A pooling strategy of a PCR-based assay to detect Angiostrongylus cantonensis in snail intermediate host, Pomacea canaliculata

Pooling field specimens could reduce the number of assay and thus increase the efficiency in detecting and screening pathogen infections by polymerase chain reaction (PCR)-based assay. We investigated a pooling strategy in diagnosis of Angiostrongylus cantonensis in Pomacea canaliculata . Two settings of specimens were prepared, divided into portions and detected by multiplex PCR. Specimens A was 0.4490 g positive lung tissue of 28 larval nodes from four snails mixed with 1.310 g negative lung tissue from six snails and divided into 32 portions. Specimens B was 0.5448 g positive lung tissue with 26 larval nodes from two snails mixed with 1.092 g negative lung tissue from seven snails and divided into 48 portions. Repeated sampling was performed and sample size-accumulated positive rate curves were drawn. According to the sample size-accumulated positive rate curves, the appropriate sample size of the two specimens were 18 and 15, respectively, which is 0.36–0.58 to the total sample size. These test characteristics and the relevant factors to the sample size would need to be determined in much larger studies and more appropriately in field populations. The result indicates that the number of larval node is not the most important, nor the only factor to the sample size. It also implies the feasibility to detect A. cantonensis in P. canaliculata by pooling strategies.