Nosema ceranae

[Jon]

I added some thymol to the winter feed for the first time this year. Apart from possible beneficial effects, it stops the sugar from fermenting once it is made up.
The link to the Turkish paper makes for very interesting reading.
Pete L who posts here sometimes has been banging the drum for winter thymol treatment for quite some time now.

The trouble with a nosema infection is that it is not necessarily obvious until you discover that a colony has dwindled to nothing by December. Nosema C. is not accompanied by the dysentery and streaking you get with Nosema Apis.
And as Gavin pointed out there is strong speculation that it may be one of the elements of CCD.
Randy Oliver's site is worth reading for background on nosema.

http://scientificbeekeeping.com/nose...about-nothing/

[Adam]

Jimbo, Gavin,

Useful info.
In Yates' Microscopy, I think there is no suggestion of removing the head or wings, just using the whole bee. In the microscopy couuse I attended this year we ground up the whole bees too. removing the unwanted bits makes sense to me. So far I haven't seen any nosema in the samples I have taken - pollen yes but I haven't got my eye in to know what the stuff is yet!

[Alvearium]

I checked out some bees for Nosema by crushing the abdominal contents alone. I had to spend some time learning to identify the numerous other parts that were seen and found it really helpful to calibrate the microscope using a calibrated slide and eyepiece. This at least gave me more confidence in guiding me to what size of object I was looking at under the 400x magnification.
The beekeeper participants in Dr Connolly's Dundee research were offered a Nosema Survey and many took it up. A few positives were found and these were checked and found to be N.ceranae. They were from a scattered area but mainly in the west. These results will be shared with SASA, but what is useful is the colonies can be followed up and perhaps some idea gained on how harmful this could be to Scottish bees. There is an article by Peter Edwards on Nosema ceranae in the Scottish Beekeeper, June 2008, p162: so the warning has been around a while. Those affected are being informed by Dr Connolly and will be deciding on the need for treatment. Fumagillin is off licence from November so we will have to rely on good IPM care and comb fumigation.Let's hope we have a better winter to give the bees a chance. The Veterinary Medicines Directorate have commissioned work on a new agent (Enilconazole) which is undergoing trials and a report should be out soon. Perhaps this will give us another life line should the disease get out of hand. The SBA will have a representative at the meeting of the VMD in London next month so hopefully some more questions can be asked.
Alvearium

[Jon]

Fumagillin is off licence from November so we will have to rely on good IPM care and comb fumigation.

The link to the Turkish research posted by Jimbo suggests that thymolated syrup is more effective than Fumidil B in nosema control and the link posted to the scientific beekeeping site suggests that a period of prolonged cold or heat is also very effective in terms of killing nosema spores. Up to now I have always fumigated any spare comb and comb taken from dead colonies with 80% acetic acid.

Is fumidil b coming off the market shortly? There were rumours last year but I never read anything official.

[Jimbo]

I heard a rumour that Fumidil B is being phased out as there may be a cancergenic link to using it. I have never seen anything official though.

[gavin]

The beekeeper participants in Dr Connolly's Dundee research were offered a Nosema Survey and many took it up. A few positives were found and these were checked and found to be N.ceranae. They were from a scattered area but mainly in the west.

That sounds to me like water-tight proof that the pesticides which bees must be exposed to in the arable east are protecting bee colonies from Nosema ceranae?!

Yes, I'm kidding, making inferences from geographic data like this is full of traps for the unwary.

[Jon]

They were from a scattered area but mainly in the west.

You see a lot more nosema when bees have been subjected to some kind of stress such as being confined inside due to bad weather or a dearth of nectar.
Weather and the time of year probably play a role re. nosema levels.

In the Turkish study Jim linked to a low level is considered to be under 5 million spores and a high infestation over 10 million. The bees cope well with the lower level so the key thing is to get an accurate measurement of the number of spores.

I once let a double brood box colony reach starvation point at the end of August and it had dwindled to a couple of frames of bees within a month. It took down several gallons of sugar syrup but the damage was already done re. the stress induced.

[Jimbo]

The problem in trying to get an accurate measurement. When you look at the Nosema slide there is a lot of pollen and bits of bee there. Does anybody know the size of the Nosema spores? as I could try filtering the homogenate through a 2 micron or 4 micron filter or centrifuge the ground up bees to increase the count accuracy

[Jimbo]

I found the answer to my own question by Googling, The answer is 2-6 microns so it should be possible to filter

[Neils]

What's the dilution of thymol to syrup for a nosema treatment?

If one were to have a ready prepared thymol/surgical spirit solution (100g to 100ml ibelieve) nominally for varroa would that be a suitable addition to a quantity of syrup? I'm not, of course, suggesting that quantity of thymol solution just using it for illustration of the solution strength.

I had used a small quantity 1-2ml per litre mainly to stop the syrup going mouldy.