A 2-year-old child attending daycare develops diarrhoea and gastroenteritis as a result of adenoviral infection. Which of the following adenoviral serotypes would most likely be responsible for this girl’s illness?

**Core Concept**
Adenoviral infections can cause a range of clinical manifestations, including gastroenteritis, respiratory tract infections, and conjunctivitis. The different adenoviral serotypes have distinct tissue tropisms and clinical presentations.

**Why the Correct Answer is Right**
Adenoviral gastroenteritis is most commonly caused by serotypes 40 and 41. These serotypes have a high affinity for the intestinal epithelium, leading to inflammation and diarrhea. The pathogenesis involves the attachment of the virus to the intestinal receptors, followed by the release of pro-inflammatory cytokines and the disruption of the intestinal barrier.

**Why Each Wrong Option is Incorrect**
**Option A:** Serotypes 4, 7, and 14 are more commonly associated with respiratory tract infections, such as pharyngoconjunctival fever and acute respiratory distress syndrome.
**Option B:** Serotype 19 is primarily linked to epidemic keratoconjunctivitis.
**Option C:** Serotype 3 is associated with epidemic keratoconjunctivitis and acute hemorrhagic cystitis, but not typically with gastroenteritis.

**Clinical Pearl / High-Yield Fact**
Adenoviral gastroenteritis is often self-limiting, but it can be severe in immunocompromised individuals, such as those with HIV/AIDS or undergoing chemotherapy.

**Correct Answer:** D.

✓ Correct Answer: D. Type 41