During the 19th century, the way that people were living and working was changing dramatically. These changes affected the risk of infectious diseases and other conditions.

Industry: As more manufacturing processes became mechanized, various work-related diseases became more common. These included lung disease, dermatitis, and "phossy jaw," a type of jaw necrosis that affected people working with phosphorous, usually in the match industry.Urban sprawl: Cities started to expand rapidly, and certain health problems, such as typhus and cholera, became more common as a result.Travel: As people traveled between various parts of the world, they carried diseases with them, including yellow fever.

Meanwhile, scientific advances at that time started to make new treatments possible.

Scientific breakthroughs: As "germ theory" developed, scientists began to test and prove the principles of hygiene and antisepsis in treating wounds and preventing infection. New inventions included the electrocardiograph, which records the electrical activity of the heart over time.Communications: As postal services and other communications improved, medical knowledge was able to spread rapidly.Political changes: Democracy led to people demanding health as a human right.

The 19th and 20th centuries saw breakthroughs occurring in infection control. At the end of the 19th century, 30 percent of deaths were due to infection. By the end of the 20th century, this figure had fallen to less than 4 percent.