Efficacy of Urine and Saliva as Non-Invasive Alternatives for Malaria Diagnosis in a HighTransmission Setting in Southwestern Cameroon

Background Ensuring rapid, accurate diagnosis and effective treatment is critical to sustaining gains and achieving the ultimate goal of malaria elimination. Invasive blood-based diagnosis is hindered by low compliance and socio-cultural barriers, highlighting the need for non-invasive alternatives in malaria detection. The study evaluated the potential of urine and saliva as non-invasive alternatives for malaria diagnosis. Methods Individuals who provided informed consent, visiting the sample collection sites were enrolled. Demographic and clinical data were recorded in individual case report forms. Blood, urine, and saliva were collected for malaria detection using CareStart RDT. Blood samples were also examined by light microscopy to determine parasite load and some used for the preparation of dried blood spots. DNA was extracted using the chelex-100 method and subjected to Plasmodium speciation by nested PCR. Results The diagnostic sensitivities of saliva and urine RDT using PCR as reference were respectively 61.0% and 57.9% while the specificities were both 96.0% with Plasmodium falciparum being the most prevalent parasite species in the study site. Conclusions The sensitivities of Carestart RDT using urine and saliva were below the 90% threshold required by WHO for confident diagnosis of malaria. Urine and saliva are therefore unsuitable replacements for blood using blood-based Carestart RDT in malaria diagnosis.