Evaluation of saliva collected by the Self-Lollisponge® device for diagnosis of malaria in children.

The Self-Lollisponge® device was used to collect saliva in children with malaria. Malaria antigens, namely, P. falciparum histidine-rich proteins 2 (PfHRP2) and Plasmodium lactate dehydrogenase (pLDH) were detected in blood and saliva samples. Subsequently, replicate samples with malaria antigens were stored at room temperature (28 °C) and 6 °C for 7 days. Malaria antigens were detected on days 1, 3, and 7. In the blood, PfHRP2 was detected in all 212 malaria samples, while pLDH was detected in 117 of the 212 samples (55.2 %). In the saliva, PfHRP2 was detected in 99/212 (46.7 %) samples while pLDH was detected in 111 of the 117 (94.8 %) samples whose corresponding blood had the pLDH detected. Compared to the blood samples, the overall sensitivity and accuracy of using saliva to detect PfHRP2 antigens were 46.7 % (95 % CI: 39.8-53.7 %) and 56.9 % (95 % CI: 50.6-63 %), respectively. Further, the overall sensitivity and accuracy for the detection of saliva-pLDH were 94.8 % (95 % CI: 89.2-98.1 %) and 96.4 % (95 % CI: 92.3-98.7 %), respectively. The PfHRP2 antigens were preserved for three days at 6 °C but at room temperature, the stability was for just a day. Nonetheless, the pLDH reduced comparatively faster, irrespective of the storage temperature.