Malaria : Prevention of Infection

by CDC

(Page 5 of 14)

Infection is prevented when malaria-carrying Anopheles mosquitoes are prevented from biting humans.

Vector control aims to reduce contacts between mosquitoes and humans. Some vector control measures (destruction of larval breeding sites, insecticide spraying inside houses) require organized teams (for example, from the Ministry of Health) and resources that are not always available.

An alternate approach, insecticide-treated bed nets (ITNs) combines vector control and personal protection. This intervention can often be conducted by the communities themselves and has become a major intervention in malaria control.

Prevention of Disease

Administration of antimalarial drugs to vulnerable population groups does not prevent infection, which happens through mosquito bites. But drugs can prevent disease by eliminating the parasites that are in the blood, which are the forms that cause disease. Pregnant women are the vulnerable group most frequently targeted. They may receive, for example, "intermittent preventive treatment" (IPT) with antimalarial drugs given most often at antenatal consultations during the second and third trimesters of pregnancy.

Partnerships for Malaria Control

Successful malaria control activities require coordinated actions by:

• National authorities (especially the Ministry of Health)
• International organizations (such as the World Health Organization and UNICEF)
• Governmental and nongovernmental agencies
• The private sector
• The communities.

To enhance coordination, various partnerships have formed, the most prominent being the Roll Back Malaria global partnership.

Activities for Malaria Control

The main activities necessary for carrying out malaria control interventions are:

• Health education (also called Information-Education-Communication, IEC), where the communities are informed of what they can do to prevent and treat malaria.
• Training and supervision of health workers, to ensure that they carry out their tasks correctly.
• Provision of equipment and supplies (e.g., microscopes, drugs, bed nets) to allow the health workers and the communities to carry out the interventions.

Barriers to Malaria Control

Malaria control is made difficult by several technical and administrative problems.

Drug-resistant malaria parasites hinder case management by decreasing the efficacy of antimalarial drugs and by requiring the use of alternate drugs that are often more costly, less safe and less easy to administer.

Insecticide resistance decreases the efficacy of interventions that rely on insecticides such as insecticide-treated bed nets and insecticide spraying.

Inadequate health infrastructures in poor countries are unable to conduct the recommended interventions.

The people most exposed to malaria are often poor and lack education. They often do not know how to prevent or treat malaria. Even when they do know, they often do not have the financial means to purchase the necessary products, such as drugs or bed nets.

Epidemiology

Factors That Determine The Occurrence of Malaria

Factors that determine the occurrence of malaria are those that influence the three components of the malaria life cycle:

Anopheles mosquitoes must be present, which are in contact with humans, and in which the parasites can complete the "invertebrate host" half of their life cycle

Humans must be present, who are in contact with Anopheles mosquitoes, and in whom the parasites can complete the "vertebrate host" half of their life cycle. Malaria parasites must be present.

Notes:

In rare cases malaria parasites can be transmitted from one person to another without requiring passage through a mosquito (from mother to child in "congenital malaria", or through transfusion, organ transplantation or shared needles)

Some species of monkeys and apes can be experimentally infected with some of the four "human" malaria parasite species, and in nature some apes are infected with parasites similar to those infecting humans. But for all practical purposes the role of an animal reservoir is negligible.

About the Author

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