Clinical and epidemiologic studies on the hepatitis C virus (HCV) in the western Brazilian Amazon region are scarce. However, reports of clinical cases of hepatitis or pathologies associated to the HCV infection are frequent. In the state of Acre, there have been no studies on the population with the greatest exposure to parenteral transmission of virus infection. The objective of this study was to determine the prevalence of HCV infection among health care workers (HCWs) in this region. Of 2,338 HCWs, 646 were randomly selected for this study. The presence of antibody to HCV was determined. If these persons were antibody positive, they were tested for HCV RNA and the viral genotype was determined. The seroprevalence of antibody to HCV was 4.8% (31 of 646), and 3.7% (24 of 646) of those tested had detectable HCV RNA. Among these 24 viremic cases, HCV genotype 1 was most common (n = 16), followed by genotypes 3 (n = 6), 2 (n = 1), and an unidentified genotype. Infection with HCV (identified by a polymerase chain reaction) was more frequent among those with lower educational levels and lower incomes, those who lived for a longer period in the city of Rio Branco, those who reported intravenous use of vitamin complexes, those with a history of dental treatment, those with alcoholism, and women with history of caesarian parturition. The high prevalence of patients with HCV observed among HCWs in the city of Rio Branco and risk factors indicate the need for prevention and control programs, in addition to assistance programs, because this region is also hyperendemic for hepatitis B virus and hepatitis D virus.

Resumo No Brasil, os inquéritos sorológicos têm assinalado taxa de infecção pelo vírus do dengue de 25% a 56%, porém esses estudos foram realizados em populações de cidades de médio ou grande porte. No presente estudo, são descritas duas epidemias de febre clássica de dengue (DEN) no Estado da Bahia. A primeira, ocorrida em 1987 e causada pelo sorotipo DEN-1 em Ipupiara e, a segunda, causada pelo DEN-2, em Prado e que ocorreu em 1995. O diagnóstico laboratorial foi realizado utilizando o teste de inibição da hemaglutinação (IH). Em 1995, foram coletadas 461 amostras sorológicas de uma população de 3.868 habitantes em Ipupiara (região da Chapada Diamantina) e 228 de um total de 9.126 habitantes em Prado (Litoral Extremo Sul). A soro-positividade das amostras foi de 11,9% (55/461) em Ipupiara e 17,5% (40/228) em Prado. Não houve diferença, estatisticamente significante, quanto a idade e o gênero entre os indivíduos soro-positivos e negativos das duas cidades estudadas. Entretanto, em Ipupiara os soro-positivos (15,9% vs. 9,3%) relataram, mais freqüentemente (p < 0,03), residência ou viagens para outros Estados do Brasil. Com base nos dados, estimou-se a ocorrência de 460 e 1.597 casos da infecção em Ipupiara e Prado, respectivamente. Em conclusão, nas cidades de menor porte a dinâmica da infecção pelo vírus do dengue, provavelmente, tem características peculiares, porque nessas localidades a prevalência é menor em conseqüência das menores potencialidades de desenvolvimento do Aedes aegypti. Palavras-chaves: Dengue. Epidemia. Inquérito soro-epidemiológico. Bahia.Abstract Serologic studies in Brazil have indicated a 25% to 56% prevalence of dengue virus infections. However, these studies were carried out in populations of middle-sized and larger cities. The present study describes two epidemics of classic dengue fever in two small cities in the State of Bahia. The first occurred in 1987, in Ipupiara and was caused by dengue serotype-1 (DEN-1), the second occurred in 1995, in Prado and was caused by dengue serotype-2 (DEN-2). The laboratory diagnosis was made by the hemagglutination-inhibitation test. 461 serum samples were collected in 1995 in Ipupiara (district of Chapada Diamantina) out of a population of 3,868 and 228 samples out of a total of 9,126 inhabitants of Prado (in the Southernmost coastal region). The seropositivity of the samples was 11.9% (55/461) in Ipupiara and 17.5% (40/228) in Prado. These were no statistically significant differences as to age and sex between seropositive and seronegative individuals of the two cities studied. However, the seropositive cases in Ipupiara indicated a higher percentage (15.9% vs. 9.3%) of residency in or travel to other states of Brazil (p<0.03). Based on these data we estimate the occurrence of 460 and 1,597 cases of infection in Ipupiara and Prado, respectively. In conclusion, dengue virus infections in smaller cities probably have singular characteristics, since they exhibit a lesser prevalence of seropositivity caused by decreased breeding possibilities of Aedes...

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