Which of the following waterborne diseases still occur in developed countries?

Viral gastroenteritis is characterized by inflammation of the stomach and intestines, often caused by viruses such as norovirus and rotavirus. It is primarily transmitted through contaminated water, food, or surfaces, making waterborne transmission a significant route for these infections in both developed and developing countries. Outbreaks of viral gastroenteritis are not uncommon in developed nations, especially in places where hygiene and sanitation might be compromised, like cruise ships or large gatherings.

In contrast, infectious hepatitis B is mainly transmitted through blood and bodily fluids rather than through water, so it doesn't qualify as a waterborne disease. Malaria is transmitted by mosquitoes, not through water sources, and rabies is primarily spread through animal bites. Therefore, while these other diseases can certainly be serious health concerns, viral gastroenteritis remains a pertinent example of a waterborne illness that continues to affect populations in developed countries.