3. Polio

Polio is a disease which has been all but eradicated throughout the world through both vaccinations and improved health standards. This infectious pathogen invades the human body through the ingestion of human fecal matter; usually through contaminated food or drink. Symptoms of polio begin anywhere from six to 20 days after infection and range from fever and sore throat to nausea, vomiting and constipation.

In about one percent of cases, poliovirus will enter the central nervous system by infecting the spine and brain; leading to paralytic disease. Roughly two to five percent of children and 15 to 30 percent of adults will die once polio has caused paralysis.