Scielo RSS <![CDATA[Revista Panamericana de Salud Pública]]> http://www.scielosp.org/rss.php?pid=1020-498920050001&lang=en vol. 17 num. 1 lang. en <![CDATA[SciELO Logo]]> http://www.scielosp.org/img/en/fbpelogp.gif http://www.scielosp.org <![CDATA[<B>Visual inspection with acetic acid for cervical cancer screening outside of low-resource settings</B>]]> http://www.scielosp.org/scielo.php?script=sci_arttext&pid=S1020-49892005000100001&lng=en&nrm=iso&tlng=en OBJECTIVES: To assess visual inspection with acetic acid (VIA) as a screening tool for use in a well-equipped health center in Peru, to evaluate VIA as an alternative or adjunct to the Papanicolaou (Pap) smear, and to determine if VIA can play a role in settings other than low-resource ones. METHODS: This was a prospective study of 1 921 asymptomatic women living in Lima, Peru, carried out in 1999 and 2000. The study was performed at a cancer center equipped with the latest-generation technology and highly trained oncologists. The women underwent a complete clinical evaluation, including a Pap smear and VIA. Participants with any positive test were referred for colposcopy and biopsy. RESULTS: More women tested positive by VIA than on the Pap smear (6.9% vs. 4.2%; P = 0.0001). There were 35 women with histologic cervical intraepithelial neoplasia grade 1 (CIN 1); of these, 15 were detected by Pap and 20 by VIA (P = 0.4). A diagnosis of CIN 2 or 3 (CIN 2-3) was confirmed in a total of 13 cases; Pap detected 5 of the cases and VIA 11 of the cases (P = 0.06). The positive predictive value for detection of CIN 2+ was 8.3% for VIA and 6.3% for Pap (P = 0.5). Most importantly, while only 2.3% of patients with a positive VIA were lost to follow-up before colposcopy, that was true for 26.3% of the women with a positive Pap smear (P <0.0001). CONCLUSIONS: VIA is useful for detection of precursor lesions of cervical cancer not only in low-resource settings but also in well-equipped health centers and cancer centers. In these non-low-resource settings, VIA has a positive predictive value comparable to the conventional Pap smear, but it is more likely to achieve earlier diagnosis, follow-up, and treatment than cytology- based screening.<hr/>OBJETIVOS: Determinar si la inspección visual con ácido acético (IVAA) es útil como prueba de tamizaje en un centro de salud peruano con buena dotación de equipo; si se presta para uso en lugar del Papanicolaou o en combinación con él, y si tiene alguna utilidad en lugares donde no hay escasez de recursos. MÉTODOS: En 1999 y 2000 se realizó un estudio prospectivo con 1 921 mujeres asintomáticas que habitaban en Lima, Perú. El estudio se llevó a cabo en un centro de cancerología dotado de las tecnologías más modernas y de oncólogos con una sólida formación. A las mujeres se les sometió a un examen clínico completo, con todo y prueba de Papanicolaou e IVAA. A las que tuvieron resultados positivos en cualquiera de estas pruebas se les remitió para estudio con colposcopia y biopsia. RESULTADOS: Hubo un mayor número de mujeres con resultados positivos a la IVAA que al Papanicolaou (6,9% frente a 4,2%; P = 0,00001). Treinta y cinco mujeres tuvieron una neoplasia cervical intraepitelial grado I (NCI I) en el examen histológico; a 15 de ellas se les detectó la lesión mediante el Papanicolaou y a 20, mediante la IVAA (P = 0,4). Se confirmó el diagnóstico de NCI 2 ó 3 (NCI 2-3) en 13 casos, de los cuales 5 se detectaron mediante el Papanicolaou y 11, mediante la IVAA (P = 0,06). El valor pronóstico de un resultado positivo en el diagnóstico de NCI 2+ fue de 8,3% en el caso de la IVAA y de 6,3% en el del Papanicolaou (P = 0,5). El resultado de mayor importancia es que 26,3% de las mujeres con un resultado de Papanicolaou positivo abandonaron el seguimiento antes de la colposcopia, mientras que eso solamente sucedió en 2,3% de las pacientes con un resultado positivo en la IVAA (P < 0,0001). CONCLUSIONES: La IVAA sirve para detectar lesiones precursoras del cáncer cervicouterino no solo en lugares con pocos recursos, sino también en centros de salud y de cancerología bien dotados de instrumental moderno. En lugares donde los recursos escasean, un resultado positivo en la IVAA tiene un valor pronóstico semejante al del Papanicolaou convencional, pero es más probable que culmine en el diagnóstico temprano, seguimiento y tratamiento de la paciente que el tamizaje de tipo citológico. <![CDATA[<B>Acute diarrheal disease</B>: <B>a public health challenge in Colombia</B>]]> http://www.scielosp.org/scielo.php?script=sci_arttext&pid=S1020-49892005000100002&lng=en&nrm=iso&tlng=en OBJETIVOS: Establecer la relación entre la infección por rotavirus y la deshidratación por diarrea en niños colombianos menores de 5 años y determinar los factores de riesgo de la diarrea con deshidratación. MÉTODOS: Se realizó un estudio de casos y testigos en un hospital urbano de Bogotá, Colombia, entre abril de 2000 y febrero de 2001. Se seleccionaron 290 niños menores de 5 años de edad de uno u otro sexo; de ellos 145 estaban hospitalizados por enfermedad diarreica aguda (EDA) con deshidratación (casos) y 145 tenían diagnóstico de EDA sin signos de deshidratación (testigos). A todos los niños se les realizó un examen físico completo. Las madres respondieron un cuestionario con variables demográficas; socioeconómicas; de conocimientos, actitudes y hábitos higiénicos; y de acceso a los servicios de salud. Se determinó la presencia de rotavirus en muestras de heces fecales tomadas durante las primeras 48 horas del ingreso al estudio. RESULTADOS: Se encontró una asociación estadística entre la diarrea con deshidratación y la presencia de rotavirus en las muestras de heces (razón de posibilidades [RP] = 3,46; intervalo de confianza de 95% [IC95%]: 1,71 a 7,00), el peso al nacer <2 600 g (RP = 7,79; IC95%: 3,47 a 18,01) y el tiempo de lactancia materna inferior a 3 meses (RP = 3,17; IC95%: 1,66 a 6,13). El riesgo de presentar deshidratación se asoció con las condiciones socioeconómicas desfavorables, los hábitos higiénicos inadecuados de la familia del niño y una menor escolaridad materna. CONCLUSIONES: La calidad inadecuada de las acciones de promoción y prevención en una población con fácil acceso a los servicios de salud favoreció la aparición de casos de diarrea con deshidratación. La infección por rotavirus desempeña un papel importante en la gravedad de la EDA en niños colombianos.<hr/>OBJECTIVES: To establish the relationship between rotavirus infection and dehydration from diarrhea in Colombian children under 5 years of age, and to identify risk factors for diarrhea with dehydration. METHODS: A case-control study was performed in an urban hospital in Bogotá, Colombia, between April 2000 and February 2001. The sample was composed of 290 children of both sexes under 5 years of age; of these children, 145 of them were hospitalized for acute diarrheal disease (ADD) with dehydration (cases), and 145 had a diagnosis of ADD but no signs of dehydration (controls). All children underwent a complete physical examination. Mothers responded to a questionnaire containing items on demographic and socioeconomic variables, as well as on knowledge, attitudes, and practices with regard to hygiene, and on access to health services. RESULTS: An association was detected between diarrhea with dehydration and the presence of rotavirus in fecal samples (odds ratio [OR] = 3.46; 95% confidence interval [95% CI]: 1.71 to 7.00), birth weight < 2 600 g (OR = 7.79; 95% CI: 3.47 to 18.01), and breastfeeding for less than 3 months (OR = 3.17; 95% CI: 1.66 to 6.13). The risk of having dehydration was associated with low socioeconomic status, poor hygienic practices among the child's family members, and mother's low educational level. CONCLUSIONS: The ineffectiveness of health promotion and disease prevention activities in a population with easy access to health services set the stage for the appearance of cases of diarrhea with dehydration. Rotavirus infection plays an important role in the severity of ADD among Colombian children. <![CDATA[<B>Equity and access to health care for pregnant women in Campinas (SP), Brazil</B>]]> http://www.scielosp.org/scielo.php?script=sci_arttext&pid=S1020-49892005000100003&lng=en&nrm=iso&tlng=en OBJETIVO: Comparar a atenção à saúde recebida durante a gestação, o parto e o puerpério por mulheres de dois estratos de renda familiar per capita (menos de 1 salário-mínimo e 1 ou mais salários-mínimos). MÉTODO: Estudo observacional transversal realizado em amostra aleatória de 248 mulheres residentes no Município de Campinas, Estado de São Paulo, que tiveram filhos entre abril de 2001 e março de 2002. Informações sobre aspectos sócio-demográficos, morbidade materna e atenção à saúde no pré-natal, parto e puerpério foram obtidas por meio de entrevistas domiciliares. O cuidado no pré-natal foi analisado com base no índice de Kessner, no índice de adequação da utilização do cuidado pré-natal (Adequacy of Prenatal Care Utilization) e no índice proposto pelos autores a partir das recomendações do Ministério da Saúde. Na época do estudo, o salário-mínimo correspondia a 180 reais, ou 71,40 dólares. RESULTADOS: As gestantes do grupo de renda inferior tinham menor escolaridade e eram, em maior proporção, adolescentes, pretas ou pardas e solteiras. O pré-natal foi realizado pelo SUS em 73,7% das gestantes de menor renda, contra 33,3% do grupo de maior renda. As gestantes de menor renda iniciaram o pré-natal mais tardiamente e fizeram um número menor de consultas. Entretanto, alguns indicadores de qualidade da atenção, como exames de rotina, teste anti-HIV, percentual de parto cesáreo e permanência do recém-nascido com a mãe em alojamento conjunto, foram melhores nas gestantes de menor renda. Os grupos foram semelhantes em relação a orientações recebidas, exames clínicos, laqueadura no pós-parto e prevalência de baixo peso e de prematuridade. A inadequação do cuidado pré-natal, embora significativamente maior para as mulheres de menor renda, ocorreu num percentual relativamente baixo. CONCLUSÕES: As diferenças sócio-demográficas observadas entre os dois grupos não se reproduziram na mesma intensidade e direção nas variáveis relativas às condições e à atenção à saúde. Os resultados sugerem que a organização dos serviços públicos de saúde em Campinas tem viabilizado em alguns aspectos a promoção da eqüidade na saúde.<hr/>OBJECTIVE: To compare the health care received during pregnancy, delivery, and the puerperium by women belonging to two different per capita family income strata: less than 1 minimum wage, and 1 or more minimum wages. METHOD: This is a cross-sectional observational study that was carried out with a random sample of 248 female residents of the city of Campinas, in the state of São Paulo, Brasil, who had given birth between April 2001 and March 2002. Socio-demographic data, as well as information concerning maternal morbidity and health care during pregnancy, delivery, and the puerperium, were obtained through home interviews. The Kessner index, the Adequacy of Prenatal Care Utilization index, and an index proposed by the authors based on the recommendations of the Brazilian Department of Health were used to assess the adequacy of prenatal care. The minimum wage in Brazil at the time of the study was 180 reais (approximately 71.4 US dollars). RESULTS: The lower income group included a larger proportion of women with low schooling, as well as adolescents, black women, and single women. Prenatal care was provided by the public Unified Health System to 73.7% of the women in the lower income group, versus 33.3% in the higher income group. The women in the lower income group started attending prenatal care later and had fewer visits in all than higher-income women. However, some health care quality indicators, such as performance of routine laboratory tests and anti-HIV antibody testing, the proportion of cesarean sections, and the frequency of infant rooming-in, showed more favorable figures in the lower income group. Both groups received comparable counseling and had similar rates of clinical testing, post-delivery tubal sterilization, low birthweight children, and premature delivery. Although a significantly higher number of women in the higher income group received optimal prenatal care, the percentage of cases of inadequate care in the lower-income group was still relatively low. The frequency of health problems during pregnancy did not differ significantly between groups, except for anemia and vaginal hemorrhage, which were more frequent among women in the lower-income group (P < 0.001 and P = 0.033, respectively). CONCLUSIONS: Despite marked socio-demographic differences between women in the two income categories, resulting in different living conditions, there were no significant differences between groups in terms of health problems during pregnancy or the quality of the prenatal care received. These results suggest that the organization of public health services in Campinas has succeeded in promoting equity in health care, at least to a certain extent. <![CDATA[<B>HIV infection in mobile populations</B>: <B>the case of Mexican migrants to the United States</B>]]> http://www.scielosp.org/scielo.php?script=sci_arttext&pid=S1020-49892005000100004&lng=en&nrm=iso&tlng=en OBJECTIVE: Previous studies have indicated varying rates of HIV infection among labor migrants to the United States of America. Most of these studies have been conducted with convenience samples of farmworkers, thus presenting limited external validity. This study sought to estimate the prevalence of HIV infection and risk factors among Mexican migrants traveling through the border region of Tijuana, Baja California, Mexico, and San Diego, California, United States. This region handles 37% of the migrant flow between Mexico and the United States and represents the natural port of entry for Mexican migrants to California. METHODS: From April to December 2002 a probability survey was conducted at key migrant crossing points in Tijuana. Mexican migrants, including ones with a history of illegal migration to the United States, completed an interview on HIV risk factors (n = 1 429) and an oral HIV antibody test (n = 1 041). RESULTS: Despite reporting risk factors for HIV infection, none of the migrants tested positive for HIV. CONCLUSIONS: Our findings contrast with previous estimates of HIV among labor migrants in the United States that were based on nonprobability samples. Our findings also underline the need for early HIV prevention interventions targeting this population of Mexican migrants.<hr/>OBJETIVO: Estudios anteriores han revelado diferentes tasas de infección por VIH en la población de obreros itinerantes que han ingresado en los Estados Unidos de América. La mayoría de esos estudios se efectuaron con muestras de trabajadores agrícolas tomadas por conveniencia, y por lo tanto su validez externa ha sido limitada. El presente estudio se realizó con el fin de calcular la prevalencia de la infección por VIH y de sus factores de riesgo en los obreros itinerantes mexicanos que se desplazan por el territorio fronterizo de Tijuana, Baja California, México y San Diego, California, Estados Unidos. Esta zona, por donde pasan 37% de los obreros itinerantes que vienen de México a los Estados Unidos, es el natural puerto de entrada de trabajadores mexicanos que van a California. MÉTODOS: De abril a diciembre de 2002 se realizó una encuesta por conveniencia en diferentes puntos clave de Tijuana por donde cruzaban la frontera los obreros itinerantes. Los obreros, entre ellos algunos con antecedentes de inmigración ilegal a los Estados Unidos, completaron una entrevista sobre los factores de riesgo de infección por VIH (n = 1 429) y fueron sometidos a una prueba oral para la detección de anticuerpos contra el VIH (n = 1 041). RESULTADOS: Aunque los obreros indicaron tener factores de riesgo asociados con la infección por VIH, ninguno de ellos tuvo un resultado positivo en la prueba detectora de VIH. CONCLUSIONES: Estos resultados difieren radicalmente de los obtenidos anteriormente al usar muestras no probabilísticas para calcular la tasa de infección por VIH en obreros itinerantes en los Estados Unidos. Resaltan, además, la necesidad de llevar a cabo intervenciones tempranas para prevenir la infección por VIH en obreros itinerantes mexicanos. <![CDATA[<B>Liver changes in workers at an oil refinery and in a reference population in the state of Bahia, Brazil</B>]]> http://www.scielosp.org/scielo.php?script=sci_arttext&pid=S1020-49892005000100005&lng=en&nrm=iso&tlng=en OBJETIVO: Determinar a prevalência de alterações nas enzimas hepáticas de trabalhadores de uma refinaria de petróleo localizada no Estado da Bahia em comparação a uma população de referência não ocupacionalmente exposta a produtos químicos, e descrever os fatores associados à variação nessa prevalência. MÉTODO: Foram avaliados os trabalhadores da refinaria e os funcionários do escritório da gerência administrativa da empresa, situada em Salvador, capital do Estado da Bahia. Estudaram-se amostras de sangue de 692 trabalhadores da refinaria e de 377 trabalhadores da população de referência. Classificaram-se como casos de alterações hepáticas indivíduos que apresentaram valores acima dos padrões de referência simultaneamente para gama-glutamiltransferase (GGT) (>50 U/L para o sexo masculino e >32 U/L para o sexo feminino) e alanina aminotrans- ferase (ALT) (>50 U/L). Foram coletadas informações sobre idade, sexo, peso, altura, tempo de serviço, uso de álcool, hábito de fumar, exercício físico, exposição ocupacional a produtos químicos, uso de equipamento de proteção individual e antecedentes médicos de hepatite, icterícia e obesidade. RESULTADOS: A prevalência de alterações hepáticas na refinaria foi de 15,3% (IC95%: 12,5 a 18,1), contra 3,8% (IC95%: 1,8 a 5,8) na população de referência. A análise de regressão logística múltipla estimou que os trabalhadores da refinaria apresentavam uma prevalência de alterações hepáticas 3,56 vezes maior (IC95%: 1,99 a 6,38) do que a prevalência observada na população de referência, independentemente de outras covariáveis relevantes, como obesidade, prática de exercícios físicos, fumo e bebida alcoólica. CONCLUSÕES: Os resultados sugerem que a exposição ocupacional desempenha um papel importante na determinação das alterações hepáticas nos trabalhadores dessa refinaria de petróleo.<hr/>OBJECTIVE: To determine the prevalence of liver changes in workers at an oil refinery located in the state of Bahia, Brazil, as compared to a reference population with no occupational exposure to chemical products, and to describe the factors associated with the observed differences in prevalence. METHODS: We studied workers at the refinery and at the company's central management office located in the city of Salvador, which is the state capital. Blood samples of 692 refinery workers and 377 workers from the reference population were analyzed. Cases were defined as individuals presenting high serum levels of both gamma-glutamyltransferase (GGT) and alanine aminotransferase (ALT) (GGT > 50 U/L for males and > 32 U/L for females; ALT > 50 U/L). Data were collected on age, sex, weight, height, years working for the company, use of alcohol, smoking habits, physical exercise, occupational exposure to chemical products, use of personal safety equipment, and medical history of hepatitis, jaundice, and obesity. RESULTS: The prevalence of liver changes among refinery workers was 15.3% (95% CI: 12.5 to 18.1), vs. 3.8% (95% CI: 1,8 to 5,8) in the reference population. According to multiple logistic regression analysis, the prevalence of liver changes among refinery workers was 3.56 times greater (95% CI: 1,99 to 6,38) than in the reference population, regardless of the presence of other relevant co-variables, such as obesity, exercise, smoking, and alcohol consumption. CONCLUSIONS: These results suggest that occupational exposure may play a major role in the development of liver changes among workers at the oil refinery where the study was carried out. <![CDATA[<B>Epidemiology and genetics</B>: <B>a strategic alliance in the new millennium?</B>]]> http://www.scielosp.org/scielo.php?script=sci_arttext&pid=S1020-49892005000100006&lng=en&nrm=iso&tlng=en Although the information derived from biological markers could conceivably be used to overcome some of the problems intrinsic to virtually all epidemiologic study designs-case definition, true exposure level, host susceptibility and resistance to factors of interest, the misclassification of study subjects (false positive and false negative test results), etc.-, we are still unable to resolve all such problems with the tools available at present. Biological markers seem more promising as potential indicators of the degree of susceptibility than as indicators of disease occurrence, an application requiring further technical refinement. Currently biological markers are employed in public health mainly to screen for particular diseases. Unfortunately, these markers have their limitations. For one thing, it is unlikely that they will completely eliminate the problem of false positive and false negative results, since DNA from solid tumors undergoes slight degradation due to necrosis and since genetic markers are susceptible to the effects of exposure to medication, diet, sex, ethnicity, and even the circadian cycle. And even if false positives and negatives were ultimately eliminated, it would be impossible to use many of the analytical tools based on two by two tables, such as the chi squared test, logistic regression, the Poisson regression, Cox' proportional hazards ratio, etc., since such tools rely on comparisons of the number of false positives and negatives in the exposed and non-exposed groups. Finally, albeit no less important, certain ethical issues must be carefully considered before allowing the massive use of human genetic markers, which could lead to violations of the rights of individuals, families, and communities if carried out in an indiscriminate, unregulated fashion. Epidemiology is rapidly broadening its scope, a trend that will continue into the future; new analytical tools will be developed, and the working hypotheses to which such tools will be applied will change. At present the scientific community is paying increased attention to this field of study, but more research and discussion are needed to respond to many of the questions for which we have no satisfactory answers yet. <![CDATA[<B>¿Puede la exposición al tráfico provocar el infarto del miocardio?</B>]]> http://www.scielosp.org/scielo.php?script=sci_arttext&pid=S1020-49892005000100007&lng=en&nrm=iso&tlng=en Although the information derived from biological markers could conceivably be used to overcome some of the problems intrinsic to virtually all epidemiologic study designs-case definition, true exposure level, host susceptibility and resistance to factors of interest, the misclassification of study subjects (false positive and false negative test results), etc.-, we are still unable to resolve all such problems with the tools available at present. Biological markers seem more promising as potential indicators of the degree of susceptibility than as indicators of disease occurrence, an application requiring further technical refinement. Currently biological markers are employed in public health mainly to screen for particular diseases. Unfortunately, these markers have their limitations. For one thing, it is unlikely that they will completely eliminate the problem of false positive and false negative results, since DNA from solid tumors undergoes slight degradation due to necrosis and since genetic markers are susceptible to the effects of exposure to medication, diet, sex, ethnicity, and even the circadian cycle. And even if false positives and negatives were ultimately eliminated, it would be impossible to use many of the analytical tools based on two by two tables, such as the chi squared test, logistic regression, the Poisson regression, Cox' proportional hazards ratio, etc., since such tools rely on comparisons of the number of false positives and negatives in the exposed and non-exposed groups. Finally, albeit no less important, certain ethical issues must be carefully considered before allowing the massive use of human genetic markers, which could lead to violations of the rights of individuals, families, and communities if carried out in an indiscriminate, unregulated fashion. Epidemiology is rapidly broadening its scope, a trend that will continue into the future; new analytical tools will be developed, and the working hypotheses to which such tools will be applied will change. At present the scientific community is paying increased attention to this field of study, but more research and discussion are needed to respond to many of the questions for which we have no satisfactory answers yet. <![CDATA[<B>Se mide el punto en que fracasan tres clases de antirretrovíricos</B>]]> http://www.scielosp.org/scielo.php?script=sci_arttext&pid=S1020-49892005000100008&lng=en&nrm=iso&tlng=en Although the information derived from biological markers could conceivably be used to overcome some of the problems intrinsic to virtually all epidemiologic study designs-case definition, true exposure level, host susceptibility and resistance to factors of interest, the misclassification of study subjects (false positive and false negative test results), etc.-, we are still unable to resolve all such problems with the tools available at present. Biological markers seem more promising as potential indicators of the degree of susceptibility than as indicators of disease occurrence, an application requiring further technical refinement. Currently biological markers are employed in public health mainly to screen for particular diseases. Unfortunately, these markers have their limitations. For one thing, it is unlikely that they will completely eliminate the problem of false positive and false negative results, since DNA from solid tumors undergoes slight degradation due to necrosis and since genetic markers are susceptible to the effects of exposure to medication, diet, sex, ethnicity, and even the circadian cycle. And even if false positives and negatives were ultimately eliminated, it would be impossible to use many of the analytical tools based on two by two tables, such as the chi squared test, logistic regression, the Poisson regression, Cox' proportional hazards ratio, etc., since such tools rely on comparisons of the number of false positives and negatives in the exposed and non-exposed groups. Finally, albeit no less important, certain ethical issues must be carefully considered before allowing the massive use of human genetic markers, which could lead to violations of the rights of individuals, families, and communities if carried out in an indiscriminate, unregulated fashion. Epidemiology is rapidly broadening its scope, a trend that will continue into the future; new analytical tools will be developed, and the working hypotheses to which such tools will be applied will change. At present the scientific community is paying increased attention to this field of study, but more research and discussion are needed to respond to many of the questions for which we have no satisfactory answers yet. <![CDATA[<B>Encuesta de salud de escolares del Caribe</B>: <B>urge reforzar los factores protectores</B>]]> http://www.scielosp.org/scielo.php?script=sci_arttext&pid=S1020-49892005000100009&lng=en&nrm=iso&tlng=en Although the information derived from biological markers could conceivably be used to overcome some of the problems intrinsic to virtually all epidemiologic study designs-case definition, true exposure level, host susceptibility and resistance to factors of interest, the misclassification of study subjects (false positive and false negative test results), etc.-, we are still unable to resolve all such problems with the tools available at present. Biological markers seem more promising as potential indicators of the degree of susceptibility than as indicators of disease occurrence, an application requiring further technical refinement. Currently biological markers are employed in public health mainly to screen for particular diseases. Unfortunately, these markers have their limitations. For one thing, it is unlikely that they will completely eliminate the problem of false positive and false negative results, since DNA from solid tumors undergoes slight degradation due to necrosis and since genetic markers are susceptible to the effects of exposure to medication, diet, sex, ethnicity, and even the circadian cycle. And even if false positives and negatives were ultimately eliminated, it would be impossible to use many of the analytical tools based on two by two tables, such as the chi squared test, logistic regression, the Poisson regression, Cox' proportional hazards ratio, etc., since such tools rely on comparisons of the number of false positives and negatives in the exposed and non-exposed groups. Finally, albeit no less important, certain ethical issues must be carefully considered before allowing the massive use of human genetic markers, which could lead to violations of the rights of individuals, families, and communities if carried out in an indiscriminate, unregulated fashion. Epidemiology is rapidly broadening its scope, a trend that will continue into the future; new analytical tools will be developed, and the working hypotheses to which such tools will be applied will change. At present the scientific community is paying increased attention to this field of study, but more research and discussion are needed to respond to many of the questions for which we have no satisfactory answers yet. <![CDATA[<B>The epidemiologic transition in Peru</B>]]> http://www.scielosp.org/scielo.php?script=sci_arttext&pid=S1020-49892005000100010&lng=en&nrm=iso&tlng=en En el presente trabajo se examina la transición epidemiológica en el Perú y se demuestra que los cambios observados en la situación de salud del país constituyen un buen ejemplo del modelo de transición no occidental que describe los cambios epidemiológicos producidos a lo largo del tiempo en países en desarrollo en función de tres etapas. Actualmente el Perú se encuentra en la tercera etapa de este modelo y tiene una carga de morbilidad que abarca tres componentes. Tiene, en primer lugar, problemas antiguos que aún no se han resuelto, como el de las enfermedades infecciosas "tradicionales" (por ej., las infecciones respiratorias agudas) y el de las elevadas tasas de mortalidad materna. También tiene, en segundo lugar, algunos problemas que apenas empiezan a aflorar: las enfermedades cardiovasculares y las neoplasias malignas se están incrementando, el paludismo y otras enfermedades más antiguas están reapareciendo, y la infección por VIH y el sida, más algunas otras enfermedades, han surgido por primera vez. En tercer lugar, el Perú adolece de una poca disponibilidad de buenos servicios de salud. En este contexto, el presente trabajo examina la gran falta de equidad en el Perú en lo concerniente a algunos indicadores de salud importantes (por ej., la esperanza de vida, la tasa de mortalidad, la tasa de fecundidad, y el acceso a seguro médico y a servicios de salud), a la luz del concepto de "polarización epidemiológica". Este último es un proceso según el cual la distribución desigual de la riqueza, de los riesgos de salud, y de los servicios de atención sanitaria redunda en diferencias cada vez mayores en el estado de salud de una población, y en una "brecha de salud" que se ensancha progresivamente entre pobres y ricos. Demostramos que la situación de salud del Perú ilustra todas las características del modelo de transición polarizada y prolongada, que es una variante del modelo de transición no occidental y que explica este proceso de polarización epidemiológica. Para hacerle frente a la triple carga de morbilidad y la polarización epidemiológica en el Perú, es necesario distribuir más uniformemente el desarrollo social y económico, procurando reducir la brecha entre ricos y pobres en lo referente a algunos factores determinantes destacados (por ej., el ingreso, la educación, la nutrición y los servicios de salud). Todo esto se conseguirá solo mediante grandes inversiones en la salud pública, la adopción de un enfoque integral por el Gobierno peruano, y el completo compromiso del Ministerio de Salud y de los formuladores de las políticas de salud y de otras áreas. <![CDATA[<B>The SAPUVET and SPVet networks</B>: <B>an integration model in veterinary public health between Europe and Latin America</B>]]> http://www.scielosp.org/scielo.php?script=sci_arttext&pid=S1020-49892005000100011&lng=en&nrm=iso&tlng=en This paper underscores the need for animal health professionals to play a more significant role in the sphere of public health, particularly during natural disasters and other emergency situations which can reduce the availability of safe foods from animal sources. In order to help readers understand the importance of the emerging field of veterinary public health (VPH), the authors review the importance and current status of VPH in different countries and assess the role that veterinarians can play in overcoming situations that threaten human health. The last section discusses the need for training veterinarians in VPH and the important role that veterinarians can play within international public health organizations and multidisciplinary groups, such as SAPUVET and SPVet networks. <![CDATA[<b>A multidisciplinary approach to scaling up HIV/AIDS treatment and care</b>: <b>the experience of the </b><b>Bahamas</b>]]> http://www.scielosp.org/scielo.php?script=sci_arttext&pid=S1020-49892005000100012&lng=en&nrm=iso&tlng=en Las Bahamas han estado poniendo en práctica un proceso de ampliación intensivo, práctico e integrado que ha provocado un rápido aumento del número de personas con infección por VIH o sida que tienen acceso al tratamiento con antirretrovíricos y a la atención de salud. Este proceso de rápida ampliación se ha visto facilitado por el establecimiento de un equipo multidisciplinario con gran experiencia en ciertas áreas clave, por la creación de una metodología para identificar carencias en los servicios de salud, y por la adopción de un plan que aprovecha los recursos existentes y los logros obtenidos en el pasado. Sigue habiendo la necesidad de preparar recursos humanos con la capacidad para responder a las exigencias del proceso de ampliación, así como de identificar nuevas fuentes de financiamiento para garantizar su sustentabilidad.