Scorpion stings cases surge 250% in Brazil

WORLDWIDE:

Brazilian cities are experiencing an alarming surge in scorpion populations, researchers have warned, with unplanned urbanisation and climate breakdown fuelling a sharp rise in human-sting encounters.

Between 2014 and 2023, more than 1.1 million scorpion stings were officially reported, according to the Brazilian notifiable diseases information system.

That figure marks a 250% increase over the past decade, signalling what experts now consider a public health crisis.

The study, published in Frontiers in Public Health, attributes the increase to Brazil’s rapid and often unregulated urban growth.

In densely populated informal settlements such as favelas — where infrastructure is weak and waste management is poor — scorpions have found ideal conditions to thrive.

“Urbanisation in Brazil has profoundly reshaped ecosystems,” said lead author Dr Manuela Berto Pucca, an assistant professor at São Paulo State University.

“Cities unintentionally offer everything scorpions need: plenty of shelter in walls, drains, and debris, warmth, and an abundant food supply in the form of cockroaches and other insects.”

A perfect habitat

Scorpions particularly favour sewer systems, which provide constant warmth, limited predators, and access to food.

Their resilience makes them difficult to eradicate: some species can survive for more than 400 days without food and can reproduce without mating, a process known as parthenogenesis.

These characteristics, coupled with warmer temperatures, intense rainfall, and periods of drought — all intensified by climate change — have boosted scorpion survival rates and reproduction cycles.

Preliminary data for 2024 suggests that scorpions caused nearly 200,000 stings and 133 deaths in Brazil in that year alone. The study projects 2 million additional sting cases between 2025 and 2033 if current conditions persist.

But researchers caution that the true numbers may be significantly higher, as many Brazilians opt for self-treatment or never report their stings.

“I’ve been working in places where scorpion stings are a daily fear, especially in poor and crowded areas,” said Pucca. “The numbers showed us that in the future the problem will be bigger than it is now.”

Vulnerable populations at risk

Though only 0.1% of reported stings are fatal, vulnerable populations — particularly children and the elderly — face higher risks.

In many cases, the sting causes intense pain, burning, swelling, redness, nausea, and tingling, symptoms that may persist for days.

Brazil’s public health system provides free treatment and anti-venom, available in emergency care centres and hospitals across the country.

Still, researchers are calling for more robust public health interventions, including education, infrastructure improvements, and pest control initiatives.

“If someone is stung, don’t wait for symptoms to worsen – go to the nearest healthcare facility immediately,” said Prof Eliane Candiani Arantes, a co-author from the University of São Paulo.

Not enemies, but survivors

Despite the rising danger, experts stress that scorpions are not inherently aggressive. They sting in self-defence and play an important ecological role by controlling pest populations and supporting urban biodiversity.

“They are not our enemies,” Pucca said. “These animals act defensively, not offensively. They’re part of the natural world and play essential ecological roles.”

Prevention and preparedness

Simple public health measures can help reduce encounters. Experts recommend sealing wall cracks, checking clothes, shoes, and towels, keeping homes clean and dry, and using drain screens to block access from sewers.

Dr Manuela González-Suárez, an ecologist at Reading University, who was not involved in the study, said the data is striking.

“The numbers are much higher than I would expect... this is a significant increase,” she said, while also noting that increased awareness may have led to more reports.

Prof Nibedita Ray-Bennett of the University of Leicester, and president of the Avoidable Deaths Network, said the study underscores the need for urgent and coordinated action at the policy level.

“This issue is not just environmental; it is socio-economic and political,” she said.

A regional issue with wider implications

The authors warn that Brazil is not alone. Countries across South and Central America, including Paraguay, Bolivia, Mexico, Guyana, and Venezuela, have seen a “particularly alarming rise in scorpionism” in recent decades.

In Europe, more than 35 native scorpion species are known to exist, though no comprehensive studies have yet been done on population trends or sting data.

As global temperatures continue to rise and cities expand further into wild habitats, scientists say similar public health concerns may emerge elsewhere if proactive measures aren’t taken.