Prevalence and subtype distribution of Blastocystis sp. isolates from poultry in Lebanon and evidence of zoonotic potential

Stéphanie Greige (1, 2) , Dima El Safadi (2) , Noémie Bécu (1) , Nausicaa Gantois (1) , Bruno Pereira (3) , Magali Chabe (1) , Sadia Benamrouz-Vanneste (1, 4) , Gabriela Certad (1, 5, 6) , Rima El Hage (7) , Marianne Chemaly (8) , Monzer Hamzé (2) , Eric Viscogliosi (1)

1 CIIL - Centre d’Infection et d’Immunité de Lille - INSERM U 1019 - UMR 9017 - UMR 8204
2 LMSE - Laboratoire Microbiologie Santé et Environnement [Tripoli, Liban]
3 CHU Clermont-Ferrand
4 UCL FGES - Université Catholique de Lille - Faculté de gestion, économie et sciences
5 UCL FMM - Université catholique de Lille - Faculté de médecine et de maïeutique
6 GHICL - Groupe Hospitalier de l'Institut Catholique de Lille
7 IRAL - Institut de Recherche Agronomique Libanais
8 Laboratoire de Ploufragan - Plouzané

Background: Blastocystis sp. is a common protozoan parasite frequently identified in the digestive tract of humans and a large variety of animal hosts worldwide, including birds. It exhibits a large genetic diversity with the identification of 17 subtypes (STs), most of them with low host specificity. ST6 and ST7 were identified in birds and suggested to represent avian STs only in the context of scarce small-scale epidemiological surveys. Moreover, these two STs also account for a significant proportion of human infections whose zoonotic origin has never been clearly confirmed. Therefore, molecular screening of Blastocystis sp. was conducted by quantitative real-time PCR for fecal samples from poultry farms and their in-contact humans from slaughterhouses in Lebanon. In parallel, a control group consisting of patients hospitalized in the same geographical area and reporting no contact with poultry was also screened for the presence of the parasite. Results: The overall prevalence of Blastocystis sp. was shown to reach around 32% in chicken samples and 65% in the farms screened. All the avian isolates were subtyped and belonged to either ST6 or ST7, with a large predominance of ST6. Fifty-four percent of slaughterhouse staff members were positive for Blastocystis sp. compared with a similar prevalence of 56% in hospitalized patients. ST3 was predominant in both human cohorts followed by either ST1 then ST2 among slaughterhouse staff or by ST2 then ST1 among hospitalized patients. ST6 was also identified in two slaughterhouse workers and not in the group of hospitalized patients. Gene sequence identity was observed between chicken and human ST6 isolates from the same slaughterhouse. Conclusions: Our data revealed a high prevalence of Blastocystis sp. in chicken samples and confirmed that ST6 and ST7 represented avian-adapted STs. Among both human cohorts, Blastocystis sp. infection was shown to exceed 50% with a predominance of ST3. The identification of ST6 in slaughterhouse staff members confirmed the zoonotic transmission of this ST through repeated and direct contact between chickens and their handlers.

Mots clés: Blastocystis sp.; Intestinal parasite; Molecular epidemiology; Real-time quantitative PCR; Subtyping; Transmission; Zoonosis; Avian parasitology

Domaines: Parasitologie; Médecine vétérinaire et santé animale; Santé publique et épidémiologie

Stéphanie Greige, Dima El Safadi, Noémie Bécu, Nausicaa Gantois, Bruno Pereira, et al.. Prevalence and subtype distribution of Blastocystis sp. isolates from poultry in Lebanon and evidence of zoonotic potential. Parasites & Vectors, 2018, 11, pp.389. ⟨10.1186/s13071-018-2975-5⟩. ⟨hal-02399491⟩