Contact your agricultural extention agent.  He/She will be very interested in
looking at that hive.  Mine has contacted all the known beekeepers to keep an
eye out for hives with no varroa.  They are looking for genetic answers.  You
may have a winner there,  or.. you might have just been very lucky so far.
 
 
 
 
Hi again, i have a hive that seems to never have any varroa,