For what i experienced, it started with 2 people i new becoming ill with this virus inVirginia, while another, who lived in my house visited.
The last day of the visit, the person visiting became ill, but returned home never the less.
3 days later, it was diagnosed as Bronchitis, but was negative for our current Flu tests.
A neighbor who we talk to became sick, her and her baby. Again the tests were negative for flu, but came back with pnuemonia for her. the baby recovered rapidly.
2 more days and the other person in our house became ill. The onset was so rapid that he cooked dinner feeling fine, but by 9:30 was coughing and sneezing, by morning his voice was gone.
He also had bronchitis.
I became sick 3 days later, but began anti viral therapy immediately and it did not develop into any thing more.
The husband of the neighbor and a friend who comes and visits often at our house. became sick yesterday.
She started anti-viral theraphy and is recovering rapidly, he did not and is getting worse.
This has all the markings of an influenza, but is not showing up on tests.
It is rapid and as a virus, supresses our immune system and so secondary bacterial infections are common.
I did everything i could at the house to minimize my exposure, but it just was not enough.