title: Looking at protists as a source of pathogenic viruses.
abstract: In the environment, protozoa are predators of bacteria and feed on them. The possibility that some protozoa could be a source of human pathogens is consistent with the discovery that free-living amoebae were the reservoir of Legionella pneumophila, the agent of Legionnaires' disease. Later, while searching for Legionella in the environment using amoeba co-culture, the first giant virus, Acanthamoeba polyphaga mimivirus, was discovered. Since then, many other giant viruses have been isolated, including Marseilleviridae, Pithovirus sibericum, Cafeteria roenbergensis virus and Pandoravirus spp. The methods used to isolate all of these viruses are herein reviewed. By analogy to Legionella, it was originally suspected that these viruses could be human pathogens. After showing by indirect evidence, such as sero-epidemiologic studies, that it was possible for these viruses to be human pathogens, the recent isolation of some of these viruses (belonging to the Mimiviridae and Marseilleviridae families) in humans in the context of pathologic conditions shows that they are opportunistic human pathogens in some instances.
authors.affiliation: Aix-Marseille University, Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes (URMITE), UM63, CNRS 7278, IRD 198, INSERM U1095, Facultés de Médecine et de Pharmacie, Marseille, France; Institut Hospitalo-Universitaire (IHU) Méditerranée Infection, Pôle des Maladies Infectieuses et Tropicales Clinique et Biologique, Fédération de Bactériologie-Hygiène-Virologie, Centre Hospitalo-Universitaire Timone, Assistance Publique, Hôpitaux de Marseille, Marseille, France. Electronic address: bernard.lascola@univ-amu.fr.
authors.forename: Bernard
authors.initials: B
authors.lastname: La Scola
mesh_terms: D000656:Amoeba / Q000821:virology*; D004266:DNA Virus Infections / Q000821:virology; D004267:DNA Viruses / Q000302:isolation & purification*; D006801:Humans; D009894:Opportunistic Infections / Q000821:virology
keywords: Giant virus; Marseillevirus; Mimivirus; NCLDV; Protozoa