ABSTRACT Background The recognition of the causal association between Zika virus (ZIKV) infection during pregnancy and congenital abnormalities including microcephaly underlines the importance of preventing this disease in pregnant women (PW) and women of childbearing age (WCA). Although Brazil and other Latin American countries reported a significant reduction in the number of ZIKV infections in recent years, epidemic waves can recur in settings with previous outbreaks as conditions for transmission remain optimal and susceptible populations are continuously replenished. Methods: In this cross-sectional study, we enrolled 64 PW and 260 non-pregnant WCA attending routine medical appointments in two primary care units in São Paulo, Brazil, and assessed knowledge and attitudes about ZIKV infection and prevention. Results: Most women reported knowing that ZIKV is transmitted through the bite of Aedes mosquitos, and most knew that acute symptoms are similar to those seen in Dengue infection. Furthermore, most participants correctly described that ZIKV infection during pregnancy may cause detrimental outcomes for the newborn. However, most ignored that ZIKV infection can be asymptomatic, and only 15% knew about the risk of ZIKV sexual transmission. We found no statistically significant differences between PW and WCA regarding knowledge about ZIKV sexual transmission. Knowledge about ZIKV sexual transmission was significantly associated with education; among participants with ≤12 schooling years, only 9.0% (95%CI 3.4-18.5%) correctly answered that ZIKV can be sexually transmitted, compared to 12.9% (95%CI 8.2-18.8%) among participants with 12-14 schooling years, and to 24.4% (95%CI 15.9-34.9%) of participants with ≥15 schooling years (p = 0.015). Education remained independently associated with knowledge about sexual transmission of ZIKV in a multivariate logistic regression model adjusted for age, race and pregnancy status (p = 0.022). Conclusion: Our findings underscore the urgent need of educational and family planning programs that may help prevent detrimental outcomes of ZIKV infection in an endemic area of Brazil.

ABSTRACT Background: Test-seeking is associated with HIV in Brazilian blood donors. This study sought to investigate the frequency with which three different donor groups: deferred donors, accepted donors who tested HIV positive [HIV (+)], and accepted donors who tested infectious disease markers negative [IDM (−)], came to the blood bank at the suggestion of a health care professional. Study design and methods: Donors deferred for reporting high-risk behaviors and participants in an HIV risk factor case-control study completed a confidential audio computer-assisted self-interview (ACASI) that included two questions related to health care professionals and test-seeking. Results: Of 4013 enrolled deferred donors, 468 (11.8%) reported a health care professional suggested donation as a way to be tested for infection. Of 341 HIV (+) and 791 IDM (−) participants, 43 (12.6%) and 11 (1.4%), respectively, reported a health care professional suggested donation as a way to be tested for infection. Physicians were the most frequently reported source of referral: [(61.5% of deferred, 69.1% of HIV (+), and 9.1% of IDM (−) donors)]. Conclusion: HIV (+) donors and deferred donors were 10 times more likely to report test-seeking behavior by suggestion of health care professional than IDM (−) donors. If true, efforts should be made to educate health care professionals and blood donors on how to safeguard the blood supply, emphasizing that HIV testing should be done at volunteer testing centers rather than at the blood centers.

O eritrovírus infecta células precursoras eritroides, determinando a interrupção temporária da eritropoese. Neste contexto, é importante o conhecimento das principais doenças hematológicas que podem estar associadas à presença do vírus, principalmente quando estão presentes em condições mórbidas, tais como nas anemias hemolíticas hereditárias. Este trabalho tem como objetivo relatar as principais doenças hematológicas que cursam com a infecção pelo eritrovírus B19.

Erythroviruses infect precursor erythroid cells, determining a temporary disruption of erythropoiesis. Thus, knowledge of the main hematological diseases that may be associated with the virus is important, especially when they are present in morbid conditions, such as in hereditary hemolytic anemia. This paper aims at reporting the main hematological diseases that are associated with erythrovirus infections.

Um vírus recentemente identificado e denominado como vírus SEN (SENV) tem sido considerado como um possível agente causador das hepatites não A-E. Trata-se de um DNA vírus de cadeia única, não-envelopado, pertencente à superfamília Circoviridae, com prevalência bastante variável em indivíduos saudáveis. Embora sua principal via de transmissão parece ser a parenteral, outras formas de transmissão não podem ser excluídas. Apesar da prevalência da infecção pelo SENV ser mais freqüente em pacientes com doenças hepáticas do que na população geral, não existem evidências comprovando que a infecção isolada por este vírus cause hepatite aguda ou que a co-infecção com os vírus das hepatites A, B ou C piore o curso da doença hepática. Em indivíduos com doença hepática preexistente não foram observadas diferenças estatisticamente significantes nos níveis de alanina aminotransferase (ALT) e nos achados histológicos hepáticos quando comparados os pacientes com e sem a infecção associada pelo vírus SEN. Diferente das infecções crônicas causadas pelos vírus B e C, a infecção pelo SENV não tem sido considerada como um fator de risco para o desenvolvimento de carcinoma hepatocelular. Finalmente, apesar da maior prevalência da infecção pelo vírus SEN em pacientes transfundidos, não existe evidência clara da relação causal entre este agente infeccioso e a hepatite pós-transfusional não A-E. Novos estudos são necessários para se definir a patogênese e a importãncia clínica da infecção pelo vírus SEN.

SENV, a new, recently-identified human virus, has been considered a possible causative agent of non-A to E hepatitis. It is a single stranded, non-enveloped DNA virus classified within the Circoviridae family. Prevalence in different populations shows great variability with differences between countries and ethnic groups. Although parenteral route is an efficient way for virus transmission, other routes of transmission cannot be excluded. The effect of SENV on acute and chronic liver diseases has been studied. In spite of the fact that the prevalence of SENV is higher among patients with hepatic disorders, there is no evidence that SENV infection is able to cause acute hepatitis or to change the clinical course of hepatitis A, B or C. There is also no evidence that alanine aminotransferase (ALT) is higher or that the histological parameters are worse in patients with hepatic disorders co-infected with SENV as compared to patients without co-infections. Unlike chronic hepatitis B Virus or Hepatitis C Virus infection, SENV infection has not been considered a risk factor for developing hepatocellular carcinoma. Finally, although it is clear that the prevalence of SENV is higher in blood transfusion recipients, there is no clear evidence that this virus is the causative agent of post-transfusion hepatitis. Further studies are needed to define the clinical importance of SENV infection.

The first description of the human T-lymphotropic virus type 1 (HTLV-1) was made in 1980, followed closely by the discovery of HTLV-2, in 1982. Since then, the main characteristics of these viruses, commonly referred to as HTLV-1/2, have been thoroughly studied. Central and South America and the Caribbean are areas of high prevalence of HTLV-1 and HTVL-2 and have clusters of infected people. The major modes of transmission have been through sexual contact, blood, and mother to child via breast-feeding. HTLV-1 is associated with adult T-cell leukemia/lymphoma (ATL), HTLV-associated myelopathy/tropical spastic paraparesis (HAM/ TSP), and HTLV-associated uveitis as well as infectious dermatitis of children. More clarification is needed in the possible role of HTLV in rheumatologic, psychiatric, and infectious diseases. Since cures for ATL and HAM/TSP are lacking and no vaccine is available to prevent HTLV-1 and HTLV-2 transmission, these illnesses impose enormous social and financial costs on infected individuals, their families, and health care systems. For this reason, public health interventions aimed at counseling and educating high-risk individuals and populations are of vital importance. In the Americas this is especially important in the areas of high prevalence.

La primera descripción del virus de la leucemia humana de células T tipo 1 (VLHT-1) se hizo en 1980, y al poco tiempo, en 1982, se descubrió el VLHT-2. Desde entonces las características principales de estos virus, a los que a menudo se les llama VLHT-1/2, se han estudiado exhaustivamente. Centroamérica, América del Sur y el Caribe son áreas con una alta prevalencia de VLHT-1 y VLHT-2 donde hay conglomerados de personas infectadas. Las principales vías de transmisión han sido el contacto sexual, la sangre y sus derivados, y la de madre a hijo por la leche materna. El VLHT-1 se asocia con la leucemia o el linfoma de células T maduras (LTM), la mielopatía o paraparesia tropical espástica ligada al VLHT (M/PTE), y la uveítis ligada al VLHT, así como con la dermatitis infecciosa de la infancia. Se necesita más información acerca del posible papel que desempeña el VLHT en la aparición de enfermedades reumáticas, psiquiátricas e infecciosas. En vista de que no se dispone de ninguna cura para la LTM ni la M/PTE, como tampoco de ninguna vacuna para prevenir la transmisión del VLHT-1 y VLHT-2, estas enfermedades acarrean enormes costos sociales y económicos para las personas infectadas, sus parientes y los sistemas de salud. Por este motivo, las intervenciones sanitarias orientadas a asesorar e instruir a personas y poblaciones en alto riesgo revisten una importancia crítica. En el continente americano esto cobra aun más importancia en zonas de alta prevalencia.

Há na literatura vários estudos filogenéticos e de distribuição de genótipos do chamado "Vírus GB-C" ou da "Hepatite G", mais conhecido pela dupla sigla "GBV-C/HGV". Ocorre que, em sua grande maioria, estas pesquisas foram realizadas com amostras de grupos ligados epidemiologicamente e não com indivíduos representativos da população geral. O presente estudo é uma continuação do primeiro trabalho no Brasil feito com este tipo de amostragem. Trata-se de análise filogenética e distribuição genotípica do GBV-C/HGV a partir de amostras isoladas dentre mais de 1.000 indivíduos da cidade de São Paulo. Para tanto, um fragmento de 728 pares de base da região 5' não-codificadora (5´NCR) do genoma viral, de 24 amostras, foi sequenciado e submetido à analise filogenética. Foram identificados os genótipos 1, 2a e 2b nas respectivas freqüências: 8,3% (2/24), 50% (12/24) e 41,7% (10/24). Concluindo, São Paulo apresenta uma distribuição de genótipos semelhante à publicada para outros estados e regiões do Brasil, endossando a idéia de que os tipos 1 e 2 teriam vindo com os africanos e europeus, respectivamente, e portanto estariam na população do país desde a sua formação.

There has been several studies worldwide on phylogenetics and genotype distribution of the GB-virus C / Hepatitis G virus (GBV-C/HGV). However, in their great majority, those investigations were based on some epidemiologically linked group, rather than on a representative sampling of the general population. The present is a continuation of the first study in Brazil with such a population; it addresses the GBV-C/HGV phylogenetics and genotype distribution based on samples identified among more than 1,000 individuals of the city of São Paulo. For this purpose, a 728 bp fragment of the 5´non-coding region (5´NCR) of the viral genome, from 24 isolates, was sequenced and subjected to phylogenetic analysis. Genotypes 1, 2a and 2b were found at 8.3% (2/24), 50% (12/24) and 41.7% (10/24), respectively. In conclusion São Paulo displays a genotype distribution similar to the published data for other States and Regions of Brazil, endorsing the notion that types 1 and 2 would have entered the country with African and European people, respectively, since its earliest formation.

OBJECTIVE: In 1998, the Brazilian Ministry of Health made it mandatory for all blood banks in the country to screen donated blood for human immunodeficiency virus (HIV) concomitantly using two different enzyme immunoassay (EIA) tests. Concerned with the best use of available resources, our objective with this study was to evaluate the usefulness of conducting two EIA screening tests instead of just one. METHODS: We analyzed data from 1999 through 2001 obtained by testing 698 191 units of donated blood using two EIA HIV screening tests concomitantly at the Pro-Blood Foundation/Blood Center of São Paulo (Fundação Pró-Sangue/Hemocentro de São Paulo), which is a major blood center in the city of São Paulo, Brazil. All samples reactive in at least one of the two EIA tests were submitted for confirmation by a Western blot (WB) test, and the persons who had donated those samples were also asked to return and provide a follow-up sample. RESULTS: Out of the 698 191 blood units that were donated, 2 718 of them (0.4%) had to be discarded because they were reactive to at least one of the EIA tests. There were two WB-positive donation samples that were reactive in only one HIV EIA screening test. On their follow-up samples, both donors tested WB-negative. These cases were considered false positive results at screening. Of the 2 718 donors who were asked to return and provide a follow-up sample, 1 576 of them (58%) did so. From these 1 576 persons, we found that there were two individuals who had been reactive to only one of the two EIA screening tests and who had also been negative on the WB at screening but who were fully seroconverted on the follow-up sample. We thus estimated that, in comparison to the use of a single EIA screening test, the use of two EIA screening tests would detect only one extra sample out of 410 700 units of blood. CONCLUSIONS: Our data do not support the use of two different, concomitant EIA screening tests for HIV. The great majority of HIV-positive donors have already seroconverted and will be detected using only a single EIA screening test. Only persons who are going through the process of seroconversion may be missed by using a single EIA test and detected using two EIAs for screening. To screen out these individuals and decrease the residual risk of HIV transmission from the blood donated in our center, the use of other techniques, such as nucleic acid testing (NAT) or a p24 antigen assay, would be more effective.

OBJETIVO: En 1998, el Ministerio de Salud de Brasil decretó que todos los bancos de sangre en el país debían someter toda la sangre donada a un tamizaje para la detección del virus de la inmunodeficiencia humana (VIH) usando concomitantemente dos inmunoensayos enzimáticos (IEE) diferentes. Nuestro objetivo al realizar el presente estudio, resultado de un afán por sacar el máximo provecho a los recursos disponibles, ha sido evaluar la utilidad de hacer un tamizaje con dos IEE en lugar de uno solo. MÉTODOS: Analizamos datos de 1999-2001 obtenidos como resultado del tamizaje de 698 191 unidades de sangre donada mediante dos IEE aplicados concomitantemente en la Fundación Pro-Sangre del Centro de Sangre de São Paulo (Fundação Pró-Sangue/ Hemocentro de São Paulo), que es un centro hematológico importante en la ciudad de São Paulo, Brasil. Toda muestra que fue reactiva en por lo menos uno de los dos IEE fue sometida a un inmunoblot de Western (WB) a manera de confirmación, y a las personas que habían donado la sangre positiva también se les pidió que regresaran para proporcionar una muestra de seguimiento. RESULTADOS: De las 698 191 unidades de sangre que fueron donadas, hubo que descartar 2 718 (0,4%) porque mostraron reactividad a uno de los IEE o ambos. Dos de las muestras donadas que mostraron positividad en el WB fueron reactivas en solamente uno de los IEE de tamizaje. En lo que respecta a las muestras de seguimiento, ambos donantes tuvieron resultados negativos en el WB. Estos resultados se consideraron positivos falsos para fines del tamizaje. De los 2 718 donantes a quienes se les pidió que regresaran para proporcionar una muestra de seguimiento, 1 576 (58%) cumplieron. De estas 1 576 personas, dos habían mostrado reactividad a solamente uno de los IEE de tamizaje, con resultados negativos en el WB, pero habían mostrado una seroconversión completa en la muestra de seguimiento. Por consiguiente, nuestra conclusión es que el tamizaje con dos IEE, en comparación con uno solo, permitiría detectar solamente una muestra adicional de un total de 410 700 unidades de sangre. CONCLUSIONES: Nuestros datos no respaldan la conveniencia de usar concomitantemente dos IEE diferentes para el tamizaje del VIH. La gran mayoría de los donantes con positividad a VIH ya habrán tenido una seroconversión y se pueden detectar con un solo IEE. Solamente aquellas personas que están aún en proceso de seroconversión podrían no ser detectadas mediante un solo IEE, pero sí con dos. Para identificar a estas personas y reducir cualquier riesgo residual de transmitir el VIH por medio de la sangre donada en nuestro centro, sería más eficaz el uso de otras técnicas, tales como las pruebas a base de ácidos nucleicos o un ensayo a base de Agp24.

OBJECTIVE: To describe the trends in the profile of blood donors from 1995 through 2001 at a large blood center in the city of São Paulo, Brazil, particularly following the initiation in 1998 of marketing strategies aimed at substituting replacement donors with altruistic repeat donors. METHODS: Using an information system that had been established at the Pro-Blood Foundation/Blood Center of São Paulo (Fundação Pró-Sangue/Hemocentro de São Paulo) in 1994, we collected information on sex, age, and type of donation for the years 1995-2001. We classified blood donors as either replacement blood donors (if they stated that the reason for donating was that they had a friend or relative in the hospital) or as altruistic donors. First-time blood donors were those who had not donated in our institution since the establishment of the information system. RESULTS: The percentage of repeat altruistic blood donors increased over time as first-time replacement donors declined for both genders. The proportion of altruistic donors climbed from 20% of all blood donors in 1995 to 57% in 2001. In 2001, first-time blood donors represented only 52% of all donors, as contrasted to 88% in 1995. Female donors increased from 20% to 37% of the donors over the period studied. CONCLUSIONS: Our data provide evidence that the São Paulo population has responded well to the marketing strategies that have been introduced in our institution. We believe that similar promotional efforts elsewhere in Brazil would produce comparable, positive results.

OBJETIVO: Describir las tendencias observadas de 1995 a 2001 en el perfil de los donantes de sangre de un gran centro de hemoterapia en la ciudad de São Paulo, Brasil, particularmente después del lanzamiento en 1998 de estrategias de mercadeo orientadas a sustituir los donantes por reemplazo por donantes altruistas a repetición. MÉTODOS: Usando un sistema de información que había sido establecido en la Fundación Pro-Sangre/Hemocentro de São Paulo (Fundação Pró-Sangue/Hemocentro de São Paulo) en 1994, obtuvimos información acerca del sexo y la edad de los donantes y el tipo de donación para el período de 1995-2001. Clasificamos a los donantes de sangre en donantes de reemplazo (si su motivo para donar sangre era la presencia de un pariente u amigo en el hospital) o bien en donantes altruistas. Las personas que donaban su sangre por primera vez fueron aquellas que nunca habían donado sangre en nuestra institución desde que se estableció el sistema de información. RESULTADOS: El porcentaje de donantes altruistas a repetición aumentó a lo largo del tiempo a medida que el número de donantes de reemplazo que donaban sangre por primera vez se redujo en ambos sexos. La proporción de donantes altruistas subió de 20% de todos los donantes en 1995 a 57% en 2001. En 2001, los donantes que donaban por primera vez representaban solamente 52% de todos los donantes de sangre, en comparación con 88% en 1995. La proporción de mujeres donantes subió de 20 a 37% de todos los donantes en el período estudiado. CONCLUSIONES: Nuestros datos confirman que la población de São Paulo, Brasil, ha respondido bien a las estrategias de mercadeo que han sido adoptadas en nuestra institución. Consideramos que la adopción de iniciativas de promoción similares en otras partes del Brasil daría resultados positivos de igual naturaleza.

OBJETIVO: Analisar a evolução, de 1991 a 2001, do descarte sorológico na Fundação Pró-Sangue/Hemocentro de São Paulo, o maior banco de sangue da América Latina, e verificar a prevalência de doenças infecciosas entre doadores dessa instituição no ano de 2001. MÉTODOS: Foram compilados os dados de descarte sorológico relativos aos anos de 1991 a 2001. Para determinar a prevalência de doenças infecciosas, foram analisadas 9 942 amostras triadas em novembro de 2001, sendo as amostras reativas submetidas a testes confirmatórios. RESULTADOS: Foi encontrada uma diminuição percentual significativa de descarte, de 20% em 1991 para 9% em 2001. A prevalência de doenças infecciosas entre doadores em 2001 foi de 0,04% para vírus da imunodeficiência humana (VIH); 0,21% para vírus da hepatite C (VHC); 0,06% para vírus T-linfotrópico humano (HTLV); para vírus da hepatite B (VHB), as prevalências foram de 0,14% para anti-HBc + HBsAg, 1,68% para anti-HBc + anti-HBs e 1,67% para anti-HBc isolado; 1,10% para sífilis; e 0,14% para doença de Chagas. CONCLUSÃO: A diminuição no descarte e a prevalência de doenças infecciosas entre doadores da Fundação Pró-Sangue/Hemocentro de São Paulo em 2001 refletem o aumento na porcentagem de doadores de repetição nesse banco de sangue.

OBJECTIVES: To analyze the changes in the proportion of blood units discarded from 1991 through 2001 at the Pro-Blood Foundation/Blood Center of São Paulo (Fundação Pró-Sangue/Hemocentro de São Paulo), which is the largest blood bank in Latin America, and to determine the prevalence of infectious diseases among donors at the Blood Center in November 2001. METHODS: We compiled data concerning the discarding of blood units due to the presence of serological markers for communicable diseases at the Blood Center during the period from 1991 through 2001. To determine the prevalence of infectious diseases, 9 942 screened samples were analyzed in November 2001; all reactive samples underwent confirmatory tests. RESULTS: Over the study period there was a significant decrease in the percentage of units discarded, from 20% in 1991 to 9% in 2001. In November 2001 the prevalence of infectious diseases among donors was: 0.04% for human immunodeficiency virus (HIV), 0.21% for hepatitis C virus (HCV), 0.06% for human T-lymphotropic virus (HTLV), 0.14% for Chagas' disease, and 1.10% for syphilis. For hepatitis B virus, the prevalences found were: 0.14% for anti-HBc and HBsAg, 1.68% for anti-HBc and anti-HBs, and 1.67% for isolated anti-HBc. CONCLUSIONS: The decrease in the discarding of blood units and in infectious diseases among donors at the Blood Center of São Paulo reflects the increase in the Center's percentage of repeat donors.

OBJECTIVE: To evaluate the quality of serological screening of blood donors in five groups of blood banks in Latin America that participated over the 1997-2000 period in an external serology quality control project developed with support from the Pan American Health Organization (PAHO). METHODS: With assistance from PAHO, the Serology Authority of the Pro-Blood Foundation/Blood Center of São Paulo (Fundação Pró-Sangue/Hemocentro de São Paulo), of São Paulo, Brazil, carried out the external quality control project and served as its "organizing center" (OC). The OC developed five external serology quality control "programs" (ESQCPs), or external evaluation activities, for the respective groups of participating blood banks. There was one ESQCP each in 1997, 1999, and 2000, and there were two in 1998. In these five programs, the number of participating blood banks ranged from 13 to 21, and the number of countries ranged from 11 to 16. In each program, the OC used a set of 24 blinded sera samples with different reactivities for the various infectious agents for which screening is obligatory in Brazil. Each participating institution in each program received a sera set, to be processed using that institution's standard screening procedures. After returning its results to the OC, each participant received an answer key for the sera set, to be used in evaluating its own performance. All the individual results were kept strictly confidential. At the end of each program, the OC prepared and sent to all the participants a final report that contained information on the overall results from that program. RESULTS: An analysis of the five programs showed that there was a lack of homogeneity among the countries with respect to the strategies and the parameters used in screening blood donors. Few laboratories screened for human T-cell-lymphotropic virus (beginning with the 1997 program, the respective rates were 17%, 27%, 35%, 39%, and 45%). Rates of screening were also low for antibodies to the hepatitis B core antigen (again, beginning with the 1997 program, the rates were 42%, 27%, 39%, 50%, and 60%). There were also important differences with respect to which tests and which combinations of tests were used, making it hard to compare the types of screening done. In the five programs, with the various tests used, the overall rate of false positive results fluctuated around 2%. The highest false positive rate for any of the tests, 4.6%, was for antibodies against the hepatitis C virus. The lowest false positive rate, 0.4%, was for antibodies against Trypanosoma cruzi. CONCLUSIONS: These results show the need for PAHO to continue using these external quality control programs as well as other activities in order to strengthen the procedures for serological screening in blood banks in Latin America, until there is more uniformity in the procedures that the countries use.

OBJETIVOS: Con el apoyo de la Organización Panamericana de la Salud (OPS), desarrollamos entre 1997 y 2000 cinco programas de control externo de la calidad en serología (PCECS) en los que participaron entre 13 y 21 bancos de sangre de 11 a 16 países de América Latina. El objetivo fue evaluar el desempeño de los bancos de sangre con respecto al tamizaje serológico realizado en donantes de sangre. MÉTODOS: Como herramienta de trabajo utilizamos conjuntos de 24 muestras de sueros anónimos con reactividades variables para los parámetros de uso obligatorio en el tamizaje serológico de donantes de sangre en Brasil. En cada PCECS enviamos un multipanel a cada institución participante para que lo procesara en las mismas condiciones de su rutina de tamizaje. Cada participante recibió la clave del multipanel para autoevaluación, después de haber devuelto los resultados obtenidos en su laboratorio. Se mantuvo siempre la más estricta confidencialidad sobre los resultados obtenidos individualmente. Al terminar de cada programa, el Centro Organizador (Superintendencia de Serología de la Fundação Pró-Sangue/Hemocentro de São Paulo) elaboró un informe final que contenía toda la información obtenida en el programa y que fue enviado a los participantes. RESULTADOS: En el análisis de los cinco PCECS se observó falta de homogeneidad entre los países con respecto a las estrategias y a los parámetros utilizados en el tamizaje de donantes de sangre. Pocos laboratorios practicaron el tamizaje de los virus linfotrópico de células T humanas (HTLV) (17%, 27%, 35%, 39% y 45%, respectivamente y en orden creciente para los cinco PCECS) y de anticuerpos contra el antígeno nuclear del virus de la hepatitis B (anti-HBc) (42%, 27%, 39%, 50% y 60%). También se observaron diferencias importantes en cuanto a las pruebas o combinaciones de pruebas utilizadas, lo cual puede dificultar el estudio comparativo de los tipos de tamizaje. El número total de resultados positivos falsos osciló alrededor del 2%, correspondiendo el mayor valor al tamizaje de anticuerpos contra el virus de la hepatatis C (anti-VHC) (4,6%) y el menor a anti-Trypanosoma cruzi (0,4%). CONCLUSIONES: Los resultados obtenidos en este trabajo demuestran la necesidad de continuar las acciones de la OPS en América Latina para reforzar los procedimientos de tamizaje serológico en bancos de sangre, incluso los PCECS, hasta que se consiga una uniformidad de procedimientos en la Región de las Américas.

A prevalência da infecção pelo vírus "TT" (TTV) foi investigada pela técnica da Reação da Polimerase em Cadeia (PCR) em grupos considerados de baixo risco (doadores de sangue e crianças/adolescentes saudáveis) e de alto risco de exposição parenteral (hemofílicos); todos provenientes da cidade de São Paulo. Oligonucleotídeos empregados como primers, homólogos à região não traduzível (UTR) do genoma viral, mostraram-se muito mais universais, revelando frequências muito mais altas em ambos os grupos ( > ou = 81%) do que os primers anteriormente utilizados, baseados na região genômica traduzível "N22" (doadores de sangue, 5,5%, e hemofílicos, 42,3%). O "PCR-UTR" também revelou um perfil interessante em crianças/adolescentes saudáveis: alta prevalência nos primeiros anos de vida e queda significativa em meninos adolescentes. O "PCR-N22", por sua vez, apresentou alta frequência em hemofílicos que receberam derivados de sangue fresco (58%) relativa àqueles que foram tratados com fatores de coagulação submetidos à inativação viral (9,4%) e doadores de sangue (5,5%).

The prevalence of TT virus (TTV) infection was investigated by Polymerase Chain Reaction (PCR) in low- (blood donors and healthy children/adolescents) and high-risk (hemophiliacs) groups from São Paulo, Brazil. Primers based on the untranslated region (UTR) of the viral genome proved to be much more ubiquitous, leading to much higher frequencies for both groups ( > or = 81%) than the earlier N22-PCR directed to the open reading frame 1 (blood donors, 5.5%, and hemophiliacs, 42.3%). The UTR-PCR also revealed an interesting profile for healthy children/adolescents: very high prevalence at the early years and significant decrease in male teenagers. The N22-PCR, in turn, demonstrated higher frequency in hemophiliacs treated with fresh blood products (58%), than in those treated with virus-inactivated clotting factors (9.4%) and blood donors (5.5%).

A amamentação é o meio mais freqüente de transmissão vertical do HTLV-I. No entanto, crianças não amamentadas mostram-se infectadas em freqüências que variam de 4 a 14%. Nestes casos, os meios mais prováveis de infecção devem ser através da placenta ou por contaminação no canal de parto. Quarenta e um filhos de portadoras do HTLV-I aleitados artificialmente foram submetidos a pesquisa do vírus pela reação em cadeia da polimerase. 81,5% destas crianças nasceram através de cesária eletiva. Nenhum caso de infecção pelo HTLV-I foi detectado. Este fato indica que a infecção por via transplacentária é pouco freqüente e que é provável que o parto artificial tenha contribuído para a ausência de transmissão do vírus.

The most frequent pathway of vertical transmission of HTLV-I is breast-feeding, however bottle fed children may also become infected in a frequency varying from 4 to 14%. In these children the most probable routes of infection are transplacental or contamination in the birth canal. Forty-one bottle-fed children of HTLV-I seropositive mothers in ages varying from three to 39 months (average age of 11 months) were submitted to nested polymerase chain reaction analysis (pol and tax genes). 81.5% of the children were born by an elective cesarean section. No case of infection was detected. The absence of HTLV-I infection in these cases indicates that transmission by transplacental route may be very infrequent.