Dee, here in the US, large commercial operations are treated and medicated for a host of situations.
Diseases such as Nosema ceranae,
Pests and parasites such as Varroa and Tracheal mites,
and other battles, such as hive beetles, etc.
Since huge operations (and some not so huge) ship their bees cross country to pollinate giant agri-business such as almonds, avocados, apples and cherries, bees are exposed to different dangers, so the large operations have to medicate and treat for these things on a regular basis.
“For example, 220,000 beehives a year pollinate alfalfa seed to be grown for cattle feed.” - http://www.oregonlive.com/opinion/index.ssf/2010/03/no_way_to_treat_a_bee.html
These commercialized bees are born and raised in this medicated environment.
When small, hobbiest beeks purchase bee packages from giant commercial operations, they are purchasing bees that have been medicated.
Once removed from this environment, their natural abilities to fight pests and disease has been compromised, and left to “fend for themselves,” without the previous medications and chemicals, many colonies simply don’t survive.
Michael Bush is VERY knowledgeable about bees. He teaches me something new on a very regular basis.
The push towards more hygienic bees is now being looked at as a tool in the fight against Verroa.
But bees raised to dependency on chemicals to treat it may not have the natural ability, meaning the beek has to then chemically treat…
It is a risk the hobbiest beek has to take when ordering and purchasing bee packages.
Like the admonishment to check your bee supplier for africanized honeybees (Arizona, Texas, and Californian suppliers are the biggest risks), to a lesser extent, suppliers need to be checked for how medicated their bees are.
“Readily available,” unmedicated, naturally-raised, 'hygienic" bees are available, but you may have to hunt for them, and they may well be pricier than commercially offered bee packages.
We got lucky the first year, and got burned badly the second.
But learned in the process.
To some extent, nations other than the US have less concern, as their regulations may prohibit such excessive medicating of bees. I do not know.
I DO know that in the US, purchasing commercial bee packages can be a “pig in a poke” situation when you use Google and just have a list of suppliers.
That is why I keep reiterating to contact local beekeepers in your area, or a beekeepers association near you, to ask them who they go through, or where you may find “local” bees.
Hope this helps!
~M