A group of 26 passengers developed acute gastrointestinal illness after a cruise. What is the most likely causative agent?

Norovirus is the most likely causative agent in this scenario due to several key characteristics of the virus and the situation described. Norovirus is a highly contagious virus that is one of the most common causes of acute gastroenteritis worldwide, especially in enclosed environments such as cruise ships. It is notorious for spreading rapidly among large groups of people, often leading to outbreaks.

The symptoms typically include vomiting, diarrhea, and stomach cramps, which align with the acute gastrointestinal illness reported in the passengers. Additionally, norovirus can be transmitted through contaminated food or water, direct contact with infected individuals, and contact with contaminated surfaces, making it particularly relevant in the context of a cruise where close quarters and shared facilities can facilitate its spread.

In comparison, while other pathogens such as Campylobacter jejuni and Escherichia coli O157 can also cause gastrointestinal illnesses, they are less commonly associated with outbreaks on cruise ships. Campylobacter typically spreads through undercooked poultry or contaminated water, and E. coli O157 is often linked to contaminated food products, which might not be as prevalent in this scenario involving a large group of people in a controlled setting. Rotavirus primarily affects children and is less likely to cause outbreaks in adult populations like those typically found on a