Dengue situation in Brazil by year 2000.

Dengue virus types 1 and 2 have been isolated in Brazil by the Department of Virology, Instituto Oswaldo Cruz, in 1986 and 1990 respectively, after many decades of absence. A successful continental Aedes aegypti control program in the Americas, has been able to eradicate the vector in most countries in the 60's, but the program could not be sustained along the years. Dengue viruses were reintroduced in the American region and the infection became endemic in Brazil, like in most Central and South American countries and in the Caribbean region, due to the weaning of the vector control programs in these countries. High demographic densities and poor housing conditions in large urban communities, made the ideal conditions for vector spreading. All four dengue types are circulating in the continent and there is a high risk of the introduction in the country of the other two dengue types in Brazil, with the development of large epidemics. After the Cuban episode in 1981, when by the first time a large epidemic of dengue hemorrhagic fever and dengue shock syndrome have been described in the Americas, both clinical presentations are observed, specially in the countries like Brazil, with circulation of more than one dengue virus type. A tetravalent potent vaccine seems to be the only possible way to control the disease in the future, besides rapid clinical and laboratory diagnosis, in order to offer supportive treatment to the more severe clinical infections.