Instituto Butantan

Listen for a moment. Under the trees, the city's traffic fades to a low hum. Birds call from the canopy. Somewhere nearby, a group of schoolchildren goes quiet, pressed against a low wall, staring down at something coiled in the grass. This is Instituto Butantan, in the west of São Paulo. It is a green campus of old buildings and shaded paths. It is also one of the places where Brazil learned how to survive its own snakes.

The institute began as an emergency. At the very end of the nineteenth century, bubonic plague reached the port of Santos, down on the coast. São Paulo needed serum, and it needed it fast. A laboratory was set up on an old farm called Butantan, far from the crowded city centre. The work began there around 1900, and the institute was formally established in 1901. The plague was the first problem. But a much older one was waiting in the fields.

That older problem was snakebite. In rural Brazil, farm workers met venomous snakes every day in the coffee plantations and pastures. Many died, and many more lost limbs. The young doctor who led the new laboratory was Vital Brazil. He had seen these deaths with his own eyes in the countryside. He turned the laboratory toward a simple, urgent question: how do you save a person in the hours after a bite?

Here is the first surprise. Vital Brazil showed that antivenom is not one universal cure. A serum made against one type of snake often does little against another. The venom of a rattlesnake works differently from the venom of a lancehead. So the institute had to make different sera for different snakes. This idea of specificity shaped the treatment of snakebite well beyond Brazil, and it is still the basis of the work done here today.

To make antivenom, you need venom. And to get venom, you need snakes — a great many of them. So the institute made an unusual deal with the countryside. Farmers caught snakes and sent them here in wooden boxes, often by train. In return, they received vials of serum and the means to send more snakes. Picture a railway station in the early twentieth century, with crates of live snakes arriving among the sacks of coffee.

The method itself is old and still in use. Venom is collected from the snakes by hand, in a process often called milking. Small doses are then given to horses over time. The horses build up antibodies in their blood. That blood is processed into serum, which is the antivenom given to patients. Horses have played this quiet role here for more than a century. Their part is easy to forget, but it has saved many lives.

Now look around the grounds. The campus feels more like a park than a laboratory. Tall trees shade the paths. Old buildings with pale walls and red tile roofs stand between the newer research blocks. Students, families, and scientists in lab coats share the same walkways. Remember that this is not a museum frozen in the past. It is a working public health institute, and the production halls are only a short walk from where you stand.

The outdoor snake enclosures draw most visitors first. They are open pits with low walls, grass, and small domed shelters. The snakes are often hard to spot. They lie still in the shade, the same colour as the earth and the dry leaves. Take your time. Once your eyes adjust, you may see a shape that you thought was a branch. Then it moves, slowly, and the whole crowd seems to breathe in.

Inside the biological museum, the glass cases hold live snakes, lizards, spiders, and scorpions. You will see some of the species that shaped the institute's history. The jararaca is one of them, a lancehead snake common in this region. The rattlesnake is another, with its dry warning sound. Look also for the coral snakes, with their bright rings of red, black, and white. Their colour is a warning, and it is worth taking seriously.

Here is the second surprise. Venom is not only a danger — it can also become medicine. Research on the venom of the jararaca helped lead to a family of drugs that lower blood pressure. Millions of people around the world now take medicines of this kind. Many of them have no idea that the story begins with a snake from the forests and fields of southeastern Brazil.

The institute has also known loss. In 2010, a fire destroyed a large part of its scientific collection of preserved snakes and other animals. That collection had grown over many decades, and it was one of the most important of its kind. Much of it could not be replaced. Scientists have worked since then to rebuild the collection. It is a reminder that a scientific archive is fragile, and that it takes generations to build.

In recent years, the name Butantan became known far beyond São Paulo. During the COVID-19 pandemic, the institute partnered with a Chinese company to produce a vaccine for Brazil. It was called CoronaVac. For many Brazilians, it was the first vaccine they received against the virus. The institute also produces large amounts of flu vaccine for the national health system every year. The small emergency laboratory of 1901 has become a major vaccine producer.

The campus has several smaller museums, and each one tells a different part of the story. The historical museum looks at the early laboratory and its first years. The microbiology museum moves from snakes to the invisible world of bacteria and viruses. Together they show how one place moved from one public health crisis to the next, for more than a century. If you have time, visit more than one.

Before you leave, stop on one of the shaded paths for a minute. Listen to the birds, and to the soft sound of footsteps on the walkway. Behind those walls, people are still working with venom, horses, and vaccines, much as they have done for generations. When you walk out past the gates, the city will grow loud again. But somewhere in a hospital today, someone may be alive because of the work done here.