Polio Symptoms & signs
Polio can be a minor illness, known as the abortive type of polio. This occurs in 80%-90% of clinical infections, chiefly in young children, and does not reach the CNS. In this case, symptoms and signs include slight fever, malaise, sore throat, headache, and vomiting 3-5 days after exposure. Recovery occurs in 24-72 hours.
When polio is a major illness, symptoms usually appear without prior illness, particularly in older children and adults, 7-14 days after exposure. Symptoms include
- fever,
- severe headache,
- stiff neck,
- stiff back,
- muscle pain,
- areas of hyperesthesia (increased sensation), and
- paresthesia (altered sensation).
What is the history of polio?
Picture of iron lung used to move air in and out of lungs by pressure changes; SOURCE: CDC/GHO/Mary Hilpertshauser
The history of polio dates back about 6,000 years. Egyptian mummies have been found with withered and malformed limbs that likely occurred because of polio infection. In 1789, the first description of polio was recorded, and in 1834, the first documented epidemic occurred on the island of St. Helena. In 1855, Dr. Guillaume Benjamin Amand Duchenne showed polio involved the anterior horn cells (nerve cells) of the spinal cord. Landsteiner and Popper discovered the virus in 1908. The Iron lung was developed in the late 1920s to help some polio survivors with polio breathe. One of the most famous people who had polio was U.S. President Franklin D. Roosevelt (1882-1945). The polio virus was first cultivated in tissue culture (1949), and in 1951, the three types of poliovirus were isolated and identified. During the mid-1950s (1954), the first large-scale trial of the vaccine developed by Dr. Jonas Salk (dead virus vaccine) was administered by injection, and in 1958, Dr. Albert Sabin’s vaccine (live attenuated virus) was administered as an oral vaccine. In 2000, the U.S. switched to using inactivated polio vaccine by injection. Other countries still may use the oral poliovirus vaccine. Because polio viruses survive only in humans and are transmitted only by human contact, the World Health Organization (WHO) is trying to eradicate polio worldwide. This attempt has been relatively successful with a 99% decrease in polio infections worldwide. In 2014, WHO announced that Southeast Asia was polio-free. However, some countries in Africa and the Middle East still have new infections caused by polio because of areas that cannot be reached by vaccine workers. Unfortunately, when there is war in these regions, polio makes a comeback because vaccine efforts are interrupted. The WHO still believes that polio eradication, like smallpox, may happen in the near future.