Malaria

What causes malaria? The disease is caused by the bite of the female anopheles mosquito, which passes the malarial parasite from one human to another.

Symptoms. The most obvious symptom is high fever, but there can be other symptoms such as diarrhea.

How widespread is it? Malaria threatens over two billion people in 100 countries in the tropics. More than 100 million people catch the disease each year, and a million die from it, mainly children under five years old and pregnant women. In Africa, malaria kills around one child in 20.

Prevention. One way of preventing malaria is to eradicate the anopheles mosquito, but attempts to do this have not yet been successful. The other is to protect yourself by taking anti-malarial drugs wearing long-sleeved shirts and long trousers, using insect repellents and sleeping under mosquito nets. Unfortunately, in many places the malarial parasite has become resistant to anti-malarial drugs, and the prob­lem is getting worse.

Rabies

What causes rabies? Rabies is caused by a virus, which affects the brain. It can affect all warm-blooded animals, and can be passed to humans through a bite by an infected animal.

Symptoms. At first victims experience pain on swallowing; later, they

become terrified of water, the very sight of which can cause paralysis. The patient eventually dies in a coma.

How widespread is it? Most countries in the world have rabies, and in some countries it is a serious problem. In Thailand, 100,000 people a year need treatment after animal bites. One country with no rabies is Britain, which has strict controls on the entry of animals from other countries. There are fears that a rabid animal could enter Britain through the Channel Tunnel.

Prevention and cure. People and their pets can be vacci­nated against rabies, and there have been attempts to vaccinate wild animals by putting out food containing the vaccine.

Once rabies has developed, there is no cure, but there is a treat­ment for people who have just been bitten. This is very unpleasant, and involves a course of 17 injections in the stomach wall.

Cholera

What causes cholera? Cholera is caused by a bacterium V. cholerae. A person can become infected by drinking water or eating food contaminated by bacterium.

Symptoms. Diarrhea and vomiting.

How widespread is it? There are cholera outbreaks every year in different parts of the world. They are most common in places with unsafe water supplies and poor sanitation.

Prevention. Drink only water that has been boiled or treated with chlorine or iodine. Ice and ice cream made with untreated water can also lead to infection. Only eat food that has been cooked and still hot when served.

Avoid raw seafood and other raw food except fruit and veg­etables that you have peeled yourself. Keep flies off your food -they may have been in contact with infected materials.

Cure. Cholera can be treated by antibiotics, but the real danger is death by dehydration, which can happen in a matter of only a few hours. The most important treatment is therefore dehydration - putting back the water that has been lost. Patients should drink a large amount of water mixed with oral dehydration salts (ORS). In more serious cases, where patients cannot hold down liquid, this can be given via a drip. Dehydration treatment will save the lives of nearly all cholera patients.

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