Final answer:
The greatest impact on the number of cholera cases following a natural disaster is the contamination of water sources, as disrupted sanitation systems allow for rapid spreading of the cholera-causing bacterium, Vibrio cholerae.
Step-by-step explanation:
Outbreaks of cholera are more common after natural disasters because such events frequently disrupt the sanitation systems that prevent disease transmission by maintaining clean water. Among the options provided, contamination of water sources has the greatest impact on the number of cholera cases post-natural disaster. When sanitation systems fail, pathogens like Vibrio cholerae, the bacterium causing cholera, rapidly contaminate water supplies, leading to widespread outbreaks. Contaminated drinking water carrying the bacterium can cause severe diarrhea, dehydration, and can be fatal without treatment. The implementation of water purification, treatment of sewage water, and ensuring personal hygiene are vital strategies for cholera prevention and reducing the risk of epidemics, especially in areas affected by natural disasters.