Which of the following diseases is NOT associated with exposure to sewage?

Malaria is not associated with exposure to sewage because it is primarily transmitted through the bites of infected female Anopheles mosquitoes, which breed in standing water rather than sewage. The focus for malaria prevention is on controlling mosquito populations and protecting against bites, rather than on sanitation and sewage exposure.

In contrast, diseases like polio, cholera, and infectious hepatitis are linked to contaminated water sources, often as a result of sewage exposure. Polio can spread through fecal-oral transmission, typically in areas with inadequate sanitation. Cholera is caused by consuming water contaminated with the Vibrio cholerae bacterium, frequently found in sewage-contaminated water. Infectious hepatitis (hepatitis A) also spreads via the fecal-oral route, often through contaminated food and water resulting from poor sanitation practices.

Therefore, malaria is distinct from these other diseases due to its transmission method, which does not involve sewage-related contamination.