WebMD:
“Adenoviruses are a group of common viruses that infect the lining of your eyes, airways and lungs, intestines, urinary tract, and nervous system. They’re common causes of fever, coughs, sore throats, diarrhea, and pink eye.”
Therefore, since adenoviruses are common, and what those kids are having is not common, then whatever they have is new. And nationwide. Just so happens that recent volumes of immigration is new and nationwide.
What the kids have is a common virus in the setting of chronic illness, compromised immune systems and likely lung problems to start with. There is nothing new about adenovirus. Immigration brings a lot of problems but this is not one of them. And I didn’t even have to look it up on web md