revision preference src: Open defecation, monsoon flooding, and a lack of water treatment made it easier for a child to swallow more polio virus. Children with too few doses of vaccine were not fully protected and sometimes got polio. <SEP> tgt: Open defecation, monsoon flooding, and a lack of water treatment made it easier for a child to swallow more polio virus. As a result, children with too few doses of vaccine were not fully protected and sometimes got polio.