**Question:** Traveller's diarrhoea is caused by-

A. Salmonella
B. Shigella
C. Campylobacter
D. Rotavirus

**Correct Answer:** C. Campylobacter

**Core Concept:** Traveller's diarrhoea is a common gastrointestinal disorder experienced by individuals who travel to areas with poor sanitation and contaminated water sources, leading to an increased risk of bacterial and parasitic infections.

**Why the Correct Answer is Right:** Campylobacter is a group of bacteria that can cause traveler's diarrhoea, particularly Campylobacter jejuni. When travelers consume contaminated food or water, they are at risk of contracting this infection. C. jejuni is particularly prevalent in underdeveloped regions with poor sanitation and inadequate food handling practices.

**Why Each Wrong Option is Incorrect:**

A. Salmonella: While Salmonella can cause gastroenteritis, it is less likely to be found in traveler's diarrhea due to its preference for causing enterocolitis, an inflammation of the large intestine.
B. Shigella: While Shigella can cause enterocolitis, it is less common in traveler's diarrhea compared to Campylobacter.
D. Rotavirus: Rotavirus is a common cause of viral gastroenteritis in children, but is less likely to be the primary cause of traveler's diarrhoea, which is more commonly associated with bacterial and parasitic infections.

**Clinical Pearl:** Traveler's diarrhoea can be prevented through proper sanitation, food handling guidelines, and avoiding contaminated food and water sources. If diarrhoea occurs, it is essential to consult a healthcare professional for appropriate diagnosis and treatment, as the symptoms may resemble those of other gastrointestinal disorders.