Mitochondrial PCR-based malaria detection in saliva and urine of symptomatic patients

Malaria can be diagnosed in saliva and urine using mitochondrial PCR detection of Plasmodium DNA.

Blood, saliva and urine were collected from 99 febrile patients referred to health centers in Sistan and Baluchestan Province, southeastern Iran, from May to November 2011. The mitochondrial cytochrome b gene of Plasmodium falciparum and Plasmodium vivax was targeted in saliva, urine and blood samples using nested PCR.

Nested PCR proved to be more sensitive than microscopy for the diagnosis of sub-microscopic and mixed-species infections. The results of nested PCR amplifications of saliva and urine samples showed the same specificity of 97% and sensitivity of 91% and 70%, respectively. Nested PCR amplifications of saliva samples and microscopy showed the greatest area under the receiver operating characteristic (ROC) curve and were more accurate than nested PCR amplifications of urine samples.

Nested PCR amplification of saliva samples showed good levels of detection of mitochondrial Plasmodium DNA as compared to nested PCR of blood (к=0.84; AUC=0.94), which was used as a reference standard. Based on the results of nested PCR as well as the advantages of saliva sampling, we suggest that saliva could be an alternative to blood, in malaria diagnosis, in cases where repeat sampling is required. Further studies are needed to validate these findings.