Which viral infection is known to cause severe dehydration in young children?

Rotavirus is known for causing severe dehydration in young children primarily due to its role in inducing gastroenteritis. This viral infection typically leads to acute diarrhea and vomiting, which can result in significant fluid loss. In young children, who are generally more vulnerable to dehydration, this can quickly become a critical issue if not managed properly.

Rotavirus infections are particularly prevalent among infants and toddlers, and the dehydration that results can necessitate hospitalization and intravenous fluid replacement in severe cases. Vaccines have been developed to help prevent rotavirus infections and are recommended to reduce the incidence and severity of gastroenteritis in young children.

The other options do not primarily lead to dehydration in the same way. Rubella typically presents with mild symptoms such as rash and fever, while Norovirus can cause gastroenteritis but is more commonly associated with outbreaks in older children and adults, causing symptoms that may not be as severe in the very young. Hepatitis A, while it can lead to liver inflammation, does not generally cause the profuse diarrhea and vomiting characteristic of rotavirus infections.