Polio is caused by which of the following organisms?

Virus

The correct answer is Option (4) -Virus

Polio, short for poliomyelitis, is a highly contagious viral infection caused by the poliovirus, which primarily affects young children. The virus is transmitted through person-to-person contact, primarily via the fecal-oral route or less commonly through contaminated food or water. Once the virus enters the body, it multiplies in the intestines and can then spread to the nervous system, leading to paralysis in some cases.

The symptoms of polio can vary widely, ranging from asymptomatic infection to severe paralysis. In cases where paralysis occurs, it typically affects the legs but can also affect the muscles of the arms, neck, and diaphragm, potentially leading to breathing difficulties.

The introduction of polio vaccines, particularly the oral polio vaccine (OPV) and the inactivated polio vaccine (IPV), has led to significant reductions in the incidence of polio worldwide. Vaccination efforts, along with improved sanitation and hygiene practices, have contributed to the near-eradication of polio in many parts of the world.