Pathogenesis, Treatment and Complications:

With the first attack of P.falciparum, fever is usually irregular rather than occurring with a regular, repeating pattern as seen with a tertian fever in subsequent attacks, and there are usually no relapses unlike with P.ovale and P.vivax where hypnozoites are formed (14). Fever is not always present, and rigors may or may not be present. The temperature may rise above 41°C, over several days, and the fever is produced as the schizonts mature, at 48 hour intervals usually for P.falciparum. The different malarias produce fevers of different frequency, depending on how long it takes to complete shizogony in erythrocytes. Malaria is especially dangerous to pregnant women and small children. Severe and complicated malaria is usually caused by delay in treating an uncomplicated attack of P.falciparum.

The patient will complain of headache, fever and aches and pains all over the body, and diarrhoea and abdominal pain are sometimes present. Spleen and liver are often palpable on clinical examination. This may be misdiagnosed as influenza in non endemic areas, and, unless treated promptly, the clinical picture can deteriorate rapidly (15). A patient with severe and complicated malaria will often present with impaired consciousness, weakness, and jaundice. Other complications are cerebral malaria (unrousable coma), generalised convulsions, normocytic anaemia, renal failure, hypoglycaemia, fluid, electrolyte and acid-base disturbances, pulmonary oedema, circulatory collapse, shock, disseminated intravascular coagulation, hyperpyrexia, hyperparasitaemia, and malarial haemoglobulinurea. These features may occur singly or in combinations.

As to whether the Plasmodium parasites cause their mosquito hosts such discomfort and morbidity is a matter of debate, with several contrasting opinions stressed. It does seem that mosquitoes who are carrying the malaria parasite do experience decreased life expectancy and higher mortality rates than their non infected counterparts.

Back in the human, the immune response is very important. Cell mediated immunity plays an active role and, in immune individuals, a large increase in IgG production (specific to antigens such as the circumsporozoite proteins on the sporozoites) occurs. Vaccines are currently being developed against three stages of the parasite: gametocytes, sporozoites, and intra-erythrocytic merozoites (14). The most important part of host defence seems to be antibody production, hence non-immune individuals visiting endemic areas are very vulnerable.

Pathogenesis, Treatment and Complications:

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