Season One Edit. Beckett's initial relationship with Castle was strained because she viewed him as immature and reckless. She suspected (correctly) that Castle was using his research as an excuse to pursue her, and only tolerated his presence at the request of Captain Montgomery.
What causes croup in children. Croup in children is most often caused by the parainfluenza virus, a respiratory virus not related to the flu. But it can also be caused by other respiratory viruses including the flu. Yes, croup is contagious.
This type of croup is thought to be caused by an allergy or by reflux from the stomach. It can be scary because it comes on suddenly, often in the middle of the night. Your child may go to bed well and wake up in a few hours, gasping for breath.