The dengue epidemic

Mosquitoes have been with us for a long time. It is highly unlikely that they can be eliminated in that sense of the word. Mosquitoes act as vectors for a number of dreaded and deadly diseases, which are also no closer to eradication. While mosquito-borne diseases can be controlled through a combination of medication and the use of insecticide or biological control methods, the best response would be taking steps to prevent mosquito-borne diseases in the first place.

Sri Lanka and indeed a number of other countries in the region are facing virtually an epidemic of dengue. Even the developed countries have not been spared. The World Health Organization says some 2.5 billion people, two fifths of the world's population, are now at risk from dengue and estimates that there may be 50 million cases of dengue infection worldwide every year.

The number of Dengue cases here has risen to 24,001 while 240 people have died of the disease so far this year, the Epidemiological Unit of the Health Ministry said. The Epidemiological Unit said in its latest statistics that of the 24,001 cases, the highest number of patients were reported from June totalling 7,048. It is followed by July with 6,843 cases being reported.

This represents a sharp increase as only 4,156 Dengue cases and 85 deaths were reported for the whole of 2008. The majority of these cases have been reported from Gampaha, Kegalle, Kandy and Colombo districts. This is an alarming situation by any yardstick.

In this country, there is a tendency to blame the authorities for everything that goes wrong. The dengue epidemic is no exception. There have been many calls for the resignation of those at the helm of the health service. Yes, there are areas where the authorities could and should have fared better, but their stepping down would not necessarily solve the problem.

The society should turn the search light inwards to probe the very roots of the problem.

The truth is that we have neglected the upkeep of our surroundings, at a personal level. Mosquitoes are allowed to breed in every nook and corner, giving rise to not only dengue but malaria and filaria as well. The prevalence of dengue at this high rate can only mean that preventive measures as well as public awareness campaigns by authorities are not working as they should.

A fair share of the blame should fall on Local Government authorities who are notorious for not clearing garbage dumps and drains. They don't send workers on oil spraying campaigns anymore. And what happened to blood testing for mosquito-borne diseases? The Local Government authorities should get their act together if they are honestly committed to eradicate dengue and other such diseases.

The dengue epidemic has reached such vast proportions that the Government had to seek international expertise to contain it. We are told that a Cabinet memorandum will soon be submitted to implement the recommendations included in the report submitted by two Cuban epidemiologists Dr. Aramis Martinez and Dr. Ms Yelina who arrived in Sri Lanka on July 21 to study the spread of the dengue epidemic.

The report has mentioned strategies used by the Cuban Government to control a dengue epidemic and recommended measures such as implementing `spot fines', aerial spray of Bacillus thuringiensis israelensis (BTI) and using BTI for water tanks and other water containers at homes and strengthening vector surveillance.

According to their estimates, the use of BTI is not all that expensive, which is a plus point. But biological control systems must always be deployed with caution and they may not work in all regions of the world. The environmental factors should also be taken into consideration.

The report also says that the garbage clearance system in Sri Lanka is not methodical, which we already know is a fact of life here. There are worries that the disease might get more rampant with the proper onset of monsoons rains.

But there are other developments that might prove to be useful in the long term. The first promising development is the real possibility of having an effective vaccine for dengue. A US company has started the first phase of clinical studies with its dengue vaccine. The study of the monovalent dengue vaccine is being conducted at the St. Louis University Center for Vaccine Development.

Meanwhile, scientists have claimed that the human trials for the first genetically engineered malaria vaccine will start early next year.

An international team from the US, Japan and Canada has developed a weakened strain of the malaria parasite which they claim will be used as a live vaccine against the disease. The vaccine has already worked perfectly on laboratory mice. As we know, malaria is even more dangerous than dengue, killing more than one million people worldwide every year. Malaria is still prevalent in Sri Lanka as well.

But that gives rise to another pertinent question. Why have our research institutes and universities failed to address this issue? This question applies to our entire region. This is a poor reflection on their capabilities and initiative. More resources must be allocated to areas such as vaccine and drug development. It goes without saying that the vaccine being developed by the US company, if it becomes successful, will be expensive. On the other hand, if we developed a vaccine or another effective deterrent, a lot of foreign exchange can be saved in the long run.

Impediments to such initiatives must be identified and rectified.

We have seen reports of another development, again from the US. We may one day spend less time swatting mosquitoes if researchers succeed in their efforts to produce a repellent that works longer, with less odour, than most of today's sprays and lotions.

Scientists produced 23 new compounds after teaching a computer to recognize which chemicals would do the best job of warding off mosquitoes, according to research presented last week at the "American Chemical Society" in Washington. Ten of the new compounds gave almost 40 days' protection, more than twice the amount from DEET, the most common product in repellents.

In other words, the new repellants will give 24 hours protection if worn on garments as opposed to the 12 hours possible with today's best ones.

Repellant treated garments are an exciting field in bio and textiles engineering right now. Sri Lanka has just seen the launch of a 'treated' mosquito net, which can apparently maintain the anti-mosquito property for four straight years. It is heartening to note that a local company is involved in this effort. More private companies should be involved in research and manufacturing processes vis-à-vis mosquito control. It will only be a matter of time before longer lasting treated nets and clothes are manufactured.

In the meantime, nothing works better than tried and tested preventive measures such as clearing garbage, stagnant water, blocked water etc. These cost little or no money and often a Shramadana effort can show results. The media must play a pro-active role in educating the public on the benefits of such steps.

The Government should monitor the performances of all Local Government bodies with regard to the eradication of mosquito breeding places. I do not whether it is possible to take punitive action against Local Bodies which fail to discharge their duties under the existing legal framework, but the public expect them to be penalized. They should put their own houses in order before fining or penalizing the public on the failure to clear mosquito breeding grounds.

The public hospitals are doing a thankless job, managing a dengue epidemic while trying to contain new entrants such as swine flu. Death can be prevented if the disease is detected early.

Unfortunately, there have been instances when people have neglected the onset of symptoms and suffered tragic consequences. It is advisable to visit the nearest hospital without delay if dengue symptoms, given elsewhere on this page, appear. The hospitals must be equipped with all facilities to combat dengue and other mosquito borne diseases.

We hope the Health Ministry and provincial health authorities will take all steps to implement the recommendation of the Cuban doctors. These recommendations, if properly managed and implemented, offer a ray of hope for containing the dengue epidemic.

Public cooperation and participation will be vital in this exercise. If we are not keen on keeping disease at bay, we cannot expect the authorities to do it all for us.