Breaking the reproduction/re-infection cycle was key. Pickup up dog turds did make a difference, so too the widespread use of preventative drugs in pets. Not

Breaking the reproduction/re-infection cycle was key. Pickup up dog turds did make a difference, so too the widespread use of preventative drugs in pets. Not spitting in the street. Wearing shoes. Bathing in clean/chlorinated water, drinking clean water, proper sewage, and tacking any local infections with serious drugs ... all these things add up to cut the reinfection rate to the point that the parasites stopped spreading.