The first half of the 20th century saw epidemics of polio ravage the world, leaving many children and adults paralysed. This spurred a surge in funding for research into a vaccine, with several being developed in the 1950?s. Since then Polio has been almost eradicated throughout the world, although civil war has seen the disease re-emerge in Syria.
How Does Polio Spread?
The polio virus is a very contagious disease that infects the intestinal tract. It is so contagious that it has been known to infect the entirety of a population exposed to it. Transmission usually arises from contact with faecal matter, typically from food which has been fertilized or otherwise come into contact with human waste. It can also be transmitted through contact with saliva. Nine out of ten cases of polio result in no symptoms developing. However, one in ten people will develop symptoms similar to the flu, and one in a hundred will see the virus infect the central nervous system.
Symptoms & Effects of Polio
It is this 1% of cases which result in the most recognisable result of polio, paralysis. If the virus invades the nervous system it begins to attack nerve cells in the spinal cord, brain stem and motor cortex, destroying the pathways our brain uses to control muscles. This results in an inability to move those muscles. Though the exact muscles affected can differ, it can involve limbs, the face, and even control of the lungs. This is the reason that the iron lung was invented, a machine which used pressure to mechanically open and close someone with polio?s lungs. Even after the disease runs its course, which can be as long as six weeks, the paralysis may be permanent. Further, paralysis can result in skeletal deformation, particularly in limbs, leaving the victim further disabled.
Thankfully, polio is almost completely eradicated, particularly in developed nations. Only three countries still have endemic polio: Nigeria, Pakistan and Afghanistan, though surrounding countries infrequently are reinfected. Conflict and limited funding mean that efforts to eradicate the disease in those countries are still hampered, but it is hoped that in the coming years polio will be fully and finally wiped off the face of the earth.