What public health measure helps prevent poliovirus transmission?

• A. Sanitation and clean water access
• B. Border screening at ports
• C. Mandatory vaccination of travelers
• D. Quarantine of infected individuals

Answer: (A)

Poliovirus spreads mainly through the fecal-oral route, so the best way to prevent transmission is to improve sanitation and ensure access to clean drinking water. When sewage is properly managed and water sources are free of fecal contamination, the virus has fewer chances to reach new people, which lowers transmission in the whole community and protects vulnerable groups. Vaccination remains crucial for individual protection and herd immunity, but environmental controls tackle the main transmission pathway directly and have the broadest impact on stopping spread. Border screening and quarantine miss many cases because people can shed the virus before symptoms appear, and these measures do not reliably interrupt environmental transmission. Mandatory vaccination of travelers is not as effective a population-wide strategy for preventing community transmission as improving sanitation and water safety.