Do Vampyres decompose rapidly upon death or turn to dust? Of course they don?t. If this were true, the papers and scientists would be all over it by now.
Do Vampyres spontaneously combust upon death. While we have all heard of people that have spontaneously combust, the reason for it is not due to being a Vampyre. Sorry if it wasn't what you wanted to hear. There have been few instances where a person appears to have com-busted and most if not all have been explained.
Can Vampyres shape shift in the physical world? Of cores they can't silly. What they can do, is mentally shift in the physical realm and shift in form on the astral level just as many other enlightened people can do.
Can Vampyres fly? Sure they can, providing they have a plane ticket or take a ride in a helicopter or other means of air travel. Can't you fly the same way?
Do Vampyres need to keep soil from their home lands with them at all times? Um, no. Do some people considering themselves Vampyres do this? More than likely, there are many pretentious people out there and many buy into the role-playing drama.
Is hepatitis V virus what creates Vampyres? No, that has to do with a TV show. Please take the time to look at the TV links below and notice it's to a Mini-series. There is also a Hep D virus listed regarding true blood, although there is no such thing in the medical field that I know of. I believe it's only Hep B and C.