title: Incidence of human T cell lymphotropic virus type 1-associated myelopathy/tropical spastic paraparesis in a long-term prospective cohort study of initially asymptomatic individuals in Brazil.
abstract: The incidence of human T cell lymphotropic virus type 1 (HLTV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is not well defined in the literature. Several studies have reported different incidence rates, and recent publications suggest a higher incidence and prevalence of HAM/TSP. The interdisciplinary HTLV Research Group (GIPH) is a prospective open cohort study of individuals infected with HTLV-1/2. This study describes the demographic data and HAM/TSP incidence rate observed in 181 HTLV-1-seropositive individuals and compares the results with previous reports in the literature. HAM/TSP was diagnosed on the basis of the World Health Organization diagnostic criteria and De Castro-Costa et al. [Proposal for diagnostic criteria of tropical spastic paraparesis/HTLV-I-associated myelopathy (TSP/HAM). AIDS Res Hum Retroviruses 2006;22:931-935]. Seven HAM/TSP incident cases were observed during the follow-up. The HAM/TSP incidence density was 5.3 cases per 1,000 HTLV-1-seropositive cases per year (95% confidence interval: 2.6-10.9), with a mean follow-up of 7±4 years (range: 1 month to 15 years). HAM/TSP was more frequent in women in their 40s and 50s with probable infection via the sexual route. The HAM/TSP incidence density among HTLV-1-seropositive cases observed in the present study is higher than that in previous studies. HAM/TSP may be underdiagnosed in countries like Brazil where HTLV infection is prevalent. Orientation and prevent transmission of HTLV programs are needed. Currently, preventing HTLV-1 transmission is the most effective way to reduce the impact of HAM/TSP on society.
authors.affiliation: Fundação Hemominas, Belo Horizonte-Minas Gerais, Brazil. lcfromanelli@yahoo.com.br
authors.forename: Luiz Cláudio Ferreira
authors.initials: LC
authors.lastname: Romanelli
authors.forename: Paulo
authors.initials: P
authors.lastname: Caramelli
authors.forename: Marina Lobato
authors.initials: ML
authors.lastname: Martins
authors.forename: Denise Utsch
authors.initials: DU
authors.lastname: Gonçalves
authors.forename: Fernando Augusto
authors.initials: FA
authors.lastname: Proietti
authors.forename: João Gabriel Ramos
authors.initials: JG
authors.lastname: Ribas
authors.forename: Marcelo Grossi
authors.initials: MG
authors.lastname: Araújo
authors.forename: Anna Bárbara de Freitas
authors.initials: AB
authors.lastname: Carneiro-Proietti
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D058070:Asymptomatic Diseases / Q000453:epidemiology*; D001938:Brazil / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D015490:HTLV-I Infections / Q000097:blood / Q000453:epidemiology* / Q000209:etiology; D015368:Human T-lymphotropic virus 1; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015493:Paraparesis, Tropical Spastic / Q000150:complications / Q000453:epidemiology* / Q000821:virology; D011446:Prospective Studies; D055815:Young Adult