All can cause permanent disability. Some can cause death. Polio is caused by a virus that attacks the central nervous system and can cause permanent paralysis, leading to crippling, and occasionally death when the muscles used in breathing are paralyzed. There is no specific treatment for polio, and antibiotics are not effective against the virus. Now that children are routinely vaccinated against polio, the disease has almost disappeared in the United States and Canada.
Diphtheria is caused by a bacteria that infects the nose, throat, and vocal cords.
Diphtheria can cause death by interfering with breathing, attacking the heart, and paralyzing muscles. Even if antibiotics are given, at least one out of ten people who gets diphtheria dies of it. Routine vaccination has almost eliminated the disease in the US and Canada. The coughing can be so frequent and violent that it interferes with eating, drinking, and even breathing. Three in 1000 unimmunized children who get pertussis will have encephalitis, or inflammation of the brain as a complication.