Pathogens may be viruses, bacteria, protists, or fungi they are just microorganisms that can cause diseases. Bacteria are microscopic and once bacteria find their way into the body they release toxins that make us feel sick. Examples of bacterial infections are cholera, typhoid, food poisoning, and gonorrhea. Although bacteria are very small viruses are much smaller, they are among the smallest organisms we know of. Viruses not only enter the body but they enter cells and reproduce inside cells, they reproduce hundreds of thousands of times and eventually cause the host cell to explode. The virus then passes out through the airwaves, bloodstreams or other and can spread through populations. Examples: flu, influenza, measles, mumps, the common
