Typhoid fever is a serious bacterial infection that spreads through contaminated food and water. The disease causes high fevers, severe headaches, stomach pain, and extreme weakness that can last for weeks. Before modern medicine, typhoid killed many people, especially in crowded cities where clean water was hard to find.

The bacteria that cause typhoid (called Salmonella Typhi) live in human intestines and spread when water or food gets contaminated by waste from infected people. This happens when sewage systems fail or when people don't have access to clean drinking water. Even after someone recovers, they can still carry the bacteria and spread it to others without knowing.

The most famous carrier was Mary Mallon, a cook in New York City in the early 1900s, who became known as “Typhoid Mary.” She unknowingly infected dozens of families she worked for because she carried the bacteria but never felt sick herself.

Today, typhoid fever is rare in places with modern plumbing and water treatment, but it still affects millions of people each year in parts of the world where clean water is scarce. Vaccines can prevent it, and antibiotics can cure it if caught early. The disease reminds us how important clean water and good sanitation are for keeping communities healthy.