Most common cause of traveller’s diarrhea is:
**Core Concept**
Traveller's diarrhea is a common condition affecting individuals traveling to areas with inadequate sanitation and hygiene. The primary cause is the ingestion of contaminated food or water, leading to an imbalance in the gut microbiota.
**Why the Correct Answer is Right**
The most common cause of traveller's diarrhea is the ingestion of bacteria such as *Escherichia coli* (E. coli), particularly the enterotoxigenic E. coli (ETEC) strain. ETEC produces heat-stable and heat-labile toxins that stimulate the intestinal epithelial cells to secrete fluid and electrolytes, resulting in diarrhea. This pathogen is commonly found in food and water contaminated with human feces.
**Why Each Wrong Option is Incorrect**
**Option A:** Norovirus is a common cause of viral gastroenteritis, but it is not the most common cause of traveller's diarrhea.
**Option B:** Rotavirus is a significant cause of diarrhea in children, but it is not typically associated with traveller's diarrhea.
**Option C:** Campylobacter is a common cause of bacterial gastroenteritis, but it is not the most common cause of traveller's diarrhea.
**Clinical Pearl / High-Yield Fact**
To prevent traveller's diarrhea, it is essential to practice good hygiene, such as washing hands frequently, avoiding undercooked food, and drinking bottled or filtered water.
**Correct Answer: C. Campylobacter**