Evaluation of a real-time PCR assay for diagnosis of schistosomiasis japonica in the domestic goat

BACKGROUND: Schistosomiasis japonica is an infectious disease caused by Schistosoma japonicum that seriously endangers human health. Domestic animals have important roles in disease transmission and goats are considered a primary reservoir host and source of infection. The prevalence and intensity of schistosomiasis infections have significantly decreased in China, and a more sensitive, specific detection method is urgently needed. The aim of this study was to develop a real-time PCR assay for accurate detection of S. japonicum infection in goats. METHODS: A real-time PCR method for detecting schistosomiasis japonica in goats was developed by amplification of a specific S. japonicum DNA fragment, and validated using a total of 94 negative and 159 positive plasma and serum samples collected in our previous study of S. japonicum infection. Both plasma and serum samples were evaluated by real-time PCR and enzyme-linked immunosorbent assay (ELISA). In addition, 120 goat plasma samples from an S. japonicum-endemic area (Wangjiang) and 33 from a non-endemic region (Weihai) were collected and evaluated using our method. RESULTS: The sensitivity and specificity of the real-time PCR for detecting infected samples were 98.74% (157/159, 95% CI: 95.53–99.85%) and 100% (94/94, 95% CI: 96.15–100%), respectively. For the ELISA, sensitivity and specificity were 98.11% (156/159, 95% CI: 94.59–99.61%) and 90.43% (85/94, 95% CI: 82.60–95.53%), respectively. Further, we found positivity rates for S. japonicum infection in Wangjiang and Weihai of 8.33% (10/120, 95% CI: 4.07–14.79%) and 0% (0/33, 95% CI: 0–10.58%), respectively. CONCLUSIONS: The results of this study indicate that our real-time PCR method exhibits higher sensitivity and specificity than ELISA and is a useful method for detection of S. japonicum infection in goats.