Prevalence and molecular characterisation of Balantioides coli in pigs raised in Italy

Balantioides coli is the only ciliated protist of both human and veterinary interest and colonises the large intestine of several hosts, including humans and pigs. Given the scarcity of data on B. coli circulation in pigs in Italy, a study was planned to record its prevalence and genetic types and compare the analytical sensitivity of two copromicroscopic techniques. For this purpose, 880 faecal samples were collected from pigs raised in 22 farms located in northern Italy and analysed with the sedimentation and the FLOTAC® dual technique, employing sodium chloride and zinc sulphate flotation solutions, and the Cohen's kappa coefficient was calculated to assess the agreement between these methods. Conventional PCR to amplify the ribosomal internal transcribed spacer region (ITS) was subsequently performed on 22 samples, one for each farm, which were positive for B. coli cysts by sedimentation; when more than one sequence was detected in the chromatograms, the PCR products were cloned. Overall, 813 samples were positive for B. coli cysts by sedimentation (92.4%), and moderate concordance with the zinc-based FLOTAC® technique was observed, whereas the agreement was slight with the salt-based FLOTAC® technique. Among the 22 sequenced samples, type B was amplified in 19 samples, type A in two samples, and both A and B types were co-expressed in one sample. This study demonstrated a high prevalence of B. coli in Italian pigs; further insights are needed to trace its distribution and genetic polymorphism in other pig production categories and in humans, defining its public health significance.