[الدكتور أحمد باذيب]

After 9-16 days they return to the blood and penetrate the red cells, where they multiply again, progressively breaking down the red cells. This induces bouts of fever and anaemia in the infected individual. In cerebral malaria, the infected red cells obstruct the blood vessels in the brain. Other vital organs can also be damaged often leading to the death of the patient.

Malaria is diagnosed by the clinical symptoms and microscopic examination of the blood. It can normally be cured by antimalalial drugs. The symptoms, fever, shivering, pain in the joints and headache, quickly disappear once the parasite is killed. In certain regions, however, the parasites have developed resistance to certain antimalarial drugs, particularly chloroquine. Patients in these areas require treatment with other more expensive drugs. Cases of severe disease including cerebral malaria require hospital care.
In endemic regions, where transmission is high, people are continuously infected so that they gradually develop immunity to the disease. Until they have acquired such immunity, children remain highly vulnerable. Pregnant women are also highly susceptible since the natural defence mechanisms are reduced during pregnancy.
Malaria has been known since time immemorial, but it was centuries before the true causes were understood. Previously, it was thought that "miasma" (bad air or gas from swamps - "mal air ia") caused the disease. Surprisingly in view of this, some ancient treatments were remarkably effective. An infusion of qinghao (Artemesia annua ) has been used for at least the last 2000 years in China, its active ingredient (artemisinin) having only recently been scientifically identified. The antifebrile properties of the bitter bark of (Cinchona ledgeriana ) were known in Peru before the 15th century. Quinine, the active ingredient of this potion was first isolated in 1820 by the pharmacists.
Although people were unaware of the origin of malaria and the mode of transmission, protective measures against the mosquito have been used for many hundreds of years. The inhabitants of swampy regions in Egypt were recorded as sleeping in tower-like structures out of the reach of mosquitoes, whereas others slept under nets as early as 450 B.C.
Systematic control of malaria started after the discovery malaria parasite by Laveran in 1889 (for which he received the Nobel Prize for medicine in 1907), and the demonstration by Ross in 1897 that the mosquito was the vector of malaria. These discoveries quickly led to control strategies and with the invention of DDT during the World War II, the notion of global eradication of the disease. Effective and inexpensive drugs of the chloroquine group were also synthesized around this time.


The hope of global eradication of malaria was finally abandoned in 1969 when it was recognised that this was unlikely ever to be achieved. Ongoing control programs remain essential in endemic areas. Malaria is currently endemic in 91 countries with small pockets of transmission occurring in a further eight countries. Plasmodium falciparum is the predominant parasite. More than 120 million clinical cases and over 1 million deaths occur in the world each year.
Eighty per cent of the cases occur in tropical Africa, where malaria accounts for 10% to 30% of all hospital admissions and is responsible for 15% to 25% of all deaths of children under the age of five. Around 800,000 children under the age of five die from malaria every year, making this disease one of the major causes of infant and juvenile mortality. Pregnant women are also at risk since the disease is responsible for a substantial number of miscarriages and low birth weight babies.
Malaria thus has social consequences and is a heavy burden on economic development . It is estimated that a single bout of malaria costs a sum equivalent to over 10 working days in Africa. The cost of treatment is between $US0.08 and $US5.30 according to the type of drugs prescribed as determined by local drug resistance. In 1987, the total "cost" of malaria - health care, treatment, lost production, etc. was estimated to be $US800 million for tropical Africa and this figure is currently estimated to be more than $US1,800 million.
The distribution of malaria varies greatly from country to country and within the countries themselves. In 1990, 75% of all recorded cases outside of Africa were concentrated in nine countries: