Abstract:
Malaria is a potential medical emergency and should be treated accordingly. Delays in diagnosis and treatment are leading causes of death in many countries. The availability of rapid, simple diagnostic tools to substitute microscopy in malaria diagnosis will assist in the control of malaria by allowing therapy to be accurately administered. Emphasis has, recently been placed on alternative methods such as the use of acridine orange in malaria diagnosis using conventional fluorescence microscope or an interference filter system, but these were not considered a useful tool in field conditions due to weak illumination or high cost of the microscopes. This was the first study to use acridine orange in terms of their visual colours for malaria diagnosis. With acridine colour change, the infected individuals showed bright greenish yellow while the uninfected showed deep greenish yellow. Further trial was also made on the use of LDH substrate in combination with acridine solution based on colour changes, with the infected indicating bright brownish orange while the uninfected showed deep brownish orange. Thick and thin blood smears of Giemsa stain was used to estimate the parasite density and to determine the specific specie (Plasmodium falciparum). The evaluation of lactate dehydrogenase levels and concerntration of the study population showed mean values of 125.70±90.27unit/l and 0.0013±0.001mmol/l respectively. Though malaria infected individuals had higher LDH levels and concentrations than the uninfected individuals there was still no significant difference (p > 0.05) in the mean LDH levels and concentrations of infected and uninfected individuals. Statistically, of 100 individuals sampled, the prevalence according to the various methods were 65% for microscopy, 49% for acridine colour change and 51% for the combination (LDH substrate+ acridine solution). There was stronger agreement between the combinations with microscopy than in the acridine-microscopy relation. Generally, the sensitivity and NPV (Negative Predictive Value) for acridine colour change-microscopy were 75.38% and 68.63% respectively with 100% specificity PPV (Positive Predictive Value) while the sensitivity and NPV for the combination-microscopy relation were 78.46% and 71.43% with excellent specificity and PPV. Based on these findings, the study suggested that the use of these new methods could serve as alternatives to microscopy especially in most local setting where microscopy or trained technicians are unavailable.
