When "Plasmodium" enters the blood, they are then 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 shows symptoms of 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". Weeks or months later, the "Plasmodium" can leave the liver to the blood, and the person will get sick again.
"P. falciparum" is the most dangerous type of malaria. It makes people sicker than those with other types of malaria, 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.
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:
Every year, 300 to 700 million people get malaria. It kills 1 million to 2 million people every year. 90% of the deaths occur in Africa. Most of the people who die from malaria are children. Even if children do not die, many have brain damage.
Many of these deaths might be stopped with medicine or mosquito control. But many of the places malaria may be found are in poor countries. These countries do not have enough money to stop the mosquitoes, or to give people medicine. Money, however, is not the only problem. A country must have an organised medical system to provide services. Many countries in central Africa have been disrupted by warfare and conflict between groups, and general unrest. Also, easy solutions to kill the parasites do not exist as they did 50 years ago. This is because the insects are resistant to many insecticides, and the "Plasmodium" parasite is highly resistant to quinine and most other common drugs. This is a normal evolutionary process: the chemicals weed out the non-resistant organisms, and the offspring of the few resistant organisms multiply.
Symptoms are changes in someone's body that are signs for 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 the body temperature is high. The fever from malaria usually comes very suddenly. The people who have malaria often feel like they had influenza.
Symptoms of malaria are:
Signs of malaria:
Complications are problems that happen because of 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.
A clinical diagnosis is based on the signs and symptoms of a disease, it is a diagnosis made without medical testing. In the case of malaria one of the main symptoms which may lead to a clinical diagnosis of malaria is a fever.
Any clinical diagnosis of malaria should be confirmed by a trained professional based upon laboratory results as soon as it is possible.
A Malaria rapid diagnostic test is a blood test which can confirm a diagnosis of malaria in about twenty minutes. RDTs are not foolproof and have a number of drawbacks, and as such a negative rapid diagnostic test should not be accepted at face-value and follow-up with malaria microscopy is necessary.
To see if patients 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.
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 is resistant to some medicines. So the medicines to treat malaria in Africa are different from the medicines to treat malaria from South America.
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. 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". So people have to be tested to see if they have G6PD-deficiency before they take "primaquine".
Falciparum is the worst kind of malaria. People with "falciparum" malaria should be treated in a hospital if they are:
Even people who are treated with medicines at home should stay with the doctor for 8 hours. This is to make sure they do not get sicker.It also makes sure they can take the medicines by mouth. Malaria does not start to become a life-threatening disease until it has been a couple of weeks after the bite without being treated.
"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. Quinine is taken by mouth.
There are three ways to prevent malaria:
"Vector control" is one way to stop malaria. Vector means an organism that carries an infectious disease to another organism. For malaria, the vector is the "Anopheles" mosquito.
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. DDT worked very well for vector control. It killed mosquitoes. It did not make people very sick at the time it was used. It did not cost very much money. Other chemicals for vector control had not been invented yet.
In many places mosquitoes became resistant to DDT. This meant that DDT did not work anymore in these areas. Scientists worried that DDT was making people and animals sick. It killed a lot of wildlife too. DDT also stays in the environment for a long time. For these reasons, people mostly use other chemicals for vector control. "Organophosphate" or "carbonate" pesticides are used, like "malathion" or "bendiocarb".