Authors

I Owusu-Frimpong¹; LB Debrah²; EJ Tettevi¹; S Armoo¹; NA Kuma¹; YA Ashong³; FT Aboagye¹; IK Duah⁴; B Idun¹; MY Osei-Atweneboana¹;  ¹ Council for Scientific and Industrial Research Water Research Institute, Ghana;  ² Kwame Nkrumah University Of Science and Technology, Ghana;  ³ Noguchi Memorial Institute for Medical Research, University of Ghana, Ghana;  ⁴ College of Nursing and Midwifery and Allied Health Sciences, Nalerigu, Ghana

Discussion

The application of quantitative PCR has been useful in the diagnosis and management of parasitic diseases. In the case of schistosomiasis, different qPCR assays have been developed from different target sequences. The mitochondrial genome has been established to be ideal for the development of a diagnostic assay since it is highly conserved and numerous in a single cell. Moreover, a well-designed SYBR Green qPCR assay is cost-effective compared to a TaqMan probe-based qPCR assay. With schistosomiasis still devastating many developing countries, it is imperative to have a cost-effective diagnostic qPCR assay which sensitive and specific. Therefore, we developed a schistosome species-specific SYBR green qPCR assay to independently target the COX 1 gene of S. haematobium and S. mansoni. This study used previously extracted DNA samples from 200 stool and 150 urine specimens collected from an epidemiological survey conducted at Tomefa, an endemic schistosomiasis community. Schistosome species-specific primers were designed and synthesized from the COX1 gene of S. mansoni and S. haematobium for the SYBR green qPCR assay. The lowest DNA detection limit was estimated as 0.122 pg and 1.216 pg for S. mansoni and S. haematobium, respectively. The outcome of the diagnostic parameter estimation by the bayesian latent class analysis (BLCA) showed a prevalence of 36.0% and 91.7% for S. haematobium and S. mansoni, respectively. Test sensitivity and specificity were estimated as 93.7% and 92.3%, respectively, for the detection of S. haematobium, whereas the sensitivity and specificity of S. mansoni were 82.6% and 90.3%, respectively. The Ct values of the positive diagnostic test ranged from 19.93 to 31.16 for S. mansoni and from 27.43 to 37.09 for S. haematobium. The correlation between the Ct values and microscopic egg counts for both S. mansoni in stool and S. haematobium in urine estimated r values of −0.365 (p < 0.01) and −0.253 (p < 0.035), respectively. The developed COX1 SYBR Green qPCR assay for S. mansoni and S. haematobium detections presented in this paper has proven effective and could be applicable to epidemiological surveys for treatment monitoring. It is a quick, efficient, and accurate procedure, which can be a good substitute for schistosomiasis qPCR assays that rely on probes.