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On the whirling disease in rainbow trout
By Professor Dr. Bruno Hofer Statement from the Royal Bavarian Center for Biological Studies of Fish General Fishing Newspaper, 1903  Editor’s note: This article is a translation of the original description of Myxobolus cerebralis by Dr. Bruno Hofer in 1903. The article was originally published in German and was translated into English by Karolina Krauss at Montana State University through the Whirling Disease Initiative in 2006. Dr. Mansour El-Matbouli of the University of Munich then reviewed the translation to ensure fidelity of the technical content. Since the publication is so often cited by English speakers, we wanted to make a high quality English translation available. You may download the article on the Whirling Disease Initiative Web site at http://whirlingdisease.montana.edu/biblio/default.htm.The rainbow trout is a fortunate type of fish in that it is affected only by few diseases, even in the unfavorable conditions of our fish-farms where they are kept crowded together in small spaces and are fed and fattened with more or less unnatural food. The disease to be described in the following—the whirling disease—occurs only rarely; since the inception of the Institute for Biological Studies, fish with this disease were received only twice for examination, and only once live fish in which the symptoms of the disease could be observed. At first, the diseased fish show no outwardly visible signs, they swim in a lively way among the other fish of the species, at least in the aquarium, but suddenly one or another fish will start to swim madly around in circles, that is, it bends the body in a half-circle to the left or to the right and performs cramp-like circular movements ten to twenty times in a row. Afterwards, the fish lies exhausted on the bottom, only to get up again and swim in a normal position and to move for hours in an apparently normal way. This state can last for days or weeks, until the fish finally sticks out without any visible change.
Finally, I would welcome further information about the appearance of the whirling disease from fish hatcheries, in particular, examination material to determine whether the disease is caused by the same parasite in other locations as well. At this point in time, we have no detailed information about the development of the infection or about the manner in which it occurs. Suggested citation: Hofer, B. 1903. Ueber die Drehkrankeit der Regenbogenforelle. Allgemeine Fischerei Zeitung 28:7-8. Board meeting travels to New York top
Mini-symposium successful and stimulating in Lake Placid top During the 136th Annual Meeting of the American Fisheries Society (AFS) in Lake Placid, New York, leaders in whirling disease research and management participated in a day-long mini-symposium, “Whirling disease: what’s going on and what can we do about it?.” Presentations covered a wide spectrum of geographical areas and research topics to provide a comprehensive update on what we know and how to improve management. If you missed this mini-symposium, you can access the abstracts and selected Powerpoint presentations online through the Whirling Disease Initiative Web site. The meeting was organized by Phil Hulbert, Bob Gresswell, Liz Galli-Noble and Kajsa Stromberg through the Whirling Disease Initiative. Thank you to everyone who participated. Nebraska confirmed as 24th state to detect parasite top  The Whirling Disease Initiative recently confirmed that Nebraska is the 24th state to detect the parasite Myxobolus cerebralis. The list of detections includes states that have detected M. cerebralis at least once in a hatchery, a wild fish population, or both. The list does not indicate the continued presence of the parasite or the extent of distribution within the state. According to Dean Rosenthal of the Nebraska Game and Parks Commission, the whirling disease parasite was first detected in Nebraska in spring 2001 among trout in a private hatchery near the town of Valentine. Testing in 2002 confirmed the continued presence of M. cerebralis. The facility has not been re-licensed to sell fish since 2002 and is no longer in business. The hatchery’s discharge water went into the Niobrara River, which does not support wild trout populations in that area due to high summer water temperatures. However, tributaries to the Niobrara River downstream from Valentine do support wild trout. At this time, the distribution of M. cerebralis in the wild is unknown, and all operating hatcheries in the state are free of the parasite.Whirling Disease Initiative joins Stop Aquatic Hitchhikers in Yellowstone Region outreach project top  When it comes to the management of natural resources, a consensus is generally hard to reach in mixed company. Yet, when a group of resource managers, biologists and non-profits gathered this spring to discuss aquatic nuisance species, an agreement was easily reached – an agreement to pursue public outreach activities in the Greater Yellowstone Area. This idea came to fruition in late September when an unusual group assembled in Jackson, Wyoming. Representatives from state governments, federal agencies, academic institutions, non-profit organizations, and the regional business community gathered to discuss how to work together to effectively protect the aquatic resources of the Greater Yellowstone Area. The U.S. Fish and Wildlife Service Stop Aquatic Hitchhikers program and the Federation of Fly Fishers organized the workshop. The day began with an educational session about the problems posed by aquatic nuisance species, which led into a strategizing session to decide how this broad partnership could educate and influence the public. The group committed to work together on a regional basis to craft a campaign that will educate the public about aquatic invasive species and encourage the public to adopt behaviors that prevent their spread. Whirling disease is a concern in the Greater Yellowstone Area and the Whirling Disease Initiative will support the outreach effort with information and materials. It’s particularly exciting to see how engaged the business community is in this effort. “Collective industry action is the only viable way to combat the threat that aquatic nuisance species pose for all of us, and the recent GYA workshop was definitely a step in the right direction,” said Whitney McDowell, Marketing Manager for Simms Fishing Products. “It all comes down to public awareness and education, and as a leading manufacturer, Simms is fully committed to both immediate and long-term initiatives to help educate both our retail partners and consumers about aquatic invasive species and how they can be a part of the solution.” To participate, join the Stop Aquatic Hitchhikers partnership online (http://www.protectyourwaters.net) or contact Leah Elwell, Conservation Coordinator for the Federation of Fly Fishers at (406) 222-9369 or conserve@fedflyfishers.org. Whirling disease leads to conflict in Utah top  At a recent legislative hearing in Utah, the fight over whirlingdisease management reached a new level of hostility. According to the Salt Lake Tribune, the hearing dissolved into fisticuffs as private fish growers accused the state Department of Agriculture of mishandling its fish health regulatory responsibilities. At the root of this conflict is a dispute over regulation of whirling disease in aquaculture. Originally, the Utah Division of Wildlife Resources was charged with regulating fish health in private aquaculture. This changed in the early 1990s, when legislation placed fish health regulation under the Utah Department of Agriculture. After this transfer of authority, a Fish Health Policy Board was established made up of representatives from the Division of Wildlife Resources, the Department of Agriculture, and the sport fishing community. The Fish Health Policy Board is then responsible for setting fish health policy and monitoring for disease among aquaculture producers. The whirling disease parasite was first detected in Utah in 1991. Since that time, the whirling disease parasite has become dispersed in the state’s coldwater aquaculture industry. When the parasite was detected, it often dealt a severe financial blow to the producer. Their infected fish were disposed of and facilities were disinfected and renovated. Sometimes these expenses were enough to drive the company out of business. As the economic consequences continued to mount, the industry became increasingly vocal about the problem. This year, several Utah fish producers filed suit against the state Department of Agriculture, charging that the agency’s testing protocols were inaccurate. The growers claimed that their facilities were quarantined following a single, unreliable test. The Department of Agriculture says the tests are reliable and that a single test is sufficient. They will re-test a facility once disinfection has occurred. In September 2006, a hearing on the issue was conducted by the Interim Committee on Natural Resources, Agriculture, and Environment. Several legislative options have been discussed including a deregulation of Myxobolus cerebralis in the state’s aquaculture industry, and a requirement that the state compensate growers who are forced to destroy fish stocks. The outcome remains unclear while stakeholders have their say and policymakers hash it out. Resource for researchers: The Myxozoan Network By Jerri Bartholomew top  In view of the ever-increasing interest in myxozoan parasites, a group of researchers got together during the 2003 European Association of Fish Pathologists meeting in Malta and agreed to initiate a network for scientists involved with myxozoan research. The network has two main objectives:
Special sessions on myxozoan research have been held at the 2005 European Association of Fish Pathologists meeting in Copenhagen, Denmark and the 2006 International Symposium on Aquatic Animal Health in San Francisco. The session summary for the 2005 meeting and abstracts from the 2006 meeting are available on the Myxozoan Network Web site.
If you are interested in becoming part of the network, please fill in the subscription form on the website. Network members receive periodic email newsletters and are listed in our online network contacts database. Q&A from the “Ask an Expert” files top Q: Is it possible to acquire whirling disease in a hatchery facility by importing eyed salmonid eggs from sources that are not certified whirling disease free? A: Yes, it is possible to acquire the whirling disease parasite in a hatchery facility by importing salmonid eggs from sources that are not certified disease free. It is true that whirling disease is not vertically transmitted from broodstock to eggs; however, the water used to transport the eggs could carry the parasite and transmit it to the receiving facility. It is recommended that hatcheries never import fish or fish eggs from sources whose disease status is unknown. If this cannot be avoided, careful handling of the water used to transport the eggs and disinfection will reduce the risk of disease. Disinfection of eggs with iodine is generally recommended, both for M. cerebralis and for other pathogens. Q: I caught a lake trout with signs of whirling disease. I hear that all salmonids can be infected with the exception of lake trout. Do you have information that would confirm that lakers are an exception?
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