Microscopy is more reliable than questionnaire-based methods in the diagnosis of malaria in school children

The objectives of the study were to determine by the use of a structured questionnaire the prevalence of malaria and its associated symptoms amongst school children and to relate these to the prevalence of malaria determined by microscopic examination. The questionnaire was administered to 840 pupils of classes 3, 5 and 7 (age range 5-16 years) in 17 primary schools of the Kumba Health District of Cameroon. Blood samples were collected from the same individuals for identification of malaria parasites. The prevalence rate by microscopic examination was 41.4% significantly higher (P<0.001) than 23.9% obtained by questionnaire survey. Headache and fever had similar prevalence rates (53.6% and 53.0% respectively) which were significantly higher (P<0.001) than the prevalence rate of malaria by microscopic examination. Other malaria hyphen;related symptoms gave rates which greatly underestimated the prevalence of malaria (P<0.001). There was no significant correlation between the prevalence rates obtained by questionnaire and the rate of malaria by microscopy. The sensitivity and specificity of these screening tests for malaria were all low. The use of the microscope as a malaria diagnostic tool at primary health care unit is strongly recommended.