You are a Peace Corps volunteer physician in a developing country.

You are a Peace Corps volunteer physician in a developing country. You notice that some of the villages you visit have a high incidence of a parasitic disease, but other nearby villages are unaffected. Investigating you find the villages with disease are in wet areas with lots of snails and frogs, while the disease-free villages are in drier places but have lots of insects and mice. From this information, what might you reasonably conclude about the type of parasite responsible for the disease?