Polio is an infectious disease caused by a virus. It has been virtually eradicated from the Western world thanks to vaccination but it is still a problem in developing countries. In 95 percent of cases, there are no symptoms at all and this is called asymptomatic polio. In four to eight percent of cases, there are symptoms and polio can take one of three forms: abortive polio (has flu-like symptoms); non-paralytic polio (has neurological symptoms such as photosensitivity and neck stiffness, and paralytic polio (which occurs in 0.1 to two percent of cases). Treatment is mainly through preventative vaccination but other options include iron lungs, ventilators, fluids, bed rest, massage, and homoeopathy.