Dengue Fever in Brazil During the World Cup

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SAO PAULO — After experiencing a host of problems, including workers’ strikes and delays in construction, the 2014 FIFA World Cup is has begun. Now, however, one of the chief issues is the risk of an outbreak of dengue fever in Brazil and among spectators.

Dengue fever is spread between humans through contact with Aedes mosquitos, particularly Aedes aegypti, which act as carriers for the virus. This mosquito is particularly adept at breeding in very little water. As a result, dengue fever spreads throughout urban areas where it is difficult to eliminate all sources of standing water due to poor sanitation and water storage.

The mosquito is able to come into contact with more people in densely populated cities, spreading the disease faster and making prevention challenging. Unfortunately, 85 percent of Brazil’s population lives in cities and is thus in danger of getting the disease. The more people contract dengue fever, the more it spreads, starting a vicious cycle.

Thus far, dengue fever has no vaccine, no cure and no specific treatment, making it a difficult disease to combat when it is endemic. All this means that World Cup spectators go into Brazil armed with only bug stray and nets to protect them.

Brazil has been combating dengue fever for decades, and the disease is gaining strength in recent years. The country saw 1.4 million cases in 2013, making it the frontrunner with the highest incidence in the world. Some 50 million people are affected worldwide, resulting in 1 million deaths a year. On top of that, 2.5 billion people – over 40 percent of the world’s population – are at risk.

A 2010 study by the Institute of Collective Health and the Oswaldo Cruz Foundation found that in a single neighborhood in Brazil, 95 percent of adults have been exposed to dengue fever. So far this year, Brazil has seen 60,000 cases. 6,000 of these occurred in Sao Paulo, one of Brazil’s largest cities and the place where the opening ceremonies for the World Cup were held.

Brazil’s constant struggle with dengue fever could have a serious impact on the World Cup. It is not predicted that stadiums will have a problem with mosquitos because they are designed to have no places for water to collect, but spectators visiting the cities are at risk for coming into contact with infected mosquitos.

Before the games began, the Lancet Infections Diseases Journal evaluated the risk of getting dengue fever at each of the 12 match-hosting cities. The results were gathered by taking into account all factors that could perpetuate dengue fever like rain levels, temperature for the past twenty years, population density and altitude of cities hosting matches. The journal found that the cities with a medium risk are Rio de Janerio, Belo Horizante, Salvador and Manaus, while the high-risk cities are Natal, Fortaleza and Recife. San Paulo, where opening ceremonies were held, falls into the lowest risk group. It is predicted that 100 to 300 cases per 100,000 people will come out of the medium risk cities and over 300 cases from the high-risk venues.

A big concern is the possibility of global dispersion of the disease. There is a risk that travelers will become infected in Brazil and bring the disease back to their home countries, where it could spread if the correct kind of mosquito lives there. While a full-blown outbreak is not expected when travelers return home, there is the potential for the infection to spread.

While dengue fever is difficult to control, Brazil has taken steps in preparation for the World Cup to decrease the likelihood of an outbreak, while increasing readiness. Early warning systems have been established in 553 micro-regions around the country to alert the proper authorities of any unusual spikes in cases during the games.

With this knowledge, more precautions to protect spectators can be taken and cases can be isolated immediately. On top of this, significant efforts were taken to empty all stagnant water sources in proximity to the stadiums that could act as breeding grounds for the vector mosquitos with the hope of reducing the amount of mosquitos in the general vicinity where spectators will be congregated. Only time will tell if these methods prove effective in preventing an outbreak.

Brazil struggled with dengue fever before the World Cup and will continue to combat it afterwards. Regardless, the country will face scrutiny if a lack of preparation results in the spread of the disease to other nations. The number of dengue cases resulting from the tournament could be as interesting as the results of the World Cup itself. Keep an eye out for both.

Sources: WHO, Business Insider, Bloomberg Business Week, NPR, BBC, The Guardian,
Photo: McGill

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