to offer a possible reason WHY parvo is so rampant -
I have a feeling that since the price of small breeds is so out of hand - dogs now to being smuggled across the border and sold like drugs.

High priced small breeds are now such a money maker that they're coming in from Mexico and sold at flea markets... or to so called BRREEDERS/Brokers ....who in turn are selling them to the public.... where they can infect other dogs they come in contact with ......
Texas is seeing higher numbers too -
I feel SO sorry for the puppies of the world these days - People used to sell puppies at a reasonable price...but the higher the prices go - the more people are jumping on the bandwagon - which is BAD BAD BAD FOR ALL Dogs.
edited to add - this is ONLY MY OPINION - not fact - just something to think about