​Infectious Diseases and Microbiology - Poliomyelitis ( Poliovirus)

​Infectious Diseases and Microbiology - Poliomyelitis (  Poliovirus) 
The poliovirus is the cause of poliomyelitis. The fecal-oral route is the means by which poliovirus spreads. The only natural hosts for epidemiology are humans. Thanks to vaccinations, polio has been all but eliminated in the Western Hemisphere. The rate of paralytic polio is still high in developing nations.


The majority of poliovirus infections (90–95%) have no symptoms. The most prevalent clinical form of poliomyelitis, known as "abortive poliomyelitis," is typified by a flu-like sickness with fever, headache, sore throat, and nausea that resolves on its own without any lasting effects on the central nervous system. Poliomyelitis, either nonparalytic or paralytic, is the consequence of a small percentage (~1%) of poliovirus infections. The hallmarks of nonparalytic poliomyelitis include fever, headache, and stiff neck, along with other aseptic meningitis symptoms, which are then followed by a spontaneous recovery. The hallmark of paralytic poliomyelitis is asymmetric flaccid paralysis, which typically affects the legs. About 25% of those who survive paralytic poliomyelitis develop postpolio syndrome. Thirty to forty years after an acute polio infection, the syndrome manifests itself as atrophy, weariness, discomfort, and muscle weakness.

After ingestion, the poliovirus first causes infection in the throat and gastrointestinal tract before migrating to draining lymph nodes and ultimately reaching the central nervous system (CNS). The anterior horn of the spinal cord's motor neurons are directly killed by CNS invasion, which causes paralysis as a result. IgA and IgG antibody responses are mostly responsible for poliovirus clearance and infection recovery.

Antibodies specific to the poliovirus are used to identify cases of the virus in cell culture. To diagnose and differentiate between the poliovirus and other enteroviruses, RT-PCR is utilized.
 The poliovirus has no known cure. A live, attenuated (Sabin), or dead (Salk) vaccine can prevent polio. In the US, the killed polio vaccine is advised due to infrequent instances of live vaccine-associated paralytic polio.