Febre amarela: estudo de um surto

Abstract

Introduction: Recently, there appeared in Brazil high-risk yellow fever areas, as a result of the transmission of the disease in regions that had been indemne many years. The State of Minas Gerais was one of the most affected States in the country, with occurrences between 2001 and 2003. As it is endemic in the tropical areas of the Americas and Africa, yellow fever is marked by acute fever caused by an arbovirus, which can be urban or selvatic. Its vectors are the mosquitoes Aedes aegypti, Aedes albopictus, Haemagogus and Sabethes. AIM: to characterize the outbreaks of yellow fever from 2002 to 2003, in Minas Gerais. Methodology: descriptive study, with data collection on the occasion the outbreak occurred. From the population of infected individuals, the cases selected had been investigated and confirmed. These individuals, 36 in all, were all from the municipalities in the jurisdiction of the Gerência Regional de Saúde de Diamantina (Regional Health Management of theMunicipality of Diamantina). The study was approved by the research ethics committee and developed in such a way as to guarantee full compliance with the ethical precepts required. Results: It was concluded that it was an autoctonous outbreak of selvatic yellow fever. Lowlevels of vaccinal coverage against yellow fever were found as well as low levels of detection of lighter cases of the disease. Among the individuals studied, 33(91.7%) were male. They ranged in age from 16 to 67. They all came from the rural area and 18(50%) of them came from the municipality of Serro. Nineteen (52.8%) of the cases were classified as serious and 12 (33.3%) died of the disease, all of whom male. Clinical laboratory criterion confirmed 33 (91.7%) of the ill patients and 3(8.3%) by epidemiologic links. The patients had fever, headaches, vomit, jaundice, myalgia, oliguria and signs of hemorrhage. The data collectedfrom the results of the biochemical tests proved very heterogeneous.Discussion: The surveillance of hemorrhagic fevers is decisive in the diagnosis of the outbreak of yellow fever. It was deduced that there is a causal relationship between deforestation, epizooty and outbreak of the disease in humans, since the investigation disclosed a large number of recently deforested areas in the region. As a result of the presenteconomic development and the growing tourism industry a change in the environment is expected, which includes the felling of trees, heavier volume of traffic and movement of people, which can aggravate the risk of the spread of the selvatic form of the disease and its ensuing urbanization. When the development of the clinical seriousness from light to moderate was evaluated, the mean concentration of transaminases, ureia and creatinine presented a fall, but the clinical condition from light and moderate to serious presented an increase in the mean value in almost all tests. Conclusion: By describing the epidemiologic and clinic findings in a sample of adults suffering from yellow fever, this study contributes to the diagnosis and classification of the disease besides pointing to breaches in the epidemiologic surveillance.