Enteroparasitas e Capillaria SP entre o grupo Surui, Parque Indigena Aripuana, Rondonia

Este trabalho apresenta dados de enteroparasitas encontradas em índios da comunidade tribal de Suruí, em Rondônia, na Região Amazônica do Brasil. As seguintes espécies foram encontradas: Ascaris lumbricoides (53,3%), Ancilostomidae (43,3%), Strongyloides stercoralis (33,3%), Taenia sp. (5,8%), Trichuris trichiura (5,0%), Hymenolepis nana (4,1%), Giardia lamblia (3,3%), Entamoeba histolytica complex (0,8%) e Enterobius vermicularis (0,1%). O encontro de Capillaria sp. nas fezes de dois individuos é discutido.

Geographic distribution of HBsAg subtypes in Brazil

HBsAg positive serum samples (896) from five brazilian regions were analysed for HBsAg subtypes. The presence of five different subtypes (ayw2, ayw3, ayw4, adw2 and adw4) was detected. In Northern region subtypes adw4 (41.2%) and adw2 (37.2%) were predominant. In the North East only subtype adw2 was encountered. In Central West, South-East and South, subtypes ayw2, ayw3, adw2 and adw4 were present, with predominance of adw2 in Central West and South East (84.3% and 69.4% respectively) whereas in the South the predominant subtype was ayw3 (41.9%) followed by ayw2 (36.4%). Subtypes ayw1, ayr and adr were not found among the samples studied. These results show the difference in the incidence of HBsAg subtypes in the different regions of Brazil and their significance in relation to the colonization and migrations in this country.

Alternative approaches in schistosomiasis control

Measures for for the control of schistosomiasis were implemented in Egypt begining 1922. This shows that developing endemic countries are facing this problem for near 70 years. However, results in the control of this infection have not been satisfactorily obtained in spite of the technologies and strategies recently developed. The idea that the social and economic components are relevant in the control of schistosomiasis is not new although its extension and profundity have not usually been well understood. More recently; most of the workers have recognized that the distribution of the prevalence rates of schistosomiasis should not be neglected in the control of the infection. At present field work projects on the control of schistosomiasis are being developed in rural areas of two Brazilian states (Espirito Santo and Pernanbuco). The adopted strategy aims to interfere in the complex relationships between amn and his bio-social-cultural environment, without forgeting tha the unequal distribution of the space is a consequence of the political and economic organization of the Society.

Internalization of components of the host cell plasma membrane during infection by Trypanosoma cruzi

Epimastigote and trypomastigote forms of Trypanosoma cruzi attach to the macrophage surface and are internalized with the formation of a membrane bounded vacuole, known as the parasitophorous vacuole (PV). In order to determine if components of the host cell membrane are internalized during formation of the PV we labeled the macrophage surface with fluorescent probes for proteins, lipids and sialic acid residues and then allowed the labeled cells to interact with the parasites. The interaction process was interrupted after 1 hr at 37ºC and the distribution of the probes analyzed by confocal laser scanning microscopy. During attachment of the parasites to the macrophage surface an intense labeling of the attachment regions was observed. Subsequently labeling of the membrane lining the parasitophorous vacuole containing epimastigote and trypomastigote forms was seen. Labeling was not uniform, with regions of intense and light or no labeling. The results obtained show that host cell membrane lipids, proteins and sialoglycoconjugates contribute to the formation of the membrane lining the PV containing epimastigote and trypomastigote T. cruzi forms. Lysosomes of the host cell may participate in the process of PV membrane formation.

Prevalence of hepatitis B and C virus markers among malaria-exposed gold miners in Brazilian Amazon

Hepatitis B and C virus markers were assessed during a survey on malaria in gold mine camps in southern Brazilian Amazon in order to identify risk factors associated to these viral diseases. The study comprised 520 subjects, most of them were gold miners. Missing subjects totaled 49 (8.6%). Among these 520, 82.9% had HBV markers and 7.1% were HBsAg positive. Previous hospitalization, surgery, sexually transmitted diseases and incarceration were quite common among surveyed people, but there is no association between total HBV markers and these factors. On other hand, HBsAg was independently associated to history of sexually transmitted diseases and history of surgery after adjustment. The most frequent HBsAg subtypes identified, adw2 (59%), predominates in populations of Northeast Brazil. The most surveyed people were immigrants coming from that area suggesting that immigrants carried HBV themselves to the study area. Immunoblot (RIBA) confirmed-anti-HCV were found in 2.1%. The only variable associated to anti-HCV in multivariate analysis was illicit intravenous drug. Lack of HCV infection in subjects with such a high HBV markers prevalence reinforces the opinion that HCV is transmitted by restricted routes when compared to HBV. Furthermore, gold miners in Amazon may be considered as a risk group for HBV infection, but not for HCV.

Relation between Hepatitis B Carrier Status and Antibody against Synthetic Plasmodium falciparum Erythrocyte Surface (pf155 - RESA) Antigen

A survey on Plasmodium infection was carried out in gold mine camps located in the Brazilian Amazon. Antibody against P. falciparum ring-infected erythrocyte surface antigen (RESA) was quantified by an enzyme-immunoassay in order to assess P. falciparum exposure. Hepatitis B, a common infection in this area, was also investigated by serologic markers. Among 520 sampled subjects, 517 (99.4%) admitted previous symptomatic malaria, 106 (20.4%) had positive thick smears for malaria, 82.9% had HBV markers, and 7.1% were HBsAg positive. Anti-RESA titers was significantly lower in HBV carriers than in people with resolved HBV infection suggesting that the anti-RESA immune response could be supressed by HBV carrier status. Moreover, immunedeficient responses to both infections may take place in some subjects causing concomitant lower anti-RESA response and incapacity to clear HBV.

Viral Hepatitis Markers in Antepartum and Postpartum Women in Rio de Janeiro, Brazil

A seroprevalence study was carried out among a group of women in Rio de Janeiro to determine the prevalence of different markers for viral hepatitis given the limited data among healthy populations. Blood samples collected and tested from 874 women before or after delivery in a public county maternity hospital demonstrated age to be directly related to markers for hepatitis A virus and hepatitis B virus (HBV) infection. The prevalence of HBV and hepatitis C virus infection were lower than that observed in the blood donor population and might be explained by the younger age group and gender.

Hepatitis A Outbreak in a Public School in Rio de Janeiro, Brazil

From June 1 to July 1 1999, an outbreak involving 25 cases of hepatitis A occurred in a public school in Rio de Janeiro, Brazil. Since these cases were notified to the State Health Department, the National Reference Center for Hepatitis Viruses (CNRHV) was required to investigate the extent of hepatitis A virus (HAV) dissemination. Blood samples from all students were tested for IgM and total anti-HAV antibodies using a commercial enzyme-linked immunoassay (ELISA). At the same time, a questionnaire was completed in order to identify possible risk factors for HAV infection. The environmental investigation showed that there was no fecal contamination of the water supply. The epidemiological investigation demonstrated that almost 50% of this population was susceptible to HAV infection and probably person-to-person transmission was the principal mode of virus dissemination. In this situation, a massive vaccination campaign could control the HAV infection.

Seroepidemiological markers of enterically transmitted viral hepatitis A and E in individuals living in a community located in the North Area of Rio de Janeiro, RJ, Brazil

We investigated the seroprevalence of hepatitis A virus (HAV) and hepatitis E virus (HEV) infection in subjects living in the community of Manguinhos, Rio de Janeiro, Brazil, and assisted at the Health Unit of Escola Nacional de Saúde Pública, Fundação Oswaldo Cruz. After formal consent, individuals were submitted to an interview using a standardized questionnaire. Anti-HAV and anti-HEV antibodies were detected by ELISA. Statistical analysis was carried out using the Epi-Info 6.04b software, to investigate possible associations between serological markers and risk factors. Results were regarded as significant when p value < 0.05. Although a high prevalence of anti-HAV was observed (87%), almost 50% of subjects under the age of 10 were susceptible to HAV infection, an unexpected rate in endemic areas. This fact could be attributed to improvements in environmental sanitation, occurring in this area in the last years. The increasing proportion of susceptible people may result in outbreaks of HAV infection, since the virus still circulates in this area, as verified by the detection of anti-HAV IgM in some individuals. No statistical association was met between HAV infection and the risk factors here assessed. The anti-HEV IgG prevalence found in this population was 2.4%, consistent with the one found in non-endemic areas.

Antimicrobial susceptibility determined by the E test, Löwenstein-Jensen proportion, and DNA sequencing methods among Mycobacterium tuberculosis isolates discrepancies, preliminary results

Mycobacterium tuberculosis strains resistant to streptomycin (SM), isoniazid (INH), and/or rifampin (RIF) as determined by the conventional Löwenstein-Jensen proportion method (LJPM) were compared with the E test, a minimum inhibitory concentration susceptibility method. Discrepant isolates were further evaluated by BACTEC and by DNA sequence analyses for mutations in genes most often associated with resistance to these drugs (rpsL, katG, inhA, and rpoB). Preliminary discordant E test results were seen in 75% of isolates resistant to SM and in 11% to INH. Discordance improved for these two drugs (63%) for SM and none for INH when isolates were re-tested but worsened for RIF (30%). Despite good agreement between phenotypic results and sequencing analyses, wild type profiles were detected on resistant strains mainly for SM and INH. It should be aware that susceptible isolates according to molecular methods might contain other mechanisms of resistance. Although reproducibility of the LJPM susceptibility method has been established, variable E test results for some M. tuberculosis isolates poses questions regarding its reproducibility particularly the impact of E test performance which may vary among laboratories despite adherence to recommended protocols. Further studies must be done to enlarge the evaluated samples and looked possible mutations outside of the hot spot sequenced gene among discrepant strains.

Association of human leukocyte antigen DQ1 and dengue fever in a white Southern Brazilian population

Dengue is an infectious disease of viral etiology transmitted by the mosquitoes Aedes aegypti, A. albopictus, and A. scutellaris. It can develop either as a benign form or as a severe hemorrhagic form. Previous work showed an association of the hemorrhagic form with human leukocyte antigens (HLA), suggesting a role of genetic factors in disease susceptibility. Nevertheless, data on HLA association with the classical form of the disease is scarce in literature. Sixty-four patients and 667 normal individuals, living in the state of Paraná, Southern Brazil, were used as test and control group, respectively. The patients developed the disease during a virus 1 dengue outbreak either in Maringá city in 1995 (47) or in Paranavaí city in 1999 (17). The diagnostic was confirmed through serology and/or viral culture. HLA class I and II typing was performed by the classical microlynfocitotoxicity test using monoclonal antisera and fluorobeads. Qui-square statistical analysis confirmed a positive association with HLA-DQ1 (76.6% vs 57.7%; p = 0.005243; pc = 0.026215). HLA-DR1 also presented an increased frequency in the test group, not statistically significant after p correction though (32.8% vs 15.9%; p = 0.005729; pc = 0.080206). In conclusion, genetic factors may play a role on the susceptibility to the classical dengue, virus 1, in the Brazilian population. Further independent studies should be performed in the Brazilian population to confirm these preliminary data.

Value of morphotyping for the characterization of Candida albicans clinical isolates

Until recently, morphotyping, a method evaluating fringe and surface characteristics of streak colonies grown on malt agar, has been recommended as a simple and unexpensive typing method for Candida albicans isolates. The discriminatory power and reproducibility of Hunter's modified scheme of Phongpaichit's morphotyping has been evaluated on 28 C. albicans isolates recovered from the oral cavity of asymptomatic human immunodeficiency virus-positive subjects, and compared to two molecular typing methods: randomly amplified polymorphic DNA (RAPD) fingerprinting, and contour clamped homogeneous electric field (CHEF) electrophoretic karyotyping. Morphological features of streak colonies allowed to distinguish 11 different morphotypes while RAPD fingerprinting yielded 25 different patterns and CHEF electrophoresis recognized 9 karyotypes. The discriminatory power calculated with the formula of Hunter and Gaston was 0.780 for morphotyping, 0.984 for RAPD fingerprinting, and 0.630 for karyotyping. Reproducibility was tested using 43 serial isolates from 15 subjects (2 to 6 isolates per subject) and by repeating the test after one year storage of the isolates. While genetic methods generally recognized a single type for all serial isolates from each of the subjects studied, morphotyping detected strain variations in five subjects in the absence of genetic confirmation. Poor reproducibility was demonstrated repeating morphotyping after one year storage of the isolates since differences in at least one character were detected in 92.9% of the strains.