The development of immunity to polio efficiently blocks person-to-person transmission of wild poliovirus, thereby protecting both individual vaccine recipients and the wider community.
Additional environmental sources include fecal-contaminated lakes, nonchlorinated municipal water supply, petting farm animals and unhygienic person-to-person contact.
Mosquito-borne diseases involve the transmission of viruses and parasites from animal-to-animal, animal-to-person, or person-to-person, without afflicting the insect vectors with symptoms of disease.