When German soccer enthusiast Katzn Bärga touched down in Brazil on Sunday, after 18 long months of anticipation, authorities across the nation were scrambling to make final preparations for the start of one of the largest and most widely televised sporting events on the globe.

Now, tens of thousands of international visitors are making their way to the country’s Emerald Coast to attend the opening match of the 2014 FIFA World Cup in São Paulo, a city that was in the tight grip of a drought-induced water crisis barely one month ago.

But while a catastrophic situation was narrowly avoided by the transfer of water reserves into the metropolitan area’s parched reservoirs, Brazil may not be out of the woods just yet.

There are potential electricity “blackouts” to prepare for, dengue fever epidemics to combat and a possible El Niño weather system to keep an eye on.

Brazilian citizen Leandro Zanotto said dengue, a mosquito-transmitted disease, is a “big problem” where he lives in Campinas, just north of the São Paulo metro area, though he’s not sure what to think about the precarious hydroelectricity situation because officials “are saying nothing about it.”

For Bärga, however, it seems the excitement of the international soccer competition is enough to keep budding concerns at bay. “Forget dengue – we are infected with football fever!” he said.

Keeping some in the dark

São Paulo state’s largest water system, the Cantareira, wasn’t the only casualty of the worst drought to hit Brazil in decades. The country’s leading source of electricity also took a big hit, as rain-dependent reservoirs at many of the hydropower plants dropped to critically low levels.

At the height of the drought in February, millions of people in Brazil were shrouded in darkness for up to two hours when their electricity cut out. The fear, now, is that it could again happen during the two-month, multibillion-dollar event.

According to Ildo Luís Sauer, director of the Institute for Energy and the Environment at the University of São Paulo, there’s “a chance” a blackout could occur in the country during the World Cup due to a “critical situation of excess demand” on the national electricity grid.

“Usually, in Brazil, during World Cup hours – especially during evening games – you have a composition of huge demand because everyone is at home watching them,” he said.

But it is a risk that the sprawling country seems unwilling to take.

Javier Diaz, a senior energy analyst at Bentek, said Brazil is attempting to preserve hydro inventory levels by importing and burning more liquefied natural gas, “especially with the [arrival of the] World Cup.”

“Brazil’s monthly LNG imports broke new records in February and March, importing 95 percent and 76 percent more than in 2013,” he said in an email.

In fact, the country is currently firing all of its thermal power plants – LNG, coal, diesel and fuel oil – said Sauer, who added that it’s “quite unusual.”

If a blackout does happen during the months of June and July, however, it won’t be the 12 World Cup host cities that are left in the dark. Should there be an excessive peak in electricity demand, grid operators can select which areas of the country will have power cut off. This way, a complete breakdown of the system can be avoided.

“They would cut demand to the areas that are not connected to the World Cup,” he said. “It would likely happen in the remote regions, not in the capital cities. They can even cut out parts of several states.”

Regardless, FIFA requires its stadiums to be equipped with backup power supplies such as generators and uninterruptible power supply systems (UPS) that can provide electricity for up to three hours.

“We’ll have huge amounts of tourists and press, so people need power,” added Sauer. “But I think they’ll be able to manage it.”

Fumigating the streets

Blackout or not, there is something much more perilous lurking around some of Brazil’s well-lit stadiums: dengue fever, a tropical disease carried by mosquitoes, mostly the Aedes aegypti kind.

According to the Centers for Disease Control and Prevention, symptoms – which usually set in four to six days after infection and last up to 10 days – include high fever; pain behind the eyes; muscle, joint and bone pain; excruciating headaches; mild bleeding; nausea; and vomiting.

In some rare cases, however, the disease can become life-threatening.

While Brazil’s Ministry of Health said in a statement that dengue cases usually taper off by the end of May and have decreased 63 percent compared to the same period last year, a recent study in the journal The Lancet Infectious Diseases found that there are three World Cup host cities in the northeast that are still at high risk of dengue: Recife, Fortaleza and, particularly, Natal. Between them, they will host 15 games.

“The key message is, avoid mosquito bites because there is no dengue vaccine or specific treatment,” said Rachel Lowe, lead study author from the Catalan Institute of Climate Sciences in Spain.

Ian Patton, an American traveler in South America, contracted dengue fever during an outbreak in Argentina in 2008. “It’s terrible,” he said. “I stayed home for a week, hallucinated and drank Gatorade.”

In the Campinas metropolitan area, about an hour’s drive north of the São Paulo stadium, dengue fever has reached epidemic levels, according to Rosalice Carvalho de Castro, a coordinator of infectious diseases at one of the local health centers.

She said in an email that stagnant water is a big contributor to the disease, since it serves as a breeding ground for mosquitoes, and added that 90 percent of the dengue cases she’s seen have been contracted indoors.

“We’re telling people to take care of swimming pools and empty tires and flower vases … anything with water,” she added. In the meantime, “the streets are being fumigated to kill the bugs and larvae.”

If a World Cup visitor feels ill upon returning home, Lowe said, the individual should promptly notify the authorities so they can administer a test to determine whether it’s dengue fever.

“It’s always a probability,” she added. “The transmission is never interrupted in Brazil’s densely populated, warm cities.”

Mad dogs, Englishmen and El Niño

And, according to climate experts at the University of Reading, forecasts suggest that conditions in Brazil may get a lot warmer in the coming months due to the possible development of an El Niño weather system.

Nick Klingaman, one of the university’s scientists, said in an official news release that there is a 60 percent chance El Niño conditions will be in place by July.

“It is now looking likely that there will be an El Niño event in 2014, with the chances of one occurring in time for the World Cup tournament more than twice the average,” he said.

“If it does occur, it would increase the risk of uncomfortably hot and dry conditions in Brazil during June and July, especially in the southern and eastern parts of the country, where England are playing their second and third group games (in São Paulo, against Uruguay, and Belo Horizonte, where they play Costa Rica).”

But regardless of whether an El Niño develops, Walter Leal Filho, a professor of environment and technology at Manchester Metropolitan University, argues that it’s Brazil’s diverse climate that may end up affecting the performance of the players during the World Cup.

In a recent article published in the International Journal of Climate Change Strategies and Management, Filho writes that while conditions tend to be dry in the southeast during the months of June and July, there will be much rainfall in the northeast of the country. He adds that temperatures among host cities will vary, as well, from hot to cold, depending on their location.

“But even though one has to be aware of the links between climate conditions and sports,” he concludes, “it is unlikely rainfall, temperature or humidity will take away all the fun and the joy an event of this nature brings about.

“By all measures, the FIFA 2014 World Cup in Brazil, the first one to be held in the country after the 1950 games, is expected to be a great success.”