Most disease-causing organisms or pathogens are small, and it is not possible to detect them with the naked eye. Such pathogens are called microbes. Bacteria, viruses and microscopic fungi are all examples of microbes.

Humans can also have parasites that grow to large sizes. For example, the tapeworm is a parasite that lives in the human gut and can grow to over a meter in length. The tapeworm causes weight loss and fever, among other things. Such parasites often end up in humans in the form of small eggs or larvae, but later grow larger.

The most effective way to protect yourself against pathogens is through good hygiene. This means eating food that contains the least possible microbes, prepared with clean hands and in clean rooms. Microbes cannot be avoided completely, nor do they have to be, because some of them are hugely beneficial to us.

Washing your hands refularly is one of the central features of good hygiene!