title: Toxoplasma gondii seroprevalence in the Portuguese population: comparison of three cross-sectional studies spanning three decades.
abstract: Toxoplasma gondii is an obligate intracellular protozoan infecting up to one-third of the world's population, constituting a life threat if transmitted from mother to child during pregnancy. In Portugal, there is a lack of knowledge of the current epidemiological situation, as the unique toxoplasmosis National Serological Survey was performed in 1979/1980.
  
  
  
  We studied the seroprevalence trends in the Portuguese general population over the past 3 decades, by assessing chronological spread cross-sectional studies, with special focus on women of childbearing age, by age group, region and gender.
  
  
  
  The T. gondii overall seroprevalence decreased from 47% in 1979/1980 to 22% (95% CI 20% to 24%) in 2013. Generally, we observed that the prevalence of T. gondii IgG increased significantly with age and it decreased over time, both in the general population and in the childbearing women (18% prevalence in 2013).
  
  
  
  The scenario observed for the latter indicates that more than 80% of childbearing women are susceptible to primary infection yielding a risk of congenital toxoplasmosis and respective sequelae. Since there is no vaccine to prevent human toxoplasmosis, the improvement of primary prevention constitutes a major tool to avoid infection in such susceptible groups.
authors.affiliation: National Reference Laboratory of Parasitic and Fungal Infections, National Institute of Health, Lisbon, Portugal.
authors.forename: Maria João
authors.initials: MJ
authors.lastname: Gargaté
authors.affiliation: National Reference Laboratory of Parasitic and Fungal Infections, National Institute of Health, Lisbon, Portugal.
authors.forename: Idalina
authors.initials: I
authors.lastname: Ferreira
authors.affiliation: National Reference Laboratory of Parasitic and Fungal Infections, National Institute of Health, Lisbon, Portugal.
authors.forename: Anabela
authors.initials: A
authors.lastname: Vilares
authors.affiliation: National Reference Laboratory of Parasitic and Fungal Infections, National Institute of Health, Lisbon, Portugal.
authors.forename: Susana
authors.initials: S
authors.lastname: Martins
authors.affiliation: Clinical laboratory Dr. Joaquim Chaves, Lisbon, Portugal.
authors.forename: Carlos
authors.initials: C
authors.lastname: Cardoso
authors.affiliation: Department of Epidemiology, National Institute of Health, Lisbon, Portugal.
authors.forename: Susana
authors.initials: S
authors.lastname: Silva
authors.affiliation: Department of Epidemiology, National Institute of Health, Lisbon, Portugal.
authors.forename: Baltazar
authors.initials: B
authors.lastname: Nunes
authors.affiliation: Department of Infectious Diseases, National Institute of Health, Lisbon, Portugal.
authors.forename: João Paulo
authors.initials: JP
authors.lastname: Gomes
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007074:Immunoglobulin G; D007223:Infant; D008297:Male; D008875:Middle Aged; D011174:Portugal / Q000453:epidemiology; D011247:Pregnancy; D015995:Prevalence; D016036:Seroepidemiologic Studies; D014122:Toxoplasma / Q000302:isolation & purification*; D014123:Toxoplasmosis / Q000453:epidemiology*; D055815:Young Adult
chemical_list: D007074:Immunoglobulin G
keywords: EPIDEMIOLOGY; INFECTIOUS DISEASES; PARASITOLOGY