photo: a Brazilian yellow scorpion.
As temperatures in Brazil climb, dangerous yellow scorpions are moving into cities like São Paulo. Courtesy Butantan Institute

Hotter conditions and urbanization trends have made cities like São Paulo prime habitat for the deadly stinging creatures.

SÃO PAULO, Brazil—The dim lights of a gas station along the Avenida 11 de Junho in central São Paulo at first glance seem to illuminate an unremarkable intersection in the huge Brazilian metropolis. But experts say this collection of apartment blocks, grocery stores, and late-night pizzerias is the epicenter of a creature infestation worthy of science fiction: the rise of Tityus serrulatus, the deadly yellow scorpion.

Just about every shop and home in the nearby vicinity has seen one recently. At night, the predatory arthropods lurk at the entrance of supermarkets, crawl up kitchen sinks, and skitter into second-story bedrooms. Some residents have been victims of their venomous stings.

“It is like a time bomb,” says Anilton Gulfier, who lives in the neighborhood. He’s come across scorpions at his father-in-law’s house in both the kitchen and the garage this year. “I think scorpions are an enormous threat when they get inside a house. The problem is when this bomb goes off, finding treatment is difficult.”

André Sanchez, owner of a nearby coffee shop, found two scorpions in his store last month. “I was raised in the countryside, so I was not as startled as most people,” says Sanchez. “But I am surprised to find them here in the city—it is a thing of the fields.”

When questioned in an adjacent street, one young man, accompanied by his wife, quips: “There’s so many we’ll be eating them on skewers like in Thailand soon.”

According to the Brazilian health ministry, the number of people stung by yellow scorpions across Brazil jumped more than tenfold since the turn of the century, from 12,000 in 2000 to 156,000 last year. The stings can cause seizures, vomiting, and excruciating pain. Most aren’t fatal for adults, but young children are very vulnerable. Last month a 7-year-old girl died after being stung by a scorpion in Franco da Rocha, part of the São Paulo metropolitan region. The girl was transferred to a hospital that did not have the necessary anti-venom and died later that day.

In a separate incident this month, a 12-year-old boy was stung on his toe when returning home through a bike path in Sertãozinho, in the northern São Paulo region. The family managed to capture the arachnid and went to the emergency room of São Francisco hospital, but the boy couldn’t be saved.

Last week, several scorpions were even found in Brazil’s Senate, but a statement from a parliamentary advisor denied there was an infestation in the building.

What’s behind the invasion? Blame climate change, in part. The creatures are flourishing in the hotter, wetter conditions of recent years. “Their growth is optimal in warm and humid weather and, because of the mean temperature in winter season is becoming higher, there are more favorable conditions for their reproduction and growing,” says Dimas Tadeu Covas, director of the Butantan Institute, one of the official bodies that produces anti-venom in Brazil from its pool of 15,000 captive species. Tityus serrulatus is parthenogenetic—females can give birth without needing a male partner—and can produce up to 30 offspring several times a year. Scorpions are most active at dawn or dusk, peaking during the hottest months of the year in the Southern Hemisphere, from December to February.

Urbanization is also part of the scorpion’s success story. The rate of stings in the country’s southeastern region, which contains major cities such as São Paulo, Rio de Janeiro, and Belo Horizonte, rose from 5.2 per 100,000 inhabitants in 2000 to 82.1 in 2018, making it second only behind the tropical northeast. The yellow scorpion is thriving in cities because of the lack of natural predators like owls, frogs, lizards, and skunks. Urban life is also offers ample prey in the form of the cockroaches that gather around piles of trash the city often fails to clean up.

“Most scorpions are now being found in urban areas,” says Covas. “Poor sanitary conditions are associated with the phenomenon, as the nearby presence of waste and garbage attract cockroaches.” He adds that “scorpion expansion has achieved such a high level that currently they can be found in sewage systems, cemeteries, and construction material warehouses, even in reasonably clean areas, and thus easily entering inside the houses.”

Some experts have raised concerns that Brazilian cities, with their spotty infrastructure and large number of residents living in informal settlements, aren’t adequately prepared for a scorpion crisis. “The problem has been increasing for a long time but it has the potential to get a lot worse,” says Hamilton Carvalho, a researcher at the University of São Paulo. “You have this complex issue because there is poor garbage management, but also there is only one place in the entire city of São Paulo where one can find the anti-venom. Inevitably, it is the poorest who have the worst provision of service. The service needs to be expanded and decentralized.”

Currently, municipal scorpion mitigation efforts in São Paulo are hardly adequate for a metro of 22 million: The city only offers daytime patrols based on complaints made by residents. (The city did not respond to requests for comment.) But one sign of success in tackling the issue has come from the Americana prefecture in São Paulo state, which has been conducting night captures of scorpions using ultraviolet light—which causes the bodies of scorpions to glow, making them easier to detect—in strategic parts of the city. Last year, a five-man team caught 13,034 of the creatures and sent the majority to the Butantan Institute.

For São Paulo residents bracing for the worst, Carvalho points to Epidemiological Surveillance Center advice: Shake out your clothes and shoes before putting them on, apply screens to floor drains or sinks, and “preserve the natural enemies of scorpions” such as nocturnal birds, lizards, geckos, and frogs.

“The summer of scorpions is coming,” he says.

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