Docstoc

Malaria

Document Sample
Malaria Powered By Docstoc
					Malaria



KEY FACTS


    •    Malaria is a life-threatening disease caused by parasites that are transmitted to people through
         the bites of infected mosquitoes.
    •    A child dies of malaria every 30 seconds.
    •    There were 247 million cases of malaria in 2006, causing about 880,000 deaths, mostly among
         African children.
    •    Malaria is preventable and curable.
    •    Approximately half of the world's population is at risk of malaria, particularly those living in
         lower-income countries.
    •    Travellers from malaria-free areas to disease "hot spots" are especially vulnerable to the
         disease.
    •    Malaria takes an economic toll - cutting economic growth rates by as much as 1.3% in countries
         with high disease rates.




Malaria is caused by parasites of the species Plasmodium. The parasites are spread to people through
the bites of infected mosquitoes.

There are four types of human malaria:

    1.   Plasmodium   falciparum
    2.   Plasmodium   vivax
    3.   Plasmodium   malariae
    4.   Plasmodium   ovale.

Plasmodium falciparum and Plasmodium vivax are the most common. Plasmodium falciparum is the
most deadly.

TRANSMISSION

Malaria transmission rates can differ depending on local factors such as rainfall patterns (mosquitoes
breed in wet conditions), the proximity of mosquito breeding sites to people, and types of mosquito
species in the area. Some regions have a fairly constant number of cases throughout the year - these
countries are termed "malaria endemic". In other areas there are "malaria seasons" usually coinciding
with the rainy season.

Large and devastating epidemics can occur when the mosquito-borne parasite is introduced into areas
where people have had little prior contact with the infecting parasite and have little or no immunity to
malaria, or when people with low immunity move into areas where malaria cases are constant. These
epidemics can be triggered by wet weather conditions and further aggravated by floods or mass
population movements driven by conflict.

SYMPTOMS

The common first symptoms – fever, headache, chills and vomiting – usually appear 10 to 15 days after
a person is infected. If not treated promptly with effective medicines, malaria can cause severe illness
and is often fatal.

WHO IS AT RISK?

Most cases and deaths are in sub-Saharan Africa. However, Asia, Latin America, the Middle East and
parts of Europe are also affected. In 2006, malaria was present in 109 countries and territories.
Specific risks follow.


    •    Travellers from malaria-free regions, with little or no immunity, who go to areas with high
         disease rates are very vulnerable.
    •    Non-immune pregnant women are at high risk of malaria. The illness can result in high rates of
         miscarriage and cause over 10% of maternal deaths (soaring to a 50% death rate in cases of
         severe disease) annually.
    •    Semi-immune pregnant women risk severe anaemia and impaired fetal growth even if they
         show no signs of acute disease. An estimated 200 000 of their infants die annually as a result of
         malaria infection during pregnancy.
    •    HIV-infected pregnant women are also at increased risk.

TREATMENT

Early treatment of malaria will shorten its duration, prevent
                                                                          Related links
complications and avoid a majority of deaths. Because of its
considerable drag on health in low-income countries, malaria disease
management is an essential part of global health development.             :: Global Malaria Programme
Treatment aims to cure patients of the disease rather than to diminish
the number of parasites carried by an infected person.                    :: Roll Back Malaria Partnership

                                                                         :: Malaria (Special Programme
The best available treatment, particularly for P. falciparum malaria, is
                                                                         for Research and Training in
a combination of drugs known as artemisinin-based combination
                                                                         Tropical Diseases, TDR)
therapies (ACTs). However, the growing potential for parasite
resistance to these medicines is undermining malaria control efforts
(see below). There are no effective alternatives to artemisinins for the
treatment of malaria either on the market or nearing the end of the drug development process.

WHO recommends:


    •    prompt treatment for all episodes of disease (within 24 hours of the onset of symptoms if
         possible);
    •    use of insecticide-treated nets for night-time prevention of mosquito bites;
    •    for pregnant women in highly endemic areas, preventive doses of sulfadoxine–pyrimethamine
         (IPT/SP) to periodically clear the placenta of parasites;
    •    indoor residual spraying to kill mosquitoes that rest on the walls and roofs of houses.

WHO guidelines for the treatment of malaria [pdf 1.85Mb]

DRUG RESISTANCE

Drug resistance to commonly used antimalarial drugs has spread very rapidly. In order to avoid this for
artemisinins, they should be used in combination as ACTs, and artemisinin monotherapy (use of one
artemisinin drug versus the more effective combination pill) should not be used. The less effective
single-drug treatment increases the chance for parasites to evolve and become resistant to the
medicine. Intensive monitoring of drug potency is essential to protect against the spread of resistant
malaria strains to other parts of the world.

WHO recommends continuous monitoring and is assisting countries as they work to strengthen drug
observation efforts.

More information on resistance

PREVENTION

Prevention focuses on reducing the transmission of the disease by controlling the malaria-bearing
mosquito. Two main interventions for vector control are:


    •    use of mosquito nets treated with long-lasting insecticide, a very cost-effective method;
    •    indoor residual spraying of insecticides.
These core interventions can be locally complemented by other mosquito vector control methods (for
example, reducing standing water habitats where insects breed, among other approaches).

INSECTICIDE RESISTANCE

Mosquito control efforts are being strengthened in many areas, but there are significant challenges,
including:


    •   increasing mosquito resistance to key insecticides DDT and pyrethroids, particularly in Africa;
    •   a lack of alternative, effective insecticides;
    •   changing behaviours of local malaria-bearing mosquitoes, which can result from vector control
        efforts (as insects move to more hospitable areas).

There are no equally effective and efficient insecticide alternatives to DDT and pyrethroids, and the
development of new pesticides is an expensive, long-term endeavour. Vector management practices that
enforce the sound management of insecticides are essential.

Insecticide resistance detection should be a routine feature of national control efforts to ensure that the
most effective vector control methods are being used.

More information on vector control

ECONOMIC IMPACT

Beyond the human toll, malaria wreaks significant economic havoc in high-rate areas, decreasing Gross
Domestic Product (GDP) by as much as 1.3% in countries with high levels of transmission. Over the
long-term, these aggregated annual losses have resulted in substantial differences in GDP between
countries with and without malaria (particularly in Africa).

Malaria’s health costs include both personal and public expenditures on prevention and treatment. In
some heavy-burden countries, the disease accounts for:


    •   up to 40% of public health expenditures
    •   30% to 50% of inpatient hospital admissions
    •   up to 60% of outpatient health clinic visits.

Malaria disproportionately affects poor people who cannot afford treatment or have limited access to
health care, and traps families and communities in a downward spiral of poverty.

ELIMINATION

Recent data shows that large-scale use of WHO recommended strategies could rapidly reduce malaria,
especially in areas of high transmission such as Africa. WHO and Member States have made significant
gains in malaria elimination efforts. For example, the Maldives, Tunisia and the United Arab Emirates
have eliminated malaria. Country successes are due to intense national commitments and coordinated
efforts with partners.


This fact sheet was taken from WHO – www.who.int