Malaria risk factors
|
Malaria Microchapters |
|
Diagnosis |
|---|
|
Treatment |
|
Case studies |
|
Malaria risk factors On the Web |
|
American Roentgen Ray Society Images of Malaria risk factors |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Please help WikiDoc by adding more content here. It's easy! Click here to learn about editing.
Overview
Common risk factors for malaria include thalassemias and Duffy antigen. Sickle cell disease and G6PD deficiency are known to confer protection against malaria and have a particularly high rate of incidence in tropical populations which are at a higher risk for contracting malaria.
Risk Factors
Children
- In areas with high P. falciparum transmission (most of Africa south of the Sahara), newborns will be protected during the first few months of life presumably by maternal antibodies transferred to them through the placenta. As these antibodies decrease with time, these young children become vulnerable to disease and death by malaria. If they survive repeated infections to an older age (2-5 years) they will have reached a protective semi-immune status. Thus in high transmission areas, young children are a major risk group and are targeted preferentially by malaria control interventions.
- In areas with lower transmission (such as Asia and Latin America), infections are less frequent and a larger proportion of the older children and adults have no protective immunity. In such areas, malaria disease can be found in all age groups, and epidemics can occur.
Travel
Travel to endemic areas is a risk factor for malaria.
Pregnancy
Pregnancy decreases immunity against many infectious diseases. Women who have developed protective immunity against P. falciparum tend to lose this protection when they become pregnant (especially during the first and second pregnancies). Malaria during pregnancy is harmful not only to the mothers but also to the unborn children. The latter are at greater risk of being delivered prematurely or with low birth weight, with consequently decreased chances of survival during the early months of life. For this reason pregnant women are also targeted (in addition to young children) for protection by malaria control programs in endemic countries.
Behavioral Factors
Human behavior, often dictated by social and economic reasons, can influence the risk of malaria for individuals and communities. For example:
- Poor rural populations in malaria-endemic areas often cannot afford the housing and bed nets that would protect them from exposure to mosquitoes. These persons often lack the knowledge to recognize malaria and to treat it promptly and correctly. Often, cultural beliefs result in use of traditional, ineffective methods of treatment.
- Travelers from non-endemic areas may choose not to use insect repellent or medicines to prevent malaria. Reasons may include cost, inconvenience, or a lack of knowledge.
- Human activities can create breeding sites for larvae (standing water in irrigation ditches, burrow pits)
- Agricultural work such as harvesting (also influenced by climate) may force increased nighttime exposure to mosquito bites
- Raising domestic animals near the household may provide alternate sources of blood meals for Anopheles mosquitoes and thus decrease human exposure
- War, migrations (voluntary or forced) and tourism may expose non-immune individuals to an environment with high malaria transmission.