title: Risk factors for Toxocara spp. seroprevalence and its association with atopy and asthma phenotypes in school-age children in a small town and semi-rural areas of Northeast Brazil.
abstract: Toxocara canis, Toxocara cati, are roundworms that live in the intestines of dogs and cats, respectively, and are predominantly agents of human toxocariasis. Studies have suggested that Toxocara spp. seroprevalence increases levels of total and aeroallergen-specific IgE (sIgE), asthma prevalence and asthma morbidity. Nevertheless, other work reported a negative association between Toxocara spp. seropositivity with skin hypersensititity and a positive association with sIgE. The objective of the present study was to evaluate risk factors for acquiring Toxocara spp. infection and to investigate possible significant association between its seroprevalence with atopy and asthma. Students from elementary schools, residents in a small town and its surroundings of Northeast Brazil, underwent blood sampling to measure levels of anti-Toxocara spp. IgG, peripheral blood eosinophils, and specific IgE to aeroallergens. We used univariable and multivariable logistic regression analyses to assess possible risk factors for Toxocara spp. seropositivity and its association with atopy, wheeze/asthma with asthma phenotypes, in a sample of 791 elementary school children aged 6-13 years. Toxocara spp. seroprevalence reached 63.6%; 49.9% had sIgE; 7.2% and 3.3% had atopic wheeze/asthma and non-atopic wheeze/asthma respectively. Risk factors associated with Toxocara spp. seropositivity were: contact with dogs (adj. OR 2.33; 95% CI=1.70-3.19) and cats (adj. OR 3.09; 95% CI=2.10-4.55), and male sex (adj. OR 2.21; 95% CI=1.62-3.02). The presence of anti-Toxocara IgG was statistically associated with blood eosinophils >4% and >10% (adj. OR 1.84; 95% CI=1.33-2.55 and adj. OR 2.07; 95% CI=1.45-2.97, respectively), and atopy (adj. OR 2.00; 95% CI=1.49-2.68), but it was not associated with wheeze/asthma. Concluding, the results obtained in this study showing the association of Toxocara spp. seroprevalence with sIgE may suggest a possible immunological cross-reactivity between IgE epitopes from Toxocara spp. and aeroallergens.
authors.affiliation: Instituto de Ciências da Saúde, Universidade Federal da Bahia, Salvador, Bahia, Brazil. Electronic address: marciasilva25j@yahoo.com.br.
authors.forename: Márcia B
authors.initials: MB
authors.lastname: Silva
authors.affiliation: Centro de Ciências da Saúde. Universidade Federal do Recôncavo da Bahia, Santo Antônio de Jesus, Bahia, Brazil. Electronic address: ana_moreno22@yahoo.com.br.
authors.forename: Ana L M
authors.initials: ALM
authors.lastname: Amor
authors.affiliation: Instituto de Ciências da Saúde, Universidade Federal da Bahia, Salvador, Bahia, Brazil. Electronic address: nsleo@yahoo.com.br.
authors.forename: Leonardo N
authors.initials: LN
authors.lastname: Santos
authors.affiliation: Instituto de Ciências da Saúde, Universidade Federal da Bahia, Salvador, Bahia, Brazil. Electronic address: alana_alcantara@hotmail.com.
authors.forename: Alana A
authors.initials: AA
authors.lastname: Galvão
authors.affiliation: Escola de Nutrição, Universidade Federal da Bahia, Salvador, Brazil. Electronic address: oviv1@yahoo.br.
authors.forename: Aida V
authors.initials: AV
authors.lastname: Oviedo Vera
authors.affiliation: Instituto de Ciências da Saúde, Universidade Federal da Bahia, Salvador, Bahia, Brazil. Electronic address: eduardossilva06@gmail.com.
authors.forename: Eduardo S
authors.initials: ES
authors.lastname: Silva
authors.affiliation: Faculdade de Farmácia, Universidade Federal da Bahia, Salvador, Bahia, Brazil. Electronic address: cynara.barbosa@gmail.com.
authors.forename: Cynara Gomes
authors.initials: CG
authors.lastname: Barbosa
authors.affiliation: Faculdade de Farmácia, Universidade Federal da Bahia, Salvador, Bahia, Brazil; Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil. Electronic address: mari@bahia.fiocruz.br.
authors.forename: Marilda S
authors.initials: MS
authors.lastname: Gonçalves
authors.affiliation: Centro de Investigación en Enfermedades Infecciosas, Pontificia Universidad Católica del Ecuador, Quito, Ecuador; St George's University of London, Division of Clinical Sciences, Cranmer Terrace, London SW17 ORE, UK. Electronic address: pcooper@sgul.ac.uk.
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Cooper
authors.affiliation: Instituto de Ciências da Saúde, Universidade Federal da Bahia, Salvador, Bahia, Brazil. Electronic address: cavfigueiredo@gmail.com.
authors.forename: Camila A
authors.initials: CA
authors.lastname: Figueiredo
authors.affiliation: Escola de Nutrição, Universidade Federal da Bahia, Salvador, Brazil. Electronic address: ritaribeiroufba@gmail.com.
authors.forename: Rita de Cassia
authors.initials: RC
authors.lastname: Ribeiro
authors.affiliation: Instituto de Ciências da Saúde, Universidade Federal da Bahia, Salvador, Bahia, Brazil. Electronic address: neuzalcantara@gmail.com.
authors.forename: Neuza Maria
authors.initials: NM
authors.lastname: Alcântara-Neves
mesh_terms: D000293:Adolescent; D000818:Animals; D000909:Antibodies, Helminth / Q000097:blood*; D001249:Asthma / Q000453:epidemiology*; D001938:Brazil / Q000453:epidemiology; D002415:Cats; D002648:Child; D004285:Dogs; D005260:Female; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000453:epidemiology*; D008297:Male; D015995:Prevalence; D012307:Risk Factors; D012424:Rural Population / Q000706:statistics & numerical data; D012574:Schools / Q000706:statistics & numerical data; D016036:Seroepidemiologic Studies; D013334:Students / Q000706:statistics & numerical data; D014119:Toxocara / Q000302:isolation & purification*; D014120:Toxocariasis / Q000453:epidemiology* / Q000276:immunology*
chemical_list: D000909:Antibodies, Helminth
keywords: Asthma; Atopy; Risk factors; Specific IgE; Toxocariasis