The Impact of Malaria, a Leading Cause of Death Worldwide
 

Statistics

Malaria is one of the most severe public health problems worldwide. It is a leading cause of death and disease in many developing countries, where young children and pregnant women are the groups most affected.

According to the World Health Organization’s

• At the end of 2004, some 3.2 billion people lived in areas at risk of malaria transmission in 107 countries and territories.
• Between 350 and 500 million clinical episodes of malaria occur every year.
• At least one million deaths occur every year due to malaria.
• About 60% of the cases of malaria worldwide and more than 80% of the malaria deaths worldwide occur in Africa south of the Sahara.

Geography

Malaria occurs mostly in poor, tropical and subtropical areas of the world  The area most affected is Africa south of the Sahara, where an estimated 90% of the deaths due to malaria occur. This is due to a combination of factors:

• A very efficient mosquito vector (Anopheles gambiae) assures high transmission
• The predominant parasite species is Plasmodium falciparum, which causes the most severe form of malaria
• Local weather conditions often allow transmission to occur year round
• Scarce resources and socio-economic instability hinder efficient malaria control activities.

In other areas of the world malaria is a less prominent cause of deaths, but can cause substantial disease and incapacitation, especially in rural areas of some countries in South America and Southeast Asia.

Who Is Most Vulnerable

Pregnant woman having a blood smear taken at an antenatal clinic at the Maela Camp in Thailand near the Myanmar border. Pregnant women are at increased risk of malaria.

Persons most vulnerable are those with no or little protective immunity against the disease. In areas with high transmission (such as Africa south of the Sahara), the most vulnerable groups are:

• Young children, who have not yet developed immunity to malaria
• Pregnant women, whose immunity is decreased by pregnancy, especially during the first and second pregnancies
• Travelers or migrants coming from areas with little or no malaria transmission, who lack immunity.

In areas with lower transmission (such as Latin America and Asia), residents are less frequently infected. Many persons may reach adult age without having built protective immunity and are thus susceptible to the disease.

How Malaria Affects People's Health

Malaria can affect a person's health in various ways.

• People who have developed protective immunity (through past infections, as is the case with most adults in high transmission areas) may be infected but not made ill by the parasites they carry
• In most cases, malaria causes fever, chills, headache, muscle ache, vomiting, malaise and other flu-like symptoms, which can be very incapacitating
• Some persons infected with Plasmodium falciparum can develop complications such as brain disease (cerebral malaria), severe anemia, and kidney failure. These severe forms occur more frequently in people with little protective immunity, and can result in death or life-long neurologic impairment

Child being transfused in Kinshasa, DR Congo. Malaria is the principal cause of severe anemia, necessitating transfusion, in children in DR Congo.

• People subjected to frequent malaria infections (such as young children and pregnant women in high transmission areas) can develop anemia due to frequent destruction of the red blood cells by the malaria parasites. Severely anemic patients might receive blood transfusions which, in developing countries, can expose them to HIV and other bloodborne diseases
• Babies born to women who had malaria during their pregnancy are more often born with a low birth weight or prematurely, which decreases their chances of survival during early life
• In developing countries, the harmful effects of malaria may combine with those of other highly prevalent diseases and conditions, such as malnutrition, HIV/AIDS, and anemia of all causes. Such combinations can have severe results, especially if they occur repeatedly.