Dengue: Myths and facts

'Hospitals are full and ICUs are packed; the two hospitals I work for have 50 patients each suffering from malaria and dengue. Television broadcasts are non-stop, and people have begun to panic. It is shameful that a mosquito-borne infection like dengue is nowhere near control.'

Dr P Jagannath, Chairman, Department of Surgical Oncology, Lilavati Hospital and Research Centre, and Professor of Gastrointestinal Oncology, Asian Institute of Oncology, S.L. Raheja Hospital, shares some interesting facts about dengue, debunks popular myths, and throws light on necessary steps to take in case someone contracts the dreaded disease.

Facts about dengue

1. Dengue is spread by Aedes mosquitoes. It is the female mosquito that bites, as it needs blood to lay eggs. The peak biting happens at dawn and dusk. The mosquito becomes infectious approximately seven days after it has bitten a person having the virus. It lays eggs and dies in two weeks.

2. Construction sites with stagnant pools of water are 'literal piles of ammunition'. These stagnant pools of water are never sprayed. Almost all the workers working there are partially suffering from either dengue or malaria, and are a fertile source of the virus or malarial parasite.

3. In case of confirmed dengue, for seven days you have to ensure that mosquitoes all around are completely eradicated. Yes, it can be eradicated.

Debunking popular myths

Myth 1: We are affluent and will not be affected by dengue and malaria.

There is absolutely no way that your posh apartment can really protect you. In every home, you will find plants, flowerpots, toilet bowls and cisterns, ornamental containers, etc. Also all homes have curtains, which are very often drawn to keep pollution at bay. Look closer and you will discover that lurking behind these curtains are the safe havens of mosquitoes.

Myth 2: Spraying by municipality staff controls mosquitoes, and so it is their responsibility.

Not true. Mosquitoes are in your home, not outside. They hide behind curtains, under sinks, in the pots and everywhere else. During public (mosquito control) spraying, these mosquitoes comfortably migrate to your home. Every time I sit in my car, there are a couple of mosquitoes accompanying me on my trip. So there is no escape from mosquitoes.

Myth 3: We use mosquito repellent vapourisers, so we are safe.

A closer look at the composition of these repellents -- and in fact after testing them too -- I discovered that most of them contain allethrin or pyrethrin (analogue). I can actually spot mosquitoes merrily going around despite the use of these vapourisers, because their concentration is not adequate to repel mosquitoes.

Despite having vapourisers placed 24/7 in every single room in my house, I still had plenty of mosquitoes at home.

Myth 4: There are plenty of effective herbal mosquito repellents in the market.

When I wanted to purchase a mosquito repellent, I checked online on Amazon and Flipkart. There were plenty of herbal mosquito repellents. However, I cannot vouch for their effectiveness, as I have not seen any tests for them.

I then looked up at the recommendations of the Centre for Disease Control (CDC) for best mosquito repellents and discovered that CDC recommends DEET N, N-Diethyl-meta-toluamide.

I was surprised that in India we do not have DEET-based mosquito repellents. I really cannot say why DEET, an effective agent used in 10-20 per cent concentration, which is recommended by CDC, is not available in India.

Things you must know:

Mosquito nets

Mosquito nets are of very little use. That is because you normally use these nets at night, while Aedes mosquitoes bite at dawn or dusk. So while they have little utility, these nets do not ensure complete protection against dengue.

Protection from mosquito bites

1. The best option is to apply mosquito repellent on the exposed parts of your body. As we don't have DEET-based repellents in India, the next best option seems to be Odomos or similar products. Remember to apply it every evening, and not at night.

2. However, the most effective step would be to spray in potential breeding areas like behind curtains, under sinks, in cisterns, in potted plants, empty pots, etc. In the absence of DEET, allethrin-based mosquito repellents like Hit mosquito spray can be used.

3. It is time to get rid of unwanted potted plants, pots, empty vases, etc.

4. Kitchens, unfortunately, are the biggest culprits. Be ruthless in ensuring that there is effective garbage disposal and spray under the sink, cupboards and storage areas.

5. Dispose off junk now!

What if a family member or friend is diagnosed with dengue?

If there is suspicion, contact your doctor immediately. Dengue is like any other viral fever.

The confirmatory test is NS1 Test. Not all fever is dengue fever. We are fortunate that nearly 95 per cent of dengue infections have a self-limiting course.

However, the real problem is the blood counts, particularly platelet counts that start falling.

Platelets are those blood cells which are responsible for blood clotting. The real risk of dengue fever is that there can be bleeding if the platelet count drops substantially.

By 'substantially' I mean that the normal platelet counts are around 2-3 lakh, and these can come down to even less than a lakh. Bleeding can occur after it drops to 20, 000 or below.

This is unpredictable. It does not happen in every case, but that's a cause for worry and the patient will need to be admitted in a hospital. So that every day the blood count needs to be tested to ensure that the platelet and white cell count is monitored.

Treatment for dengue

1. Plenty of intake of oral fluids (2-3 litres a day) is important. A bland diet is important to maintain good nutrition and oral intake.

2. The only drug to be given is Paracetamol 650 mg, 3-4 times a day, and not more than that. You can sponge to reduce fever, if it is more than 101-102 degrees.

3. The fever is likely to remain for at least six days unrelentingly.

4. Do not give Bruffen or Aspirin like Combiflam or Dispirin for fever.

5. Antibiotics have no role till the White Blood Cells (WBC) show a fall below 2000.

What to do when the platelet counts starts falling?

This is a very difficult question to answer. There are no drugs available to increase platelets in dengue, as it is due to destruction of platelets by cytokines. The production is normal.

I researched, and found many anecdotes and articles on the use of papaya leaf extract. I wanted to look into the scientific information available. As allopathy does not offer any solution for platelets, people have panicked and started planting papayas in their backyard. Papaya leaf extract in the form of pills, which are exorbitantly priced, have disappeared from the market.

At this point, I can only say that as a doctor, I cannot recommend papaya leaves, but in desperation if someone wishes to use it, go ahead!

*Disclaimer: The opinion expressed here are personal and not that of any hospital.

Photograph: Curtis Palmer/Creative Commons