Molecular detection of Blastocystis from animals in Italy: subtypes distribution and implications for the zoonotic transmission

Abstract

Background: Blastocystis is a common intestinal protist distributed worldwide infecting humans and a wide range of domestic and wild animals. It exhibits an extensive genetic diversity and so far, 26 subtypes (STs) have been identified in animal hosts, ten of them (ST1-ST9 and ST12) reported in humans with varying prevalence. Since several STs are common to humans and animals it has been proposed that a proportion of human infections may have a zoonotic origin. Aims of the present study were to: 1) genetically detect Blastocystis in faecal samples of farmed animals and wild carnivores; 2) investigate the distribution of Blastocystis STs in different animal hosts; 3) provide a first study on the Blastocystis STs circulating between animals and humans in Italy.Methods: Fresh faecal samples (N=269) were collected from carnivores and farmed animals in different Italian provinces and submitted to genomic DNA extraction and PCR amplification followed by both sequence and phylogenetic analysis (Neighbour Joining and Maximum Parsimony)Results: Blastocystis was detected in 50% of the farmed animals (42 out of 84), and 19 of them were successfully subtyped. Conversely, all the faecal samples (N=185) from domestic and wild carnivores (dogs, cats, foxes) tested in the present study, resulted negative. Phylogenetic analysis showed the finding of ST5, ST7, ST9 and ST10 in the samples from animals. The comparison with sequences of Blastocystis STs previously detected from humans in Italy showed the ST7, as a potential source of zoonotic transmission.Conclusions: The present study represents the widest epidemiological survey so far performed in animals in Italy. Further epidemiological studies using molecular approaches are required to determine the occurrence and distribution of Blastocystis STs in other potential animal reservoirs and to define the pathways of zoonotic transmission.

Subtype–host patterns and genetic differentiation of Blastocystis sp. in the Philippines

“…ST5 allele 16 was the most commonly encountered in pigs and ST allele 2 was the most commonly encountered in macaques. In comparison, ST5 allele 115 was the most commonly encountered in pigs from Italy [ 92 ] and ST1 allele 2 was the most commonly identified in long-tailed macaques from Thailand [ 72 ]. Not much data on allele distribution is available for animals and water samples.…”

First report of Blastocystis subtype ST25 in calves in Turkey

“…The prevalence of Blastocystis varies significantly depending on geographical location and host type (Ruaux and Stang 2014). In studies conducted on cattle, the prevalence was reported as 21.4% in Brazil (Moura et al 2018), 22.7% in Arabia (Abuodeh et al 2019), 32.1% in Spain (Abarca et al 2021, 10.3% in China (Zhu et al 2017), 6.7% in Korea (Lee et al 2018, 80% in Colombia (Ramírez et al 2014), 34.5% and 43.8% in Malaysia (Hemalatha et al 2014, Kamaruddin et al 2020, 71% in Japan (Abe et al 2002) and 33% in calves in Italy (Gabrielli et al 2020).…”

“…shows a wide genetic diversity. It has been reported that 26 subtypes (ST) have been defined in animals so far and ST10 is the most common subtype in cattle in the world (Aynur et al 2019, Gabrielli et al 2020. It was reported that two subtypes, ST10 and ST14, were detected in cattle in the southwest of Turkey and ST14 was more common (Aynur et al 2019), ST10 was detected in cattle and sheep in the Central Anatolia and Central Black Sea Region (Onder et al 2021), and in a different study conducted also in the Central Anatolia Region, the ST10 subtype was determined in cattle (Tavur and Önder 2022).…”