This from Centers for Disease Control, regarding an outbreak of Rift Valley Fever in the Garissa and Wajir districts of Kenya:

(excerpt) "Two thirds of the 66 patients who provided information on potential risk factors reported having an animal that was recently ill. The most frequently reported RVF risk factors during the 2 weeks preceding illness onset were drinking unboiled (raw) milk (72%); living within 100 meters of a swamp (70%); having an ill animal (67%); drinking milk from an ill animal (59%); working as a herdsman (50%); having a dead animal (50%); and slaughtering an animal (42%)."