Peter Keating wrote

>I know of no research that has been done regarding indoor wintering health
hazards

When I was at the Canadian Honey Council meeting in Edmonton in January
1995, there was paper presented by a person on what microbes etc were found
inside a wintering house.  It listed all the "bugs' that were found and some
were not good for human health.  Not sure if I still have a reference but
will look and let you know.  Either someone at CHC or CAPA might be able to
give you a reference.

Trevor Weatherhead
AUSTRALIA