The dengue problem

Emeritus Professor E. R. Jansz

While acknowledging that the dengue problem is a serious one that must be wiped out, I am not sure of the strategy being employed. I feel it should be (i) An all year effort - not dengue months, etc. (ii) It should be teamwork aimed at wiping out dengue mosquito breeding sites.

I feel the strategy of taking people with a few unidentified mosquito larvae to the Police Station and Magistrate Court using health inspectors, doctors, Police, Navy, social workers etc. can be counter-productive when the main sites of larvae breeding are not even looked at.

I feel that the first step is to train PHIs properly to identify potential breeding sites and the dengue larvae. Having worked with two researchers on dengue larvae, I am sure that there are many who can train PHIs and doctors in the easy technique of detecting the dengue larvae. Having taught thousands of doctors and spoken to many of them, I find that most can identify the adult dengue mosquito Aedes aegypti and Aedes albopictus but not their larvae. Certainty the PHI and doctor who came to my premises had to be told by me the typical features of the dengue larvae.

I am not sure if blanket fumigation killing off most insects is ecologically sound. In fact it is hard to find a grasshopper or earth worms these days. Even in the case of fumigation, I understand the procedure followed when a dengue patient reports to hospital, is for the hospital to inform the MC/UC/ etc for the fumigation process to take place. I know of a house in Rajagiriya where there were four dengue patients, I advised them to go directly to the MC and fumigation took place, but there are open wells in that area which are ideal for breeding dengue larvae. (Interestingly the official fumigator arrived three-four weeks later).

Social workers

I like to embark on a case history which I know well. In an area where no dengue had been reported, about 20 householders were hauled up to the Police. In my premises the female social worker remarked that there were mosquitoes in the garden. I told her to look over the wall five metres away where there were plenty of breeding grounds for all types of mosquitoes. She did not want to walk the five metres (I wondered why they pay her a salary). In contrast a month later a Survey Department team had no qualms in walking in that two-three acre area.

No doubt some of the persons taken in were very careless and deserved the treatment, but a few cases defy explanation.

Case I

A restaurant owner had washed some frozen chicken. The drainage water was supposed to contain dengue larvae. The water comes from a tap and the chicken from a reputed dealer. I am not sure if I was misled.

Case II

A bucket was washed and turned upside down. Overnight rain had filled a small rim on top of the upturned bucket. After a couple of days dengue larvae were claimed to be in it. Again misleading was a possibility.

Case III

An old lady (73) I believe had a flower pot she could not reach; larvae were spotted in it. This was plausible but was the procedure she had to undergo tempered with humanity?

I am sure that the majority of PHIs and doctors are honest and hardworking, but it is just possible there may be one or two who are unscrupulous. Therefore, if there is a system of rewards, this should be monitored carefully. Let me take our own case. Since 2009 we have been visited by PHIs, PHIs and Police, Municipal Council Fumigants several times. On the first occasion I was told to get rid of my Rampe groves.

This was logical so I did so immediately. Next I was told to get rid of my Kohila plantation which was grown along the wall mainly as the thorny plant provided security. However, since it also harboured rats which could carry leptospirosis, I got rid of it too.

Next I was told to burn the coconut branches as it could provide water for dengue larvae breeding.

He did not know that if the branch was turned rib (ekel) upward water could not collect and piles of leaves would rapidly deteriorate providing organic fertilizer. But to prevent argument, I burnt leaves causing air pollution and a consequent drop in coconut yield in 2011 and 2012.

Next I was asked to get rid of my plantain trees. This was too much. I asked him for his name and number and stated that I would inquire from higher authorities. He quickly retracted his request. I decided to take out the plants to one adult plant and one suckling to help drying out.

Dengue mosquito

The biggest joke came from a PHI in Kalutara who told a former colleague of mine to cut his mango trees. This was because mango leaves are pointed at the distal end and could hold a water droplet that the dengue mosquito could lay its eggs in. Now if we were to cut all the trees with pointed leaves that hang downward, our planet species diversity could be under threat!

We had visits from sprayers, bottle collectors, from 2009 to early 2012, who found no dengue mosquito breeding places in our premises. By that time with our security plants gone, our garden was invaded almost daily for any produce.

We had a shock in May 2012 when a huge team arrived and found two bottles in the corner of our garden with a couple of larvae in each. To me their breathing apparatus was far too long for dengue larvae. There were other puzzling aspects, those types of bottles had never been used in our household.

Further our garden was flooded in April with muddy water yet there was no mud in the bottles. The bottles may have come recently from the thieves, who on two or three occasions were pursued by the Police at that point in the garden. I suppose even at the age of 70 and chronically ill I should have examined every nook and cranny in the garden after a shower.

The bottom line is train your PHIs in all aspects of the dengue fight. This battle may take years. It may take as a first step, the training of trainers. And when the trainers go to work there must be a mechanism to ensure that the PHIs have absorbed the training.

(Some sort of test?) Above all let all of us forget the arrogance and work as a team. By the way what happened to the Cuban BTI and ITI, BTI which had so much propaganda?