title: Identification of an atypical strain of toxoplasma gondii as the cause of a waterborne outbreak of toxoplasmosis in Santa Isabel do Ivai, Brazil.
abstract: Multilocus DNA sequencing has identified a nonarchetypal strain of Toxoplasma gondii as the causal agent of a waterborne outbreak in Brazil in 2001. The strain, isolated from a water supply epidemiologically linked to the outbreak, was virulent to mice, and it has previously been identified as BrI. Using a serologic assay that detects strain-specific antibodies, we found that 13 (65%) of 20 individuals who were immunoglobulin (Ig) M positive during the outbreak possessed the same serotype as mice infected with the purported epidemic strain. The remaining 7 individuals, plus additional IgM-negative, IgG-positive individuals, possessed 1 of 4 novel serotypes, the most common of which matched the serotype of mice infected with strains isolated from chickens foraging near the outbreak site. The latter strains likely reflect the genetic diversity of T. gondii circulating in highly endemic regions of Brazil. The serotyping assay proved a useful tool for identification of specific individuals infected with the outbreak agent.
authors.affiliation: Jules Gonin Eye Hospital and the Department of Ophthalmology, University of Lausanne, Lausanne, Switzerland.
authors.forename: Jean D
authors.initials: JD
authors.lastname: Vaudaux
authors.forename: Cristina
authors.initials: C
authors.lastname: Muccioli
authors.forename: Erick R
authors.initials: ER
authors.lastname: James
authors.forename: Claudio
authors.initials: C
authors.lastname: Silveira
authors.forename: Spencer L
authors.initials: SL
authors.lastname: Magargal
authors.forename: Calvin
authors.initials: C
authors.lastname: Jung
authors.forename: J P
authors.initials: JP
authors.lastname: Dubey
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Jones
authors.forename: Mehmet Z
authors.initials: MZ
authors.lastname: Doymaz
authors.forename: David A
authors.initials: DA
authors.lastname: Bruckner
authors.forename: Rubens
authors.initials: R
authors.lastname: Belfort
authors.forename: Gary N
authors.initials: GN
authors.lastname: Holland
authors.forename: Michael E
authors.initials: ME
authors.lastname: Grigg
mesh_terms: D000818:Animals; D001938:Brazil / Q000453:epidemiology; D004196:Disease Outbreaks; D004797:Enzyme-Linked Immunosorbent Assay; D005838:Genotype; D006801:Humans; D051379:Mice; D012703:Serotyping; D013045:Species Specificity; D014122:Toxoplasma / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D014123:Toxoplasmosis / Q000453:epidemiology* / Q000469:parasitology*; D014871:Water Microbiology