Malaria is a serious and sometimes fatal disease caused by a parasite that commonly infects a
certain type of mosquito which feeds on humans. People who get malaria are typically very sick with
high fevers, shaking chills, and flu-like illness. Although malaria can be a deadly disease, illness and
death from malaria can usually be prevented.
Malaria is generally caused by a parasite Plasmodium falciparium and transmitted by female
3.2 billion People live in areas at risk of malaria transmission in 106 countries and territories.The
disease is widespread in the tropical and subtropical regions that exist in a broad band around the
equator. This includes much of Sub-Saharan Africa, Asia, and Latin America. In 2015, there were 214
million cases of malaria worldwide. This resulted in an estimated 438,000 deaths, 90% of which occurred
Two important currently used antimalarial drugs are derived from plants whose medicinal values had
been noted for centuries: artemisinin from the Qinghaosu plant (Artemisia annua, China, 4th century)
and quinine from the cinchona tree (Cinchona spp., South America, 17th century).
This map shows an approximation of the parts of the world where malaria transmission occurs. For
more detailed information about the occurrence of malaria transmission in specific countries, please
use the interactive Malaria Map Application.
The classical (but rarely observed) malaria attack lasts 6-10 hours. It consists of
a cold stage (sensation of cold, shivering)
a hot stage (fever, headaches, vomiting; seizures in young children)
And finally a sweating stage (sweats, return to normal temperature, tiredness).
More commonly, the patient presents with a combination of the following symptoms:
Nausea and vomiting
In countries where cases of malaria are infrequent, these symptoms may be attributed to influenza, a
cold, or other common infections, especially if malaria is not suspected. Conversely, in countries
where malaria is frequent, residents often recognize the symptoms as malaria and treat themselves
without seeking diagnostic confirmation ("presumptive treatment").
Physical findings may include:
Enlargement of the liver
Increased respiratory rate
Diagnosis of malaria depends on the demonstration of parasites in the blood, usually by microscopy.
Additional laboratory findings may include mild anemia, mild decrease in blood platelets
(thrombocytopenia), elevation of bilirubin, and elevation of aminotransferases.
Severe malaria occurs when infections are complicated by serious organ failures or abnormalities in
the patient's blood or metabolism. The manifestations of severe malaria include
Cerebral malaria, with abnormal behavior, impairment of consciousness, seizures, coma, or other
Severe anemia due to hemolysis (destruction of the red blood cells)
Hemoglobinuria (hemoglobin in the urine) due to hemolysis
Acute respiratory distress syndrome (ARDS), an inflammatory reaction in the lungs that inhibits
oxygen exchange, which may occur even after the parasite counts have decreased in response to
Abnormalities in blood coagulation
Low blood pressure caused by cardiovascular collapse
Acute kidney failure
Hyperparasitemia, where more than 5% of the red blood cells are infected by malaria parasites
Metabolic acidosis (excessive acidity in the blood and tissue fluids), often in association with
Hypoglycemia (low blood glucose). Hypoglycemia may also occur in pregnant women with
uncomplicated malaria, or after treatment with quinine.
Severe malaria is a medical emergency and should be treated urgently and aggressively.
In P. vivax and P. ovale infections, patients having recovered from the first episode of illness may
suffer several additional attacks ("relapses") after months or even years without symptoms.
Relapses occur because P. vivax and P. ovale have dormant liver stage parasites. Treatment to
reduce the chance of such relapses is available and should follow treatment of the first attack.
An Anopheles stephensi mosquito shortly after obtaining blood from a human (the droplet of blood is
expelled as a surplus). This mosquito is a vector of malaria, and mosquito control is an effective way of
reducing its incidence.
Methods used to prevent malaria include medications, mosquito elimination and the prevention
of bites. The presence of malaria in an area requires a combination of high human population
density, high anopheles mosquito population density and high rates of transmission from humans
to mosquitoes and from mosquitoes to humans.
Vector control refers to methods used to decrease malaria by reducing the levels of transmission
by mosquitoes. For individual protection, the most effective insect repellents are based on DEET
or picaridin. Insecticide-treated mosquito nets (ITNs) and indoor residual spraying (IRS) have
been shown to be highly effective in preventing malaria among children in areas where malaria
is common. Prompt treatment of confirmed cases with artemisinin-based combination therapies
(ACTs) may also reduce transmission.
Walls where indoor residual spraying of DDT has been applied. The mosquitoes remain on the wall until
they fall down dead on the floor.
A mosquito net in use.
Mosquito nets help keep mosquitoes away from people and reduce infection rates and
transmission of malaria. Nets are not a perfect barrier and are often treated with an insecticide
designed to kill the mosquito before it has time to find a way past the net. Insecticide-treated nets
are estimated to be twice as effective as untreated nets and offer greater than 70% protection
compared with no net.
Indoor residual spraying is the spraying of insecticides on the walls inside a home. After
feeding, many mosquitoes rest on a nearby surface while digesting the bloodmeal, so if the walls
of houses have been coated with insecticides, the resting mosquitoes can be killed before they
can bite another person and transfer the malaria parasite.
There are a number of other methods to reduce mosquito bites and slow the spread of malaria.
Efforts to decrease mosquito larva by decreasing the availability of open water in which they
develop or by adding substances to decrease their development is effective in some locations.
Electronic mosquito repellent devices which make very high frequency sounds that are supposed
to keep female mosquitoes away, do not have supporting evidence.
Community participation and health education strategies promoting awareness of malaria and the
importance of control measures have been successfully used to reduce the incidence of malaria in
some areas of the developing world. Recognizing the disease in the early stages can stop the
disease from becoming fatal. Education can also inform people to cover over areas of stagnant,
still water, such as water tanks that are ideal breeding grounds for the parasite and mosquito, thus
cutting down the risk of the transmission between people. This is generally used in urban areas
where there are large centers of population in a confined space and transmission would be most
likely in these areas. Intermittent preventive therapy is another intervention that has been used
successfully to control malaria in pregnant women and infants, and in preschool children where
transmission is seasonal.
There are a number of drugs that can help prevent or interrupt malaria in travelers to places
where infection is common. Many of these drugs are also used in treatment. Chloroquine may be
used where chloroquine-resistant parasites are not common. In places where Plasmodium is
resistant to one or more medications, three medications—mefloquine (Lariam), doxycycline
(available generically), or the combination of atovaquone and proguanil hydrochloride
(Malarone)—are frequently used when prophylaxis(prevention) is needed. Doxycycline and the
atovaquone plus proguanil combination are the best tolerated.
Simple or uncomplicated malaria may be treated with oral medications. The most effective
treatment for P. falciparum infection is the use of artemisinins in combination with other
antimalarials (known as artemisinin-combination therapy, or ACT), which decreases resistance
to any single drug component. These additional antimalarials include: amodiaquine,
lumefantrine, mefloquine or sulfadoxine/pyrimethamine. Another recommended combination is
dihydroartemisinin and piperaquine. ACT is about 90% effective when used to treat
uncomplicated malaria. To treat malaria during pregnancy, the WHO recommends the use of
quinine plus clindamycin early in the pregnancy (1st trimester), and ACT in later stages (2nd
and 3rd trimesters). In the 2000s (decade), malaria with partial resistance to artemisins emerged
in Southeast Asia. Infection with P. vivax, P. ovale or P. malariae usually do not require
hospitalization. Treatment of P. vivax requires both treatment of blood stages (with chloroquine
or ACT) and clearance of liver forms with primaquine.
Severe and complicated malaria are almost always caused by infection with P. falciparum. The
other species usually cause only febrile disease. Severe and complicated malaria are medical
emergencies since mortality rates are high (10% to 50%). Cerebral malaria is the form of severe
and complicated malaria with the worst neurological symptoms. Recommended treatment for
severe malaria is the intravenous use of antimalarial drugs. For severe malaria, parenteral
artesunate was superior to quinine in both children and adults. In another systematic review,
artemisinin derivatives (artemether and arteether) were as efficacious as quinine in the treatment
of cerebral malaria in children. Treatment of severe malaria involves supportive measures that
are best done in a critical care unit. This includes the management of high fevers and the seizures
that may result from it. It also includes monitoring for poor breathing effort, low blood sugar,
and low blood potassium.
Drug resistance poses a growing problem in 21st-century malaria treatment. Resistance is now
common against all classes of antimalarial drugs apart from artemisinins. Treatment of resistant
strains became increasingly dependent on this class of drugs. The cost of artemisinins limits their
use in the developing world. Malaria strains found on the Cambodia–Thailand border are
resistant to combination therapies that include artemisinins, and may therefore be untreatable.
Exposure of the parasite population to artemisinin monotherapies in subtherapeutic doses for
over 30 years and the availability of substandard artemisinins likely drove the selection of the