The Impact of Malaria

by CDC

(Page 9 of 14)

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.

Geography

Malaria occurs mostly in poor, tropical and subtropical areas of the world (Geographic Distribution). 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

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

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.

Areas Where Malaria Is Not Endemic

In countries where malaria transmission has never existed or has been eliminated, such as the United States, the great majority of cases occur in returning travelers or in migrants arriving from areas where malaria is transmitted ("imported" malaria). However malaria remains a health threat for people who live in these countries:

Most patients have no protective immunity, and when they get malaria they can develop a rapidly severe, even fatal disease.

Health-care providers are unfamiliar with malaria, and this can cause delayed or incorrect diagnosis and treatment of the disease.

Under certain conditions, malaria patients can transmit parasites to local mosquitoes, which can in turn infect local residents. Left unchecked, this course of events can re-introduce malaria in a previously malaria-free area.

Social and Economic Toll

Malaria imposes substantial costs to both individuals and governments.

Costs to individuals and their families include: purchase of drugs for treating malaria at home; expenses for travel to, and treatment at, dispensaries and clinics; lost days of work; absence from school; expenses for preventive measures; expenses for burial in case of deaths.

Costs to governments include: maintenance of health facilities; purchase of drugs and supplies; public health interventions against malaria, such as insecticide spraying or distribution of insecticide-treated bed nets; lost days of work with resulting loss of income; and lost opportunities for joint economic ventures and tourism.

Such costs can add substantially to the economic burden of malaria on endemic countries and impede their economic growth. It has been estimated in a retrospective analysis that economic growth per year of countries with intensive malaria was 1.3% lower than that of countries without malaria.

About the Author

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The Centers for Disease Control and Prevention (CDC) is one of the 13 major operating components of the Department of Health and Human Services (HHS), which is the principal agency in the United States government for protecting the health and safety of all Americans and for providing essential human services, especially for those people who are least able to help themselves.