HTLV-I/II e doadores de sangue: determinantes associados à soropositividade em população de baixo risco

OBJECTIVE: Blood donors in Brazil have been routinely screened for HTLV-I/II since 1993. A study was performed to estimate the prevalence of HTLV-I/II infection in a low risk population and to better understand determinants associated with seropositivity. METHODS: HTLV-I/II seropositive (n=135), indeterminate (n=167) and seronegative blood donors (n=116) were enrolled in an open prevalence prospective cohort study. A cross-sectional epidemiological study of positive, indeterminate and seronegative HTLV-I/II subjects was conducted to assess behavioral and environmental risk factors for seropositivity. HTLV-I/II serological status was confirmed using enzyme-linked immunosorbent assay (EIA) and Western blot (WB). RESULTS: The three groups were not homogeneous. HTLV-I/II seropositivity was associated to past blood transfusion and years of schooling, a marker of socioeconomic status, and use of non-intravenous illegal drugs. CONCLUSIONS: The study results reinforce the importance of continuous monitoring and improvement of blood donor selection process.OBJETIVO: Doadores de sangue no Brasil têm sido avaliados sorologicamente para o HTLV-I/II desde 1993. Assim, realizou-se estudo para estimar a prevalência dessa infecção em população de baixo risco e para melhor compreender os determinantes associados à soropositividade. MÉTODOS: Doadores de sangue soropositivos (n=135), soroindeterminados (n=167) e soronegativos (n=116) foram arrolados como participantes de uma coorte aberta e prevalente. Estudo transversal dos participantes desses três grupos avaliou fatores de risco comportamentais e ambientais para soropositividade. O status sorológico foi definido usando a reação de EIA (enzyme linked immunosorbent assay) e o teste Western blot (WB). RESULTADOS: Os três grupos apresentaram heterogeneidade entre si. A soropositividade mostrou-se associada à história pregressa de transfusão de sangue, em nível educacional, como um marcador de condição socioeconômica e ao uso de drogas ilegais não endovenosas. CONCLUSÕES: Os resultados confirmam a importância de um monitoramento e refinamento do processo de seleção dos doadores de sangue

Núcleos familiares infectados pelo vírus linfotrópico decélulas T humanas: determinantes epidemiológicos e genéticos (Belo Horizonte, 1997-2005)

Exportado OPUSMade available in DSpace on 2019-08-12T19:43:54Z (GMT). No. of bitstreams: 1 bernadette_correa_catalan_soares.pdf: 4253277 bytes, checksum: 9aa77251caefa647e07aaf0af5671fce (MD5) Previous issue date: 10A revisão da Epidemiologia global do HTLV-I nos permitiu avaliar onde estamos em relação a vários aspectos concernentes ao vírus. Se estamos cientes da sua distribuição geográfica, com tendência à formação de aglomerados, se já compreendemos bem as formas detransmissão e doenças claramente a ele associadas (leucemia de células T do adulto e mielopatia associada ao HTLV), muito nos falta caminhar na busca de esclarecimentos sobre o papel do vírus em outras possíveis patologias, sobre os mecanismos patogenéticos e sobre os fatores de risco / proteção que pudessem explicar porque a grande maioria dos infectados permanece assintomática. As altas taxas de prevalência encontradas no estudo de familiares e parceiros sexuais estáveis de infectados sugerem agregação familiar da infecção, motivando-nos a buscar outros fatores de risco (genéticos? Ambientais?) para a infecção. Também nos alertam sobre a importânciade se pesquisar a infecção em pessoas relacionadas aos infectados (mesmo assintomáticos), a fim de deter a disseminação silenciosa do vírus. O tipo II do HTLV é menos prevalente que o tipo I, mas é encontrado com maior freqüência em populações específicas (usuários de drogas injetáveis e populações nativas das Américas). Ter encontrado uma família HTLV-II em meio a uma coorte de doadores de sangue soropositivos, nos impulsionou os estudos moleculares que apontaram a evidência de transmissão vertical e horizontal na mesma família. Essas formas de transmissão são bem caracterizadas para o tipo I, mas ainda controversas para o tipo II, segundo alguns autores.A questão mais desafiadora para pesquisadores do HTLV-I/II continua sendo o porquê a maioria dos infectados persiste como portadora assintomática. Autores japoneses apontam a possibilidade de que essa explicação resida na eficiência da resposta imune de cada indivíduo, resposta essa condicionada pelos genes HLA (antígenos leucocitários humanos). Com a tipagem HLA de famílias infectadas pelo vírus, percebemos que existem semelhanças e diferenças entre os resultados japoneses e brasileiros, sugerindo que os alelos HLA nãocontrolam isoladamente o desfecho nos infectados. Desde que não há tratamento para as doenças associadas ao HTLV e uma vacina não está disponível, o custo social e financeiro para o indivíduo, sua família e o sistema é imenso. Por essa razão, intervenções em saúde pública direcionadas para aconselhamento e educação de indivíduos e populações em alto risco são de fundamental importância.The review of epidemiologic aspects of human T-lymphotropic virus type I let us to assess where we are. We know well about the geographic distribution of the virus and its trend to clustering; we understood the major modes of transmission and the HTLVs causative role in major disease association (adult T cell leukemia-ATL and HTLV associated myelopathy- TSP/HAM). But we still have a long way to run in search of other answers and more and better studies are needed for other apparent disease outcomes, to clarify pathogenesis and on the promoting / inhibition factors that could explain why the great majority of infected subjects remains health carriers. The high prevalence rates found in the family studies point to family aggregation of infection, leading us to look for other distant factors (environmental? genetic?) that could contribute to this, and underline the importance of screening test for infected individual relatives and sexual partner, in order to detain HTLV silent dissemination. HTLV type II is less prevalent than type I in Brazil, but is often found among UDI and American native population. We found a family infected with HTLV-ll among a seropositive former blood donors cohort and this challenge us to molecular studies. The results point tovertical and horizontal transmission of the virus. These modes of transmission are well defined to HTLV-I but some doubts persist for type II, according some researches. The major question related to HTLV keeps going why the great majority remains as health carriers. Japanese researches report the importance of the individual immune responseconditioning the outcome in infected people. Since the efficiency of the immune answer is established by the HLA alleles, we decide to type some infected families. There were found similarities and differences among Japanese and Brazilian studies, and these results suggestHLA alleles could not control alone the disease outcome in the infected individuals. Since there is not curative treatment of ATL and HAM/TSP and a vaccine is unavailable, the social and financial cost for the individual, his/her family and the health system is immense. For this reason, public health interventions aimed at counseling and educating high riskindividuals and populations are of paramount importance

Vírus-T linfotrópico humano em familiares de candidatos a doação de sangue soropositivos: disseminação silenciosa Human T-cell lymphotropic virus in family members of seropositive blood donors: silent dissemination

OBJETIVO: Verificar a ocorrência de transmissão do vírus-T linfotrópico humano entre familiares de portadores assintomáticos, identificados por ocasião de doação de sangue; e avaliar a provável direção da transmissão em parceiros sexuais com o mesmo diagnóstico sorológico (concordantes). MÉTODOS: Entre março de 1997 e junho de 2003 foram estudados familiares e parceiros sexuais estáveis de doadores de sangue soropositivos (e assintomáticos) para o vírus-T linfotrópico humano dos tipos I e II. O diagnóstico foi obtido pelos testes imunoenzimático e Western blot. Para determinar a direção da transmissão, foram coletados, através de um questionário, dados demográficos e comportamentais. Os participantes do estudo residiam na região metropolitana de Belo Horizonte, capital do Estado de Minas Gerais. RESULTADOS: A soroprevalência geral para o vírus-T linfotrópico humano do tipo I foi de 25,9% entre 352 familiares de 343 pacientes soropositivos (334 positivos para o tipo I e 9 positivos para o tipo II). Em mães, parceiros sexuais e filhos de doadores soropositivos a prevalência foi de 36,6% (15/41), 35,9% (42/117) e 17,5% (34/194), respectivamente. Os dados obtidos acerca de fatores de risco indicaram maior eficiência de transmissão no sentido do homem para a mulher. CONCLUSÕES: As taxas de prevalência sugerem agregação familiar da infecção por vírus-T linfotrópico humano. A transmissão se deu principalmente por via sexual (horizontal). Deve-se avaliar a presença do vírus em pessoas relacionadas a indivíduos infectados, mesmo se assintomáticos, para melhor compreensão da transmissão e implementação de medidas mais eficazes de prevenção contra a disseminação do vírus.<br>OBJECTIVE: To investigate human T-cell lymphotropic virus transmission among family members of asymptomatic carriers identified through blood donor screening tests; and to determine the most likely direction of transmission in sexual partners having the same (concordant) serological diagnosis. METHODS: Between March 1997 and June 2003 the relatives and steady sexual partners of seropositive, asymptomatic blood donors were investigated for the presence of human T-cell lymphotropic virus types I and II. Diagnosis was based on enzyme-linked immunoassay and Western blot. To determine the direction of transmission, demographic and behavioral data were obtained through questionnaires. All participants lived in the metropolitan region of Belo Horizonte, capital of the state of Minas Gerais, Brazil. RESULTS: The overall prevalence of infection with human T-cell lymphotropic virus type I was 25.9% among 352 relatives of 343 seropositive patients. The prevalence rates in mothers, sexual partners, and children of seropositive donors were 36.6% (15/41), 35.9% (42/117), and 17.5% (34/194), respectively. The demographic and behavioral data obtained suggest greater efficiency of male-to- female transmission. CONCLUSIONS: The observed prevalence rates suggest there is familial aggregation of human T-cell lymphotropic virus infection. The main transmission mode was horizontal (sexual). It is important to identify the presence of the virus in family members of infected individuals, even if they are asymptomatic. Doing so may lead to a better understanding of how the virus spreads and to more efficient measures for preventing disease transmission

HTLV-I/II and blood donors: determinants associated with seropositivity in a low risk population

OBJECTIVE: Blood donors in Brazil have been routinely screened for HTLV-I/II since 1993. A study was performed to estimate the prevalence of HTLV-I/II infection in a low risk population and to better understand determinants associated with seropositivity. METHODS: HTLV-I/II seropositive (n=135), indeterminate (n=167) and seronegative blood donors (n=116) were enrolled in an open prevalence prospective cohort study. A cross-sectional epidemiological study of positive, indeterminate and seronegative HTLV-I/II subjects was conducted to assess behavioral and environmental risk factors for seropositivity. HTLV-I/II serological status was confirmed using enzyme-linked immunosorbent assay (EIA) and Western blot (WB). RESULTS: The three groups were not homogeneous. HTLV-I/II seropositivity was associated to past blood transfusion and years of schooling, a marker of socioeconomic status, and use of non-intravenous illegal drugs. CONCLUSIONS: The study results reinforce the importance of continuous monitoring and improvement of blood donor selection process

HTLV-I/II and blood donors: determinants associated with seropositivity in a low risk population

OBJECTIVE: Blood donors in Brazil have been routinely screened for HTLV-I/II since 1993. A study was performed to estimate the prevalence of HTLV-I/II infection in a low risk population and to better understand determinants associated with seropositivity. METHODS: HTLV-I/II seropositive (n=135), indeterminate (n=167) and seronegative blood donors (n=116) were enrolled in an open prevalence prospective cohort study. A cross-sectional epidemiological study of positive, indeterminate and seronegative HTLV-I/II subjects was conducted to assess behavioral and environmental risk factors for seropositivity. HTLV-I/II serological status was confirmed using enzyme-linked immunosorbent assay (EIA) and Western blot (WB). RESULTS: The three groups were not homogeneous. HTLV-I/II seropositivity was associated to past blood transfusion and years of schooling, a marker of socioeconomic status, and use of non-intravenous illegal drugs. CONCLUSIONS: The study results reinforce the importance of continuous monitoring and improvement of blood donor selection process

Heterogeneous geographic distribution of human T-cell lymphotropic viruses I and II (HTLV-I/II): serological screening prevalence rates in blood donors from large urban areas in Brazil

Brazil may have the highest absolute number of HTLV-I/II seropositive individuals in the world. Screening potential blood donors for HTLV-I/II is mandatory in Brazil. The public blood center network accounts for about 80.0% of all blood collected. We conducted a cross-sectional study to assess the geographic distribution of HTLV-I/II serological screening prevalence rates in blood donors from 27 large urban areas in the various States of Brazil, from 1995 to 2000. Enzyme immunoassay (EIA) was used to test for HTLV-I/II. The mean prevalence rates ranged from 0.4/1,000 in Florianópolis, capital of Santa Catarina State, in the South, to 10.0/1,000 in São Luiz, Maranhão State, in the Northeast. EIA prevalence rates are lower in the South and higher in the North and Northeast. The reasons for such heterogeneity may be multiple and need further studies

Global epidemiology of HTLV-I infection and associated diseases.

Epidemiologic aspects of human T-lymphotropic virus type I (HTLV-I) infection have been thoroughly studied over the course of approximately 25 years since its first description. The geographic distribution of the virus has been defined, with Japan, Africa, Caribbean islands and South America emerging as the areas of highest prevalence. The reasons for HTLV-I clustering, such as the high ubiquity in southwestern Japan but low prevalence in neighboring regions of Korea, China and eastern Russia are still unknown. The major modes of transmission are well understood, although better quantitative data on the incidence of transmission, and on promoting/inhibiting factors, are needed. Epidemiologic proof has been obtained for HTLV-I's causative role in major disease associations: adult T-cell leukemia (ATL), HTLV-associated myelopathy/tropical spastic paraparesis (HAM/TSP), HTLV-associated uveitis and infective dermatitis. However, more and better studies are needed for other apparent disease outcomes such as rheumatologic, psychiatric and infectious diseases. Since curative treatment of ATL and HAM/TSP is lacking and a vaccine is unavailable, the social and financial cost for the individual, his/her family and the health system is immense. For this reason, public health interventions aimed at counseling and educating high-risk individuals and populations are of paramount importance