Which of the following is the most common source of infectious diseases in water supplies?

• A. Airborne transmission
• B. Vector-borne organisms
• C. Fecal contamination
• D. Industrial chemical runoff

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the context of infectious diseases related to water supplies. Infectious diseases in water are typically caused by pathogens that enter water sources and infect humans upon consumption or contact.
2. Step 2: Review the modes of transmission listed: airborne transmission, vector-borne organisms, fecal contamination, and industrial chemical runoff. Consider which of these directly relates to contamination of water supplies.
3. Step 3: Recognize that airborne transmission involves pathogens spread through the air, which is less relevant to waterborne diseases since it does not directly contaminate water.
4. Step 4: Understand that vector-borne organisms are transmitted by vectors like mosquitoes, which is a different route of infection and not primarily related to water contamination.
5. Step 5: Identify fecal contamination as the most common source of infectious diseases in water supplies because feces can contain bacteria, viruses, and parasites that contaminate water and cause diseases such as cholera, typhoid, and dysentery.