
It seems there's an unusually high incidence of Parvo at the moment in certain parts of the counrtry including places where it has never before been a problem. In some areas it has made the local newspapers - I have heard of vets sending out warnings to their clients in others.
I would try to get the true picture from your vets - it seems that one outbreak reported on the front page of local news in an area where I have family was very limited, and only affected a few dogs that belonged to travellers.