Malaria - Simple English Wikipedia

# Malaria

### From Wikipedia, a free encyclopedia written in simple English for easy reading.

Malaria is an infectious disease. People get malaria when a parasite gets in the blood. A parasite is an organism that lives off of another organism called a host. A parasite takes from the host organism, but does not help it. Instead, it harms the host.

The parasite that causes malaria is a protozoan called Plasmodium. Protozoa are organisms with only one cell, but they are not bacteria. Bacteria are smaller and simpler than protozoa.

Electron micrograph of a malaria sporozoite

There are four species (kinds) of Plasmodium that cause malaria in people:

- Plasmodium falciparum
- Plasmodium knowesli
- Plasmodium malariae
- Plasmodium ovale
- Plasmodium semiovale
- Plasmodium vivax

P. vivax and P. falciparum cause the most malaria in people. Falciparum malaria is the worst kind, and kills the most people.

## [edit] How do people get malaria?

People usually get malaria from mosquitoes. The Plasmodium goes into people by mosquitoes bites. The Plasmodium is in the mosquito's saliva. (Saliva is moisture, or spit, made in the mouth.) The mosquito's saliva carries the Plasmodium into the person. The person is then infected with Plasmodium. This makes the person have the disease malaria.

The kind of mosquito that carries malaria is the anopheles mosquito. Only the female mosquito gives people malaria.

A few people do not get malaria from mosquitoes. A baby can get it while inside his mother. This is called maternal-fetal transmission. People can also get malaria from a blood transfusion. This is when someone gives blood to another person. People can also get it from using a needle that someone else used first.

## [edit] How Plasmodium lives in people

When Plasmodium get in a person, they are called sporozoites. Sporozoites go to the liver, where they make many more sporozoites. Then they change into a different form of Plasmodium. This form is the merozoite. The merozoites go into the red blood cells, then they make many more merozoites.

The merozoites break out of the red blood cells again and again. When they do this, the person gets very sick, and looks like someone with malaria. This happens every few days, and is called a paroxysm.

P. vivax and P. ovale can live in the liver for a long time. A person can look well, but still have the Plasmodium in the liver. This is called a dormant phase. Then weeks or months later, the Plasmodium go from the liver to the blood, and the person gets sick again.

P. falciparum is the worst kind of malaria. It makes people sicker, because there are more of them in the blood. Also, with falciparum malaria, the red blood cells are sticky. This makes the red blood cells block blood vessels. If blood vessels are blocked, this can hurt what the blood vessel brings blood to, and can hurt people's organs.

## [edit] Who is affected by malaria

Pregnant women and children are hurt most by malaria. When they get malaria, they get sicker.

40% of people live in a place where there is malaria. Malaria is in these places:

- Africa
- Asia (mostly in India, the Middle East, and Southeast Asia)
- Central and South America
- Hispaniola
- Eastern Europe
- South Pacific (the part of the Pacific ocean south of the equator)

Every year, 300 to 700 million people get malaria. It kills 1 million to 2 million people every year. The biggest problem is in Africa. 90% of the people who die from malaria are there. Most of the people who die from malaria are children. In Africa, 20% of children under five die from malaria. Even if children do not die, many have brain damage.

Most of these deaths could be stopped with medicine or with ways to stop mosquitoes. UNICEF says: the medicine that costs the most for malaria is only $2.40 to help one adult. But many of the places where malaria lives are poor countries. These countries do not have enough money to stop the mosquitoes, or to give people medicine.

## [edit] Symptoms of malaria

Symptoms are changes in your body that show you have a disease. Most people who get malaria get symptoms 10–30 days after they get infected (the Plasmodium gets in their blood.) But some people can get symptoms after only a week, and some may be infected with malaria and not have symptoms for a year.

The most common symptom of malaria is fever, when your body temperature is high. The fever from malaria usually comes very suddenly. Malaria can feel like you have influenza.

Symptoms of malaria are:

- Arthralgia (pain in joints)
- Headache (pain in head)
- Vomiting
- Feeling very tired or sleepy
- Anemia (low red blood cell levels in the blood)
- Jaundice (yellow skin and eyes)
- Cough
- Enlargement of liver or spleen (enlargement means it gets bigger)
- Sweating (when water comes out of your skin)
- Chills (when you feel very cold)
- Delirium (when people are very confused because of a disease. They may look drunk. They may not be able to talk.)
- Coma (when people are not conscious. They look like they are asleep, but you cannot wake them.)
- Fast heart rate
- Low blood pressure

## [edit] Complications from malaria

Complications are problems that happen because you have a disease.

Pregnant women and young children have more complications. People who get malaria for the first time have more complications. Falciparum malaria has the most complications.

Complications of malaria are:

- Cerebral malaria (brain malaria)
  - To have cerebral malaria, you must have:
    - P. falciparum in the blood.
    - Coma, many seizures, or long Delirium
  - If no medicine is given, people always die.
  - Even if medicine is given 15%-20% of people with it die.
- Seizures (if only one seizure happens it is not cerebral malaria)
- Damage to the brain
- Blackwater fever
  - Many red blood cells break open and the hemoglobin in the cells gets into the blood.
  - This hemoglobin is put in the urine and makes it look very dark.
  - Without the right care this can make the kidneys stop working.
- Pulmonary edema
  - This is fluid in the lungs that makes it hard to breathe.
  - Pregnant women get this much more.
  - 80% of people who get this complication die.
- Very low blood sugar
  - Children and pregnant women get this more.
  - This can cause people to look like they are drunk or to be in a coma.
- Hemolysis
  - This means breakdown of red blood cells.
  - It can cause blackwater fever, jaundice, and symptoms of anemia.
- Coagulopathy (not being able to stop bleeding)

## [edit] How doctors tell if someone has malaria

In places where malaria is, there may not be good medical care. People may diagnose malaria just by people having symptoms. Diagnose means to learn if a person has a disease. Doctors diagnose people sometimes just by symptoms. This is called a clinical diagnosis. Doctors also use tests to see if people have a disease.

Giemsa stain shows malaria trophozoite in red blood cell

If a person has symptoms and is in a place where there is malaria, they might have malaria. To see if they have malaria, doctors may do a blood test. This test is called a Giemsa blood smear. Blood is put on a slide which is a thin piece of glass. The Giemsa stain is put on the slide. This stain helps doctors see the malaria. Then they look at the slide under a microscope. The Plasmodium is seen in the red blood cells.

Sometimes the blood smear will not show Plasmodium even if the person has malaria. This can be because the stain was not good. It can also be because the microscope was not good. Or it can be because the person looking in the microscope did not know what Plasmodium look like.

There are other tests to diagnose malaria. These are more expensive. People do not use them as much. Sometimes people test to see if the Plasmodium is resistant to medicines to treat malaria. Resistance means the medicine cannot hurt the Plasmodium. This means that taking the medicine will cure someone with malaria, because it will not kill the Plasmodium.

## [edit] How to treat malaria

People with different kinds of malaria need different medicines. The medicine that works for one kind of malaria may not for another kind. So it is very important to know which species of Plasmodium the person has.

If the species is not known, the person should be given medicine and care like they have falciparum malaria - the worst kind.

It is also important to know where the person got malaria. Plasmodium in some places are resistant to some medicines. So the medicines to treat malaria in Africa are different from the medicines to treat malaria from South America.

It is important for doctors to learn about malaria treatment. Resistance to medicines changes. Places where there was no resistance can get resistant malaria. So doctors need to know when this changes. If a doctor treats a person with malaria, he should know what places in the world have resistant malaria. If he has not treated a person in a long time, he should check before treating people.

### [edit] Treatment of malaria other than falciparum

Everywhere except New Guinea, the treatment is the same. In New Guinea most P. vivax is resistant to chloroquine. It can be treated with quinine, but this medicine can make people sick. Everywhere else, non-falciparum malaria is treated with chloroquine.

Chloroquine kills the Plasmodium in the blood. But the Plasmodium in the liver is not killed by chloroquine. P. vivax and P. ovale both stay in the liver a long time. This is the dormant phase. Another medicine must be given with chloroquine for P. vivax and P. ovale. This is to kill the Plasmodium in the liver. If this other medicine is not given, malaria can come back after months. It can even come back five years later.

The medicine used to kill malaria in the liver is primaquine. In southeast Asia, some P. vivax is resistant to primaquine. Most other places, primaquine works very well.

Some people get very sick from primaquine. Some people do not make enough of an enzyme in the blood. This enzyme is called Glucose-6-Phosphate-Dehydrogenase (Acronym G6PD). People who do not have enough have a disease called G6PD deficiency. (Deficiency means you do not have enough.) People with G6PD-deficiency get very very sick if they take primaquine. It makes their red blood cells all die. This can even kill them. So people have to be tested to see if they have G6PD-deficiency before they take primaquine.

Medicines to kill P. vivax and P. ovale in the liver are not safe for pregnant women. So a pregnant woman must usually take chloroquine until she has her baby.

### [edit] Treatment of falciparum malaria

Falciparum is the worst kind of malaria. Most people who die from malaria have falciparum.

Many people with falciparum malaria must be treated in a hospital. People with falciparum malaria should be treated in a hospital if they are:

- Very sick
- Children
- Pregnant
- Sick for the first time with malaria
- Not able to take medicines by mouth

Even people who are treated with medicines at home should stay with the doctors for 8 hours. This is to make sure they do not get sicker. It also makes sure they can take the medicines by mouth.

Falciparum malaria also has more resistance to medicines. This makes it much harder to treat. Falciparum malaria is always treated with two or more medicines. Doctors choose the medicines by where in the world the person got malaria. Different places have P. falciparum that is resistant to different medicines.

The most important resistance is chloroquine-resistance. In some places in the world, P. falciparum is killed by chloroquine. In some places it is chloroquine-resistant. This means chloroquine does not kill it. In these places quinine can be used.

If people are very sick and cannot swallow medicines, they get intravenous (acronym IV) medicine. Intravenous means given into a vein. The IV medicine used for very bad chloroquine-resistant falciparum malaria is quinine. If people got malaria in a place with no chloroquine-resistance other medicines can be used. But sometimes doctors still use IV quinine. This is to be very certain they will kill the P. falciparum.

If the P. falciparum is not chloroquine-resistant people do not usually take quinine. This is because quinine can make people sick. If people get sick from quinine, it is called Cinchonism. Symptoms of cinchonism are:

- tinnitus (hearing a noise in ears)
- nausea and vomiting
- headache (pain in the head)
- Seeing badly

Quinine is also taken by mouth.

## [edit] How to prevent malaria

The best way to treat malaria is to not get it!

There are three ways to prevent malaria:

- Control mosquitoes
- Keep mosquitoes from biting you
- Take medicine to keep from getting sick if you get bitten, especially if you happen to be in a part of the world where people get malaria.

### [edit] Control mosquitoes

Vector control is the best way to stop malaria. Vector means an organism that carries an infectious disease to another organism. For malaria, the vector is the anopheles mosquito. It carries Plasmodium to people.

There are many way to do good vector control. The best ways are different in different places. This depends on the environment. It also depends on how much malaria is in the place. It also depends on how much money people have. If a way to do vector control costs too much money, people in a poor place cannot pay for it. So the best way to do vector control in the United States is different than the best way to do vector control in South Africa.

The most used method of vector control is pesticides. These are chemicals that kill the mosquito. The first pesticide used for vector control was DDT (dichlorodiphenyltrichloroethane.) DDT was first used in World War II.

DDT works very well for vector control. It kills mosquitoes. It does not make people very sick. It does not cost very much money. There are other chemicals that be used. But none is as good, cheap, and lasts as long as DDT.

But some people do not want us to use DDT. Some people worry that it will make humans and animals sick. Scientists think it might cause hormones to not work right. It might also make people and animals have trouble reproducing (getting pregnant and making babies.) But these problems are not certain. And if it does cause problems, it will probably be a small problem.

Scientists have learned that DDT stays in the environment for a long time. They learned also that DDT used in one place may go all over the world. DDT used in Africa may go to Europe. So people are worried that DDT used today will stay in the world for a long time.

But this is not a good or fair argument. Most of the people who worry about DDT live in the developed world (countries like Germany, Canada, and the United States who have a lot of money.) DDT staying in the environment of the developed world may cause problems for a few people in the future. But today we know malaria kills millions of people every year. Malaria kills two children every minute. Almost all of these children die in poor countries.

Many poor countries cannot pay for other chemicals. So they use DDT. This is the only chemical they can buy. The World Health Organization says using DDT in these countries is good. If a country can pay for better and safer chemicals to kill mosquitoes, they should not use DDT. But if a country can only pay for DDT, they should use DDT.

In some places in the world, mosquitoes are not killed by DDT. They are resistant to DDT. The places where mosquitoes are DDT-resistant are:

- Sri Lanka
- India
- Pakistan
- Turkey
- Central America

Other pesticides must be used in these places. Organophosphate or carbamate pesticides are used, like malathion or bendiocarb. These cost more money than DDT.

### [edit] Keeping mosquitoes from biting

The mosquito that carries malaria comes more at dawn (when the sun comes up) and dusk (when the sun goes down.) Be most careful at these times.

Wear long pants and shirts with long sleeves.

Wear mosquitoes repellent (this is a chemical that mosquitoes do not like, so they do not bite.) Mosquitoes will bite through thin cloth. So repellent should be used on skin and clothes.

Pesticides can be used in rooms to kill mosquitoes.

When sleeping outside, people use a mosquito net. This is made from cloth that air can go through but keeps mosquitoes out. It is put over a bed where people sleep to keep mosquitoes out. Sometimes people also use it when they are not sleeping.

### [edit] Taking medicine to keep from getting sick

People can take medicine when they are in a place where there is malaria. This medicine makes you get malaria less. This is called prophylaxis.

Some people take prophylactic medicines for years. Many people in areas where there is malaria do not have the money to buy this medicine.

People who live where there is no malaria usually have not had malaria. The first case malaria is usually much worse. So people from places where there is no malaria may take prophylactic medicines when they go to places where there is malaria.

The kind of prophylactic medicines people take depends on where they are. This is because not all medicines work on the malaria in every place. Some Plasmodium are resistant. Even if the right medicine is used, it does not always work. Sometimes people get malaria even if they take prophylaxis. Sometimes this is because people do not take the medicine the right way. But even if it is taken right, it does not always work.

To make them work best, prophylactic medicines have to be taken the right way. The medicine should start before going to an area with malaria. Most medicines should be taken for 4 weeks after coming home. One medicine (Malarone) only needs to be used for one week after coming home.

## [edit] Links

These may be unsimple

- [WHO malaria information]
- [US Centers for Disease Control 'Malaria Facts']
- [Medecins Sans Frontieres (Doctors Without Borders) information about malaria]
- [Medline Plus about malaria]

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Categories: Medicine | Diseases | Biology

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