In Dengue mosquitoes:

Female bites, not the male - Prof. Herbert Aponso

The illness may present with high fever lasting 4 to 6 days; sometimes the fever is moderate and subsides in 3 to 4 days. Other features include: severe aches and pains, especially in the joints (“breakbone fever”), faintish or giddy feeling, tearing from the eyes, red eyes, nausea, vomiting and a marked loss of appetite.

Dengue fever (DF) was first reported from the African countries; its name is probably derived from the Swahili word dinga, signifying the gait of the patient with severe aches and pains. In Sri Lanka, epidemics have been reported since 1967, especially after the rainy seasons, as explained below.

In the present epidemic it is reported that during this year dengue has so far (up to June 8th) affected over 25,000 persons of whom 116 have died, compared to less than half that number for the whole of 2008.

DF is caused by four types of related viruses. One type of virus, which causes the disease on one occasion, does not offer protection against subsequent infections by any of the other three. Due to this reason, one attack does not confer protection (immunity) against the disease as in virus infections such as measles or chicken pox.

Furthermore, there is evidence that infection by a second or third virus increases the risk of the complications referred to below (DHF & DSS). The virus is transmitted from man to man by the bite of mosquitoes, which breed in containers where water collects; for this reason they are called *container mosquitoes*.

Their breeding grounds, which are important to note and remember, are mentioned below in connection with the preventive aspects.

Preventive aspects

Only the female mosquitoes bite, while the males only disturb you with a ringing noise in the ears; “the female is deadlier than the male”.

They bite mainly during daytime, particularly in the early hours of dawn and for about 2-3 hours before dark; due to this reason mosquito nets which are used during sleep do not provide complete protection from their bites, as with other mosquitoes. Though there are over 140 species of mosquitoes, there are only two types of mosquitoes that convey this infection in Sri Lanka : mainly the one called Aedes egypti, Aedes albopictus being the other one. Aedes mosquitoes are generally small in size.

They are dark in colour and have white spots and bands on parts of the body and legs which look like the type of a tiger, hence the name “tiger mosquitoe” bands on parts of the body and legs, which look like the stripes of a tiger; hence the name, “tiger mosquito”.

DHF mostly in children

Dengue Haemorrhagic Fever (DHF) occurs mostly in children and occasionally in adults. It is reckoned that about one out of 200 patients with dengue fever may develop this condition. The early features include mild bleeding in stomach, bowel, nose, eyes and gums.

This may result in vomiting, described as “coffee ground”, because the vomitus looks like brewed coffee; dark tarry stools may occur. In some patients there are tiny bleeding points in the skin, which manifest as pinkish / reddish tiny spots.

The liver is enlarged unlike in DF. At this stage, fluid may pass through the blood capillaries into the tissues around them, causing a collection of fluid inside the abdomen or around the lungs (referred to as ascites and pleural effusions respectively) *b) Dengue Shock Syndrome* (DSS).

This serious complication may occur with or without manifestations of DHF. In this condition, the brain, kidneys, heart and circulation, may be affected.

Temperature drops, but the patient is more ill, cold, clammy, and pale, with a drop in the Blood pressure and a rapid low volume pulse.. These complications may result in death within 24-48 hours.

Laboratory investigations. A platelet count below 100,000, and an increase of the Packed Cell Volume (PCV) by 10-20%, supports a diagnosis of the disease. A platelet count below 50,000 is reckoned to be dangerous; immediate treatment becomes necessary.

The diagnosis could be confirmed, if reckoned necessary, by doing an antibody test ( IgG & IgM )

It should be noted a reddish rash occurs in several viral infections, apart from dengue (or measles). It should also be noted that there is a fall in the platelet count to levels below 200,000, and even down to 150,000, in many viral infections; the layman should not panic; the doctor would keep the patient under observation, and may decide to do platelet counts often.

Features

The illness may present with high fever lasting 4 to 6 days; sometimes the fever is moderate and subsides in 3 to 4 days. Other features include: severe aches and pains, especially in the joints (“breakbone fever”), faintish or giddy feeling, tearing from the eyes, red eyes, nausea, vomiting and a marked loss of appetite.

In some cases a rash ( small red spots may appear in DHF, see below) may occur after a few days, and there may be mild enlargement of the lymph glands.

Treatment

Treatment There is no specific drug to kill the virus. Antibiotics do not kill or inactivate viruses as they do with bacteria. Drugs, such as paracetamol, are given to bring down the fever and ease the aches and pains. Aspirin should not be given to either children or adults as it may aggravate the illness; ibuprofen should be avoided.

Paracetamol is the drug of choice to control fever.. In DHF & DSS, oral and intravenous fluids are indicated; these may be dextrose-saline, plasma and/or plasma substitutes, platelet or blood transfusions. Tranexamic acid is used to prevent bleeding.

Herbal Cure

A herbal cure with the juice of papaya (papaw) leaves has been reported.

Here are 2 case histories *a) The little son was in the critical stage at the ICU when his blood platelet count drops to 15 after 15 litres of blood transfusion.

His father was so worried that he seeks another friend’s recommendation and his son was saved. He confessed to me that he gave his son raw juice of the papaya leaves.

From a platelet count of 45 after 20 litres of blood transfusion, and after drinking the raw papaya leaf juice, his platelet count jumps instantly to 135. Even the doctors and nurses were surprised.

After the second day he was discharged. Preparation: raw papaya leaves, 2pcs just cleaned and pound and squeeze with filter cloth.

You will only get one tablespoon per leaf. So two tablespoon per serving once a day. Do not boil or cook or rinse with hot water, it will loose its strength.

Only the leafy part and no stem or sap. It is very bitter but you have to swallow it.

b) A friend of mine had dengue last year. It was a very serious situation for her as her platelet count had dropped to 28,000 after 3 days in hospital and water has started to fill up her lung. She had difficulty in breathing. She was only 32-years old.

Doctor says there’s no cure for dengue. “We just have to wait for her body immune system to build up resistance against dengue and fight its own battle”.

She already had 2 blood transfusion and all of us were praying very hard as her platelet continued to drop since the first day she was admitted got some papaya leaves, pounded them and squeezed the juice out for it.

The next day, her platelet count started to increase, her fever subsided. With this treatment she recovered after 3 days*

Personal Prevention at the home level

Spraying of houses with insecticides (especially in the control of the malaria mosquito), mosquito nets (around the bed) , mosquito coils, anti-mosquito mats, electrical gadgets burning of local herbs (e.g. * maduruthala*), and various other contraptions have been used successfully.

Mosquito nets are most effective if they are impregnated with insecticides or mosquito repellents.

If you are uncomfortable with a mosquito net, mosquito coils should be used as a last resort.

Most insect sprays and mosquito coils contain pyrethrum, which is toxic to insects; however, pyrethrum has a low toxicity to human beings, but it could cause allergic reactions such as skin rashes or wheezing in allergic individuals.

A safe and effective mosquito repellent is citronella oil, which can be safely used by even children or pregnant mothers (creams are available); margosa oil may also be used , but it has an unpleasant smell. Or use a night lamp - one teaspoon of citronella oil to a quart of kerosene; or apply a few drops of citronella oil, or a citronella cream, on the exposed parts of the body.

Motor Car Gear Oil

Mosquitoes are also repelled to a certain extent by used motor car gear oil, which is available at car garages.

Keep an open container of the oil in the room; soaking some waste rag with used gear oil or sprinkling the drains with oil would also be helpful. Another claim for a mosquito killer: o Cut a plastic bottle in half; both parts are necessary o Dissolve some brown sugar in hot water in the lower half of the bottle

o When it cools down to about 70 degrees (F), add the yeast o The carbon dioxide that now forms attracts mosquitoes o Cover the bottle with a dark piece of cloth and place the top portion of the plastic bottle upside down so that it acts as a funnel o Place it where the there are the most number of mosquitoes o In about 2 weeks most of the mosquito would be killed.

For those who can afford it the whole house could be protected from mosquitoes with mosquito-proof wire netting.

Another somewhat expensive introduction, for community protection, is a mosquito trap aspirator.

This is a mechanical blower with a rechargeable battery mounted on a back pack frame, which has a collecting tube that sucks in the mosquitoes.

It was reported, in 2002, that the Medical Entomology Laboratory of the University of Florida had successfully developed a “perfect diet pill” a hormone preparation - for killing the mosquito larvae ( larvicide).

It was said to be environmentally safe and effective for all species of mosquitoes. So far, it has not been marketed.

This article has been prepared by additional contributions by Dr. Harendra de Silva, Dr. Dennis Aloysius, Dr. Tissa Vitharana and Dr. J. S. Edirisinghe.

Prevention Community level

Prevention at the Community level The control of the mosquitoes cannot be limited only to one’s own household and garden, but it has to be extended to the premises of the neighbours as well, as these mosquitoes can fly even up to half a mile.

It is therefore a community problem.

A rapid rise in the urban population, with the resultant environmental hazards, brings a greater number of people in contact with these mosquitoes, which thrive in the breeding grounds mentioned below, at the warm temperatures of the tropical countries; thus it is a tropical disease predominantly in urban and in semi-urban areas.

Compared to the other three major mosquito borne diseases in Sri Lanka (malaria, Japanese encephalitis, and filariasis), dengue is the only disease where the transmitter mosquito could be controlled by adopting simple preventive measures.

This is because these two mosquitoes, referred to as container breeding mosquitoes, breed mainly in small collections of clear rain water in : discarded tins, coconut shells and husks, discarded rubber tyres, plastic bags, bottles, machine parts, water storage barrels and jars, blocked roof gutters, flower vases, tin cans and pots, ant-traps, plants that have bottle shaped leaves that hold water, bird baths, children’s toys, yoghurt and curd cups, and such other containers.

All litter containers, tin cans, etc. should be buried.

Discarded tyres should be either pierced ( making sufficient holes ) or filled with sand; water in flower vases and ant-traps should be changed at least once in 5-6 days; it is advisable to add some salt to these vases and ant traps. Our battle to win the war against dengue is against two mosquitoes only* and not against all the others which are reported to be over 140.

A period of drying does not kill the eggs of the mosquitoes; these eggs and larvae lie dormant and can survive for months until they find collections of water to reactivate themselves.

This is the reason why dengue starts spreading during the rainy seasons. Therefore, if people are made aware of these facts and sufficiently motivated, the population of the dengue-transmitting mosquito can be brought down to insignificant proportions and the disease controlled at little or no cost.

Though there are many varieties of mosquitoes, the “war’ against Dengue revolves around the destruction of only the two mosquitoes, mentioned above. As in any other war, stringent action has to be taken for its control.

This would even include legal enactments to enable the public health authorities to take effective action against those who violate the given instructions and simple measures of prevention.

It is reported that the Health Ministry would take action against residents who ignore the repeated requests to keep their environment clean. School children, teachers, the community and non-governmental organisations, such as Sarvodaya Movement, Service clubs such as Lions, Rotary, Y’s Mens’, can play a leading role in conducting campaigns (*shramadana*) of educating and motivating the public.

Thai researchers are hopeful of developing a vaccine for the prevention of the disease.