Nosema: In the dead of winter

We had a warm spell at the end of 2010. These photos are from January 1st. I was only able to upload them now. So on January 1st of 2011; we had a +8C day. Almost all of our snow had melted over the previous 2 days. This caused an ideal opportunity for the bees to get out of the hives to relieve themselves.

I was excited for the chance to be able to see a couple of bees.

Almost no snow left!

As I got closer to the hive, I noticed some bees flying around and some bees were pulling out some of their dead. But when I got to my green hive, I saw a terrible sight.

A sure sign of Nosema? Spotty streaks of mustard-brown poop.

It was upsetting to see one of my hives with what appears to be nosema.

Mouse guard removed and some dead bees were scrapped out.

I ran into the house to check my books as to what I could do. One of my books said that Nosema is a most common sight in colonies in the spring time; after a colony has spent the winter confined to the hive. Infected colonies will build up slowly or not even at all. My book also says that you can discourage nosema by selecting a hive site that has good airflow (check) and a nearby source of fresh, clean water (check and check). This particular hive has a slatted bottom rack, and an air gap all along the top of the hive. The problem with this hive is that I waited too long to treat them with Fumagilin-B in the fall. This hive did not take in all of their treatment because their hive was already stuffed with honey stores.
The Fumagilin-B instruction sheet says that a heavily infested colony which is no longer taking in syrup may be sprayed repeatedly directly onto the bees frame by frame with 1:1 sugar syrup containing 2 g of medication per litre of syrup. I will keep a close eye on the colony and treat them as soon as I am able.

See air gap all along the sides of the top cover.

As a precaution I started lifting off the hive cover to see if their was evidence of Nosema in the hive (check by sight and smell). As I was lifting off the cover, bees started pouring out to attack me and the hive smelled amazing; like warm honey. So I assume that it is not too bad in the hive yet and that not all of the bees are affected.