A new study of tubifex worms has highlighted their potential to introduce harmful diseases.
These oligochaete worms, which are often collected from sewage-contaminated mud, are a popular food for certain tropical fish.
Hallett, Atkinson Erseus and El-Matbouli of the Fish Biology and Fish Diseases unit at the University of Munich's Institute of Biology studied "tubifex" worms purchased from a number of aquarium shops in Munich and have just reported their findings in the journal Diseases of Aquatic Organisms.
The study, which screened the worm samples for the presence of parasites was undertaken over a one year period and showed that virtually all were infected with harmful parasites:
"Of 7 samples, 6 contained infected oligochaetes; waterborne spores were present in 5 samples at the time of purchase.
"In the laboratory, 12 different types of actinosporeans were released by the oligochaetes.
"These could be assigned to 4 collective groups: triactinomyxon, aurantiactinomyxon, raabeia and hexactinomyxon; 4 novel triactinomyxons are described herein, a fifth triactinomyxon has been described earlier."
The worms sold as tubifex were in fact made up of a number of different species, including Limnodrilus hoffmeisteri and L. udekemianus as well as Tubifex tubifex.
The authors believe that their use has the potential to spread disease to new areas.
For more details see the paper: Hallett SL, Atkinson SD, Erseus C, El-Matbouli M. (2005) - Dissemination of triactinomyxons (Myxozoa) via oligochaetes used as live food for aquarium fishes. Dis Aquat Organ. 2005 Jun;65(2):137-52.