New breeding pattern alarms public

* Dengue spreads near and far

* Leading schools, the main culprits

By Manjula FERNANDO

Dr. Pradeep Kariyawasam	Apeksha Warusawithana

With the onset of the Monsoon season, fear of a looming dengue threat is in the air of inevitable deaths, suffering and grieving of departed loved ones.Dengue and rain shares a fatal bond. Recent newspaper reports indicate that the dengue mosquito has altered its breeding patterns to lay eggs in domestic wells and other new receptacles which has heightened the fear double fold, especially parents with young kids. Dengue is notorious to strike mainly the young.

The Sunday Observer visited the Medical Research Institute (MRI) and the Colombo Municipal Council to verify these reports and clarify certain grey areas for the benefit of our readers.

Consultant Virologist, MRI Dr. Sunethra Gunasena:

In Sri Lanka Dengue has become an endemic disease. Which means Dengue has settled down for good in Sri Lanka. So you come across cases all the time in fluctuating proportions. Dengue is transmitted by the mosquito, intensive numbers of dengue cases have been reported during the rainy season because mosquito breeding intensifies with the rain.

It is correct to say dengue cases go up during the monsoon season. Earlier we had dengue cases only in big cities like Colombo and so on. But now it is gradually spreading to the rural. That is because of the spread of dengue mosquito who carry the virus with them.

In the cities, adolescents and children are already exposed to the virus, may all four times and they are already immune to the disease. In the village the virus is new to the environment, so you get patients of all ages from infants to adults and the elderly, getting affected.

That is one reason for large number of dengue cases among adults in the rural.

We were earlier concentrating on dengue as a disease of the children. So, we were mostly concentrating on children.

But due to new trends, which has begun spreading to rural areas, now there are more and more adult cases getting reported. Current data as against the late ‘90s shows that there is a definite peak in the adult cases.

Early diagnosis

Unlike with children the problem with adults is that they tend to neglect fever. They delay medical attention. This is dangerous in the case of Dengue Haemmorhagic Fever (DHF). In the early stages you observed a common fever.

When you get fever, it is necessary to be cautious and be alert for other symptoms, and must go for a blood test within 3 days if the symptoms are not so severe. If the symptoms are severe and the patient looks weaker than normal, then medical advice should be sought earlier than that, where doctors will start monitoring the blood count if Dengue is suspected.

Do you have to wait for three days to do the blood test?

No. That is the ‘usual advice’ because during the very early stages it is difficult to observe a big change in the blood count. By about the third day there will be a distinctive change. But if the patient has high fever and shows other complications like, heavy vomiting, and looks seriously ill, then we should not keep the patient at home. But the parents or the guardians should decide if the patient should be referred to a doctor before that.

With any viral fever, rest is very vital. Physical activity like competitive sports and exercise should be avoided. Nutrition and intake of liquids during the first stage is important. After the initial stage of 2-3 days patients should avoid coloured drinks.

Patients with slight touch of Dengue fever could stay at home and rest while the symptoms clear off. But those with DHF, the management of the disease should be done by a professional medical staff in a hospital. Therefore hospitalisation is a must.

If the blood counts are rapidly decreasing the doctor will decide if the patient has to be admitted to hospital. If it is DHF, the doctors will have to do the fluid management in addition to monitoring. The purpose is to prevent the patient from developing severe DHF and go in for a shock, at which stage fluid restrictions have to be made. But before this stage a normal fluid intake can be maintained.

Special tests

The basic Dengue diagnosis is done by a blood count. But to identify whether it is actually Dengue, there are special tests. There are different methods to do it. We could either detect the Dengue virus, or part of the Dengue virus, or dengue viral antibodies.

Usually we rely on Dengue antibodies, because the detection of specific Dengue is not essential for the management.

It is important for surveillance and management of Dengue but not for individual management. After about three days the body would have developed antibodies to fight the virus.

If an early diagnosis is needed, then you will have to do a PCR (Polymerase Chain Reaction) test. This is not done in hospitals but at the MRI and private laboratories. We usually don’t recommend this because of the high expenses involved.

The PCR and Dengue antigen can be done only during the first three days. After 3-4 days the antibodies develop, which is a cheaper test.

For PCR and antigen tests you need to collect the samples specifically and transport them in ice, which is a painstaking process. This is not routinely done.

PCR is useful to identify the stereotype of the virus. If it is Dengue 1, 2, 3 or four. But as far as the patient management is concerned, it is not useful. It is useful community wise for the prevention and control.

Most critical factor in preventing deaths due to DHF is the identification of the critical stage. When someone gets fever he should be observed for at least 24 hours, even after the fever had subsided.

In some patients with DHF, the fever settles down when they proceed to the next stage which is the critical phase. If the patient is still feeling unfit, drowsy and continues to have loss of appetite, then it is a cause for concern.

Fever with aches and pains, and loss of appetite are symptoms of ordinary dengue fever but if the patient complaints of abdominal pain and heavy vomiting, it could be possible symptoms of DHF. (Aches and pains are synonymous even with an ordinary fever.)

It should also be noted that the time between the initial collection of blood samples and referring to the reports to doctor should be minimal if they suspect dengue. With Dengue fever, blood counts can come down drastically within a short span of time, therefore if someone suspect dengue, the reports should be collected and referred to doctors as soon as possible. This could determine the difference of life and death.

Rash - Dengue fever

Flushed hands, feet and face is a sign of dengue fever. A rash that is similar to heat rash (prickly heat) could also develop due to dengue. Not all dengue patients develop this rash.

DHF This rash is different from Dengue fever rash. You see red patches under the skin. This may sometimes spread out like a bruising. These are created by internal bleeding. If you press these spots they will not disappear.

Apeksha Warusawithana, Research Officer, Entomology Unit, MRI:

The recent newspaper reports that the Dengue mosquito has shown major breeding adaptations has not been verified by our studies conducted so far.

The reports said the dengue mosquitoes have started breeding in domestic wells which alarmed people who had already been disturbed by the increase in dengue cases within the first four months of this year.

We observed dengue larvae in wells in places like Eravur, Kalmunai in the Eastern province but this does not mean that the mosquitoes have started breeding in wells everywhere. The wells in these areas are different from ordinary wells. Their surrounding surface is smooth from the bottom. Dengue mosquito breeds in water collected in places where there is a smooth wall like plastic containers.

Major breeding sites of dengue mosquito varies from area to area, time to time and season to season. Discarded receptacles are the predominant breeding sites in many districts of the country.

Clearing of places and home gardens have been very effective due to the Government campaigns targeting the masses. But the blocked gutters still poses a serious threat. We did not pay attention to this area before. May be the mosquitoes have found a new breeding ground in blocked gutters since the receptacles in the ground level are being cleared now.

Our advice is to clean the gutters once every week or remove the gutters in places where it is not very essential. Dengue is a bigger threat than a wet wall.

She said leaf axils of plants like Bromelia and pineapple could be a new breeding site of dengue since they have not found dengue larvae during earlier inspections.

Colombo Municipal Council, Chief Medical Officer, Dr. Pradeep Kariyawasam:

The Dengue cases have increased this year. If we don’t take immediate action to get rid of the breeding places, there could be an outbreak like last year.

Last Saturday we launched a program to visit from area to area to destroy breeding sites. We are covering each and every road and creating public awareness.

The high risk areas identified by the CMC are Slave Island, Kollupitiya, Bambalapitiya, Thimbirigasyaya, Kirullapona, Maradana, Dematagoda, Aluthkade and Grandpass.

We have to cover 120,000 residences and offices and 80,000 land slots. With the limited staff it is humanely impossible for us to visit all these places. Hence, it is vital that people look after their residences. Ministries and public should join up in the city clean up program to fight Dengue threat.

Schools are our key concern. Many leading schools in the city have become dengue breeding places. According to statistics 70% of the Dengue patients are under 20 years and 45% of the total dengue affected are in the school-going age.

CMC has notified 25 schools within the city to clean up breeding places, many of them are leading schools. Schools must really think of clearing the garbage as well as blocked gutters and drains. I think schools should go for a zero garbage policy, whatever the children bring should be sent back home. Unless drastic measures are put in place this dengue threat can never be controlled.