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To define better the epidemiology and clinical impact of hepatitis delta virus (HDV) infection among hepatitis B virus (HBV) carriers in less developed countries, the authors prospectively studied a cohort of 216 Yucpa Indian HBV carriers in Venezuela. HBV carriers were followed regularly between 1983 and 1988 by physical examination, laboratory testing for liver enzymes and HBV and HDV markers, and epidemiologic history. Among the cohort, 74 (34%) were initially positive for HDV infection, and 35 additional persons became infected during the study. Risk factors for new HDV infection included living in southern Yucpa villages; being young adults (15-19 years) or young children (1-9 years), and living in a household with a person with acute HDV infection. Persons with HDV infection were at high risk of developing chronic liver disease; 56% of HDV-infected persons had moderate-to-severe chronic liver disease at the end of the study compared with none of the HBV carriers without HDV infection. Mortality rates were 6.9% and 8.8% per year, respectively, among initially HDV-positive HBV carriers and those with new HDV infection, because of rapidly progressive chronic liver disease and fulminant hepatitis; mortality was significantly lower in HBV carriers without HDV infection and in non-HBV carriers. HDV superinfection is a devastating disease in HBV carriers in tropical South America. Prevention of HBV infection with hepatitis B vaccine is the best available tool to reduce the impact of this problem.

To supplement a detailed epidemiologic study of an outbreak of viral hepatitis in Venezuelan Indians in isolated valleys, apparently resulting from delta agent infection, 10 autopsy specimens were studied histologically and immunocytochemically, and five biopsy specimens were examined. The patients were children and young adults and predominantly males. A sequence of hepatitis from focal necrosis with conspicuous small-droplet steatosis, through massive necrosis, prolonged postnecrotic collapse to early cirrhosis with massive collapse was postulated. The histologic changes tentatively suggest a cytopathic effect of the delta agent without significant indication of lymphocytotoxicity, at least in the parenchyma. Delta agent was demonstrated in hepatocyte nuclei in moderate amounts in the focal-necrotic stage and in isolated cells in the massive-necrotic stage, but in large amounts during the transition to cirrhosis. Whether these patients, in whom neither HBcAg nor HBsAg were demonstrable in the liver, suffered exclusively from superinfection of hepatitis B virus carriers and/or coinfection of hepatitis B virus with the delta agent remains to be resolved. Delta infection may occur in isolated settings with no relation to Italian origin, drug addiction, or polytransfusion. The infection is far more widely spread than previously assumed.Six years ago in Italy, Rizzetto and coworkers (1) described the delta agent as a pathogenic factor complicating infection with hepatitis B virus (HBV). It is now thought to contain a small RNA genome surrounded by delta antigen and a coat of HBV surface antigen and to elicit a specific immune response which permits clinical diagnosis of delta infection. The delta agent requires coinfection with HBV for its replication which is associated with inhibition of synthesis of HBV markers. Delta antigen can be demonstrated immunohistochemically in hepatocellular nuclei (2, 3). Delta agent frequently occurs as a superinfection in HBV carriers with preexisting, sometimes minimal, degrees of histologic injury. In these persons, superinfection produces severe deterioration of the clinical and histologic picture often with fatal progression (4,5). Histologically, exacerbation

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La identificación diferencial de Entamoeba histolytica y Entamoeba dispar es esencial para un tratamiento adecuado del paciente y con fines epidemiológicos. Para determinar la prevalencia de E. histolytica y E. dispar se estandarizó y aplicó un ensayo de PCR, utilizando oligonucleótidos específicos para cada especie. 204 muestras de heces de individuos de la comunidad de Santa Rosa de Agua (Municipio Maracaibo, Estado Zulia, Venezuela), fueron analizadas a través del examen directo con SSF (0,85%) y lugol, concentrado de formol-éter y PCR. Al examen microscópico, 42 individuos (20,58%) presentaron formas evolutivas del complejo E. histolytica/E. dispar; mientras que la técnica de PCR evidenció un total de 47 casos positivos a estas amibas; de los cuales 22 eran portadores de E. histolytica (10,78%), 16 (7,84%) de E. dispar y 9 (4,41%) presentaron infección mixta. No hubo diferencia significativa al relacionar las variables sexo y presencia de E. histolytica y/o E. dispar, ni con los grupos etarios. No existieron casos de estas amibas, en los menores de 2 años. La frecuencia observada de E. histolytica (31/204), demuestra el carácter endémico de la amibiasis en esta comunidad.

Maternal serum β-hCG and AF-AFP levels may preferentially identify those Turner syndrome pregnancies with the highest risk of fetal death.

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Objective: To identify genetic risk factors and frequency and to describe congenital defects of the fetus. Methods: The research was conducted at the Genetic Research Institute of the Faculty of Medicine. University of Zulia. Maracaibo. We studied patients who attend to the prenatal genetic clinic. According to the Genetic risk factors Identified, it indicated different prenatal diagnostic procedures: fetal echography, fetal echocardiography, triple maternal serum marker, amniocentesis for fetal karyotype and molecular analysis. Results: We included 568 patients. 79.05% of the total showed only one genetic risk factor and the 20.95% two or more. The advanced maternal age was the most frequent genetic risk factor found (40.85%), followed by first-degree family history with a congenital defect (35.21%), abnormal fetal echography (13.73%), exposure to teratogenic agents (10.39%), history of recurrent abortion (7.04%), history of fetal death (4.22%), consanguinity (1.93%), and history of neonatal death (1.76%). They were diagnosed 101 fetuses with congenital defects, one balanced translocation, two fetal deaths and 26 spontaneous abortions. Conclusion: The genetic risk factors identification, served as a starting point to indicate prenatal diagnostic procedures allowed a health evaluation of the fetus and adequate genetic counseling. Key words: Prenatal diagnosis, Risk factors, Genetic counseling.