Development of a PCR-based method for the detection of Opisthorchis viverrini in experimentally infected hamsters

Opisthorchis viverrini infection is an endemic disease that causes a seriou s public health problem in southeast Asia. especially in northeast Thailand . We have developed a PCR method using a pair of primers named OV-6F/OV-6R for detecting O. viverrini eggs in stool samples and compared it with Stoll 's egg-count method. The primers were designed based on the pOV-A6 specific DNA probe sequence which gave a 330 base pair product. The PCR method can detect a single egg in artificially inoculated faeces or as little as 2 x 1 0(-17) ng of O. viverrini genomic DNA. The method gal-e 100%, sensitivity i n all hamster groups except in animals exposed to the lon est intensity of infection (1 metacercaria/hamster). In the first month of infection, the PC R method was more sensitive than using the egg-count method in all infected groups especially in the light infections. The PCR method was also success fully used in monitoring a therapeutic study. Since the PCR method showed n o cross-reaction with Heterophyid flukes, it can be useful for specific ide ntification of O. viverrini eggs in stool samples without the risk of false positives. It also has great potential for application in clinical epidemi ological studies.