A 46-year-old Brazilian man named Leandro Marques do Nascimento says he nearly died after spending almost a month hospitalized — not just because of a venomous snake bite, but because of what he describes as a critical medical error.
According to Leandro, the incident began on March 7, 2026, while he was fishing with his wife at Parque Salto da Usina, in the municipality of Eldorado, in the interior of São Paulo state. He felt a sharp burning sensation in his leg, and upon checking, noticed bleeding and bite marks consistent with a snake attack.
He was transported to a hospital, where medical staff allegedly misidentified the snake species. Leandro says he was bitten by a jararacuçu (Bothrops jararacussu), a highly venomous pit viper native to Brazil — but the initial treatment team reportedly treated him as if he had been bitten by a rattlesnake (cascavel), a completely different species requiring a different antivenom. As a result, he claims he received 10 doses of the wrong serum. When his condition did not improve, doctors reportedly administered 10 additional doses of the same incorrect antivenom, totaling 20 doses.
The correct snake species was only identified later, with the help of artificial intelligence tools and confirmation from the renowned Instituto Butantan in São Paulo.
"A snake bite and the wrong antivenom — that's what almost cost me my life," Leandro said.
The case has sparked public debate about hospital protocols for snakebite treatment in Brazil. Medical experts stress that antivenoms are species-specific, and that accurate identification of the snake is critical to administering the correct treatment. When identification is not possible, a mixed antivenom is typically recommended.
The Instituto Butantan, Brazil's leading reference institution for venomous animal research and antivenom production, has long advocated for patients or bystanders to bring a photo of the animal to the hospital whenever safely possible, in order to assist with identification and ensure the appropriate antivenom is used.
The hospital involved has not yet issued a public response to the allegations.
Source: G1 / Globo — "Homem picado por cobra diz ter recebido 20 doses de soro contra espécie errada em hospital de SP" (April 9, 2026)