Blastocystis occurrence and subtype diversity in European wild boar (Sus scrofa) from the Iberian Peninsula

Authors: KÖSTER, PAMELA - National Center For Microbiology, The Institute Of Health Carlos Iii; FIGUEIREDO, ANA - University Of Aveiro (UA); Maloney, Jenny; DASHTI, ALEJANDRO - National Center For Microbiology, The Institute Of Health Carlos Iii; BAILO, BEGOÑA - National Center For Microbiology, The Institute Of Health Carlos Iii; TORRES, RITA - University Of Aveiro (UA); FONSECA, CARLOS - University Of Aveiro (UA); MYSTERUD, ATLE - University Of Oslo; HABELA, MIGUEL - University Of Extremadura; RIVERO-JUAREZ, ANTONIO - Cordoba University; SERRANO, EMMANUEL - Autonomous University Of Barcelona; ARNAL, MARIA C - University Of Zaragoza; FERNÁNDEZ DE LUCO, DANIEL - University Of Zaragoza; ARMANTEROS, JOSE - Collaborator; BALSEIRO, ANA - University Of Leon; CARDONA, GUILLERMO - Collaborator; CARVALHO, JOÃO - University Of Aveiro (UA); HIPOLÍTO, DÁRIO - University Of Aveiro (UA); FERNANDES, JOANA - University Of Aveiro (UA); PALMEIRA, JOSMAN - University Of Aveiro (UA); CALERO-BERNAL, RAFAEL - Complutense University Of Madrid (UCM); GONZÁLEZ-BARRIO, DAVID - National Center For Microbiology, The Institute Of Health Carlos Iii; Santin-Duran, Monica; CARMENA, DAVID - National Center For Microbiology, The Institute Of Health Carlos Iii

Submitted to: Veterinary Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/3/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: The ongoing increase of wild boar populations has fostered human-wildlife conflicts, including the transmission of emerging pathogens with zoonotic importance. Blastocystis is a ubiquitous parasite that can cause gastrointestinal illnesses and is observed in humans and animals worldwide. The role of wildlife in the epidemiology of Blastocystis is poorly understood. Thus, we have investigated the occurrence and subtype diversity of Blastocystis in free-ranging wild boars from the Iberian Peninsula using conventional molecular techniques. A total of 459 wild boar faecal samples were collected across Spain (n = 360) and Portugal (n = 99) between 2014 and 2021. Blastocystis was present in 15.3% (70/459) of the wild boars analyzed, and its occurrence was significantly higher in Portugal (34.3%, 34/99) than in Spain (10.0%, 36/360). Seven Blastocystis subtypes (ST5, ST10b, ST13–ST15, ST24b, and ST43) were detected among the surveyed wild boar populations, with greater variability detected in Portuguese samples. ST5 was identified in all Blastocystis-positive animals, whereas 11.4% of them presented mixed subtype infections. Our results demonstrate that Blastocystis ST5 is particularly adapted to infect wild boars. The additional finding of zoonotic STs reinforces the role of wild boars as spreaders of zoonotic infections with a public health significance.This information will be useful to other scientists, veterinarians, and public health agencies to better understand transmission, zoonotic potential, and public health importance of Blastocystis.

Technical Abstract: The ongoing increase of wild boar populations across Europe has fostered human-wildlife conflicts, including the transmission of emerging pathogens with zoonotic importance. Blastocystis is a ubiquitous, faecal-oral transmitted protist that can cause gastrointestinal illnesses and is observed in humans and animals worldwide. The role of wildlife in the epidemiology of Blastocystis is insufficiently understood. Thus, we have investigated the occurrence and subtype diversity of Blastocystis in free-ranging wild boars from the Iberian Peninsula using conventional PCR and next-generation amplicon sequencing of a fragment of the ssu RNA gene. A total of 459 wild boar faecal samples were collected across Spain (n = 360) and Portugal (n = 99) between 2014 and 2021. Blastocystis was present in 15.3% (70/459; 95% CI: 12.1–18.9) of the wild boars analysed, and its occurrence was significantly higher in Portugal (34.3%, 34/99; 95% CI: 25.1–44.6) than in Spain (10.0%, 36/360; 95% CI: 7.1–13.6). Seven Blastocystis subtypes (ST5, ST10b, ST13–15, ST24b, and ST43) were detected among the surveyed wild boar populations, with greater variability detected in Portuguese samples. ST5 was identified in all Blastocystis-positive animals, whereas 11.4% of them harboured ST mixed infections. Our results demonstrate that Blastocystis ST5 is particularly adapted to infect wild boars. The additional finding of zoonotic STs reinforces the role of wild boars as spreaders of zoonotic infections with a public health significance.