In DIS 31, page 170, 1957, Wolfson, Stalker and I published a note on an
infection of Drosophila stocks that sounds a little like what you are
experiencing. It turned out to be a microsporidian protozoan parasite; as
I recall it was referred by a protozoologist at Illinois (name not
recalled by me) as a species of Nosema. We got rid of it by isolating all
stocks with symptoms and redoubling our efforts to autoclave everything
that could be spared. As the note suggests, Nosema spores are ovoid, 4-5
microns in length and have an extremely thick and rigid capsule. Thus
they are easily seen in the light microscope so diagnosis is easy. I'm
sorry that this was so long ago that I cannot recall exactly what it took
to clean up, but it was certainly a serious problem. Maybe others can
respond to this.
Department of Genetics and Molecular biology
School of Medicine, University of Hawaii
Honolulu, Hawaii 96822
On Wed, 13 Sep 1995, Richard S. Jones wrote:
>> Our fly facility is struggling with an infectious fly disease (NOT MITES). The
> symptoms include significant embryonic, larval, and pupal lethality in stocks
> that carry no recessive lethal mutations. Also, 10 to 50% of affected adults
> often die within one week following eclosion. Some stocks are more susceptible
> to these symptoms than others. For example, our Oregon-R stock seems completely
> unaffected. We can "cure" a stock by bleach-dechorionating embryos, placing
> them in fresh vials, and re-establishing the stock from the resulting adults.
> However, if this stock is subsequently handled with utensils (brushes, CO2
> plate, etc.) that are used with infected flies, the symptoms return.
>> Since our facility has several hundred stocks (we don't know if all are
> infected, but don't want to take chances), the dechorionation method is an
> impractical permanent cure. Our normal food contains methyl paraben.
> Supplementing it with acid mixes, or tetracycline and/or chloramphenicol does
> not help. If anyone has had experience with such a problem, and especially if
> you can recommend an antibiotic based treatment (or other food additive type of
> treatment, since we don't really know if we are dealing with bacteria or???), we
> would greatly appreciate your advice.
>> We and our flies thank you in advance.
>> Rick Jones rjones at sun.cis.smu.edu>> Dept. of Biological Sciences
> Fondren Science Building
> Southern Methodist University
> Dallas, TX 75275
> TEL: 214-768-3810
> FAX: 214-768-3955