This means that there is no year-round transmission of poliovirus in the United States. Since 1979, no cases of polio have originated in the U.S. However, the virus has been brought into the country by travelers with polio. The last time this happened was in 1993.
Wild poliovirus has been eradicated in all continents except Asia, and as of 2020, Afghanistan and Pakistan are the only two countries where the disease is still classified as endemic.
Since the virus is easily transmitted, epidemics were commonplace in the first decades of the 20th century. The first major polio epidemic in the United States occurred in Vermont in the summer of 1894, and by the 20th century thousands were affected every year.
Wild poliovirus type 3 (WPV3) has been eradicated worldwide, according to an independent commission of experts. The news comes today—World Polio Day—and means two of the three wild poliovirus strains are now eradicated. “The achievement of polio eradication will be a milestone for global health.
1894, first outbreak of polio in epidemic form in the U.S. occurs in Vermont, with 132 cases. 1908, Karl Landsteiner and Erwin Popper identify a virus as the cause of polio by transmitting the disease to a monkey.
The death -to-case ratio for paralytic polio is generally 2%–5% among children and up to 15%–30% for adults (depending on age).
Today, only six countries in the world remain polio-endemic ( Nigeria, India, Pakistan, Egypt, Niger and Afghanistan).
Wild polio cases have decreased globally by more than 99% since 1988, but the virus is still endemic in Afghanistan and Pakistan, which report dozens of cases every year.
Four regions of the world are certified polio free —the Americas, Europe, South East Asia and the Western Pacific. Only three polio -endemic countries (countries that have never interrupted the transmission of wild poliovirus) remain—Afghanistan, Nigeria, and Pakistan.
OPV was recommended for use in the United States for almost 40 years, from 1963 until 2000. The results have been miraculous: Polio was eliminated from the United States in 1979 and from the Western Hemisphere in 1991. Since 2000, only IPV is recommended to prevent polio in the United States.
The discovery by Karl Landsteiner and Erwin Popper in 1908 that polio was caused by a virus, a discovery made by inoculating macaque monkeys with an extract of nervous tissue from polio victims that was shown to be free of other infectious agents.
Transmitted primarily via feces but also through airborne droplets from person to person, polio took six to 20 days to incubate and remained contagious for up to two weeks after.
To date, the World Health Organization (WHO) has declared only 2 diseases officially eradicated: smallpox caused by variola virus ( VARV ) and rinderpest caused by the rinderpest virus (RPV).
Some of the reasons which affect the eradication of polio are political unrest, poor health infrastructure, and government negligence. The most afflicted areas are those where militants are present and the government lacks absolute control, such as the Federally Administered Tribal Areas.
Polio is a disease that has lifelong health consequences for those infected. The poliovirus is of particular concern to public health because it spreads easily – it can circulate without causing symptoms for weeks, and so can travel great distances, entering polio -free areas by land, sea or air travel.