Football fever may be reaching a peak but public health officials in Brazil are worrying about a less metaphorical malaise. This year’s World Cup is the perfect crucible for outbreaks of dengue fever, one of humankind’s nastiest illnesses.
If England top their group, they will play on June 29 in Recife, a high-risk city for the incurable disease.
The dengue virus, virtually unheard of in Europe, is endemic in 100 countries across the tropics and subtropics. Transmitted through bites from the Aedes aegypti mosquito, it mostly causes a flu-like illness with fever, which can lead to full-blown dengue haemorrhagic fever (DHF), a potentially fatal condition in which blood vessels begin to leak. There is no vaccine and no cure. According to the World Health Organisation, there are at least 50 million infections a year, leading to half a million cases of DHF and 12,500 deaths. The day-biting mosquito thrives in Brazil’s cities, where chaotic sanitation leads to untended water containers acting as breeding grounds.
Researchers at the Catalan Institute for Climate Sciences in Barcelona devised a computer model to predict the chances of a dengue epidemic during the World Cup. They looked at dengue incidence at over 550 “microregions” across Brazil from 2000 to 2013. Then they gathered weather data from earlier this year, to forecast climatic conditions during the tournament. The disease is weather-dependent: risk soars towards the end of the rainy season.
The predictions, published last month in The Lancet Infectious Diseases, are that São Paulo, where the opening ceremony will take place, and Brasília are among five low-risk host cities (fewer than 100 cases per 100,000 people). The four medium-risk cities include Rio de Janeiro and Manaus, where England meets Italy on June 14. The highest risk, though, is in the north-eastern cities of Recife, Forteleza and Natal (more than 300 cases per 100,000 people). Fans are advised to wear insect repellent, cover up and sleep in air-conditioned rooms under mosquito nets.
The paper illustrates the work carried out in the field of mass gatherings medicine. A mass gathering (MG) risks overwhelming public health infrastructure. The WHO’s MG advisory group, set up seven years ago, has learnt from Saudi Arabia’s management of the annual Hajj, where certain vaccinations are compulsory. For the 3.5 million fans attending the football fiesta, the only goal that truly matters is getting home safely.
Clive Cookson returns next week
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