Dear non-Brazilian reader, this warning it’s just for you. Please do not come to Brazil to the World Cup 2014 and ask to your friends and family to do not come too. Why? Read some posts published on this blog (or read the Editorial) and you will know why, but now there’s a great risk to your health.
Football fever could be a dose of dengue
Fans at next year’s World Cup in Brazil may be exposed to a nasty and incurable tropical disease
The twentieth FIFA World Cup will take place in Brazil in June and July next year. This football tournament is expected to sell more than 3 million tickets and attract more than half a million international fans. But those who attend will have more to worry about than the fitness of their top goalscorers: dengue fever could be a significant problem in some of the tournament locations, and preventive measures are needed. Dengue is a persistent threat to Brazilians, as it is to billions of people throughout the tropics. It is much less familiar to others, such as Europeans. This means that FIFA, the Brazilian authorities and the World Cup sponsors must use their influence and experience to communicate the risk and what protective measures fans should take.
One thing we know already is that the dengue risk will be close to its peak when matches are played in three of the host cities: Fortaleza, Natal and Salvador, all in the northeast of the country. Much could be done by the authorities there to reduce dengue risk in the run-up to the tournament. Read more.
In the map above, the locations of the cities of the twelve stadiums in Brazil selected to host World Cup football games. The background is the probability of dengue occurrence scaled between 0 and 1. The scale moves from green (zero probability of occurrence) to red (100% probability of occurrence). Stadium names are as follows: Manaus: Arena da Amazônia; Fortaleza: Estádio Plácido Aderaldo Castelo; Natal: Arena das Dunas; Recife: Itaipava Arena Pernambuco; Salvador: Itaipava Arena Fonte Nova; Brasília: Estádio Nacional Mané Garrincha; Cuiabá: Arena Pantanal; Belo Horizonte: Estádio Governador Magalhães Pinto; Rio de Janeiro: Estádio do Maracanã; São Paulo: Arena Corinthians; Curitiba: Arena da Baixada; Porto Alegre: Estádio José Pinheiro Borda.
Dengue is a viral infection that can produce a severe fever and symptoms that may require hospitalization. It is transmitted to (and between) humans by urban-adapted, day-biting Aedes mosquitoes and is therefore a particular problem in towns and cities. To explore this risk, my colleagues and I assessed the potential levels of exposure by examining distribution maps for dengue in Brazil and records of its seasonal variation at key sites.
Like the weather, it is impossible to forecast the precise situation with regard to dengue in Brazil in 2014. We can, however, make informed guesses on the basis of averaged records of dengue in previous years. For the areas around nine of the World Cup stadiums, these records show that the main dengue season will have passed before the World Cup is held in June and July. Unfortunately, the risk remains high during these months in the northeast.
The Brazilian authorities should implement aggressive vector control in April and May, particularly around the northern stadiums, to decrease the number of dengue-transmitting mosquitoes. They can target adult Aedes mosquitoes through fogging (the use of aerosol formulations of insecticides that disperse efficiently) and can interrupt breeding by clearing sites at which the mosquitoes lay their eggs — water collected in discarded rubbish, for example. Although control efforts have failed to stem the worldwide increasing incidence of dengue and the expansion of its endemic range, considerable local, albeit transient, reductions in mosquito populations have been achieved in some places, including Singapore.
There are no vaccines or drugs against dengue, but an individual will never contract dengue if they do not get bitten by an infected mosquito in the first place. So avoiding mosquito bites is the best precaution. Select accommodation with screened windows and doors and air conditioning; use insecticides indoors; wear clothing that covers the arms and legs, especially during early morning and late afternoon, when the chance of being bitten is greatest; and apply insect repellent to clothing and exposed skin. Read more.