Nosema ceranae

[lindsay s]

Here's a link to a Scottish Government press release. I'm sorry I don't know anything about this disease.
http://www.scotland.gov.uk/News/Releases/2011/09/23123701

[gavin]

Many thanks Lindsay, very interesting. At the recent Convention Giles Budge told us a lot about the disease. It is widely reported in England now and, unlike the established Nosema apis, shows signs of being particularly prevalent where bees have been imported. There are hints from the US that either or both Nosemas are associated - with other factors - with CCD but Nc can also be present without serious effect.

PS
And that possible link with importation suggests that looking at Orkney samples would be interesting.

[Jimbo]

After the Conference last saturday I thought I would look up some information on Nosema and came across this Scientific paper. I am unable to put in a link but you can google it. The title is The Impact of Nosema apis Z Infestation of Honey bee (Apis mellifera L.) Colonies after using Different Treatment Methods and their Effects on the Population Levels of Workers and Honey Production on Consecutive Years.
Pakistan Journal of Biological Sciences 8 (8) 1142-1145,2005
Interesting reading and if the results are correct it may be time to add Thymol to your winter sugar feed.
Any comments?

[AlexJ]

Lindsay,

This American site http://www.extension.org/bee_health

contains some useful information.

Information articles under the heading 'Honey Bee Health' include, Microsporidia/Effects of Nosema and Nosema Ceranae which you might find useful.

Alex

[Jimbo]

Here is the link to the earlier post about the Nosema paper http://www.docsdrive.com/pdfs/ansinet/pjbs/2005/1142-1145.pdf

[The Drone Ranger]

Nosema Cerana was the subject of an article in The Dundee Courier the other day so now I am worried :)

[Jimbo]

I think beekeepers need to start taking Nosema a bit more serious. After the survey done in England and Wales and reported at the SBA conference. it looks Nosema Cerana was quite widespread. The results reported in the scientific paper I posted earlier showed that a therapeutic treatment of thymol in the sugar winter feed has a benificial effect over a number of years. It increased the life of the bees, gave better winter survival, increased honey yield and reduced the amount of Nosema present in the colony. I intend to count my nosema spores in my colonies over the next few weeks just to see how infected my hives are. I am not able to distinguish between Nosema apis and Nosema cerana but I would assume Fumidil or Thymol will treat both types.

[marion.orca]

This may be a silly question - but how exactly are you able to count spores, and how are you able to recognise them ? [ that's 2 questions ! ]

[Jimbo]

There is a standard method. Basically you take a sample of bees eg 25 or 50. Remove the abdomen. Add 0.5ml water for each bee eg 12.5ml for 25 or 25.0ml for 50. Grind in a mortar and pestle. Take a small sample and count on a Haemocytometer slide. Count the spores under a microscope at mag 400 from 5 ruled squares. Multiply the answer by if I remember correctly by 25,000 to give the number of spores per million per bee. The spores look like little oval shapes but smaller in length than rice. Less than 2 million spores per bee in a colony could be accepted as a healthy level. Over 5 million would be a moderate level. Over 10 million considered a high infestation. If you can't get access to a haemocytometer you can use a microscope slide but would need to work out what a low, medium and high level is in the microscope field of view.

[gavin]

It is usually either there in quantity or not at all in my experience. I couldn't find it in my bees nor in samples of colonies that died overwinter in my area but did find it in a few samples of dead bees sent to me from elsewhere in Scotland. I just mashed abdomens in a small quantity of water and looked at the resulting liquid using a microscope slide. The spores are highly refractive so they really stand out. You usually also see pollen from some of the plants the bees were foraging on.

G.

[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/nosema-ceranae-kiss-of-death-or-much-ado-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.

[Jon]

Pete L has the ratio he uses posted as a sticky on beekeepingforum.

30g of thymol crystals dissolved in 5ml of surgical spirit. This is mixed with 140 ml of boiling water with emulsifying agent (lechithin) and you put 5ml of the resulting mix in each gallon of 2:1 syrup, ie about 1g of thymol per gallon of sugar syrup.

[Adam]

The recipie needs 1 teaspoon. I bought some Lechithin today from Holland and Barrett for about £5.* Will last for about 50 years. Although its also good for cholesterol levels, heart and liver function and brain function so maybe I'll take it myself.

Jon - you need some too "ie about 1g per gallon of thymol". :)

* I thought I'd use it on my varroa infested and robbed colony.


An owner of a teaching apiary nearby uses Fumidil B because of stress from regular hive inspections his bees have to endure.

[Jon]

Oops. 1g of Thymol per gallon of syrup. Poor brain function today. Lost control of the word order in the sentence.

[Ruary]

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

I think you might have trouble fltering with fine mesh as it will be clogged up by the debris. If you want to know infestation rates you MUST use a standard amount of water per bee and then preferably use a haemocytometer. However Randy Oliver calibrated using a 'standard' drop of water ( using a disposable swizzle stick) and the field of view in his microscope and got a reasonably accurate co-relation.

[gavin]

One difficulty to be aware of is that Nosema spores are heavy. Unlike bacteria they settle out of solution very quickly so if you are trying to quantify spore density you need to agitate the solution immediately before sampling. I would imagine that even applying the suspension to the haemocytometer slide will give you problems with spores settling out. I still think that presence and (apparent) absence is enough - when they are there they are there in numbers.

[nemphlar]

I've been given a present of a mag 200 electronic mocroscope will this work for most needs or do I need to upgrade

[gavin]

Probably not good enough.

x400 for most pollen (you'll see them under x200 but not that well)
x1000 for Nosema spores

[Ruary]

Probably not good enough.

x400 for most pollen (you'll see them under x200 but not that well)
x1000 for Nosema spores

Gavin,
I do not think that you require X100 for Nosema detection, they show up well at X400.
For bacteria AFB and EFB X1000 is required.

[gavin]

Hi Ruary and Nemphlar

Nosema spores are about 1/5 to 1/10 the size of pollen grains so they are fairly small but yes, x400 should be enough. Once you know them you don't need to see them in any detail but until you have that experience you'll need to worry about Amoebae, yeast cells and fungal spores. Once you have an obvious strong positive it is really clear as the highly refractive grains are characteristic.

Gavin