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.
What is croup? Croup is a disease caused by a virus, bacteria, allergies, and inhaled irritants that leads to swelling in the airways and problems breathing. A child may have stridor, which is a high-pitched sound usually heard when the child breathes in (inspiration). Croup is most commonly caused by viruses. It is sometimes, but rarely, caused by bacteria, allergies, or reflux from the stomach. Croup is caused by a variety of different viruses. The most common virus is the parainfluenza virus.