Evaluation of a homemade saliva kit for the stabilization of plasmodium dna at room temperature

Abstract

Abstract Objectives : Most malaria diagnostic methods are invasive whereas non-invasive alternatives like saliva could be used for molecular diagnosis. However, long-term storage of saliva also requires a cold chain, which is challenging in poor countries. Current tools to conserve saliva at room temperature are not affordable (~$16/kit) for malaria endemic countries. In this cross-sectional study including 83 febrile participants, we evaluated the effectiveness of a cheaper (~$2/kit) homemade kit (Formulation f1 ) to stabilize Plasmodium DNA in saliva stored at room temperature for 12 months. The OMNIgene ® ORAL (OM-501) kit served as standard (S0 ). Results : The frequency of malaria in this study was 78.31% (65/83) using microscopy. Saliva PCR-f1 and PCR-S0 detected 59 (71.08%) and 56 (67.47%) positive malaria samples respectively. Using microscopy as gold standard, the sensitivities of PCR-S0 and PCR-f1 were 100% while the specificities were 80%, and 85%, respectively. PCR-f1 had a “very good” agreement (kappa 0.81) with microscopy compared to PCR-S0 (kappa 0.64). We obtained similar results after 12 months storage of saliva samples at room temperature (RT). Homemade kit could be effective in transportation, preservation and diagnosis of malaria parasite in saliva. Key words: Non-invasive, Saliva, DNA, Plasmodium , Malaria, Homemade kit.