Gobar Times (Down To Earth's Supplement) -- Centre for Science and Environment (CSE)

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MALARIA

"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.

Malaria affects children and pregnant women the most. Every 30 seconds a child dies of malaria

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.)

Sir Ronald Ross
THE MOSQUITO MAN
Next day (my birthday) there was better luck. I obtained four full mosquitoes. I also found out how to make insects bite; that is by wetting the bed and mosquito-net with water – this makes them hungry in a moment. By an accident I did not know that a mosquito had bitten till an hour after he had done so. I bottled him, smoked him (or rather her) and separated the abdomen; but it was now so hot and dry again that the blood dried almost as it was squeezed out so I had to moisten with normal salt solution.

-An excerpt from a letter from Ronald Ross to Patrick Mason, Secunderabad, May 15, 1895

Born in Almora, in the foothills of the Himalayas, Ronald Ross was just a carefree doctor of the British Raj who enjoyed playing golf, fishing and shooting - till he discovered the mosquito and his mentor, Patrick Mason.

In 1894, Patrick Mason told him about his theory that mosquitoes carry malaria. Ross, then in Bangalore, went about trying to infect patients by giving them water that had the remains of mosquitoes that fed on malaria patients. Ross even lied to a patient and told him mosquitoes biting him was good as they sucked out the malaria parasites. Manson infected his own son. All this just to find out about how the malaria parasite is transmitted.

By 1897, Ross was transferred to Kherwara, where there was little malaria. A frustrated Ross even thought of retiring. In January 1898 though, he was granted research leave, a part of which he spent in Assam studying kala-azar, which was then thought to be a form of malaria. Despite everything, Ross traced the malaria parasite to the salivary glands of the mosquito.

Ronald Ross now had his days of glory. When he left India in 1899, he got an immediate post in the Liverpool School of Tropical Medicine, became a Fellow of the Royal Society in two years, and finally won the Nobel Prize.

POORPERSONSPARASITE

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.

DENGUE
A Philadelphia doctor called the sickness
"BREAKBONE FEVER,"
because the achiness caused in the joints was so severe 1

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).

The only method of controlling or preventing dengue is to combat the vector mosquitoes

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.
Dengue haemorrhagic fever: A deadlier complication. Is characterized by high fever, enlargement of the liver, and circulatory failure.

Dengue shock syndrome: In severe cases, the patient's condition may suddenly worsen; temperature drops, followed by circulatory failure, and the patient may die within 12-24 hours.

There is no treatment for dengue fever. At best, bed rest, fluids, and medications to reduce fever can be administered. The only method of controlling or preventing dengue today is to combat the mosquitoes.