Malaria is a
serious, sometimes fatal, disease caused by a parasite that is transmitted from
one person to another through the bite of the Anopheline mosquito (a female
Anopheles mosquito).
(A parasite is an organism that grows, feeds, and is sheltered
on or in a different organism while contributing nothing to the survival of its
host.) Malaria parasites are so small that they can only be seen under a
microscope. They feed on the blood cells, multiply inside them and destroy
them.
The
parasite that causes malaria is a protozoan (one-celled organism) called
plasmodium (plaz-MO-dee-um). Four types
of the plasmodium parasite can infect humans:
- P. falciparum (fal-SIP-a-rum)
- P. vivax (VI-vacks)
- P. ovale (o-VOL-ley)
- P. malariae (ma-LER-ee-aa)
The World Health Organization estimates that
each year, 300 to 500 million people are infected with malaria and more than 1
million people die. More than 90% of the
people infected with malaria each year live in sub-Saharan Africa.
Who
is at risk for malaria?
Anyone who lives in, or travels to, an area of
the world where malaria is transmitted may become infected. This includes refugees, displaced persons and
labour forces entering into infected areas. However, those who are most at risk
are children under the age of five and pregnant women. The vast majority of people who die from
malaria each year are young children in Africa.
How
do you get malaria?
Most
commonly, humans get malaria from the bite of a malaria-infected mosquito. When
a mosquito bites an infected person, it ingests microscopic malaria parasites
found in the person’s blood. The malaria parasite must grow in the mosquito for
a week or more before infection can be passed to another person. Thereafter, if
the mosquito bites another person, the parasites go from the mosquito’s mouth
into the person’s blood.
Malaria can
also be transmitted by blood transfusion, and by contaminated needles and
syringes. In congenital malaria, parasites are transmitted from mother to child
before and/or during birth.
How
does the malaria parasite make you sick?
Once the malaria parasites get into a person’s
blood, they travel to the liver, enter the liver’s cells, and grow and
multiply. Then the parasites leave the liver and enter red blood cells. This may take as little as a week or as long
as several months. While the parasites are in the liver, the person does not
yet feel sick.
Once inside the red blood cells, the parasites
continue to grow and multiply. The red blood cells burst, freeing the parasites
to attack other red blood cells. Toxins (poisons) from the parasite are also
released. Once in the bloodstream, parasites can harm other organs, including
the brain, because clumps of heavily infected red blood cells start blocking
the flow of blood through the capillaries (and so, starve body tissues). At
this stage, the person starts to feel sick.
What
are the signs and symptoms of malaria?
Symptoms of malaria include fever and flu-like
illness, including shaking chills, headache, muscle aches, and tiredness.
Nausea, vomiting, and diarrhoea may also occur. Malaria may cause anaemia and
jaundice (yellow colouring of the skin and eyes) because of the loss of red
blood cells. Infection with the most dangerous type of malaria, P. falciparum, may cause kidney
failure, seizures, mental confusion, coma, and death if not promptly and
properly treated.
What
is the treatment for malaria?
Malaria can be cured with prescription drugs. The type of drugs and length of
treatment depend on which kind of malaria is diagnosed, the degree of
drug-resistance in the area where the person was infected, personal
characteristics of the patient such as age and allergies, and how severely ill
the person is at the start of treatment.
If
malaria can be prevented and cured, why do so many people die?
The main reason that people die from malaria is
because they don’t know what causes malaria or how it is spread, so they don’t
know how to protect themselves from being infected. In some cases, people don’t
realize they have malaria, and don’t seek treatment until it is too late. They may think they have a cold, the flu, or
other common infection. People who live far away from health services will
often go to local medicine sellers for advice, which is not always appropriate,
or buy medicines are not effective. In malaria-risk areas, people should seek
treatment for all fevers. Young children
and pregnant women should receive treatment within 24 hours of becoming ill.
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