Seasonal Trends with the Comparison of Venous and Capillary Blood for Diagnosis of Malaria among Children in Karachi, Pakistan

More than 250 million people are infected by malaria parasites annually while around one million children less than 5 years of age die every year due to malaria. We aimed to assess the seasonal trends and usefulness of capillary and venous blood for rapid diagnosis of malaria.

This cross-sectional study of 18 months duration was conducted at the National Institute of Child Health (NICH), Karachi. All patients reporting fever as chief complaint were recruited as study subjects. A semi-structured questionnaire was used to collect demographic information, presenting complaints, awareness of caregivers regarding malaria, preventive measures and history of malaria fever. Three ml Venous (2-3ml) as well as peripheral blood (3-4 drops) samples of all patients were collected for microscopy and rapid diagnostic tests (RDTs).

Out of total 477 patients with fever Venous and Capillary Blood RDTs methods detected 33(6.9%) and 30(6.3%) as the malaria positive while Venous and Capillary Blood Microscopy detected 30(6.1%) and 32(6.7%) cases respectively. Plasmodium Vivax infection was the most prevalent (87.9%) and majority (39.39%) of the cases occurred in the quarter, July to September.

July to September is the peak season for malaria and P. Vivax (87.9%) is the predominant strain in Karachi. Venous and capillary blood are equally useful for malaria diagnosis however, convenience and less invasiveness may justify the preference of capillary blood over venous blood for early diagnosis of malaria.