
When an epidemic or a serious outbreak happens there should be at least weekly inspection of premises where patients reside. This is very much labour intensive as the dengue mosquito can breed in as a little as a teaspoon full of water.
What we should remember is that if we miss one breeding site that means the site could have at least 100 eggs or larvae. New types of dengue fever viruses among ill foreigners from the far-east or from neighbouring countries can quickly spread into other areas and to the locals. One such situation took place about a decade ago at the Havelock City Building Complex when over 20 Chinese workers went down with dengue fever.
Therefore, we need a warning system which the Epidemiology Unit of the Ministry of Health along with our microbiologists should run by analysing the reports sent by the Medical Officers of Health and the blood samples given to investigate the disease.
Dengue fever cannot be eradicated without the support of all citizens, organisations and the community at large. The following strategy will be successful if all stakeholders participate to sustain this program.
Special emphasis must be made to clean up schools and prevent the infection spreading among school children. It is the duty of leading citizens, corporate heads and heads of Government departments to contribute to this cause.
Dengue prevention and control needs massive human resources to inspect and destroy mosquito breeding sites. Cuba sends out thousands of volunteers for this purpose and that is a best program in the world. Spraying or fogging using of chemicals has to complement such an effort in this country and we should complement with such programs too such BTi spraying, introducing Wolbachia infected male mosquitoes, fogging, etc. But the inspections of all premises and or lands is the core of any program.
There are two ways of doing this. First is to give employment to those GCE ‘A’ Level qualified youth or those awaiting entrance to universities and attach them to MOH offices, train them in dengue control, use them in inspections and pay them an allowance of at least Rs. 1,000 a day.
Two of them should be able to inspect at least 30-50 daily premises depending on the size of the land parcel under the guidance of the MOH. Funds for this purpose could be taken from halving the chemical bill as when there are less mosquitoes around, the use of chemicals could be minimised. They should be given preference when selections are made for permanent employment or for any scholarship in the future.
Secondly, to fill all the vacancies for field staff in the health sector immediately. Even if they are not trained until it is time to arrange training they could be utilised for a sustained attack against dengue mosquitoes.
Thirdly, to get large Government sector and the private sector organisations on board and make their organisations volunteer to use their staff to inspect all premises around the institution up to a radius of 200-250 yards once every week and most of the vulnerable areas will be free of mosquito breeding. The private sector can do this work under their Corporate Social Responsibility (CSR) program as a permanent project.
The Government may consider bringing in laws where it can encourage all private firms which have staff strengths of over 50 to take part in this exercise by inspecting the area around their premises up to 100-250 yards depending on the numbers of workers they have and in return granting a tax concession to such firms. This will allow the local authorities to concentrate on common areas such as bare lands, drains, canals, parks, cemeteries, marshes, etc.
We have to get schools to clean their school premises and also to use the school children and parents to inspect the neighbourhood up to at least 250 meters from all sides once a week and detect and destroy breeding sites.
Studies earlier conducted showed in no uncertain terms that by cleaning up school premises and inspecting the area around the school up to 250 meters to detect and remove mosquito breeding sites could reduce the infection rate among the children under 20 years of age by as much as 45%. This is a very important statistic as not all schools participate in such endeavours and not all children are in schools.
The strategy was based on two facts. The Aedes (dengue) mosquito breeds in little fresh water collections such as a teaspoonful of water and has a flying range of only 150 yards and if we get rid of all breeding sites or water collections within that radius no dengue mosquitoes will be able to enter school premises; the Aedes mosquito mainly bites during day time, where the peak biting times are 7:30 a.m. and 7:30 p.m. but recent studies has shown that it can be active at other times when schools are open.
We used to have such programs years ago in a project called Green Star which covered all municipal districts of the Colombo Municipal Council with greater attention placed in areas where a high incidence of dengue has been reported in that and previous years. The strategy was to cover as much as land area during the house-to-house inspections. Initially only the permanent residences and work places with garden space were selected for inspections. An area of 40-50 households was demarcated and assigned to a group of three to four field resource persons covering each area.
A Green Star sticker was issued to be pasted on the wall or gate denoting that the household or the institution was not a threat to others were that no mosquito breeding places, overgrown rank vegetation or overgrown trees, bushes, hedges were found in the premises and the residents and occupants were encouraged to have a tidy road frontage and well-maintained drains and gutters.
These Green Star project principles and criteria of yesteryear could be adapted to this program too. Apart from that schools and homes can be advised to get rid of gutters if they are not in a position to clean them regularly and if leaves from nearby trees fall into them. Branches which hang over the roofs should be cut to prevent the same.
Bromelia type plants which collect rain water in their axils should be reduced in numbers as having large numbers increase the risks of mosquito breeding. Tree-holes should be filled with sand.
Efforts should be made to see that all areas in the school premises have sunlight falling on to the earth. This reduces dark areas and mosquitoes will not find it easy to find a place hide. The same principle should be adopted in areas where thick vegetation is present. Therefore, we invite all schools to take part in such an exercise and make the school a safe place to study.
By creating DFZs through schools, Government and private institutions, we can cover the majority of the land area in the cities. Then the health sector can concentrate on the rest of the area with their staff and the recruited ‘A’ level qualified youth.
Apart from that we have to have field staff belonging to the health sector who are responsible for a given area where they will check the rest of the residences, institutions, parks, play grounds, etc. for mosquito breeding at least twice a month. The female mosquito lays around 100 eggs at a time and during her lifetime that happens about three times.
If the premises did not comply with the required standards then a notice can be issued by the Municipality under the Mosquito Borne Diseases Regulations to clean the noted areas. The following week the officers can carry out their inspections and if the criteria were still not met then a case was filed against the home/land owner to appear in courts.
We have to have such a program going again and sustainability of such a project can be maintained by PHIs visiting each of the homes on rotation to inspect whether the standards are maintained as well as to check if homes issued with notices have complied with required standards.
Every year a second phase should be started during November to January in order not to lose the momentum gained and also to extend the range to eradicate from dengue mosquitoes, all types of mosquitoes in the city especially targeting the urban poor where they spend one-tenth of their wages on mosquito coils.
Action should be taken by health authorities and external agencies such as the NGOs to complement the above program and those State institutions which are the owners of large land parcels as mentioned below.
1) Special awareness and shramadana campaigns for residents who live housing complexes, around the canal system and the marshes in the city with special emphasis on educating children,
2) Improvement of solid waste management in these areas
3) Creation of community groups, women’s groups, children’s guilds, etc. to develop positive attitudes and leadership to solve the problems
4) Chemical spraying of marshes and large canals using new equipment
5) Cleaning of canals by the Land Reclamation and Development Board, and now with the help of the Sri Lanka Navy
6) Clearing of large drains, roadside gullies by the Colombo, Dehiwala Mount Lavinia, Kaduwela Municipal Councils by using jetters and gully emptiers and solving sewerage problems in these areas are envisaged to be carried out as soon as possible
The contact telephone numbers of the District MOH, engineer, PHI, midwife and solid-waste overseer should be displayed on a board in every street so that the public can communicate with them.
Marshes and canals have become the largest mosquito breeding grounds in the city. The residents in adjacent areas suffer immensely due to bites from these mosquitoes especially at night. The labour force in the city live mainly in these marginalised areas, and lack of sleep at night due to this nuisance results in poor output at work. It is easy to organise shramadana campaigns in these areas.
The situation in Colombo was improving taking the above action throughout the years. The sanitation was gradually improved with the forces and the Police officers by supervising the clean-up campaign. That was also a catalyst for the communities to also join in.
The Railway authorities must take action to clear their reservation lands. Ports and Municipal authorities took actions to improve storm water drainage in the reservation areas. The canal system has now been fully cleared but garbage could be seen in some places.
These projects, ideas and concepts can be replicated in other areas in the country once the hotspots are covered. However, proper coordination should be in place to avoid such eventualities of duplication by using maps to demarcate areas for which each organisation is responsible. Finally, I wish to remind that prevention of dengue epidemics is every citizen’s and institution’s responsibility and not really the Government’s.
(The writer is former Chief Medical Officer of Health, Colombo.)
