title: Lausannevirus seroprevalence among asymptomatic young adults.
abstract: OBJECTIVE
  The giant Lausannevirus was recently identified as a parasite of amoeba that replicates rapidly in these professional phagocytes. This study aimed at assessing Lausannevirus seroprevalence among asymptomatic young men in Switzerland and hopefully identifying possible sources of contact with this giant virus.
  
  
  METHODS
  The presence of anti-Lausannevirus antibodies was assessed in sera from 517 asymptomatic volunteers who filled a detailed questionnaire. The coreactivity between Lausannevirus and amoeba-resisting bacteria was assessed.
  
  
  RESULTS
  Lausannevirus prevalence ranged from 1.74 to 2.51%. Sporadic condom use or multiple sexual partners, although frequent (53.97 and 60.35%, respectively), were not associated with anti-Lausannevirus antibodies. On the contrary, frequent outdoor sport practice as well as milk consumption were significantly associated with positive Lausannevirus serologies (p = 0.0066 and 0.028, respectively). Coreactivity analyses revealed an association between Criblamydia sequanensis (an amoeba-resisting bacterium present in water environments) and Lausannevirus seropositivity (p = 0.001).
  
  
  CONCLUSIONS
  Lausannevirus seroprevalence is low in asymptomatic Swiss men. However, the association between virus seropositivity and frequent sport practice suggests that this member of the Megavirales may be transmitted by aerosols and/or exposure to specific outdoor environments. Milk intake was also associated with seropositivity. Whether the coreactivity observed for C. sequanensis and Lausannevirus reflects a common mode of acquisition or some unexpected cross-reactivity remains to be determined.
authors.affiliation: Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland.
authors.forename: Linda
authors.initials: L
authors.lastname: Mueller
authors.forename: David
authors.initials: D
authors.lastname: Baud
authors.forename: Claire
authors.initials: C
authors.lastname: Bertelli
authors.forename: Gilbert
authors.initials: G
authors.lastname: Greub
mesh_terms: D000293:Adolescent; D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood*; D002695:Chlamydiales / Q000276:immunology; D004266:DNA Virus Infections / Q000453:epidemiology* / Q000821:virology; D004267:DNA Viruses / Q000276:immunology*; D005247:Feeding Behavior; D064368:Healthy Volunteers; D006801:Humans; D008019:Life Style; D008297:Male; D012307:Risk Factors; D016036:Seroepidemiologic Studies; D013557:Switzerland / Q000453:epidemiology; D055815:Young Adult
chemical_list: D000907:Antibodies, Bacterial; D000914:Antibodies, Viral