INFORMATION

Malaria must be suspected in a patient with fever of any pattern with or without other symptoms if the individual has been in a malarial zone in the last 6 months. Although he might have taken correct prophylactic measures since it is not always effective, and it does not have to make us discard the diagnosis.
It is fundamental, then, to find out if the patient has traveled abroad (Africa, Asia, The Australian Continent, Central or South America), and to which zone exactly, and when. If the clinical suspicion remains after deepening in the anamnesis, must be made the parasitological diagnosis, because the treatment depends on the species of Plasmodium, among other factors (like resistance to drugs in the zone of acquirement, clinical presentation, age...). The diagnosis relies, mainly, on the microscopic examination of peripheral blood (extension in fine layer, heavy drop dyed with Giemsa), nowadays also are used other techniques like fluorescence, immunochromatography and PCR for primary diagnosis of the malaria. In addition, in nonresident patients in endemic zones the serological methods can be useful, but in the endemic countries it has little value in diagnosis due to the high rate of antibodies in the local population.
The heavy drop has the advantage as it concentrates the parasites hence increasing sensitivity of the diagnosis but it is in the extension in fine layer where better identification of the four species can be done which can affect man: P.falciparum, P.malariae, P.vivax and P.ovale.
The most important criteria for primary diagnosis in extension in fine layer of peripheral blood are:

Author:

Juan Sahagún
Microbiological Department
Clinical Hospital University “Lozano Blesa”
Zaragoza
e-mail: astridjuan@yahoo.es

Translated by: Lalit Kumar