A PCR screen for malaria carrier infections using human saliva samples

Abstract

With endemic countries now aiming for elimination, the detection of malaria infections, with or without symptoms, is
increasingly important for monitoring and evaluation programmes. Current malaria screening methods necessitate
blood withdrawal. This invasive approach is constrained, espe cially for identifying the asymptomatic carrier
reservoir, since segments of communities with blood taboos avoid participating. Proof of concept has previously
been shown for molecular detection of malaria infection using human saliva samples. The current study optimized
saliva-based malaria detection in an area of southern Zambia. Saliva pellet fractions proved a more reliable source
of amplifiable parasite DNA compared to the soluble fraction. After optimizing DNA extraction and amplification,
saliva-based PCR showed 94.1% sensitivity and 97% specificity, using nested PCR on blood samples as gold
standard. This study demonstrates that saliva samples are a reliable non-invasive alternative to blood for the PCR
detection of asymptomatic and submicroscopic malaria reservoirs.