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Malaria
BackgroundMalaria is one of the greatest global threats to public health, causing over 300 million cases of acute illness worldwide, and resulting in over a million deaths each year, 80-90 percent of these in sub-Saharan Africa. Billions of dollars are lost each year in low productivity due to malaria. In countries with a heavy malaria burden, the disease may account for as much as 40% of public health expenditure, and up to half of outpatient visits and inpatient admissions. The overall distribution of malaria is shown in the figure below. Global distribution of malaria, 2003
The parasites are passed from one person to another by the female anopheline mosquito primarily between sunset and sunrise. The males do not transmit the disease as they feed only on plant juices. The mosquito breeds in water, each species having its preferred breeding grounds, feeding patterns and resting place. Aggravated by an inadequate health infrastructure, poor socio-economic conditions, and an increase in resistance to the drugs normally used to combat the parasite, malaria control has become more difficult. The causative pathogen is a protozoan parasite of the genus Plasmodium. Five species of Plasmodium can produce the disease in its various forms:
Of the five malaria species, P. falciparum is the most widespread and most fatal. Rapid and accurate diagnosis is a cornerstone of good malaria control. As microscopy is cumbersome and not widely available, many patients are misdiagnosed, and over-treatment and mistreatment are common. Moreover, the rapid rise of drug-resistant malaria and the introduction of more expensive artemisinin-based combination therapies increase the urgency for accurate case detection. The World Health Organization recommended, in 2004, that malaria should be confirmed by parasitologic examination prior to treatment in all patients over five years of age. However, in much of the world where malaria is endemic, microscopy services are unavailable, and patients are treated on the basis of clinical signs and symptoms only, resulting in over-diagnosis of malaria by 40-90%, as shown in the table below. This is especially true among impoverished populations in remote rural areas, where malaria takes its heaviest toll. Malaria misdiagnosis: Examples from published literature
Source: Amexo M et al. Malaria Misdiagnosis: effects on the poor and vulnerable.
Lancet 2004; 364:1896-98. The syndromic management of malaria results in overtreatment with malarial drugs of a large fraction of febrile illness actually due to other causes. In busy clinical settings this often results in neglecting proper management of bacterial meningitis, pneumonia, urinary tract infections, and other common causes of fever in children. In high transmission areas, overtreatment also wastes precious resources, reduces confidence in health care systems and may contribute to decreased compliance and the evolution of drug-resistant malaria. Overdiagnosis is more common in remote rural areas, where malaria’s casualties are greatest.
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