Poliomyelitis

The causative agent of poliomyelitis is poliovirus, a virus of the genus enterovirus with a capsid (the protein structure that encloses the nucleic acid), with a single-helix RNA genome, of which there are three serotypes: PV1, PV2, PV3, distinguished by the composition of the capsid.
Once the virus invades the host, it moves to the intestine and there begins to replicate, resulting in the symptoms of the disease. Specifically, it can remain in the intestine (in which case symptoms tend to be mild or absent), or it can enter the bloodstream, reaching the central nervous system.

It is an orofecal-transmitted disease, that is, it can be transmitted directly, through contact with the feces or urine of sick subjects, or indirectly through ingestion of contaminated food or drink. It can also be transmitted through saliva or droplets emitted through coughing or sneezing by infected individuals. The virus can affect people at any age, but generally the most vulnerable individuals are children under the age of 5.

Thanks to the eradication program initiated in 1988, polio has become a very rare disease, particularly in industrialized countries. In some developing areas of Africa, and the Middle East, the disease is a public health problem. WHO estimates that there are 200,000 cases of polio annually.

Generally, the incubation period of polio ranges from 4 to 35 days.
Symptoms initially manifest as fever, feeling of weakness, headache, stiffening of the neck, muscle pain, and vomiting. For 1% of those affected, the virus invades the nervous system causing to irreversible paralysis (usually in the lower limbs). Of these, 5-10% result in death due to paralysis of respiratory muscles.

Some of the features that allow identification of the disease are neck and back stiffness, back pain, difficulty breathing and swallowing, and the presence of abnormal reflexes. The diagnosis can then be confirmed after testing for the specific agent on a sputum or cerebrospinal fluid sample or stool sample within the first few days after the onset of the disease.

To date, there is no specific treatment for polio infections.
Treatment is based on treating symptoms and supporting vital functions, and involves a variety of interventions ranging from simple rest in mild cases, to the use of painkillers and antipyretics for flu-like symptoms, to the use of assisted ventilation, physiotherapy, and braces to cope with more severe problems.

Polio is prevalent with a higher prevalence in areas where hygiene conditions are poor and where there is no adequate public health control and governance network. The only weapon to counter the spread of poliovirus is the vaccine, which effectively protects against all serotypes of the virus.