title: Blastocystis, an unrecognized parasite: an overview of pathogenesis and diagnosis.
abstract: Blastocystis sp. is among the few enteric parasites with a prevalence that often exceeds 5% in the general population of industrialized countries and can reach 30-60% in developing countries. This parasite is frequently found in people who are immunocompromised (patients with human immunodeficiency virus/acquired immunodeficiency syndrome or cancer) and a higher risk of Blastocystis sp. infection has been found in people with close animal contact. Such prevalence in the human population and the zoonotic potential naturally raise questions about the impact of these parasites on public health and has increased interest in this area. Recent in vitro and in vivo studies have shed new light on the pathogenic power of this parasite, suggesting that Blastocystis sp. infection is associated with a variety of gastrointestinal disorders, may play a significant role in irritable bowel syndrome, and may be linked with cutaneous lesions (urticaria). Despite recent significant advances in the knowledge of the extensive genetic diversity of this species, the identification of extracellular proteases as virulence factors and the publication of one isolate genome, many aspects of the biology of Blastocystis sp. remain poorly investigated. In this review, we investigate several biological aspects of Blastocystis sp. (diversity and epidemiology, diagnosis tools and pathophysiology). These data pave the way for the following challenges concerning Blastocystis sp. research: deciphering key biological mechanisms and pathways of this parasite and clarification of its clinical impact in humans.
authors.affiliation: Clermont Université, Université Blaise Pascal, Laboratoire Microorganismes, Génome et Environnement, Clermont-Ferrand and CNRS, UMR 6023, LMGE, Aubière, France.
authors.forename: Ivan
authors.initials: I
authors.lastname: Wawrzyniak
authors.affiliation: Clermont Université, Université Blaise Pascal, Laboratoire Microorganismes, Génome et Environnement, Clermont-Ferrand, CNRS, UMR 6023, LMGE, Aubière, Clermont Université, Université d'Auvergne, JE 2526, Evolution des bactéries pathogènes et susceptibilité de l'hôte, Clermont-Ferrand and CHU Clermont-Ferrand, Service Parasitologie Mycologie, Clermont-Ferrand, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Poirier
authors.affiliation: Institut Pasteur de Lille, Centre d'Infection et d'Immunité de Lille, Inserm U1019, CNRS UMR 8204, Université Lille Nord de France, Biology and Diversity of Emerging Eukaryotic Pathogens, Lille cedex, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Viscogliosi
authors.affiliation: Institut Pasteur de Lille, Centre d'Infection et d'Immunité de Lille, Inserm U1019, CNRS UMR 8204, Université Lille Nord de France, Biology and Diversity of Emerging Eukaryotic Pathogens, Lille cedex, France and Microbe Division/Japan Collection of Microorganisms, RIKEN BioResource Center 3-1-1 Koyadai, Tsukuba-shi, Ibaraki, Japan.
authors.forename: Meloni
authors.initials: M
authors.lastname: Dionigia
authors.affiliation: Clermont Université, Université Blaise Pascal, Laboratoire Microorganismes, Génome et Environnement, Clermont-Ferrand and CNRS, UMR 6023, LMGE, Aubière, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Texier
authors.affiliation: Clermont Université, Université Blaise Pascal, Laboratoire Microorganismes, Génome et Environnement, Clermont-Ferrand and CNRS, UMR 6023, LMGE, Aubière, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Delbac
authors.affiliation: CNRS, UMR 6023, LMGE, F-63177 Aubière, France.
authors.forename: Hicham El
authors.initials: HE
authors.lastname: Alaoui
keywords: Blastocystis; diagnosis; gut; pathogenesis; subtypes