The risk to humans is probably minor unless they frequently work with fish or have compromised immune systems, researchers said, although transmission of disease from tropical fish has been shown to occur. More serious is the risk to this industry, which has grown significantly in recent years, and is now a $900 million annual business in the United States.
There are few regulations in the U.S. or elsewhere about treating ornamental fish with antibiotics, experts say. Antibiotics are used routinely, such as when fish are facing stress due to transport, whether or not they have shown any sign of disease.
“We expected to find some antibiotic resistance, but it was surprising to find such high levels, including resistance in some cases where the antibiotic is rarely used,” said Tim Miller-Morgan, a veterinary aquatics specialist with Oregon State University. “We appear to already have set ourselves up for some pretty serious problems within the industry.”
In the new study, 32 freshwater fish of various species were tested for resistance to nine different antibiotics, and some resistance was found to every antibiotic. The highest level of resistance, 77 percent, was found with the common antibiotic tetracycline. The fish were tested in Portland, Ore., after being transported from Colombia, Singapore and Florida.
Findings of the study were reported in the Journal of Fish Diseases.
The bacterial infections found in the fish included Aeromonas, Pseudomonas, Staphylococcus and others, several of which can infect both fish and humans.
“The range of resistance is often quite disturbing,” the scientists wrote in their report. “It is not uncommon to see resistance to a wide range of antibiotic classes, including beta-lactams, macrolides, tetracyclines, sulphonamides, quinolones, cephalosporins and chloramphenicol.”
Problems and concerns with antibiotic resistance have been growing for years, Miller-Morgan said. The nature of the resistance can range widely, causing an antibiotic to lose some, or all of its effectiveness.
There have been documented cases of disease transmission from fish to humans, he said, but it’s not common. It would be a particular concern for anyone with a weak or compromised immune system, he pointed out, and people with such health issues should discuss tropical fish management with their physician. Workers who constantly handle tropical fish may also face a higher level of risk.
From an industry perspective, losses of fish to bacterial disease may become increasingly severe, he said, because antibiotics will lose their effectiveness.
Anyone handling tropical fish can use some basic precautions that should help, Miller-Morgan said. Consumers should buy only healthy fish; avoid cleaning tanks with open cuts or sores on their hands; use gloves; immediately remove sick fish from tanks; consider quarantining all new fish in a separate tank for 30 days; wash hands after working with fish; and never use antibiotics in a fish tank unless actually treating a known fish disease caused by bacteria.
“We don’t think individuals should ever use antibiotics in a random, preventive or prophylactic method,” Miller-Morgan said. “Even hobbyists can learn more about how to identify tropical fish parasites and diseases, and use antibiotics only if a bacterial disease is diagnosed.”
On an industry level, he said, considerable progress could be made with improvements in fish husbandry, better screening and handling, and use of quarantines, rather than antibiotics, to reduce fish disease.
The ornamental fish industry is large and diverse, including trade of more than 6,000 species of freshwater and marine fish from more than 100 different countries. About half the supply originates in Asia, and freshwater farming of ornamental fish is a rapidly growing industry.
Also increasing is the number of trained fish veterinarians, who can help fish hobbyists to reduce disease loss and save treasured pets. More information is available from the World Aquatic Veterinary Medical Association and the American Association of Fish Veterinarians. A database of aquatic veterinarians is available online, at http://aquavetmed.info
About the OSU College of Veterinary Medicine: The primary mission of the OSU College of Veterinary Medicine is to serve the people of Oregon and the various livestock and companion animal industries by furthering the understanding of animal medical practices and procedures. Through research, clinical practice and extension efforts in the community, the college provides Oregon's future veterinarians with one of the most comprehensive educations available anywhere.
Tim Miller-Morgan | Source: EurekAlert!
Further information: www.oregonstate.edu
More articles from Agricultural and Forestry Science:
Crop Rotation with Nematode-Resistant Wheat Can Protect Tomatoes
15.05.2013 | Crop Science Society of America (CSSA)
Less O2 Triggers Grasshopper Molting, Farmers Could Benefit
14.05.2013 | Union College
A fried breakfast food popular in Spain provided the inspiration for the development of doughnut-shaped droplets that may provide scientists with a new approach for studying fundamental issues in physics, mathematics and materials.
The doughnut-shaped droplets, a shape known as toroidal, are formed from two dissimilar liquids using a simple rotating stage and an injection needle. About a millimeter in overall size, the droplets are produced individually, their shapes maintained by a surrounding springy material made of polymers.
Droplets in this toroidal shape made ...
Frauhofer FEP will present a novel roll-to-roll manufacturing process for high-barriers and functional films for flexible displays at the SID DisplayWeek 2013 in Vancouver – the International showcase for the Display Industry.
Displays that are flexible and paper thin at the same time?! What might still seem like science fiction will be a major topic at the SID Display Week 2013 that currently takes place in Vancouver in Canada.
High manufacturing cost and a short lifetime are still a major obstacle on ...
University of Würzburg physicists have succeeded in creating a new type of laser.
Its operation principle is completely different from conventional devices, which opens up the possibility of a significantly reduced energy input requirement. The researchers report their work in the current issue of Nature.
It also emits light the waves of which are in phase with one another: the polariton laser, developed ...
Innsbruck physicists led by Rainer Blatt and Peter Zoller experimentally gained a deep insight into the nature of quantum mechanical phase transitions.
They are the first scientists that simulated the competition between two rival dynamical processes at a novel type of transition between two quantum mechanical orders. They have published the results of their work in the journal Nature Physics.
“When water boils, its molecules are released as vapor. We call this ...
Researchers have shown that, by using global positioning systems (GPS) to measure ground deformation caused by a large underwater earthquake, they can provide accurate warning of the resulting tsunami in just a few minutes after the earthquake onset.
For the devastating Japan 2011 event, the team reveals that the analysis of the GPS data and issue of a detailed tsunami alert would have taken no more than three minutes. The results are published on 17 May in Natural Hazards and Earth System Sciences, an open access journal of ...
22.05.2013 | Life Sciences
22.05.2013 | Ecology, The Environment and Conservation
22.05.2013 | Earth Sciences
17.05.2013 | Event News
15.05.2013 | Event News
08.05.2013 | Event News