Final answer:
Poliomyelitis, commonly known as polio, is caused by the poliovirus and can cause paralysis by infecting and destroying motor neurons in the spinal cord's gray matter. It is highly contagious, primarily through fecal-oral transmission, and symptomatic poliovirus infections can severely impact the CNS leading to flaccid paralysis.
Step-by-step explanation:
Poliomyelitis (polio) is a disease caused by the poliovirus, which primarily targets the human gastrointestinal tract but can occasionally spread to the central nervous system (CNS), leading to serious complications such as paralysis. This viral infection affects the anterior horn cells (motor neurons) in the gray matter of the spinal cord, which can result in cell destruction and flaccid paralysis. This can include the respiratory system, necessitating the use of ventilation systems for treatment.
The reproductive cycle of poliovirus begins in the pharynx and gastrointestinal tract, after entering through the mouth, and may lead to replication in motor neurons. Contagiousness remains even in cases where the infected individual is asymptomatic, as the virus is excreted in feces and potentially through oral secretions. Poliovirus is highly contagious through fecal-oral transmission or aerosol droplets. While most infections are mild or asymptomatic, a small proportion can lead to permanent and severe outcomes.
Understanding diseases like poliomyelitis is crucial for preventive and treatment measures, as well as for distinguishing it from other neurological disorders such as Guillain-Barré syndrome and multiple sclerosis, which also affect the nervous system but have different etiologies and pathologies.