'Protozoans' is the term usually used to talk
about the protists that cause malaria in humans or in other
vertebrate erythrocytes. Protozoa belong to a large group of
eukaryotic organisms that are single-celled. These are usually
microscopic and include amoeba, ciliates, flagellates and
sporozoans. In malaria, the protozoans can also be called 'malaria
The sporozoan protozoa that cause malaria are transmitted
through a mosquito feeding upon the blood of an infected host and
ingesting a number of these parasites. The protozoa develop within
the mosquito and are secreted through its saliva to infect other
potential hosts when bitten. Once inside a human (or other
vertebrate erythrocyte hosts), they can spend a protracted period
(from weeks or months to, potentially, years) inside the host's
liver and spleen, where they reproduce in the blood (specifically,
within the red blood cells, erythrocytes).
Malaria is a vector-borne infectious disease caused by any of a
number of protozoans spread by the female
Anopheles mosquito. Only
Anopheles mosquitoes can transmit malaria, and they must have been
infected through a previous blood meal taken from an infected host.
It is common in tropical and subtropical climates in endemic areas
including much of Sub-Saharan Africa, Asia and the Americas. These
locations have significant amounts of rain fall and consistent hot
temperatures. These warm, consistent temperatures and moisture
provide mosquitoes with the environment they need to breed
continuously year round.
The causative organisms include protists of the genus
Plasmodium. The three most common organisms in malaria
infections are P. vivax, P. ovale, and P.
falciparum. Falciparum malaria is the most serious of the
three, causing about 80% of all cases of human malaria and 90% of
deaths, and is becoming more frequently drug resistant. Another
less common type of Plasmodium that can cause malaria is P.
malariae. A fifth type, P. knowlesi, is not thought
to infect humans.
To prevent the disease, a person in the areas where these
mosquitoes live should reduce the number of bites they receive.
Mosquito netting used around beds can reduce the number of
mosquitoes and bites and mosquito repellents also help.
Symptoms of malaria are fever, shivering, joint pain, vomiting,
anemia, hemoglobinuria (when your urine turns red), retinal damage,
and convulsions. The classic symptom of malaria is occurrence of
sudden coldness followed by rigors (shaking), then fever and
sweating lasting four to six hours, which occurs every two
Plasmodium falciparum - the common African type
affects 80 - 85% of malaria patients, and is the most severe form
of malaria. P. falciparum is also called a 'malign tertian
malaria', malign means "evil", and this is the type which most
often kills humans.
Plasmodium vivax - Milder than Falciparum, is the
second most common species to cause the disease malaria. It is also
called 'benign tertian malaria', benign means "good", and this type
usually doesn't kill humans.
Each year, there are approximately 515 million cases of
malaria, killing between one and three million people, the majority
of whom are young children in Africa. Young children are more prone
to getting Malaria than adults are.
Ninety percent of malaria-related deaths occur in Africa.
Malaria is commonly associated with poverty, but is also a cause of
Malaria is one of the most common infectious diseases and an
enormous public health problem.
Malaria is a disease which kills a child every 30 seconds