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Despite evidence of West Nile virus (WNV) activity in Colombia, Venezuela and Argentina, this virus has not been reported in most South American countries. In February 2009, we commenced an investigation for WNV in mosquitoes, horses and caimans from the Pantanal, Central-West Brazil. The sera of 168 horses and 30 caimans were initially tested using a flaviviruses-specific epitope-blocking enzyme-linked immunosorbent assay (blocking ELISA) for the detection of flavivirus-reactive antibodies. The seropositive samples were further tested using a plaque-reduction neutralisation test (PRNT90) for WNV and its most closely-related flaviviruses that circulate in Brazil to confirm the detection of specific virus-neutralising antibodies. Of the 93 (55.4%) blocking ELISA-seropositive horse serum samples, five (3%) were seropositive for WNV, nine (5.4%) were seropositive for St. Louis encephalitis virus, 18 (10.7%) were seropositive for Ilheus virus, three (1.8%) were seropositive for Cacipacore virus and none were seropositive for Rocio virus using PRNT90, with a criteria of > four-fold antibody titre difference. All caimans were negative for flaviviruses-specific antibodies using the blocking ELISA. No virus genome was detected from caiman blood or mosquito samples. The present study is the first report of confirmed serological evidence of WNV activity in Brazil.

Circulation of a new dengue virus (DENV)-3 genotype was recently described in Brazil and Colombia, but the precise classification of this genotype has been controversial. Here we perform phylogenetic and nucleotide-distance analyses of the envelope gene, which support the subdivision of DENV-3 strains into five distinct genotypes (GI to GV) and confirm the classification of the new South American genotype as GV. The extremely low genetic distances between Brazilian GV strains and the prototype Philippines/L11423 GV strain isolated in 1956 raise important questions regarding the origin of GV in South America.

In Pernambuco, the first dengue cases occurred in 1987. After a seven-year interval without autochthonous cases, a new epidemic occurred in 1995. Important aspects of the dengue epidemics during the period 1995-2006 have been analyzed here, using epidemiological, clinical and laboratory data. A total of 378,374 cases were notified, with 612 confirmed cases of dengue hemorrhagic fever and 33 deaths. The mortality rate was 5.4%. The incidence rate increased from 134 to 1,438/100,000 inhabitants, corresponding to the epidemics due to serotypes 2 and 3, in 1995 and 2002, respectively. Dengue mainly affected adults (20-49 years); 40.7% were male and 59.3% were female. From 2003 onwards, the number of cases among individuals younger than 15 years old increased. Out of 225 dengue hemorrhagic fever cases, 42.7% primary and 57.3% secondary infections were identified (p = 0.0279). Neurological manifestations were also observed. From 2002 onwards, serotypes 1, 2 and 3 were circulating; serotype 3 was predominant.Em Pernambuco, os primeiros casos de dengue ocorreram em 1987. Após intervalo de 7 anos sem casos autóctones, em 1995 ocorreu uma nova epidemia. Foram analisados aspectos relevantes das epidemias (1995-2006), utilizando-se dados epidemiológicos, clínicos e laboratoriais. Um total de 378.374 casos foi notificado, com 612 casos confirmados de febre hemorrágica do dengue e 33 óbitos. A taxa de mortalidade foi de 5.4%. A taxa de incidência aumentou de 134 para 1.438/100.000 habitantes, correspondente às epidemias pelos sorotipos 2 e 3, em 1995 e 2002, respectivamente. O dengue acometeu principalmente pessoas adultas (20-49 anos); 40,7% do sexo masculino e 59,3%, feminino. A partir de 2003, aumentou o número de casos em menores de 15 anos. Entre 225 casos de dengue hemorrágico, foram identificadas 42,7% e 57,3% infecções primárias e secundárias, respectivamente (p = 0.0279). Manifestações neurológicas também foram observadas. A partir de 2002, circularam os sorotipos 1, 2 e 3; predominando o sorotipo 3.

Histological and ultrastructural alterations in lung tissue of BALB/c mice infected with dengue virus serotype 2 (non-neuroadapted), by intraperitoneal and intravenous routes were analyzed. Lung tissues were processed following the standard techniques for photonic and electron transmission microscopies. Histopathological and ultrastructural studies showed interstitial pneumonia, characterized by the presence of mononuclear cells. In the mouse model, the dengue virus serotype 2 seems to led to a transient inflammatory process without extensive damage to the interalveolar septa, but caused focal alterations of the blood-exchange barrier. Endothelial cells of blood capillaries exhibited phyllopodia suggesting activation by presence of dengue virus. Morphometrical analysis of mast cells showed an expressive increase of the number of these cells in peribronchiolar spaces and adjacent areas to the interalveolar septa. Alveolar macrophages showed particles dengue virus-like inside rough endoplasmic reticulum and Golgi complex, suggesting viral replication. The tissue alterations observed in our experimental model were similar to the observed in human cases of dengue fever and dengue hemorrhagic fever. Our results show that BALB/c mice are permissive host for dengue virus serotype 2 replication and therefore provides an useful model to study of morphological aspects of dengue virus infection.

One of the main difficulties in studying dengue virus infection in humans and in developing a vaccine is the absence of a suitable animal model which develops the full spectrum of dengue fever, dengue haemorrhagic fever, and dengue shock syndrome. It is our proposal to present morphological aspects of an animal model which shows many similarities with the dengue infection in humans. BALB/c mice were intraperitoneally infected with non-neuroadapted dengue virus serotype 2 (DENV-2). Histopathological and morphometrical analyses of liver tissue revealed focal alterations along the infection, reaching wide-ranging portal and centrolobular veins congestion and sinusoidal cell death. Additional ultrastructural observations demonstrated multifocal endothelial injury, platelet recruitment, and alterated hepatocytes. Dengue virus antigen was detected in hepatocytes and in the capillar endothelium of the central lobular vein area. Liver function tests showed high levels of aspartate transaminase and alanine transaminase enzyme activity. Lung tissue showed interstitial pneumonia and mononuclear cells, interseptal oedema, hyperplasia, and hypertrophy of the bronchiolar epithelial cells. DENV-2 led to a transient inflammatory process, but caused focal alterations of the blood-exchange barrier. Viremia was observed from 2nd to 11th day p.i. by isolation of DENV-2 in C6/36 mosquito cell line inoculated with the supernatant of macerated liver, lung, kidney, and cerebellum tissues of the infected mice.

During the summer of 2002, Rio de Janeiro had a large epidemic of dengue fever; 288,245 cases were reported. A subset of 1,831 dengue hemorrhagic fever cases occurred. In this study, performed in the first half of 2002, samples from 1,559 patients with suspected cases of dengue infection were analyzed. From this total, 1,497 were obtained from patients with nonfatal cases, and 62 were obtained from patients with fatal cases. By the use of different methods, 831 (53.3%) cases, including 40 fatal cases, were confirmed as dengue infection. When virus identification was successful, dengue virus type 3 (DENV-3) was obtained in 99% of cases. Neurologic involvement was shown in 1 patient with encephalitis, confirmed by the detection of DENV-3 RNA in the cerebrospinal fluid. This explosive epidemic of DENV-3 was the most severe dengue epidemic reported in Brazil since dengue viruses were introduced in 1986.

Oral susceptibility and vertical transmission of dengue virus type 2 (DENV-2) in an Aedes albopictus sample from Rio de Janeiro was estimated. The infection (36.7%) and transmission (83.3%) rates for Ae. albopictus were higher than those of an Ae. aegypti colony used as control, 32.8 and 60%, respectively. Fourth instar larvae and females descendants of 48.5 and 39.1% of experimentally infected Ae. albopictus showed to harbor the virus. The oral susceptibility and the high capacity to assure vertical transmission exhibited by Ae. albopictus from Brazil reinforce that this species may play a role in the maintenance of the virus in nature and be a threat for dengue control in the country.

In the last decade, dengue fever (DF) in Brazil has been recognized as an important public health problem, and an increasing number of dengue haemorrhagic fever (DHF) cases have been reported since the introduction of dengue virus type 2 (DEN-2) into the country in 1990. In order to analyze the complete genome sequence of a DEN-2 Brazilian strain (BR64022/98), we designed primers to amplify contiguous segments of approximately 500 base pairs across the entire sequence of the viral genome. Twenty fragments amplified by reverse transcriptase-PCR were cloned, and the complete nucleotide and the deduced amino acid sequences were determined. This constitutes the first complete genetic characterization of a DEN-2 strain from Brazil. All amino acid changes differentiating strains related to the Asian/American-Asian genotype were observed in BR64022/98, indicating the Asiatic origin of the strain.

Dengue viruses (DEN) are found as four antigenically distinct serotypes designated DEN-1, 2, 3, and 4. Laboratory evidence that strain-intratypical variation occurs among DEN viruses has been demonstrated since the 1970s, although only with the advances in molecular technologies has it been possible to determine the genetic variability of each serotype. Genotypical identification has proven to be a useful tool for determining the origin and spread of epidemics and to correlate virulence of strains. In this report we present the results of molecular epidemiological studies with the DEN-1 and DEN-2 viruses that caused dengue epidemics in Brazil during the last decade.Os vírus dengue (DEN) apresentam propriedades antigênicas distintas que caracterizam quatro sorotipos denominados DEN-1, 2, 3 e 4. Desde a década de 70, evidências laboratoriais têm demonstrado a ocorrência de variação intratípica entre os vírus DEN; entretanto, somente com o avanço das metodologias moleculares foi possível estabelecer variantes genéticas para cada sorotipo. A identificação genotípica tem sido uma importante abordagem para determinar a origem e a dispersão de epidemias e para tentar estabelecer correlação de virulência entre as variantes dos vírus DEN. Neste trabalho, apresentamos resultados obtidos através de estudos de epidemiologia molecular realizados com amostras de vírus DEN-1 e DEN-2, que causaram epidemias no Brasil, na última década.

The present paper reports a laboratory investigation performed between the years of 2000 and 2002 to stydy a virological surveillance program introduced in the state of Piauí to support an epidemiological survey of the disease. Dengue virus type 3 (DENV-3) existence in the state was detected in May 2002 when a high number of dengue cases due to DENV-1 and DENV-2 were reported. An assessment on the population knowledge about the disease and its transmission showed that almost 50% of the population were still unaware of the epidemiological features of dengue.

UNLABELLED: / BACKGROUND: Dengue is the most important arthropod borne viral disease worldwide in terms of morbidity and mortality and is caused by any of the four serotypes of dengue virus (DENV-1 to 4). Brazil is responsible for approximately 80% of dengue cases in the Americas, and since the introduction of dengue in 1986, a total of 5,944,270 cases have been reported including 21,596 dengue hemorrhagic fever and 874 fatal cases. DENV can infect many cell types and cause diverse clinical and pathological effects. The goal of the study was to investigate the usefulness of NS1 capture tests as an alternative tool to detect DENV in tissue specimens from previously confirmed dengue fatal cases (n = 23) that occurred in 2002 in Brazil. METHODOLOGY/PRINCIPAL FINDINGS: A total of 74 tissue specimens were available: liver (n = 23), lung (n = 14), kidney (n = 04), brain (n = 10), heart (n = 02), skin (n = 01), spleen (n = 15), thymus (n = 03) and lymph nodes (n = 02). We evaluated three tests for NS1 antigen capture: first generation Dengue Early ELISA (PanBio Diagnostics), Platelia NS1 (BioRad Laboratories) and the rapid test NS1 Ag Strip (BioRad Laboratories). The overall dengue fatal case diagnosis based on the tissues analyzed by Dengue Early ELISA, Platelia NS1 and the NS1 Ag Strip was 34.7% (08/23), 60.8% (14/23) and 91.3% (21/23), respectively. The Dengue Early ELISA detected NS1 in 22.9% (17/74) of the specimens analyzed and the Platelia NS1 in 45.9% (34/74). The highest sensitivity (78.3%; 58/74) was achieved by the NS1 Ag Strip, and the differences in the sensitivities were statistically significant (p

BACKGROUND: Dengue is associated with explosive urban epidemics and has become a major public health problem in many tropical developing countries, including Brazil. The laboratory diagnosis of dengue can be carried out using several approaches, however sensitive and specific assays useful to diagnose in the early stage of fever are desirable. The flavivirus non-structural protein NS1, a highly conserved and secreted glycoprotein, is a candidate protein for rapid diagnosis of dengue in endemic countries. METHODOLOGY/PRINCIPAL FINDINGS: We aimed to evaluate the potential use of 3 commercial kits in a panel of 450 serum samples for early diagnosis of dengue in Brazil. The PanBio Early ELISA (PanBio Diagnostics) showed a sensitivity of 72.3% (159/220) and a specificity of 100%, while the sensitivity of the Platelia NS1 assay (Biorad Laboratories) was 83.6% (184/220). However, the highest sensitivity (89.6%; 197/220) was obtained by using the NS1 Ag Strip (Biorad Laboratories). A lower sensitivity was observed in DENV-3 cases by all 3 kits. Serum positive by virus isolation were more often positive than cases positive by RT-PCR by all three assays and a higher detection rate was observed during the first four days after the onset of the symptoms. The presence or absence of IgM showed no influence in the confirmation by the pan-E Early ELISA (P = 0,6159). However, a higher confirmation by both Platelia NS1 (Biorad) and Dengue NS1 Ag Strip (Biorad) in the absence of IgM was statistically significant (P

This preliminary report describes human and cow cases of poxvirus that recently ocurred in the State of Rio de Janeiro. The electron microscopic findings were consistent with parapoxviral and orthopoxviral infection. Orthopoxvirus strains were isolated from human and cow cases. Detailed viral characterization by means of genetical techniques is under investigation. Based on these informations, poxviral diseases should be also considered an emerging viral zoonosis that can affect human beings.

The presence of antibodies against rotavirus was investigated by enzyme immunosorbent assay (ELISA) in two distinct groups of children living in a shanty town in Rio de Janeiro. One hundred and thirty six plasma samples were randomly collected from children of 0 to 33 months (first group) and 255 serum samples were collected from other 85 children at ages of 2, 6 and 9 months (second group). A high percentage of antibodies were found in the newborn children and this rate decreased progressively until the age of 11 months, after which it increased again. At the age of 7 months, geometric mean antibody titers increased indicating that infection had occurred.

Os autores estudaram uma epidemia de Hepatite B em uma instituição localizada no bairro de São Cristovão na cidade do Rio de Janeiro, Brasil. Ocorreu um total de 35 casos: 30 entre os funcionários da instituição e cinco entre familiares de funcionários. Todos os casos foram considerados de hepatite aguda benigna; apenas dois não tiveram icterícia. Clinicamente, chamou-lhes a atenção um importante envolvimento articular: artralgias intensas, com grande restrição dos movimentos, durante o período de incubação e que regrediram completamente logo que a icterícia tornou-se evidente. A distribuição cronológica foi típica de infecção simultânea em fonte única. A investigação epidemiológica revelou que essa fonte foi um produto terapêutico derivado do sangue humano: gamaglobulina. As injeções foram feitas com seringas descartáveis e, ironicamente, com o objetivo de prevenir hepatite. Em dois dias de aplicação, cerca de 120 funcionários receberam a injeção de gamaglobulina, entre os quais 27 desenvolveram hepatite. O período de incubação médio foi de 116 dias. 0 Ag HB, testado em 26 pacientes, foi positivo em 12 (46,2%); oito pacientes com tempo de doença inferior a duas semanas, foram todos positivos. O surto epidêmico ocorreu em condições que caracterizaram um estudo experimental, não planejado, em seres humanos. Os autores estudaram, além do surto epidêmico de São Cristovão, oito casos vinculados ao serviço hospitalar onde trabalhavam. Esses casos apresentaram características que os distinguiram dos casos de hepatite comumente all tratados. Todos os pacientes eram de elevada classe social, com o antecedente de terem tomado injeção de gamaglobulina, da mesma procedência daquela que originou o surto epidêmico de São Cristovão. Nesses casos o período de incubação médio foi de 106 dias. Seis dos oito pacientes foram testados para o Ag HB, que foi positivo em cinco. Onze partidas da gamaglobulina foram testadas, em laboratórios de referência da Organização Mundial de Saúde, encontrando-se o Ag HB em seis (54,5%J. Os autores concluem que houve alguma falha grave no processo de preparo da gamaglobulina em apreço. E por isto deve-se ter reservas quanto á noção difundida de que esse medicamento está isento do risco de transmitir o vírus hepatite.The authors studied an epidemic of hepatítis B occurring in an institution located in the São Cristovão section of the city of Rio de Janeiro, Brasil. Of a total of 35 cases detected, 30 ocurred in employees of the institution and 5 in family members of the employees. All the cases were considered as benign acute hepatitis; all but two were iteric. Clinically, a marked articular involvement was noted, with intense arthralgia and pronounced restriction of movement, which regressed completely as soon as jaundice became evident. The chronological distribution was typical of simultaneous infection from a single source. Epidemiological investigation indicated that the source was commercially prepared pooled human gamma globulin. Ironically, injections were given, as prophylaxis against hepatitis with disposable syringes. During two days of application, approximately 120 employees received gamma globulin injections, among whom 27 developed hepatitis with a mean incubation period of 116 days. Twenty six patients were tested for HBAg, with positive results in 12 (46.2%); 8 patients tested during the first two weeks of overdisease were all positive. The epidemic outbreak occurred in conditions, though not premeditated, approximating to those of an experimental study. In addition to the São Cristovão epidemic, the authors studied 8 cases seen at the hospital Service where they worked. These cases presented characteristics distinguishing them from the the type of hepatitis case commonly treated in that hospital. All these 8 patients were of elevated socioeconomic conditions, and all had a history of having received injections of gamma globulin from the same commercial source as that which gave rise to the São Cristovão epidemic. In these cases the mean incubation period was 106 days, and 5 of 6 patients tested were positive for HB Ag. Eleven lots of gamma globulin were tested in reference laboratories of the World Health Organization, six of these (53,5%) were positive for HB Ag. The authors conclude that there was a serious lapse in the process of preparation of the gamma globulin in question. It is recommended that the widespread assumption that this product is free of risks of transmitting hepatitis virus should be accepted with reservation.

O presente trabalho descreve um estudo experimental em que foi testada a eficiência de um método para concentração de enterovírus em água de esgoto por adsorção ao hidróxido de alumínio. Adicionou-se o gel de A1 (OH)3 (na proporção de 1g para 3,78 litros) à água de esgoto previamente clarificada e com o pH acertado em 5,0. Depois de agitada por 1 hora, a mistura foi filtrada em membrana Millipore tipo AP-20. O hidróxido de alumínio, o qual permaneceu retido na membrana, foi retirado com auxílio de uma espátula e a ele se adicionou meio de Eagle com 10% de soro fetal, sendo o pH acertado em torno de 7,2 - 7,4 para se processar a eluição. A mistura foi centrifugada a 20.000g por 15 minutos, o sedimento desprezado e o sobrenadante inoculado em células da linhagem LLC-MK2 para quantificação viral. Paralelamente, foram também inoculadas em cultura de células as amostras de esgoto brutas, isto é, antes de qualquer procedimento para concentração. O método descrito se mostrou eficiente para concentrar enterovírus em água de esgoto, sendo que tornou possível detectar vírus mesmo de amostras contendo cerca de 1 unidade infecciosa por ml, das quais não se conseguiu isolamento de vírus sem concentração prévia.The efficiency of a method which uses A1 (OH)3 for concentrating enterovirus in sewage water was tested in an experimental study. Gel of aluminium hidroxide (in a proportion of 1g per 3,78 1) was added to the previously clarified sewage water with the pH adjusted to 5,0. After shaking for 1 hour, the mixture was filtered through a Millipore membrane type AP-20. The A1 (OH)3 with the adsorbed virus retained on the membrane was removed by means of a spatula. Eagles's medium with 10% foetal calf serum was used for elution and the pH was adjusted to about 7,2-7,4. The mixture was then centrifuged at 20.000 x g, the pellet discarded and the supernatant was inoculated into cells of the strain LLC-MK2 for viral quantification. In a parallel experiment, samples of crude sewage, that is, without previous concentration treatment, were inoculated into cells. This method was shown to be efficient for concentrating enterovirus in sewage water, allowing its detection in samples containing about 1 infectious unit per m1. Without a previous concentration, the isolation of virus from such diluted samples was not possible.

Realizou-se estudo do tipo duplo anonimato em 18 pacientes com hepatite aguda benigna. O gruoo experimental foi testado com uma provável droga de ação antiviral: 1-BETA-D-RIBOFURANOSIL, 1,2,4-TRIAZOLE-3- CARBOXAMIDE. O grupo controle ingeriu um placebo de lactose. Teve-se especial cuidado na seleção de pacientes, incluindo apenas pacientes que preenchessem critérios bem estabelecidos. Os pacientes foram seguidos semanalmente, avaliando-os clínica e laboratorialmente. Os resultados não evidenciaram diferenças significativas entre os dois grupos, sugerindo-se estudos com casuística mais numerosa e em regime de internação hospitalar.

Neste trabalho descreve-se uma prova de imunofluorescência direta (IFD), com o mesmo material de fragmentos de tecido hepático, fixados em formol, obtidos de casos suspeitos de infecção por febre amarela e utilizados para a histopatologia; um conjugado fluorescente foi preparado com soro de macacos sem anticorpos para hepatite A e B, previamente inoculados com a amostra vacinal 17D de febre amarela. São considerados positivos para febre amarela por esta técnica os casos que apresentaram fluoresc~encia citoplasmática de seus hepatócitos, após um tratamento prévio do tecido com tripsina a 0,1% por 2 horas a 37°C. Em 76 casos estudados, 33 considerados positivos e 34 considerados negativos na histopatologia apresentaram resultados concordantes com a reação de imunofluorescência, de 9 casos com diagnóstico duvidoso, 8 foram negativos e 1 apresentou-se positivo na prova da IFD. Materiais obtidos de casos de hepatite e de tecidos hepáticos normais foram sempre negativos na IFD para febre amarela; utilizou-se como controle positivo, células em cultura de linhagem Vero, infectadas com a mesma amostra 17D, as quais mostraram intensa fluorescência específica. A técnica descrita mostrou-se de utilidade, como uma reação específica, em complemento aos estudos patológicos, em especial no diagnóstico de casos duvidosos, com a vantagem de utilizar o mesmo material previamente fixado em formol, recebido rotineiramente pelos laboratórios responsáveis pelo diagnóstico de febre amarela no país.A direct immunofluorescence staining technique is described for the detection of yellow fever virus antigen in formalin-fixed liver tissue. Fluorescein-labelled antibody was prepared with batches of immunoglobulin from monkeys immunized with yellow fever strain 17D and show to be free of antibodies to hepatitis A and B viruses. Liver sections were digested with 0.1% trypsin for 2 hours before staining with the fluorescent conjugate. All specimens with hepatocytes showing cytoplasmatic fluorescence were considered positive. In 76 specimens tested there was agreement between histopathology and immunofluorescence in 33 positive and 34 negative cases. Of the remaining 9 specimens with doubtful histopathology, 8 were negative and 1 was positive by immunofluorescence. Specimens from hepatitis of other aetiologies were always negative. Tissue culture cells (VERO) infected with yellow fever virus strain 17D gave strongly positive reactions. The technique described is a useful addition ti histopathology in cases of doubtful diagnosis and makes use of specimens routinely received for diagnosis.

Four weeks after Containment Vaccination undertaken against the largest outbreak of smallpox occured in Brazil in 1969, that of the municipality of Utinga, Bahia, 99 samples of serum were collected from the local population. These samples were classified in four groups: a) - Individuals with a history of variola prior to the beginning of present outbreak in town (15 sera); "Previous smallpox group"; b) - Individuals with primary vaccination, with no record variola, at the time of containment measures (15 sera). "Primary vaccinated group"; c) - Individuals with no previous record of variola revaccinated with "take" at the time of containment (15 sera0, "Revaccinated group"; d) - Individuals who contracted variola in present outbreak (54 sera) these were subdivided in four sub-groups, according to dates on which cases ocurred, "Variola in outbreak group". Serological study of samples was done by tests of hemagglutination inhibition, neutralization, and complement fixation. It was observed that HI titers were significantly lower in cases of previous smallpox than in other groups. Although they were slightly higher on revaccinated individuals than on primary vaccinated group and than in the group of variola in outbreak, this difference was not significant. Those same antibodies were present in all cases of variola in outbreak, and it was found that titers decreased in direct proportion to time elapsed from occurrence of cases. Neutralizing antibodies proved to be significantly higher on the revaccinated group than on variola in outbreak group, and higher on these than on primary vaccinated and on the previous smallpox groups. In cases from the variola in outbreak it was verified that neutralizing antibodies remained stable, although with great variation in titers. Tests of complement fixation could not be undertaken on all samples, because many of them proved to have anticomplementarity. However, it was found that complement fixing antibodies diminished rapidly, becoming negative for earlier infections. Finally, the authors suggest that there would be some evidence that HI titers are lower in variola minor under Brazilian conditions than in variola major.Quatro semanas após a Vacinação de Contenção, realizada com a finalidade de controlar o maior surto de varíola ocorrido em 1969, no Brasil, no município de Utinga na Bahia, 99 amostras de sangue foram coletadas da população local. Estas amostras foram classificadas em quatro grupos: a) - Indivíduos com uma história de varíola anterior ao ínicio do surto de 1969 (15 soros); "Grupo varíola prévia"; b) - Indivíduos com vacinação primária, sem história de varíola por ocasião da vacinação de contenção (15 soros), "Grupo primo-vacinados"; c) - Indivíduos sem história de varíola prévia, revacinados com "pega" por ocasião da vacinação de contenção (15 soros), "Grupo revacinado"; d) - Indivíduos que contraíram varíola no surto de 1969 (54 soros), os quais, foram subdivididos em quatro subgrupos, de acordo com as datas em que ocorreram os casos "Grupo varíola no surto". Os estudos sorológicos foram realizados atráves testes de inibição da hamaglutinação, neutralização e fixação do complemento. observou-se que os títulos de anticorpos inibidores foram significantemente mais baixos em casos de varíola prévia de que nos outros grupos. Embora estes anticorpos se apresentassem ligeiramente mais elevados em indivíduos revacionados do que os grupos de vacinação primária e com varíola no surto, esta diferença não foi significativa. Estes mesmos anticorpos estavam presentes em todos os casos de varíola no surto e foi possível mostrar que os títulos decresciam em relação direta ao tempo decorrido após a doença clínica. Anticorpos neutralizantes mostraram ser significantemente mais elevados no grupo revacinado do que no grupo com varíolano surto e mais elevados neste último grupo do que nos grupos primo-vacinados e com varíola prévia. As provas de fixação do complemento não puderam ser realizadas em todas as amostras, porque muitas delas mostraram atividade anticomplementar. No entanto, foi possível demonstrar que os anticorpos fixadores do complemento diminuem rapidamente, tornando-se negativos nos casos de infecções antigas. Finalmente, os autores mostram que os títulos inibidores da hemaglutinação são mais baixos na varíola minor, em condições brasileiras do que na varíola major.

Dengue viruses (DEN) are found as four antigenically distinct serotypes designated DEN-1, 2, 3, and 4. Laboratory evidence that strain-intratypical variation occurs among DEN viruses has been demonstrated since the 1970s, although only with the advances in molecular technologies has it been possible to determine the genetic variability of each serotype. Genotypical identification has proven to be a useful tool for determining the origin and spread of epidemics and to correlate virulence of strains. In this report we present the results of molecular epidemiological studies with the DEN-1 and DEN-2 viruses that caused dengue epidemics in Brazil during the last decade.

Dengue viruses (DEN) are found as four antigenically distinct serotypes designated DEN-1, 2, 3, and 4. Laboratory evidence that strain-intratypical variation occurs among DEN viruses has been demonstrated since the 1970s, although only with the advances in molecular technologies has it been possible to determine the genetic variability of each serotype. Genotypical identification has proven to be a useful tool for determining the origin and spread of epidemics and to correlate virulence of strains. In this report we present the results of molecular epidemiological studies with the DEN-1 and DEN-2 viruses that caused dengue epidemics in Brazil during the last decade.