Oswaldo Cruz

Hello, my name is Oswaldo Cruz, and I want to tell you how I used science to save my city. I was born in Brazil on August 5th, 1872. My father was a doctor, and from a very young age, his work made me curious about the world of medicine. I was especially fascinated with the things you couldn't see with just your eyes. My father gave me my very own microscope, and I would spend hours looking at tiny things, amazed by the secret world it revealed. This love for science grew so strong that I knew I wanted to become a doctor, just like my father. I studied very hard, and in 1887, when I was only 15 years old, I was ready to begin my studies at medical school. I couldn't wait to learn everything I could to help people stay healthy.

After I finished medical school in Brazil in 1892, my curiosity was bigger than ever. I felt there was still so much more to learn about the tiny germs that could make people sick. So, in 1896, I traveled all the way across the ocean to Paris, France. There, I studied at a very famous school called the Pasteur Institute. It was a wonderful place where scientists were making incredible discoveries. I studied a special field called microbiology, which is the study of microscopic organisms like bacteria and viruses. I learned how these tiny germs spread from person to person and how they caused terrible diseases. I knew that this knowledge would be incredibly important, and I was determined to bring it back to Brazil to help my people.

When I returned to Brazil in the early 1900s, the capital city, Rio de Janeiro, was in serious trouble. It was a beautiful place, but it was also very sick. Terrible diseases were spreading everywhere, making many people ill. The biggest problems were yellow fever, smallpox, and the bubonic plague. People were scared, and the city was suffering. In 1903, the president of Brazil, a man named Rodrigues Alves, gave me a very big and important job. He asked me to become the Director General of Public Health and to lead the fight against these diseases. It was a huge responsibility, but I was ready. From my studies, I knew that the key was to fight the pests that carried and spread the sickness. The main culprits were mosquitoes, which spread yellow fever, and rats, whose fleas carried the bubonic plague.

I immediately put my scientific plan into action. To fight the mosquitoes, I created special teams that I called “mosquito brigades.” These groups of workers went all over Rio de Janeiro, cleaning up the city. Their most important job was to get rid of any standing water they could find—in puddles, pots, and barrels—because that’s where mosquitoes laid their eggs. However, many people didn't understand why these men were entering their homes and yards. They were angry and thought our methods were strange. At the same time, we were fighting smallpox with a vaccine. In 1904, the government passed a law that said everyone had to get the vaccine to be protected. This made people even more upset, and it led to a huge protest in the streets called the Vaccine Revolt. It was a very difficult and scary time, but I knew the science was right and that we had to keep going to save lives.

Even though it was hard, our hard work and our belief in science began to pay off. The mosquito brigades kept cleaning, and slowly, the number of people getting sick with yellow fever started to go down. By 1907, we had done it. We had defeated the yellow fever epidemic in Rio! The city was finally getting healthy again. The news of our success traveled all around the world, and people were amazed by what we had accomplished. In that same year, 1907, I traveled to Berlin, Germany, to attend an international conference on health. There, I was awarded a gold medal for our work in making Rio de Janeiro a safer place. The scientific institute where I worked was also recognized for its important research, and it was later renamed the Oswaldo Cruz Institute in my honor.

I lived to be 44 years old and passed away in 1917. Throughout my life, my mission was to use science to create a healthier and safer world for everyone. I believed that by understanding the tiny, invisible enemies that cause disease, we could protect our communities and help people live longer, better lives. Today, I am remembered in Brazil as a hero who fought for public health. The institute that bears my name is now called Fiocruz, and it has grown to become one of the most important health science centers in the world. It continues the work I started so many years ago, fighting diseases and making new discoveries to keep people everywhere safe.