What causes polio in humans?

The virus leaves an infected person in stool and can spread when sanitation or hand hygiene is inadequate. It may be transferred to food, water, surfaces, or another person’s mouth. After entering the body, poliovirus can multiply in the intestine. Many infections are mild or unnoticed, while some cause fever, headache, tiredness, nausea, or muscle pain. If the virus enters the nervous system, it can injure motor nerve cells and produce weakness or paralysis. That severe pattern is why a person with sudden loss of strength needs prompt assessment, even if earlier symptoms seemed minor.

Keep routine vaccinations up to date and ask a clinician about travel recommendations before visiting an area with polio transmission. Wash hands with soap after toilet use or changing nappies and before food preparation. Use safe drinking water and carefully handled food. If exposure is possible, contact a healthcare professional for individual advice rather than waiting for symptoms. [Childhood Immunisation](/treatments/preventive-care-and-vaccination/childhood-immunisation/) explains the role of routine vaccination.

Seek urgent care for sudden weakness, difficulty walking, a new floppy limb, problems swallowing, or breathing difficulty. Tell the clinician about recent travel, contact with someone who was unwell, and vaccination history. Until advice is provided, wash hands carefully and avoid sharing food or drinks. Do not assume that the absence of paralysis rules out infection.

Ask whether your vaccination record needs updating, whether travel changes your protection plan, and what to do after a possible exposure. If weakness or swallowing trouble is present, ask what immediate assessment is required and how household contacts should be advised.