Why is malaria such a problem and how close are we to an effective vaccine for this deadly disease?
The problem.
It was well over 100 years ago that scientists discovered the cause of malaria as a single-cell parasite called plasmodium but, even today, this life-threatening parasitic disease represents one of the international community’s most pressing public health problems.
Malaria is endemic throughout the tropical regions of the world, causing more than 300 million acute illnesses and at least one million deaths each year1
. Children under the age of 5 are particularly prone to infection, and, as a direct result of their immature immunity to disease, make up a dramatic proportion of the deaths each year. In Africa alone (where 90% of all malariaattributed deaths occur) this disease is responsible for the death of one child in 20 before the age of 52. In fact, malaria is the world’s leading cause of childhood mortality, killing one child every 30 seconds3 . Pregnant women and their unborn children are also particularly vulnerable to the disease which contributes to anaemia, premature birth and low birth weight whilst foreign travellers, who have often not developed immunity, represent another high-risk group.4
Malaria is caused by a protozoan parasite,
Plasmodium. Four species of Plasmodium can cause the disease in humans: P. vivax, P. ovale, P. malarinae and P.falciparum, which is by far the most deadly. The disease is vector-borne and is transmitted from one person to another by the bite of an infected Anopheles mosquito.
The Plasmodium parasite has a complex life cycle. Malaria infection begins when an infected female Anopheles mosquito bites a person, injecting Plasmodium parasites, in the form of sporozoites, into the bloodstream. The sporozoites pass quickly into the human liver where they reproduce rapidly, each producing tens