Comparative analysis of acon-<i>Plasmodium falciparum</i> rapid malaria diagnostic test with routine microscopy among school children and pregnant women in a rural community in Enugu State, Nigeria

Abstract

There are currently two methods for the direct diagnosis of malaria: the thin blood smear and the thick smear. A third method called the Acon-Plasmodium falciparum (Acon-Pf) (a new cheap malaria rapid diagnostic test) has been developed. This was the first study comparing the three methods in rapid malaria diagnosis among school children and pregnant women in Enugu State, Nigeria, using qualitative and quantitative questionnaires that address their knowledge, attitude, behaviour and practice. In this study, 352 whole blood samples of individuals with suspected falciparum malaria were investigated among pregnant women attending antenatal clinic and school children in rural communities in Enugu State. The following parameters were determined: intrinsic validity, predictive values, species diagnostic power and logistic factors. Acon-Pf had the following characteristics: 91.5 % sensitivity, 87.2 % specificity, 64.3 % positive predictive values, 97.6 % negative predictive values, high malaria infection rate determination of 58.7%, reduced mean packed cell volume (0.25 mmol/L) in malaria patients, correct species diagnosis including both the trophozoite and gametocyte stages of Plasmodium falciparum. The Acon-Pf positive test result ranged from light to thick coloured bands and the time required for the test was 1.3 – 15 ± 5 minutes. The cost per Acon-Pf test cassette at bulk purchase was N112.50 (US$0.90) without the service charge as compared with thick smear (N 300.00, US$ 2.50) and N 350.00 (US$ 2.90) for thin smear. The study found that Acon-Pf is suitable along side microscopy in the accurate diagnosis of malaria in Enugu State. The use of Acon- Pf and thick smear tests in parallel, first collecting the Acon-Pf results, as it contributes in reading the thin smear result for confirmation of species, diagnosis and assessment of parasitaemia. Thus, Acon-Pf test device is a viable cost effective adjunct to routine microscopy and a reliable option for malaria diagnosis in remote and emergency situations.

Keywords: Acon-Pf, Routine microscopy sensitivity, Specificity, Intrinsic validity, Predictive values, Parasitaemia, Trophozoite, Gametocyte, Diagnostic power, Epidemiology, Logistic factors

Animal Research International (2012) 9(2): 1585 – 1600