RESUMO
We evaluated the stability of hepatitis B virus (HBV) DNA in plasma samples stored at 42°C for external quality assessment (EQA) panels of viral load. To assess the stability of plasma samples containing different concentrations of HBV DNA, serial dilutions of HBV-infected samples with a viral load of 6.40 log(10) IU/mL were made to yield viral loads of 5, 4, and 3 log(10) IU/mL. These were incubated at 42°C for up to 7 days and then frozen at -70°C. Viral load testing for HBV DNA was performed for all samples using COBAS® AmpliPrep/COBAS® TaqMan® HBV Test (v.2.0, Roche, Switzerland). Results were compared with fresh frozen plasma samples as a benchmark to establish acceptable measurements on the days following sample collection. Although the results of this study demonstrated a decrease in HBV DNA viral load ranging from 0.005 to 0.30 log(10) IU/mL after storage at 42°C for up to 7 days, these values did not exceed 0.5 log(10), which is the estimated intra-assay variation for molecular tests. Thus, the insignificant decrease in viral load suggests that shipment of HBV in plasma samples at temperatures of up to 42°C is permissible if they are frozen within 7 days.
Assuntos
DNA Viral/sangue , DNA Viral/isolamento & purificação , Vírus da Hepatite B/genética , Temperatura Alta , Plasma/virologia , Temperatura Baixa , DNA Viral/genética , Vírus da Hepatite B/isolamento & purificação , Humanos , Controle de Qualidade , Reação em Cadeia da Polimerase em Tempo Real , Valores de Referência , Reprodutibilidade dos Testes , Manejo de Espécimes/métodos , Fatores de Tempo , Carga Viral/métodosRESUMO
Schistosomiasis constitutes a major public health problem, with an estimated 200 million people infected worldwide. Many areas of Brazil show low endemicity of schistosomiasis, and the current standard parasitological techniques are not sufficiently sensitive to detect the low-level helminth infections common in areas of low endemicity (ALEs). This study compared the Kato-Katz (KK); Hoffman, Pons, and Janer (HH); enzyme-linked immunosorbent assay- (ELISA-) IgG and ELISA-IgM; indirect immunofluorescence technique (IFT-IgM); and qPCR techniques for schistosomiasis detection in serum and fecal samples, using the circumoval precipitin test (COPT) as reference. An epidemiological survey was conducted in a randomized sample of residents from five neighborhoods of Barra Mansa, RJ, with 610 fecal and 612 serum samples. ELISA-IgM (21.4%) showed the highest positivity and HH and KK techniques were the least sensitive (0.8%). All techniques except qPCR-serum showed high accuracy (8295.5%), differed significantly from COPT in positivity , and showed poor agreement with COPT. Medium agreement was seen with ELISA-IgG (Kappa = 0.377) and IFA (Kappa = 0.347). Parasitological techniques showed much lower positivity rates than those by other techniques. We suggest the possibility of using a combination of laboratory tools for the diagnosis of schistosomiasis in ALEs.
Assuntos
Esquistossomose mansoni/diagnóstico , Esquistossomose mansoni/parasitologia , Esquistossomose mansoni/epidemiologia , Idoso de 80 Anos ou mais , Brasil/epidemiologia , Idoso , Humanos , Imunoensaio/métodos , Imunoensaio/estatística & dados numéricos , Testes de Precipitina/métodos , Criança , Pré-Escolar , Vigilância da População/métodos , Prevalência , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Medição de Risco/métodos , Adulto , Técnicas de Laboratório Clínico/métodos , Técnicas de Laboratório Clínico/estatística & dados numéricos , Doenças Endêmicas/estatística & dados numéricos , Adulto Jovem , Lactente , Pessoa de Meia-IdadeRESUMO
Schistosomiasis is a major public health concern, with 200 million people infected worldwide. In Brazil, this disease has been reported in 19 states, and its prevalence in the city of Barra Mansa in Rio de Janeiro State is 1 %. The parasitological diagnostic methods currently available in these areas lack sensitivity; however, enzyme-linked immunosorbent assays (ELISAs) have been employed successfully for the diagnosis of schistosomiasis by using antibodies against antigens of Schistosoma mansoni adult worms and eggs, and for the detection of circulating antigens. The objective of this study was to determine systematically the prevalence of S. mansoni infection in the peripheral areas of Barra Mansa. A cross-sectional study was conducted from April to December 2011 by using probabilistic sampling that collected 610 fecal samples and 612 serum samples. ELISA-IgG with total extracts and ELISA-IgM with trichloroacetic acid-soluble fractions were employed to detect antibodies against S. mansoni and were compared with the Kato-Katz and Hoffman parasitological techniques. Among the individuals studied, anti-S. mansoni antibodies were detected in 11.16 % (n = 71) by ELISA-IgG and in 20.75 % (n = 132) by ELISA-IgM, while the parasitological techniques showed 0.82 % (n = 5) positivity. The agreement between the two ELISA tests was 85.38 % (n = 543), and 8.65 % (n = 55) of the serum samples showed positive results in both tests. The higher positivity of the ELISA-IgM test corroborates the results of previous reports and indicates that the test may be a useful tool in epidemiological studies, particularly in areas of low endemicity for S. mansoni.
Assuntos
Anticorpos Anti-Helmínticos/sangue , Ensaio de Imunoadsorção Enzimática/métodos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Schistosoma mansoni/isolamento & purificação , Esquistossomose mansoni/diagnóstico , Adolescente , Adulto , Animais , Brasil/epidemiologia , Criança , Pré-Escolar , Cricetinae , Estudos Transversais , Fezes , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Prevalência , Schistosoma mansoni/imunologia , Esquistossomose mansoni/sangue , Esquistossomose mansoni/epidemiologia , Esquistossomose mansoni/imunologia , Adulto JovemRESUMO
Introduction: Angiostrongylus cantonensis is a natural parasite found in lung arteries of rats, which in humans may cause eosinophilic meningitis. Objective: To report the first case of eosinophilic meningitis caused by Angiostrongylus cantonensis in the city of São Paulo, Brazil. Case report: A male patient, 11 years old, living in the southern area of São Paulo, was admitted to the Pediatric Emergency Department with ongoing headaches for three days, but no fever or any other complaint. The presence of snails and rodents was reported in the peridomicile. The child was awake, lucid, oriented; muscular strength preserved, isochoric, photo reagent pupils and terminal nuchal rigidity - Glasgow Coma Scale (GCS) = 15. The laboratory tests showed a mild leukocytosis with 1736 eosinophils/mm3 and the CSF analysis disclosed 160 leukocytes/mm3 with 36% of eosinophils. The bacterial culture was negative. Computed Cerebral Tomography showed no alterations. The RT-PCR assay for detecting Angiostrongylus cantonensis larvae and DNA was negative. ELISA antibodies for IgG anti-A. cantonensis was negative in serum and undetermined in CSF and samples collected five days after the onset of symptoms. Seroconversion was observed in the sample collected 135 days later. Conclusion: the epidemiological and clinical data, the CSF alterations with eosinophilia and the seroconversion strongly suggest Angiostrongylus cantonensis eosinophilic meningitis.
Introdução: Angiostrongylus cantonensis é um parasito natural das artérias de pulmões de ratos, que pode causar, em humanos, meningite eosinofílica. Objetivo: Relatar o primeiro caso de meningite eosinofílica causado por A. cantonensis na cidade de São Paulo, Brasil. Relato de caso: Paciente do sexo masculino, 11 anos, residente na zona sul de São Paulo, foi admitido no serviço de emergência pediátrica com história de cefaléia há três dias, sem febre ou outras queixas. Relato de presença de moluscos e roedores no peridomicílio. Ao exame físico, criança desperta acianótica, anictérica, hidratada; lúcido, orientado; força muscular preservada, isocórica, pupilas fotorreagentes e rigidez de nuca terminal - Glasgow Coma Scale = 15. Exames laboratoriais indicaram leve leucocitose com 1736 eosinófilos/mm3 e a análise do líquor revelou a presença de 160 leucócitos/mm3 com 36% de eosinófilos. Cultura para bactérias negativa. Tomografia cerebral sem alterações. Pesquisa direta de larvas e de DNA por PCR-RT para Angiostrongylus cantonensis foi negativa. ELISA para anticorpos IgG anti-A. cantonensis negativo no soro e indeterminado no líquor nas amostras coletadas após cinco dias do início dos sintomas. Soroconversão observada na amostra coletada após 135 dias. Conclusão: A história epidemiológica, dados clínicos, alterações liquóricas com presença de eosinofilia e a soroconversão sugerem fortemente o diagnóstico de meningite eosinofílica por A. cantonensis.
Assuntos
Brasil/epidemiologia , Humanos , Criança , Angiostrongylus cantonensis/isolamento & purificação , Eosinofilia/diagnóstico , Eosinofilia/parasitologia , Animais , Meningite/diagnóstico , Meningite/parasitologia , Meningite/epidemiologiaRESUMO
SETTING: Goiânia City, Goiás State, Brazil. OBJECTIVES: To determine the prevalence of hepatitis C virus (HCV) infection, risk factors, HCV genotype/ subtype, HCV viral load and human immunodeficiency virus (HIV) status in patients with tuberculosis (TB) in Central Brazil. DESIGN: A cross-sectional study was carried out with 402 patients who were under tuberculosis (TB) treatment in the reference hospital for infectious diseases in Goiânia, Goiás, Central Brazil. RESULTS: The prevalence rates of HCV and HIV were respectively 7.5% and 27.6%. Two thirds of the HCV-infected patients (20/30) were HIV-positive. Age, injecting drug use (IDU) and HIV status were factors independently associated with HCV infection. HCV RNA was detected in 23 serum samples; HCV RNA levels were measured in 22/23 samples. HCV RNA level was slightly higher in HCV-HIV co-infected patients than in HCV monoinfected patients. Genotypes 1 (n = 17) and 3 (n = 6) were determined by LiPA. Using phylogenetic tree analysis of the NS5B region, subtypes 1a (n = 12), 1b (n = 2) and 3a (n = 6) were identified. CONCLUSION: These data indicate that patients with TB may benefit from integrated HIV and HCV screening, which may have an important impact upon TB management and treatment.
Assuntos
Coinfecção , Hepatite C/epidemiologia , Tuberculose/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Brasil , Criança , Pré-Escolar , Estudos Transversais , Feminino , Genótipo , Infecções por HIV/diagnóstico , Infecções por HIV/epidemiologia , Infecções por HIV/virologia , Soropositividade para HIV , HIV-1/imunologia , Hepacivirus/genética , Hepacivirus/imunologia , Hepatite C/diagnóstico , Anticorpos Anti-Hepatite C/sangue , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , RNA Viral/análise , Medição de Risco , Fatores de Risco , Tuberculose/diagnóstico , Tuberculose/terapia , Adulto JovemRESUMO
Since the identification of hepatitis C virus (HCV) in 1989 as a causative agent for a number of the extrahepatic alterations related to HCV infection an underlying immune mediated pathogenetic mechanism has been postulated. HCV-associated thrombocytopenia may be considered complex and multifactorial in origin, since different mechanisms have been implicated in its pathophysiology. With respect to autoimmune thrombocytopenia in chronic HCV infection, the detection of specific antibodies against platelet glycoproteins have been reported only in a few studies, but no systematic study has been carried out. We examined the clinical, laboratory, and virological characteristics of a case series of 10 patients with autoimmune thrombocytopenia (platelet count <150.0 x 10(9)/L) related to chronic HCV infection. Cases, six males and four females, aged 57.1 +/- 12.6 years, presented high titers of antibodies against platelet glycoprotein (GP) IIb/IIIa, GP Ia/IIa, and/or GP Ib/IX, and no other mechanism involved in the pathogenesis of HCV-associated thrombocytopenia was identified. Furthermore, cases were not associated with particular HCV genotype. Complete platelet response was observed in two patients treated with pegylated interferon plus ribavirin, and partial platelet response was seen in two patients treated with anti-D Ig and one patient treated with corticosteroids. These findings indicate that an autoimmune mechanism may play a role in the pathogenesis of HCV-associated thrombocytopenia in a proportion of these patients.
Assuntos
Anemia Hemolítica Autoimune/virologia , Hepatite C Crônica/sangue , Adulto , Idoso , Anemia Hemolítica Autoimune/sangue , Anticorpos/sangue , Anticorpos/imunologia , Antivirais/uso terapêutico , Quimioterapia Combinada , Feminino , Hepatite C Crônica/tratamento farmacológico , Humanos , Interferon alfa-2 , Interferon-alfa/uso terapêutico , Masculino , Pessoa de Meia-Idade , Contagem de Plaquetas , Glicoproteínas da Membrana de Plaquetas/imunologia , Polietilenoglicóis , Estudos Prospectivos , Proteínas Recombinantes , Ribavirina/uso terapêuticoRESUMO
The present study examined the distribution of hepatitis C virus (HCV) genotypes and subtypes in a hemodialysis population in Goiás State, Central Brazil, and evaluated the efficiency of two genotyping methods: line probe assay (LiPA) based on the 5' noncoding region and nucleotide sequencing of the nonstructural 5B (NS5B) region of the genome. A total of 1095 sera were tested for HCV RNA by RT-nested PCR of the 5' noncoding region. The LiPA assay was able to genotype all 131 HCV RNA-positive samples. Genotypes 1 (92.4%) and 3 (7.6%) were found. Subtype 1a (65.7%) was the most prevalent, followed by subtypes 1b (26.7%) and 3a (7.6%). Direct nucleotide sequencing of 340 bp from the NS5B region was performed in 106 samples. The phylogenetic tree showed that 98 sequences (92.4%) were classified as genotype 1, subtypes 1a (72.6%) and 1b (19.8%), and 8 sequences (7.6%) as subtype 3a. The two genotyping methods gave concordant results within HCV genotypes and subtypes in 100 and 96.2% of cases, respectively. Only four samples presented discrepant results, with LiPA not distinguishing subtypes 1a and 1b. Therefore, HCV genotype 1 (subtype 1a) is predominant in hemodialysis patients in Central Brazil. By using sequence analysis of the NS5B region as a reference standard method for HCV genotyping, we found that LiPA was efficient at the genotype level, although some discrepant results were observed at the subtype level (sensitivity of 96.1% for subtype 1a and 95.2% for subtype 1b). Thus, analysis of the NS5B region permitted better discrimination between HCV subtypes, as required in epidemiological investigations.
Assuntos
Regiões 5' não Traduzidas/genética , Hepacivirus/classificação , Hepatite C/virologia , Análise de Sequência de DNA/métodos , Proteínas não Estruturais Virais/genética , Sequência de Bases , DNA Viral/análise , Genótipo , Hepacivirus/genética , Hepatite C/diagnóstico , Humanos , Dados de Sequência Molecular , Reação em Cadeia da Polimerase/métodos , Diálise RenalRESUMO
The present study examined the distribution of hepatitis C virus (HCV) genotypes and subtypes in a hemodialysis population in Goiás State, Central Brazil, and evaluated the efficiency of two genotyping methods: line probe assay (LiPA) based on the 5' noncoding region and nucleotide sequencing of the nonstructural 5B (NS5B) region of the genome. A total of 1095 sera were tested for HCV RNA by RT-nested PCR of the 5' noncoding region. The LiPA assay was able to genotype all 131 HCV RNA-positive samples. Genotypes 1 (92.4 percent) and 3 (7.6 percent) were found. Subtype 1a (65.7 percent) was the most prevalent, followed by subtypes 1b (26.7 percent) and 3a (7.6 percent). Direct nucleotide sequencing of 340 bp from the NS5B region was performed in 106 samples. The phylogenetic tree showed that 98 sequences (92.4 percent) were classified as genotype 1, subtypes 1a (72.6 percent) and 1b (19.8 percent), and 8 sequences (7.6 percent) as subtype 3a. The two genotyping methods gave concordant results within HCV genotypes and subtypes in 100 and 96.2 percent of cases, respectively. Only four samples presented discrepant results, with LiPA not distinguishing subtypes 1a and 1b. Therefore, HCV genotype 1 (subtype 1a) is predominant in hemodialysis patients in Central Brazil. By using sequence analysis of the NS5B region as a reference standard method for HCV genotyping, we found that LiPA was efficient at the genotype level, although some discrepant results were observed at the subtype level (sensitivity of 96.1 percent for subtype 1a and 95.2 percent for subtype 1b). Thus, analysis of the NS5B region permitted better discrimination between HCV subtypes, as required in epidemiological investigations.
Assuntos
Humanos , /genética , Hepacivirus/classificação , Hepatite C/virologia , Análise de Sequência de DNA/métodos , Proteínas não Estruturais Virais/genética , Sequência de Bases , DNA Viral/análise , Genótipo , Hepacivirus/genética , Hepatite C/diagnóstico , Dados de Sequência Molecular , Reação em Cadeia da Polimerase/métodos , Diálise RenalRESUMO
Patterns of phenological variation and reproductive investment were studied in the dioecious shrub Baccharis dracunculifolia DC (Asteraceae), and possible consequences on survivorship were evaluated. The sex ratio was determined in a natural field population (n = 921) of B. dracunculifolia in Belo Horizonte, Brazil. Fifty-two males and 56 females were sampled at random from this population. During the reproductive season of 1999, inflorescence production, shoot growth and mortality, and xylem water potential were recorded for each individual. The population sex ratio was male-biased (1.27 : 1, P < 0.05), and was associated with a higher mortality of female shoots (38.4 vs. 23.1 %, P < 0.05), and individuals (17.8 vs. 11.5 %, P < 0.1), despite lower water stress in female plants. Flowering phenology also differed between the sexes, with males producing more inflorescences, and earlier, than females. Owing to fruit maturation, the number of inflorescences supported by females was higher than that supported by males later in the reproductive season. This occurred during the dry season, and drought stress may have been responsible for the greater female mortality. Thus, the male-biased sex ratio in this population of B. dracunculifolia is probably due to different reproductive functions of males and females. Intersexual differences in reproductive phenology had consequences for plant demography.
Assuntos
Baccharis/fisiologia , Brasil , Flores , Reprodução , Clima Tropical , ÁguaRESUMO
The authors analysed the indirect immunofluorescence assay, for the diagnosis of bancroftian filariasis using papain treated W. bancrofti microfilariae as antigen, widely used in Recife-Brazil. Sera from 50 patients with several clinical forms of the disease including asymptomatic carriers, tropical pulmonary eosinophilia, elephantiasis, filarial fever and chyluria were analysed. For the control group, 50 individuals were selected, living at least 5 years in endemic area, with neither previous DEC treatment nor clinical-laboratory evidences of the disease, called normals endemic. The sensitivity and specificity were analysed taking into account different cut off values. It was not possible to differentiate infected individuals from the control group. It was not even possible to establish any correlation with IMF titers among different clinical presentation of the disease. Crossed reactions with various intestinal helminths were considered, but no relationship was found.