http://www.arc.agric.za/institutes/ppri/main/divisions/beekeeping/varroa.htm
Here is interesting report from South Africa. We write plenty of top bar hive and small cells, how they save bees from varroa and all kinds of evil
From report you can see that varroa attach in same way in feral bee hives like in beekeeper's hives. African bees are not tolerant against varroa.
Also many secondary deseases follow varroa, like chalk brood.