Clinical features of benign malaria

P. falciparum causes the most serious type of malaria. The forms other than P. falciparum malaria are known as benign malaria (1).

Other forms of malaria have similar acute presentations to that of falciparum malaria.

• the incubation periods are longer: P. ovale, 15-18 days, P. vivax 12-17 days, P. malariae, 18-40 days (P. falciparum has an incubation period of, in general, 7-14 days) (1)

There is a prodrome of flu-like symptoms, ie headache, malaise, myalgia, anorexia, diarrhoea and cough (2).

The patient develops paroxysms lasting 8-12 hours:

• a cold stage - sensation of cold, shivering
• a hot stage - fever, headaches, vomiting; seizures in young children and
• at last a sweating stage - sweats, return to normal temperature, tiredness (3)

P. ovale and P. vivax cause fever every 3rd day, ie 1,3,5, etc. P. malariae causes fever every 4th day, ie 1,4,7, etc, in early infection however the regularity of fever may not be seen.

Relapse occurs (after a couple of months or even years) because the parasite lays dormant (the exoerythrocytic schizogony) in either the liver (P. ovale or P. vivax) or in the blood (P. malariae).

Reference:

• 1.. Lalloo DJ et al. UK malaria treatment guidelines. Journal of Infection 2007;54:111-121
• 2. National travel health network and centre 2007. Travel health information sheets - malaria
• 3. Centers for disease control and prevention 2006. Malaria