Well, actually you can't just buy Terramycin any more. You'll need a veterinarian's prescription, after he has examined the hive.
What you can buy is a field test made by VITA specifically for EFB. The tests cost $13-14 each and most bee suppliers sell them these days. If you need to order them by mail, I'd buy two in case you screw up the first one, in order to avoid having to wait for a reshipment. They each are intended for a single use. They are quite accurate.
Meanwhile I would put in place very strict isolation protocols: no using the same tools or gloves in different hives. Do not move any bees, queens, brood, frames or equipment from one hive to another, even among the apparently healthy ones. Stop making splits. Don't sell any colonies or queens or move them to a new yard until after they have been treated. Add robber screens to make sure your weakest colonies are not being robbed. Prevent swarming by any means possible. Call for a state inspection if you have those in your state.
If your test is positive take your honey off early and treat every colony in the yard.
Does this sound like a royal PITA? Well, it is that, for sure!
I can't tell enough just looking at pictures, but what I see tells me you need to get to the bottom of it ASAP, so order the tests and get some answers. It may "cure itself" on a good flow. But that will not remove the bacteria from your frames, combs and woodenware, you will likely have re-occurrences, even if you treat. The treatment is not a failure if this happens, it just means you have moved on to the equipment phase of the problem.
The "best" tactics that I know of are double shook swarms (two different sets of clean equipment per colony) combined with well-timed treatment. Even with this level of effort, expect your bees to take some time to recover even after the overt symptoms disappear.
The cardinal sign of EFB that I look for is evidence is steady egg production that doesn't result in four times as much capped brood preceded by fat, white glistening late-stage larvae stuffed in their cells. EFB is a disease that infects and kills larvae mostly before it is capped. Tragically it is the hygenic behavior of honeybees that promotes the disease. The nurse bees clean out the dead and dying larvae and in the process become contaminated with the bacteria in the dead brood's cells. This does not make the nurse bees sick, but it causes them to produce infectious brood food for the next larvae that hatch out. And so on, until there are no bees left.
You could do a sugar roll, but expect it to be low because the disease also interrupts the varroa reproduction cycle by interrupting the honey bee brood cycle.
EFB sucks, big time. I really hope your tests are negative. There seems to be a lot of it going around these days.
Nancy
