Comparison of Conventional and Molecular Diagnostic Techniques for Detection of Blastocystis sp. in Pig Faeces

Background: Blastocystis is a common protist colonizing the gastrointestinal tract of humans and various animals. Pigs have been suggested to be a reservoir for human Blastocystis infections because of high prevalence of the parasite in these animals and the presence of zoonotic subtypes. Nevertheless, epidemiological data is often misinterpreted due to the lack of standard diagnostic procedures. This study aimed to compare the sensitivity of different diagnostic techniques in detection of Blastocystis sp. in pigs. Overall, 48 individual faecal samples were collected from pigs reared in an intensive farming system (Autonomous Province of Vojvodina, Serbia) and were tested by microscopic examination of direct wet mount, in vitro cultivation in modified Jones' medium and conventional PCR for rRNA gene. Xenic in vitro cultivation in Jones’ medium showed higher sensitivity than direct wet mount when we compared it with PCR. Namely, the estimated sensitivity of direct wet mount was 46.15%, while the sensitivity of in vitro cultivation was 84.62%. Low sensitivity of conventional parasitological compared to molecular methods is proven. Thus, reports on prevalence that rely solely on microscopy of faecal samples (unprocessed or concentrated) are probably underestimating the true prevalence of the parasite.