What can ignorance about health lead to?

There is no need to think out and guess what ignorance about health can lead to. It is enough just to remember historical examples. At a time when the bubonic plague or tuberculosis destroyed entire cities, people did not understand anything about medicine, primarily due to the inability to conduct full-fledged studies of the human body. People believed that the plague was brought by witches, and the carriers of the disease were black cats. People killed cats that could prevent infection by catching mice. People can die due to lack of knowledge about health. Nowadays medicine is developing rapidly. But we ourselves must know about the rules of protection against viruses, vaccinations and personal hygiene.