Molecular detection of adeno-associated virus in cases of spontaneous and intentional human abortion.

Pregnancy failure is a common event and often of unknown cause. Some viruses are thought to cause abortions including the adeno-associated viruses (AAV), viruses which are regarded as being without any definitive association to any human disease. This study investigated AAV infection in 81 human abortions, both spontaneous and intentional that occurred up to the 23rd week of gestation. Nucleic acid of AAV-2, 3, and 5 types from 118 decidual and chorionic tissues, collected from the patients in this study, was amplified by nested-PCR. In situ hybridization (ISH) was developed with a digoxigenin-labeled AAV probe in paraffin embedded tissues from the AAV positive cases. AAV was observed in 28.4% (23/81) of the cases, of which, 78.3% (18/23) were in the decidua and 21.7% (5/23) in the extravillous trophoblast, the chorionic plate, or chorionic villi fragments. AAV-2, the only type detected, occurred in 32.3% (22/68) and in 7.7% (1/13) of the spontaneous and intentional abortions, respectively. ISH revealed AAV in the decidua, chorionic tissue or chorionic plate and extravillous trophoblast. The detection of only AAV-2 type indicates that it is the most frequent in the population studied and/or shows tissue tropism. The presence of AAV in decidual or trophoblastic cells in cases of abortion, as observed by ISH, implies that the virus could jeopardize the pregnancy. The significant predominance in spontaneous cases suggests possibly a causal association between AAV and abortion.

Accuracy and repeatability of a micro plaque reduction neutralization test for vaccinia antibodies.

The detection of neutralizing antibodies against vaccinia virus is a valuable tool for the investigation of previous smallpox vaccination. Compulsory smallpox vaccination ended in Brazil during the early 1970s, although the vaccine was available until the late 1970s. The threat of smallpox as a biological weapon has called the attention of public health authorities to the need for an evaluation of the immune status of the population. Based on our previous experience with a micro plaque reduction neutralization test (PRNT) for the evaluation of yellow fever immunity, a similar test was developed for the detection and quantification of vaccinia neutralizing antibodies. A cross-sectional study to test the repeatability and validity of plaque reduction neutralization test (PRNT) for vaccinia antibodies was performed in 182 subjects divided into two categories: subjects above 31 years old and the other > or = 35 years old. Cases were subjects considered to have been vaccinated with vaccinia virus if they declared vaccination history or evidenced vaccination marks. The assay is carried out in 96-well plates, provides results within 30 h, is easily performed, has good sensitivity (92.7%) and specificity (90.8), excellent repeatability (ICC 0.89 (0.88; 0.92)) and is thus suitable for use in mass screening of a population's antibody levels.

[Anti-parvovirus B19 IgG antibody prevalence in pregnant women during antenatal follow-up and cases of non-immune hydropsis fetalis due to parvovirus B19, in the City of Rio de Janeiro]. / Prevalência de anticorpos IgG antiparvovírus B19 em gestantes durante o atendimento pré-natal e casos de hidropisia fetal não imune atribuídos ao parvovírus B19, na Cidade do Rio de Janeiro.

With the aim of measuring the prevalence of anti-parvovirus B19 IgG antibodies during pregnancy up to 24 weeks of gestation and detecting cases of nonimmune hydrops fetalis, 249 sera from pregnant women attending a reference hospital in Rio de Janeiro city, from June 2003 to November 2004 were collected. They were followed-up until the end of pregnancy, with 17 cases of fetal hydrops detected. Four cases were caused by parvovirus B19 and two of them occurred in pregnant women living in the western zone of the city, during February 2005. Anti-parvovirus B19 IgG antibodies were found in 172 (71.6%) pregnant women (CI 95% 65.5%-77.7%); this antibody prevalence is similar to results found for others Brazilian cities. The only variable associated with previous acquisition of IgG antibodies to parvovirus B19 was number of pregnancies greater than one (p= 0.02, CI 95% 0.36-0.94).

Erythrovirus B19 infection in acquired immunodeficiency syndrome: screening by histopathology, immunohistochemistry, and in situ hybridization.

Erythrovirus B19 infects erythrocytic progenitors, transiently interrupting erythropoiesis. In AIDS patients it causes chronic anemia amenable to treatment. We looked for evidences of B19 infection in stored bone marrow material from patients with acquired immunodeficiency syndrome. Histological sections were made from stored paraffin blocks from 33 autopsies (39 blocks) and 35 biopsies (45 blocks, 30 patients) performed from 1988 to 2002. They were examined after hematoxylin-eosin (HE) staining, immunohistochemical (IHC), and in situ hybridization. HE revealed intra-nuclear inclusion bodies ("lantern cells") suggesting B19 infection in 19 sections corresponding to 19 of 63 patients examined with this test. Seven of 78 sections subjected to immunohistochemistry were positive, corresponding to 7 of 58 patients examined with this test. Fourteen sections corresponding to 13 of the 20 HE and/or IHC positive patients were subjected to in situ hybridization, with six positives results. Among the 13 patients subjected to the three techniques, only one gave unequivocal positive results in all and was considered a true positive. The frequency of B19 infection (1/63 patients) in the material examined can be deemed low.

Reactogenicity of yellow fever vaccines in a randomized, placebo-controlled trial.

OBJECTIVE: To compare the reactogenicity of three yellow fever (YF) vaccines from WHO-17D and Brazilian 17DD substrains (different seed-lots) and placebo. METHODS: The study involved 1,087 adults eligible for YF vaccine in Rio de Janeiro, Brazil. Vaccines produced by Bio-Manguinhos, Fiocruz (Rio de Janeiro, Brazil) were administered ("day 0") following standardized procedures adapted to allow blinding and blocked randomization of participants to coded vaccine types. Adverse events after immunization were ascertained in an interview and in diary forms filled in by each participant. Liver enzymes were measured on days 0, 4-20 and 30 of the study. Viremia levels were measured on days 4 to 20 of follow-up. The immune response was verified through serologic tests. RESULTS: Participants were mostly young males. The seroconversion rate was above 98% among those seronegative before immunization. Compared to placebo, the excess risk of any local adverse events ranged from 0.9% to 2.5%, whereas for any systemic adverse events it ranged from 3.5% to 7.4% across vaccine groups. The excess risk of events leading to search for medical care or to interruption of work activities ranged from 2% to 4.5%. Viremia was detected in 3%-6% of vaccinees up to 10 days after vaccination. Variations in liver enzyme levels after vaccination were similar in placebo and vaccine recipients. CONCLUSIONS: The frequency of adverse events post-immunization against YF, accounting for the background occurrence of nonspecific signs and symptoms, was shown for the first time to be similar for vaccines from 17D and 17DD substrains. The data also provided evidence against viscerotropism of vaccine virus.

Viremic blood donor found by a rapid screening method in a season of high human parvovirus B19 activity in Niterói, Rio de Janeiro, Brazil.

Erythrovirus B19 infection is usually benign but may have serious consequences in patients with hemolytic anemia (transient aplastic crisis), immunodeficiency (in whom persistent infection can lead to chronic bone marrow failure with anemia), or who are in the first or second trimester of gestation (spontaneous abortion, hydrops fetalis, and fetal death). Being non-enveloped, B19 resists most inactivation methods and can be transmitted by transfusion. B19 is difficult to cultivate and native virus is usually obtained from viremic blood. As specific antibodies may be absent, and there is no reliable immunological method for antigen detection, hybridization or polymerase chain reaction are needed for detecting viremia. A rapid method, gel hemagglutination (Diamed ID-Parvovirus B19 Antigen Test), can disclose highly viremic donations, whose elimination lessens the viral burden in pooled blood products and may even render them non-infectious. In order to obtain native antigen and to determine the frequency of viremic donors, we applied this test to blood donors in a period of high viral activity in our community. Positive or indeterminate results were re-tested by dot-blot hybridization. We tested 472 donors in 1998 and 831 ones in 1999. One viremic donor was found in 1999. We suggest that in periods of high community viral activity the gel hemagglutination test may be useful in avoiding highly viremic blood being added to plasma pools or directly transfused to patients under risk.

Clinical presentation of parvovirus B19 infection in HIV-infected patients with and without AIDS.

Human parvovirus B19 replicates in erythrocyte precursors. Usually, there are no apparent hematological manifestations. However, in individuals with high erythrocyte turnover, as in patients with sickle-cell disease and in the fetus, the infection may lead to severe transient aplasia and hydrops fetalis, respectively. In AIDS patients, persistent infection may result in chronic anemia. By contrast, in HIV-positive patients without AIDS the infection evolves as a mild exanthematous disease. Two clinical descriptions exemplify these forms of presentation. In the first, an AIDS patient presented with bone marrow failure that responded to immunoglobulin. In the second, an HIV-positive patient without AIDS had a morbilliform rash, and needed no treatment. Knowing that an AIDS patient has chronic B19 anemia lessens concern about drug anemia; protects the patient from invasive diagnostic maneuvers; and prevents the patient from disseminating the infection. In AIDS patients with pure red cell aplasia, a search for parvovirus B19 DNA in the serum or in the bone marrow is warranted.