The passage discusses the pathology and epidemiology of anterior poliomyelitis (polio). It describes how poliovirus enters the body and can cause different levels of infection from abortive poliomyelitis with flu-like symptoms to paralytic poliomyelitis which causes paralysis. During major epidemics in the early 20th century, polio outbreaks caused many cases of paralysis and even death by respiratory failure before iron lungs were developed to help patients breathe.