1. Strep or Sore Throat Slideshow Pictures
2. Take the MRSA Quiz!
3. Infectious Mononucleosis Slideshow Pictures

Medical Author:

David Perlstein, MD, MBA, FAAP

David Perlstein, MD, MBA, FAAP

Dr. Perlstein received his Medical Degree from the University of Cincinnati and then completed his internship and residency in pediatrics at The New York Hospital, Cornell medical Center in New York City. After serving an additional year as Chief Pediatric Resident, he worked as a private practitioner and then was appointed Director of Ambulatory Pediatrics at St. Barnabas Hospital in the Bronx.

View Full Profile

Medical Editor:

Charles Patrick Davis, MD, PhD

Charles Patrick Davis, MD, PhD

Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

View Full Profile

In this Article

• What is the history of polio?
• What causes polio?
• How is polio spread?
• What are signs and symptoms of polio?
• How is polio diagnosed?
• How is polio treated?
• Is there a vaccine that prevents polio?
• Where can one find more information about polio?
• Polio At A Glance
• Polio Index

The symptoms of polio are caused by the poliovirus, which is a small RNA virus that is spread through contact with the oral mucosa (mouth, nose, etc). Most commonly, the virus attaches to and infects intestinal cells, multiplies, and is excreted in the stool of the infected individual. Rarely, in 2% of the cases, the virus spreads from the gastrointestinal tract to the nervous system and causes paralytic disease.

Polio is spread in an "oral-fecal" manner. Person-to-person infection occurs by contact with infected mucus, phlegm, feces, or by contact with food and water contaminated by feces of another infected individual.

The signs and symptoms of polio differ depending on the extent of the infection. Signs and symptoms can be divided into paralytic and non-paralytic polio.

In non-paralytic polio which accounts for most individuals infected with polio, patients remain asymptomatic or develop only mild flu-like symptoms, including fatigue, malaise, fever, headache, sore throat, and vomiting. The symptoms, if present, may only last 48-72 hours, though usually they last for one to two weeks.

Paralytic polio occurs in about 2% of people infected with the polio virus and is a much more serious disease. Symptoms occur as a result of nervous system and spinal cord infection and inflammation. Symptoms can include

• abnormal sensation,



• breathing difficulty,



• difficulty swallowing,



• urinary retention,



• constipation,



• drooling,



• headache,



• mood swings,



• muscle pain and spasms, and



• paralysis.

Approximately 5%-10% of patients who develop paralytic polio often die from respiratory failure, since they are unable to breathe on their own. That is why it is imperative that patients receive appropriate medical evaluation and treatment. Prior to the vaccine era and the use of modern ventilators, patients would be placed in an "iron lung" (a negative pressure ventilator, which was used to support breathing in patients suffering from paralytic polio).