Malaria is one of the deadliest infectious diseases. While the mosquito-borne parasite has been beaten back in most countries, poverty, violence, and climate provide fertile ground in Africa for a disease that hits the youngest hardest.
 | A Good Night's SleepSulay Jongo inside a mosquito net in his home in Sierra Leone. Bed nets treated with insecticide are one of the best preventions against malaria (Photo: Reuters) |
Cases Worldwide: 350-500 million
Main Causes: Infection by mosquito bite
Distribution: Latin America, Middle East, sub-Saharan Africa, South Asia and Southeast Asia; highest prevalence in sub-Saharan Africa
Female anopheles mosquitoes spread malaria by biting infected humans, ingesting the malaria parasite, and then passing it on to other humans that they bite. The parasite goes straight to the liver where it reproduces, infects the bloodstream and starves the body of oxygen leading to fever, anaemia, and a collapsing immune system.
Mosquitoes thrive in tropical areas of the world where there is plenty of standing water in which their larvae grow. About half of the world’s population is at risk from the disease, which has many different strains, and the World Health Organization (WHO) reckons that almost one million people die every year from malaria.
The overwhelmingly majority of the victims are children in sub-Saharan Africa where the most lethal strains of the disease and the most aggressive mosquitoes are found. Unfortunately these are also areas with weak public healthcare infrastructure that lack access to medicines and simple prevention measures like mosquito bed nets treated with insecticide.
As a result, every day, over 2000 Africans die from malaria, 85 percent of them children under 5 years of age who have not built enough natural immunity to the parasite. Almost a third of malaria deaths happen in epidemics after war and other emergencies force refugees away from their homes and into makeshift housing where they are vulnerable to mosquitoes that may be carrying malaria strains to which they have little immunity.
 | Picture Gallery (click on the picture to start)Ten of the biggest medical breakthroughs that have helped make the world healthier (Photo: Reuters) |
Malaria can be beaten. The parasite was once common in parts of southern Europe and the United States but was eradicated by rising living standards, drainage of mosquito habitats, better healthcare and by killing mosquitoes through spraying insecticides. These changes in society and environment are also reducing malaria rates in Latin America, India and China.
In Africa, however, where people cannot wait for socio-economic development, bed nets, indoor spraying of insecticide, giving pregnant women preventative antimalarial drugs, and prompt treatment of those infected are critical elements of an anti-malaria strategy.
In the future, climate change is expected to spread malaria to previously uninfected areas like the East African highlands as higher temperatures and rainfall levels suit mosquitoes and the malaria parasite. In places like the Sahel, however, climate change could help decrease malaria: increasing desertification could kill off the parasite and its host.
Malaria remains a complex and resilient enemy. Some strains develop resistance to drugs. A malaria vaccine has been a holy grail for decades but work has progressed slowly.
The RTS,S vaccine was identified twenty years ago but has only recently moved into widespread testing with 16,000 children in seven African countries to be involved from early 2009. Earlier tests in Mozambique showed the vaccine reduced all cases of clinical malaria by 35 percent.
The Malaria Vaccine Initiative aims for a vaccine that is at least 50 percent effective by 2015 and a second-generation product to be 80 percent effective by 2025. Until then, simple interventions like bed nets will be the best way to ensure millions of children can sleep in safety.
editor: James Tulloch
publication date: February 25, 2009
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