Abstract
The importance of marine snails in the transfer of cercariae to fish as a provenance of zoonoses should be considered. Parasitic studies in marine snails have been uncommon in Saudi Arabia. In the present study, 550 Nerita genus of marine snails were monthly and randomly collected from January to December 2016 from Obhor bay, Saudi Arabia. The snails were subjected to light. They were crushed to evaluate the presence of larval trematodes. PCR technique was performed using the internal transcribed spacer region of ribosomal DNA (ITS-rDNA) which has been a specific primer to detect the extent of larval trematode infection in some snails infected as positive control samples and all non-infected snails to assess if they were infected or not. PCR technique showed a high prevalence of infection (55.82%) than the classical methods (21.45%). These studies can help in collecting data on the ecological importance of the distribution of disease in sympathetic fish, and the transmission of digenean trematodes disease through snails. Moreover, they can be useful in preventing and control offish and human diseases.