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Dengue epidemic strikes Rio de Janeiro — as expected

"I think I was bitten in Jacarezinho", said Cristiane Silva de Almeida, 28 years old. She has had dengue, a viral disease transmitted by the Aedes aegypti mosquito, twice. Jacarezinho is a slum district of Rio de Janeiro, Brazil, where she lives. "I was very, very ill, with many pains in my body, in my joints and pressure in my eyes. I didn't want to do or eat anything."

The latest dengue epidemic in Rio was severe, and no respecter of status. Wealthy and famous residents including several internationally known singers and artists from the richer South of Rio de Janeiro, also caught the disease this past summer — ensuring that the outbreak received more attention than usual from the media and the government.

In 1982, the first cases of dengue appeared in northern Brazil. Thereafter, the virus and the mosquito spread, and by 1986, outbreaks of the disease became routine. The state of Rio de Janeiro became the main focus of the disease this year with nearly 200 000 cases (from January to mid-April).

A single infection with dengue — which comes in four different serotypes — is painful but not often fatal. But second infection within two years with a different serotype of the virus produces dengue haemorrhagic fever (DHF), which can kill. According to the office of the State Secretary of Health, 1645 cases of DHF had occurred this year in the state by mid-April, with 56 deaths.

The epidemiologist Paulo Sabroza, of the Oswaldo Cruz Foundation, warns that other serotypes of the dengue virus circulate in neighbouring countries, and that they could be introduced into Brazil at any moment. He also says that although there is now some population immunity after infection, 11 million people are still susceptible to the virus in Rio state. Most dengue epidemics end only when the whole susceptible population has been infected, says Jorge Arias, PAHO regional assistant for the control of dengue.

Fearing larger outbreaks of DHF in future years, Arias told the Bulletin that PAHO is attempting to analyse the distribution of the four serotypes of dengue in Latin America. They are finding out what serotypes are in what countries, "how close they are to each other and how they can get in." According to PAHO, there have been 73 deaths from DHF in Latin America this year, most of them in Brazil.

Paulo Sabroza says that the Rio epidemic was predictable and, indeed, predicted — but little was done to prevent it. But Mauro Marzochi, Sub- Secretary of Health for the Municipality of Rio, defends the government: he says it was bidding for funds to prepare for the epidemic when it broke out in December, three months earlier than in previous years. For next year, Marzochi says he plans to organize insecticide spraying and to expand education on how to eliminate mosquito breeding-grounds. The people are "an ally" in combating the vector, he says.

The Brazilian Health Minister, Barjas Negri, announced the end of this year's epidemic on 25 April, and said the ministry would spend more than US$ 202 million this year to prevent and control dengue in 657 municipal districts throughout the country, including a day of "national mobilization" to eliminate mosquito breeding-sites — pools, sinks and waterbutts, abandoned tyres and water-sodden garbage dumps.

Sabroza adds that the fight against the mosquito must be continuous and not confined to epidemics. He also presses for better garbage removal services. "It is a mistake to imagine that garbage collection is for individuals to do. The garbage service in Rio de Janeiro is very poor." Sabroza sees three basic needs: proper disposal of garbage; an increase in social responsibility for the environment; and focused anti-vector efforts, with a proper strategy for training and action. These measures have been successfully implemented in other countries, he says.&nbsp

Claudia Jurberg, Rio de Janeiro

World Health Organization Genebra - Genebra - Switzerland
E-mail: bulletin@who.int