Poliomyelitis

An infectious viral disease, also called polio. It is usually mild, but in serious cases, it attacks the brain and spinal cord, sometimes causing paralysis or death. The virus is spread from the faeces of infected people to food. Airborne transmission also occurs. In countries with poor hygiene and sanitation, most children develop immunity through being infected early in life, when the infection rarely causes serious illness. In countries with better standards, this does not occur and, if children are not vaccinated, epidemics can occur. In the UK, polio is now very rare due to a vaccination programme. Most infected children have no symptoms. In others, there is a slight fever, sore throat, headache, and vomiting after a 3–5-day incubation period. Most children recover completely, but inflammation of the meninges may develop. Symptoms are fever, severe headache, stiff neck and back, and aching muscles, sometimes with widespread twitching. Often, extensive paralysis, usually of the legs and lower trunk, occurs in a few hours. If infection spreads to the brainstem, problems with, or total loss of, swallowing and breathing may result. Diagnosis is made by lumbar puncture, throat swab, or a faeces sample. Characteristic paralysis with an acute feverish illness allows an immediate diagnosis. There is no effective drug treatment for polio. Nonparalytic patients usually need bed rest and analgesic drugs. In paralysis, physiotherapy and, in some cases, catheterization, tracheostomy, and artificial ventilation are needed. Recovery from nonparalytic polio is complete. More than half of those with paralysis make a full recovery, fewer than a quarter are left with severe disability, and fewer than 1 in 10 dies. In the UK, vaccination against polio is given at about age 2, 3, and 4 months, with a booster dose at about 5 years (see immunization). Parents and carers should also be immunized because the active vaccine can cause polio.