is caused by four species of parasitic protozoa that infect human
red blood cells. Protozoa are one-celled organisms that are as sophisticated
as a human cell. Malaria parasites feed on red blood cells for a
living but .
parasites have a complex life cycle. In order to live, they need
to have both a human and a mosquito host.
mosquito host can't be just "any" mosquito. It has to be a mosquito
of the genus Anopheles.
mosquito picks up the malaria parasites from the blood of an infected
human when it feeds.
malaria parasite reproduces itself in the gut of the Anopheles
mosquito. The malaria parasites need the mosquito to continue
their life cycle. Then, the mosquito passes the malaria parasites
to the human through its salivary glands.
four different species of malaria parasites cause types of malaria
that are somewhat different from each other.
worst type is caused by Plasmodium falciparum. Infection
with Plasmodium falciparum kills approximately 1-2% of those
who come down with it. Falciparum malaria is a serious illness
characterized by fever, headache, and weakness.
of falciparum malaria include cerebral malaria, in which
the brain is infected, severe malaria, in which the parasitic infection
essentially "runs out of control," and placental malaria, in which
falciparum is a grave complication of pregnancy, and coma.
Each of these complications is very serious and often fatal.
malaria is the major type found in subSaharan Africa, where 90%
of the world's malaria cases occur.
falciparum malaria is also frequently resistant to drugs
and is becoming more common in high elevation areas of Africa, and
in portions of Asia.
other species of malaria cause a debilitating illness characterized
by spells of chills, fever and weakness. This illness generally
lasts 10-14 days, and is self-limiting in nature. The malaria caused
by these species is rarely fatal.
caused by Plasmodium vivax and Plasmodium malariae
can relapse [come back] if it is not properly treated with medicine.
in places where Plasmodium vivax has become more common,
such as India, the more dangerous Plasmodium falciparum hasn't
been far behind.