Diagnosis of malaria in a remote area of the Philippines: comparison of techniques and their acceptance by health workers and the community

Objective To compare the efficacies of remote symptom-based diagnosis of ma laria, rapid diagnostic tests and microscopy in an area of low endemicity i n the Philippines. Methods In Trial I, 350 symptomatic patients were tested within their villa ges using malaria Plasmodium falciparum (Pf)I Plasmodium Vivax (Pv) immuroc hromatographic tests (ICT tests) and blood films stored and read under loca l conditions. The slides were later restained and read. In Trial II, unsupe rvised volunteer barangay health workers prepared ICT tests and slides afte r brief training. These slides were read at rural health units. Twenty-seve r barangay health workers and 72 community members were later questioned ab out the three diagnostic strategies. Findings A history of fever alone was sensitive (95.4%) but poorly specific (16.5%) for predicting parasitaemia. The inclusion of other symptoms reduc ed the sensitivity to below 85%, while specificity remained low. The axilla ry temperature was poorly predictive. ICT tests achieved high sensitivity ( 97.9%) but many cases indicated as positive by ICT tests were negative by m icroscopy. Further analysis of these cases in Trial I indicated that ICT te sts were detecting low-level parasitaemias missed by microscopy, and that l ocal microscopy had poor accuracy. ICT tests were well accepted and accurat ely performed by barangay health workers. Conclusion These tests meet a strong desire in the community for blood-base d diagnosis and may increase the compliance and treatment-seeking behaviour of patients.