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Amostras de soro sanguineo (n: 110) de individuos de comportamento de risco e doadores de sangue da cidade de Cordoba, na Argentina, com perfis de reactividade para HIV-1 e HTLV-I/II indeterminada por Western blot (Wb), foram estudadas para anticorpos especificos contra HTLV-I/II e HIV-1 por meio do Ensaio de Imunofluorescencia Indireta (IFI). Este estudo foi realizado para caracterizar as reacoes putativas com proteinas HIV-1 e HTLV-I/II e resolver o estado da infeccao por retrovirus destes individuos. Os resultados mostram que os soros dos doadores sanguineos que apresentam padroes indeterminados para HTLV-I/II e HIV-1 no Wb nao sao reagentes contra HTLV-I/II e HIV-1 por IFI. Mas, um alto indice de amostras de individuos com alto risco com resultado indeterminado no Wb para HIV-1 e HTLV-I/II apresentaram resultados positivos para HTLV-I/II e HIV-1 por IFI, respectivamente. Nosso estudo sugere que a reatividade indeterminada para HTLV-HIV na populacao de baixo risco deve-se a uma reacao cruzada contra antigenos nao virais; e que na populacao de alto risco as amostras indeterminadas apresentam reacao cruzada entre as proteinas HIV-1 e HTLV-I/II no Wb. Estes resultados indicam que se faz preciso pesquisar a reatividade de HTLV-I/II nas amostras indeterminadas de HIV-1 e vice-versa, para confirmar o diagnostico. Por ultimo, este trabalho mostra a utilidade potencial da IFI para determinar o estado de infeccao HIV-1 e HTLV-I/II dos individuos com perfis indeterminados por Wb, permitindo assim, a resolucao do estado real de infeccao por retrovirus.

To evaluate the prevalence of enteric viruses and their possible association with diarrhea, 244 stool samples were collected from HIV-infected and uninfected patients with or without diarrhea (subgroups I-a, Ib, II-a, and II-b, respectively). Subjects were screened by polyacrylamide gel electrophoresis, latex agglutination, and enzyme immunoassays for rotaviruses, adenoviruses, picobirnaviruses, and astroviruses. Enteric viruses were found significantly more often in specimens from HIV patients (20%) than in specimens from uninfected HIV patients (0%) (p0.05). Picobirnavirus was detected in 14.63% of 82 HIV-infected patients with diarrhea, but it was detected neither in those without diarrhea (0%) (p0.05) nor in the groups of uninfected HIV subjects (0%) (p0.05). Nor could astrovirus (subgroups I-a [4.00%] versus subgroup I-b [5.26%],p0.05) or enteric adenovirus (subgroup I-a [1.22%] versus subgroup I-b [0%], p0.05) be linked to the diarrhea disorder in HIV-infected patients. Rotaviruses were not detected in any of the clinical subgroups studied. Enteric viruses were detected in 15 of 93 (16.13%) of the HIV-infected patients with CD4+ T cell count200/microl and 3 of 19 (15.79%) of those HIV-infected individuals with a CD4+ T cell count 200-499/microl, showing no significant difference (p0.05). According to our data, unusual enteric viruses such as picobirnavirus, astrovirus, and enteric adenovirus occur in HIV-infected population in Córdoba, Argentina. However, only picobirnaviruses could be significantly associated with diarrhea in these patients.

This study aimed at implementing a Nested-polymerase chain reaction (Nested-PCR) for the molecular diagnosis of human T-cell lymphotropic virus type I/II (HTLV-I and HTLV-II) infections in peripheral blood mononuclear cells of infected subjects in Argentina. The sensitivity and specificity of the assay for the detection of regional strains were assessed by comparing them with the molecular assay of reference PCR-hybridization. The Nested-PCR detected 1 MT-2 cell (³ 8 proviral copies)/1x106 non-infected cells showing high sensitivity for provirus detection. While both molecular assays showed high specificity (100%) for HTLV-I and HTLV-II detection, the sensitivity values differed: 100% for Nested-PCR and 67% for PCR-hybridization assay. Moreover, this technique showed less sensitivity for the detection of DNA sequences of HTLV-II (33%) than for the detection of DNA sequences of HTLV-I (75%). The high sensitivity and specificity of the Nested-PCR for regional strains and its low costs indicate that this assay could replace the PCR-hybridization assay for the molecular diagnosis of HTLV-I/II infections. It will be interesting to assess the usefulness of this assay as a tool for the molecular diagnosis of HTLV-I/II infections in other developing countries. Other studies that include a greater number of samples should be conducted.

Background: Human herpesvirus-6 (HHV-6) infection is widespread throughout the world. No data are available in Argentina about the loss of maternally derived HHV-6 immunity and natural infection in infants.Methods: A population of 100 pregnant women and 407 children between 1 and 15 months of age were assayed by indirect immunofluorescence to detect and quantify specific IgG anti-human herpesvirus-6 (anti-HHV-6) antibodies in Córdoba City, Argentina.Results: There was no significant difference in the positive rate between infants aged 1 to 9 months (range, 43.6–35.5%) and pregnant women (37%). Seropositive ratio dropped in the 10-month group (23.33% seropositive) and rose sharply in the 11-month group (38.89%), 12-month (60.61 %), and 13- to 15-month group (63.46%). The geometric mean titer (GMT) for infants in the 12 to 15 months age group (23.4–41.64) was significantly higher than the GMT for infants 10 months of age (11.04) (P < 0.05 with the Tukey-HSD test).Conclusions: This study shows a significant association between loss of passive HHV-6 antibody and age among infants. The results support evidence that HHV-6 enters the susceptible population at 11 months, leading to a high prevalence of antibodies in children between 13 and 15 months of age.

Diarrhea due to enteric pathogens is an important complication of advanced HIV infection. Picobirnaviruses are agents recently linked with human enteritis. In total, 197 fecal samples collected from HIV-infected and noninfected patients with and without diarrhea were investigated for the presence of rotavirus and picobirnavirus by polyacrylamide gel electrophoresis. Picobirnavirus was detected in 8.8% of 57 HIV-infected patients with diarrhea, but it was detected in neither those without diarrhea (p.018) nor in the group of subjects uninfected with HIV (p.022). All genomic electropherotypes of picobirnavirus strains had a wide pattern. Picobirnavirus genome segments varied in size between 2.4 and 2.7 and 1.6 and 1.9 kbp for the slow and fast migrating bands, respectively. Rotaviruses were not detected in any of the clinical groups studied. Two methods for the extraction of nucleic acid-phenol/chloroform and guanidinium thiocynate (GTC)/silica-were compared. Detection of picobirnavirus by polyacrylamide gel electrophoresis was 2.5 times more sensitive following guanidinium thiocynate RNA extraction. This investigation offers preliminary results about the circulation of picobirnavirus in HIV-infected patients in Córdoba, Argentina.In 1988, a new group of viruses containing a bisegmented double-stranded RNA genome was described and named "picobirnavirus" (PBV). Viruses with similar properties have subsequently been found in fecal specimens collected from HIV-infected and noninfected patients with gastrointestinal symptoms in several countries. The present study used polyacrylamide gel electrophoresis (PAGE) to examine fecal specimens from 197 HIV infected and noninfected adults, with and without diarrhea, from Cordoba, Argentina, for rotavirus and PBV. PBVs were detected in the stools of 5 HIV-infected patients with diarrhea (8.8%), but in none of the other subgroups (HIV-positive patients without diarrhea, HIV-negative patients with diarrhea, HIV-negative patients without diarrhea). 3 of the 5 stool samples positive for PBV were also positive for intestinal parasites (mixed infection), but these parasites were found with equal frequency in HIV-infected patients without diarrhea. Rotaviruses were not detected in any of the subgroups. PBV genome segments varied in size between 2.4-2.7 and 1.6-1.9 kbp for the slow and fast migrating bands, respectively. PBV detection by the PAGE technique was 2.5 times more sensitive after guanidinium thiocyanate RNA extraction. Further research is required to determine the duration of excretion of PBVs in HIV-infected patients with diarrhea and understand the immune response to infection.

Background. Measles immunization of children at 1 year of age with a single dose of the current vaccine has successfully reduced measles incidence in Argentina. However, the optimal schedule of measles vaccination of young infants would balance the risk of early loss of maternal antibody in the majority of infants with the risk of primary vaccine failure because of passive measles immunity. This study is the first to document a significant association between loss of passive measles antibody and age among infants born in 1995 and 1996 in Cordoba City, Argentina. Methods. This is a seroprevalence study of 340 infants to investigate the duration of transplacentally derived measles antibody, assayed by a neutralization test, during the first 8 months of age in C6rdoba City, Argentina. Results. The proportion with detectable neutralizing measles antibodies decreased from 85% at 1 month of age to 8% at 8 months of age. The simple logistic model with age (in weeks) as the only variable showed that the decline in the proportion of infants with a positive antibody titer was sharpest during the second and fifth months of age (6.6 and 6.8% per week during a 4-week period, respectively). Conclusions. These findings suggest that 80% of infants are susceptible to measles infection for at least 3 months before routine immunization at 12 months of age.

Recent epidemiologic studies in Buenos Aires suggest the presence of HTLV-I/II in blood banks and in the population at risk for HIV-1 infection with seroprevalence of 4% among IV drug users 0.5% in homosexual men and 0.1% in blood donors. However neither blood nor blood derivatives in Argentina are screened for these agents. Findings are presented from an HTLV-I/II seroprevalence survey conducted in Cordoba City Argentina. 312 serum samples collected during 1985-95 from HIV-1-positive subjects and others exposed to HIV through blood transfusion were screened for antibodies to HTLV-I/II. Of 10 sera reactive to Serodia HTLV-I particulate agglutination (PA) assay 6 were confirmed HTLV-I-positive and 1 was confirmed HTLV-II-positive by indirect immunofluorescence assay (IFA). Of 6 HTLV-I-positive samples on IFA 5 were confirmed positive by Western blot (WB) but 1 sample was not tested. The IFA HTLV-II-positive sample was indeterminate with a weak reaction to the p24 and p19 HTLV-I proteins. Blood banks should screen for the presence of HTLV-I/II infection in blood supplies in order to prevent their widespread dissemination in the population.