Public Enemy No.1
The monsoons are here. There is a buzz in the air, of renewed life and...and...SPLLAAATTH. Damn these millions of nasty little mosquitoes! Creatures that can kill. Most of us have suffered from malaria surely, if not the more dreaded dengue, sometimes in our lives. All thanks to this tiny terrorist. In fact, prevention is the best cure in this case. Let’s find out more about this enemy of ours and discover new attack strategies to beat it at its game.
I hate these flying creatures", screamed Sharda’s mother. “Ramu, get me the spray can! Sharda, close all windows and doors and get out for a while. Ramu, hurry!” The yelling continued for a while but everyone seemed quite used to it as this apparently is an usual evening at the Duttas’ residence. The spray can was out in a jiffy and Sharda’s mom dressed up like a masked militant, went about killing the flying creatures, with as much zeal as the terrorist she resembled.
The flying creatures here are none other than the public enemy no. 1, the pesky, stingy, buzzy and bloody mosquito (insults intended). The bad thing about a mosquito is that it not only flies and makes buzzing noises just beside our ears when we are trying to sleep, but it also BITES!! You splat it and it becomes a bloody affair.
If this was not enough, it spreads a lot of awful diseases as well; I mean, who does not know about malaria, dengue and filaria? A tiny mosquito can kill people! Getting paranoid? Should be! Why doesn’t the health ministry just order spraying of ‘mosquitocides’ by helicopters, why aren’t Baygon spray cans distributed free to all of us? Someone just rid the world of these mosquitoes!!
But...wait a minute, how come there are so many of these terrifying creatures at Sharda’s house? Has it got to do something with the big, black uncovered drain that passes just in front of it? Also, maybe, we are not following the right attack tactic. I once accidently sprayed some insecticide onto my precious money plant and it turned yellow, shriveled, and died! Why should we kill ourselves while trying to chase away this tiny insect? And if you have noticed it, they don’t even seem to mind the spray after a few days.
Can't we do something more permanent and safe? Come to think of it, the area around Anwar’s house has almost no mosquitoes. And no mosquitoes mean no malaria, right? A couple of years back, Anwar’s father, along with all the other people in their locality, had got all their drains covered, filled up all pits in the area, and released fish in the ponds behind their homes. Should this give us a clue? Let’s check it out...
Know your Mosquito!
Nasty Little Longlegged 'Fly'
A mosquito by any name...
The Spanish called them, “musketas,”, the native Hispanic Americans “zancudos.” “Musketas” is a Spanish word meaning “little fly” while “zancudos,” means “longlegged.” Scandanavians called them by a variety of names including “myg” and “myyga” while the Greeks called them “konopus.”
The use of the word “mosquito” is apparently of North American origin and dates back to about 1583. In Europe, mosquitoes were called “gnats” by the English, “Les moucherons” or “Les cousins” by French writers, and the Germans used the name “Stechmucken” or “Schnacke.” In 300 BC, Aristotle referred to mosquitoes as “empis” in his Historia Animalium where he documented their life cycle.
About 2,700 species of mosquitoes are present on earth out of which over 50 are resistant to at least one insecticide. They can whiz past you at an estimated 1 to 1.5 miles per hour and can fly pretty long distances. For instances, salt marsh mosquitoes migrate 75 to 100 miles.
The enemy also has strong smelling powers and can also smell you from 20 to 35 metres away!! It can lay eggs practically anywhere where there’s one inch deep water, that’s semi-still.
Mosquitoes have two wings with scales. Mouthparts in female form a long piercing-sucking proboscis. Males have feathery antennae. Their mouthparts are not suitable for piercing skin. They survive on plant juices.
It is suggested that they have a preference for females, soft skin, dark colours and carbon dioxide! Pregnant women are among favourites.
How to Handle Pows
Cut the sensory nerve in the mosquito’s stomach, and it will keep on sucking blood until it bursts.
Know its life cycle
Eggs are tiny white dots laid in water or moist surfaces in batches of 100-150. They darken within 12-24 hours and may hatch in 1 to 3 days depending on temperature.
Out of the eggs come out the wrigglers (larvae). Larvae of all mosquitoes live in water and have 4 developmental periods or instars. At the end of each instar, the larva sheds its skin by a process called moulting. Most larval species possess an air tube.
Unlike most other insects, the mosquito pupa is very active and lives in water. This stage lasts only for a few days. Feeding does not take place during the pupal stage.
The pupal skin splits and the adult insect emerges and flies away. Mating soon follows. The female normally takes its first blood meal after mating and then develops its first batch of eggs.
The Mosquito knows
by D.H. Lawrence
The mosquito knows full well, small as he is, he’s a beast of prey. But after all he only takes his bellyful, he doesn’t put my blood
“The Beast Within"
This poor man’s disease affects some 250 million people in the world and kills as many as 2 million every year
A disease as old as mankind. Today it affects more than 240 million people, over 40% of the world's population, in more than 100 countries in the tropics. Every year 300 million to 500 million people suffer from this disease and about 1.5 million to 3 million people die of malaria every year (85% of these occur in Africa).
We are speaking of the disease of poverty, Malaria. According to an analysis carried out by researchers at Harvard University and the London School of Tropical Hygiene, malaria knocks as much as 1.3% off the gross national product in regions such as the Indian subcontinent, Sri Lanka, and sub-Saharan Africa.
A parasite called Plasmodia is the culprit here. There are four identified varieties of this parasite causing human malaria, namely, Plasmodium vivax, P. falciparum, P. ovale and P. malariae. In India, Plasmodium vivax is common. When a female Anopheles mosquito bites, the plasmodium enters the blood of human.
The plasmodia (which are called sporozoites at this stage) travel to the liver in 30-40 minutes and start developing in the cells of the liver. They then multiply into 20-30000 merozoites, break the liver cells and get into the blood stream again. The merozoites in the blood get into the red blood cells. Each merozoite now divides into 8-32 new merozoites, which breaks the red cell and infect fresh red cells. This cycle occurs every 48-72 hours.
All the external signs of malaria like chills and fever are due to this phase. Malaria is a disease that can be treated in just 48 hours, yet it can cause death if treatment are delayed. The main method of controlling malaria is control of mosquitoes. Both the vector (mosquito) and the parasite (plasmodium) become resistant to insecticide and medicine very soon. That is, after a few times, we need to develop stronger medicine and pesticides.
Therefore, for effective malaria control, man should be targetted first, mosquitoes should be controlled next and we should keep trying to kill the parasite with effective medicine and vaccines. (Read Kill Them on page 63 for more information on mosquito control.)
Poor Persons Parastite
To envision the number of children killed by malaria annually, imagine seven jumbo jets, full of children, crashing every day.
Yet…the Welcome Trust, in a 1996 study, reported that funding for malaria research worldwide amounted to only $84 million a year – a shameful pittance for a disease of this magnitude, and 1/50th what the US alone spends on cancer. Why is there such little interest in producing a vaccine? Why is pharmaceutical industry unwilling to invest in malaria research? Simple, because the prospective market for antimalaria products is in poor countries. Because there is no guarantee that the countries needing the vaccine would be able to buy it. No profit, No cure.
A Philadelphia doctor called the sickness
because the achiness caused in the joints was so severe
In 1779-1780, reports of the first Dengue epidemics poured out from Asia, Africa, and North America. As the viruses and their mosquito vector could only be transported between countries by sailing vessels, there was usually a long gap between break of new epidemics. And it was considered a harmless disease. It’s come a long way since then. Pronounced “deng-gee” or “deng-gay,” today dengue is today a major mosquito-borne health concern. The mosquito, was discovered to be the culprit in the early 1900s. A daytime feeder, Aedes aegypti hangs out in crowded areas, feeds lightly and many times. (see Most Wanted on page 58).
Dengue is present in over 100 countries and threaten the health of more than 2.5 billion people. There are an estimated 51 million infections each year. Outbreaks are occurring with greater frequency. This may be due to increasing population in cities, as well as other factors (such as open water storage for cities, irrigation canals, rain-filled tyres, and plastic bottles), which allow mosquitoes to flourish.
It is the ‘urban disease’ while malaria is the ‘disease of poverty’. The female Aedes mosquito generally acquire the virus while feeding on the blood of an infected person. She is now capable of transmitting the virus to humans for the rest of her life. She can also transmit the virus to her next generation via eggs. There are four distinct, but closely related, viruses that cause dengue. High temperatures significantly shorten the growth periods for the dengue virus in mosquitoes and increase the rate of mosquito-human transmission of the virus.
Dengue fever: A severe, flu-like illness that rarely kills. Symptoms are high fever, severe headache, muscle pain and rash.
Easier said than done
The war between man and mosquito continues. The main weapons till now have been lethal chemicals. While these kill mosquitoes initially, they return stronger and more resistant than ever before. Then a stronger substance has to be made to carry on the fight. The chemicals get absorbed in every step of the food chain, killing us slowly but surely. Are there no other safe ways to stop the mosquito menace?
Residual Insecticides: The main method of attacking adult mosquitoes in houses is spraying the inside surfaces of the walls and roof or ceiling with a residual insecticide. The intention here is that mosquitoes will rest on the insecticide deposit and remain long enough to pick up a lethal dose. Treated bednets: Impregnating bednets with an insecticide adds a chemical barrier to the physical barrier of the net. In the world's largest treated bednet programme, in Sichuan Province, China, up to 2.25 million bednets have been treated annually. Bednets are impregnated by dipping in a pyrethroid, drying and re-hanging them.
Larval control can make a significant contribution to malaria control, and can be done in a variety of ways. See how in the article on Bioenvironmental Control below.
The idea of creating genes for a harmless Anopheles has attracted much attention from biologists. This can be done by
...and you poison everything else
In the early to mid 1950s, DDT became one of the most widely used pesticides. This was when it was thought to be completely harmless to human beings. In the 1960s, concern arose about its effects on humans.
A study in 1968 showed that Americans were consuming an average of 0.025 milligrams of DDT per day! When DDT gets into our bodies, it is stored in fatty organs as the adrenals, testes, and thyroid. It is also stored in smaller concentrations in the liver and kidneys. DDT concentrations are
...and the chemicals harm you
A survey carried out by the Malaria Research Centre (MRC), Delhi, reveals that mosquito repellents are harmful and should be avoided. The most common complaint was breathing problem, followed by eye irritation, often accompanied by bronchial irritation, headache or skin reaction. Of those using repellent cream, 11.4 per cent reported skin reaction and itching.
Of the 286 doctors covered in the survey, 165 or 57.6 per cent reported acute toxicity following use of repellents. Even those who do not immediately feel any adverse effects may be in long term danger. Mosquito nets, a “neem cream” made up of 5 parts neem oil and 95 parts coconut or mustard oil, or burning neem oil in kerosene are safe alternatives.
These Terrors can be Controlled
With no chemicals, little money, team work and some help from you
Says who? Says a number of cases from across the country. From Panaji in Goa to Khera in Gujarat, the Malaria Research Centre (MRC) had carried out plenty of experiments in Bioenvironmental Control (BC), as this is known. Everywhere, malaria cases fell by about 60% to 80%. In other words, mosquitoes were controlled.
The National Malaria Eradication Programme (NMEP) failed miserably with residual insecticide sprays and chemotherapy. Soon after this, India’s own Mosquito Man, V P Sharma went to survey a malaria epidemic in Gujarat in 1983. This saw the birth of BC in India.
The MRC was founded and for five years, Sharma fought without a single chemical. The results clearly showed success. “In Karnataka, 300 villages are now free from malaria and mosquito-borne diseases. Ahmedabad city is also another example”, says V P Sharma. “In Gujarat, where we started the project, the first year saw a 92% decline in malaria”.
1. Don’t let ‘em lay eggs.
Mosquitoes lay eggs. And if you read about their life cycle, you will know that their eggs grow up into larva. Since eggs and larvae cannot move far, it is easy to control them. BC tells us: Do not allow mosquitoes to breed (lay eggs) at all. Any place that has even an inch of stagnant water is a good place for laying eggs.
2. Kill those wrigglers!
In places where water has to remain, we can kill larvae in a number of ways:
3. Protect yourself.
So, why is malaria still a number one killer? Why do mosquitoes haunt us every day (and night)? DDT has been recognised as a killer chemical but it is still being used against mosquitoes. Ask government officials why and they will say because it is so cheap. (Cheap?? What price is our lives and health?)
On the other hand, Sharma says, “Bioenvironmental control is the cheapest way of controlling malaria, cheaper than DDT”. As against Rs 7.1 per capita cost for BC, it is Rs 9.91 for DDT. So why is DDT still being sprayed? (And it is going to be sprayed in India for the next five years!) Finally it is up to local communities to fight back their mosquitoes themselves, rather than wait for government officials to come with their DDT guns. “There are plenty of ways in which children can work against malaria”, says Sharma. And what are the ways?
"Bioenvironmental control is the cheapest way of controlling malaria, cheaper than DDT"
V P Sharma
“There are plenty of ways in which children can help prevent Malaria”