Someone at the hospital presumably dealt with the owl, Weasley. That means it was potentially exposed.

I believe the situation is in flux at the moment, and the Ministry is responding with new restrictions as necessary. What is most clear is their desire to protect this school from any exposure to the disease. We don't want them deciding it's necessary to ban all owl traffic in and out of here, though this stunt may have exactly that effect.

Yes, do please follow up with Madam Pomfrey. We will want that information when we discuss the issue. In fact, you might ask whether she would be able to attend a portion of our meeting; her input would be helpful. We can rearrange the docket as needed to accommodate her schedule.