Diseases Transmitted by Foods Contaminated by Wastewater.

A historical and world-wide review of medical and engineering literature discloses that typhoid fever, infectious hepatitis, fascioliasis, and cholera are the diseases that have been most frequently transmitted by foods contaminated by sewage or irrigation water in agricultural or aquacultural practices. Wastewater-contaminated shellfish have resulted in 28 outbreaks of illness, watercress in 10, fish in three, and shrimp in one. Vegetables contaminated by night soil or raw or partially treated sewage were reported as vehicles in 21 outbreaks. Fruits were considered as vehicles in four outbreaks. For such outbreaks to occur, a complicated chain of events must occur for agents originally present in wastewater to survive natural destructive forces and wastewater-treatment processes or to multiply so that there are sufficient numbers to cause illness.