title: A cross-sectional study on the clinical and immunological spectrum of human Leishmania (L.) infantum chagasi infection in the Brazilian Amazon region.
abstract: The objectives of this study were to identify individuals with symptomatic and/or asymptomatic infection due to Leishmania (L.) infantum chagasi; to study the two types of infection, both clinically and immunologically, and to determine the prevalence rate of infection at the beginning of the study. This was a cross-sectional study with a cohort of 946 individuals, of both genders, from the age of 1 year, living in the municipality of Barcarena, PA, Brazil, an area endemic for American visceral leishmaniasis (AVL). The leishmanin skin test (LST) and the indirect fluorescent test (IFAT), were used for the diagnosis of infection. One hundred and twenty cases of infection were diagnosed, with a prevalence rate of 12.6%; eight cases showed high seroreactivity (1280-10240, IgG) in IFAT and no LST reaction; four of these cases were typical AVL and four had subclinical oligosymptomatic infection. Using two immunological methods with a clinical examination of the infected individuals enabled the identification of five clinical-immunological profiles which may promote a better understanding of the interaction between L. (L.) i. chagasi and the human immune response: asymptomatic infection (AI) 73.4%; subclinical resistant infection (SRI) 15%; subclinical oligosymptomatic infection (SOI) 3%; symptomatic infection (AVL) 3% and indeterminate initial infection (III) 5%.
authors.affiliation: Tropical Medicine Institute, Pará Federal University, Belém, PA, Brazil.
authors.forename: José Angelo B
authors.initials: JA
authors.lastname: Crescente
authors.forename: Fernando T
authors.initials: FT
authors.lastname: Silveira
authors.forename: Ralph
authors.initials: R
authors.lastname: Lainson
authors.forename: Claudia M C
authors.initials: CM
authors.lastname: Gomes
authors.forename: Márcia D
authors.initials: MD
authors.lastname: Laurenti
authors.forename: Carlos E P
authors.initials: CE
authors.lastname: Corbett
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001938:Brazil / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007223:Infant; D018314:Leishmania infantum / Q000276:immunology / Q000302:isolation & purification*; D007898:Leishmaniasis, Visceral / Q000175:diagnosis / Q000453:epidemiology / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012882:Skin Tests / Q000379:methods; D055815:Young Adult