Difference between revisions of "Enteric Redmouth Disease"
| Line 11: | Line 11: | ||
|sub-order = | |sub-order = | ||
|super-family = | |super-family = | ||
| − | |family = Enterobacteriaceae | + | |family = [[:Category:Enterobactericeae|Enterobacteriaceae]] |
|sub-family = | |sub-family = | ||
| − | |genus = Yersinia | + | |genus = [[:Category:Yersinia species|Yersinia]] |
|species = ''Y. ruckeri'' | |species = ''Y. ruckeri'' | ||
}} | }} | ||
| + | Also Known As: '''''ERM — Redmouth — Redthroat — Yersiniosis''''' | ||
| − | + | Caused By: '''''Yersinia ruckeri'' | |
| − | |||
| − | |||
==Introduction== | ==Introduction== | ||
| − | '''Enteric redmouth disease''' is a disease of fish caused by the '''gram negative, rod shaped, slightly curved [[Bacteria|bacterium]]''', '''''Yersinia ruckeri'''''. Most of the bacteria are '''motile''' due to | + | '''Enteric redmouth disease''' is a disease of fish caused by the '''gram negative, rod shaped, slightly curved [[Bacteria|bacterium]]''', '''''Yersinia ruckeri'''''. Most of the bacteria are '''motile''' due to having '''seven or eight flagellae''', although they only function at temperatures above 9⁰C and below 35⁰C . |
| − | There are six known serovars of ''Y. | + | There are six known serovars of ''Y. ruckeri''. Many fish species involve a '''carrier state''' and are only detected when '''stressed''', becoming a significant source of disease. |
ERM can be '''acute or chronic'''. Economic losses due to the disease can be significant. | ERM can be '''acute or chronic'''. Economic losses due to the disease can be significant. | ||
| Line 33: | Line 32: | ||
Europe, North and South America and Australia. | Europe, North and South America and Australia. | ||
| − | ERM can be '''transmitted via water''' and it is poorly understood whether this is due to saprophytic function or merely prolonged survival in the presence of sediment and organic matter facilitating transmission and infection.<ref>Romalde, J. L., Barja, J. L., Magarinos, B., Toranzo, A. E (1994) '''Starvation-survival processes of the bacterial fish pathogen Yersinia ruckeri'''. Systematic and Applied Microbiology, 17:161-168</ref> The bacterium is '''shed in the faeces''' of infected fish and the quantity '''increases exponentially with stress'''. Once infected, a population can maintain the disease indefinitely. | + | ERM can be '''transmitted via water''' and it is poorly understood whether this is due to saprophytic function or merely prolonged survival in the presence of sediment and organic matter facilitating transmission and infection.<ref>Romalde, J. L., Barja, J. L., Magarinos, B., Toranzo, A. E (1994) '''Starvation-survival processes of the bacterial fish pathogen ''Yersinia ruckeri'''''. ''Systematic and Applied Microbiology'', 17:161-168</ref> The bacterium is '''shed in the faeces''' of infected fish and the quantity '''increases exponentially with stress'''. Once infected, a population can maintain the disease indefinitely. |
==Signalment== | ==Signalment== | ||
| Line 40: | Line 39: | ||
The disease is primarily of '''cultured salmonid fish''' but a number of other fish families have been found to be infected leading to the belief that its '''host range is quite diverse'''. | The disease is primarily of '''cultured salmonid fish''' but a number of other fish families have been found to be infected leading to the belief that its '''host range is quite diverse'''. | ||
| − | Young fish '''1- | + | Young fish '''1-5 months old''' are more susceptible to ERM than adults and '''brook trout''' appear to be most vulnerable.<ref> Good, C. M., Thorburn, M. A., Stevenson, R. M. W (2001) '''Host factors associated with the detection of ''Aeromonas salmonicida'' and ''Yersinia ruckeri'' in Ontario, Canada government fish hatcheries'''. ''Preventive Veterinary Medicine'', 49(3/4):165-173</ref> |
Infections have not been reported below 10⁰C. | Infections have not been reported below 10⁰C. | ||
| Line 49: | Line 48: | ||
Affected fish also have generally '''darkened skin and fins''' with haemorrhagic lesions around the '''gill tips, vent and fins and are lethargic and inappetant'''. They may have a '''distended abdomen''' leading to a “pot-bellied” appearance. Fish are often pale around the gills and may demonstrate '''exopthalmos''' with periorbital oedema. They may be seen to be swimming close to the surface. | Affected fish also have generally '''darkened skin and fins''' with haemorrhagic lesions around the '''gill tips, vent and fins and are lethargic and inappetant'''. They may have a '''distended abdomen''' leading to a “pot-bellied” appearance. Fish are often pale around the gills and may demonstrate '''exopthalmos''' with periorbital oedema. They may be seen to be swimming close to the surface. | ||
| − | '''Mortalities are frequent and variable. They may occur in small fry with virtually no preceding signs'''.<ref>Kawula, T. H., Lelivelt, M. J., Orndorff, P. E (1996) '''Using a new inbred fish model and cultured fish tissue cells to study Aeromonas hydrophila and Yersinia ruckeri pathogenesis'''. Microbial Pathogenesis, 20(2):119-125; 12</ref> Losses of 15% over a cycle are not uncommon and can reach 90% on small scale units. | + | '''Mortalities are frequent and variable. They may occur in small fry with virtually no preceding signs'''.<ref>Kawula, T. H., Lelivelt, M. J., Orndorff, P. E (1996) '''Using a new inbred fish model and cultured fish tissue cells to study '''Aeromonas hydrophila''' and '''Yersinia ruckeri''' pathogenesis'''. ''Microbial Pathogenesis'', 20(2):119-125; 12</ref> Losses of 15% over a cycle are not uncommon and can reach 90% on small scale units. |
==Diagnosis== | ==Diagnosis== | ||
Diagnosis is often presumed from '''history at a site and clinical signs but these are not specific''' and represent many other gram negative septicaemic diseases. | Diagnosis is often presumed from '''history at a site and clinical signs but these are not specific''' and represent many other gram negative septicaemic diseases. | ||
| − | Confirmation is most easily made by '''culture from tissue samples of the spleen, heart and kidney'''. Media such as '''tryptone soya''' are widely available and very effective. They can be supplemented with 5% blood to increase success. The bacterium can then be '''serologically diagnosed by traditional methods, monoclonal or polyclonal antibody testing and antigen [[ELISA testing|ELISA]]'''. | + | Confirmation is most easily made by '''culture from tissue samples of the spleen, heart and kidney'''. Media, such as '''tryptone soya''', are widely available and very effective. They can be supplemented with 5% blood to increase success. The bacterium can then be '''serologically diagnosed by traditional methods, monoclonal or polyclonal antibody testing and antigen [[ELISA testing|ELISA]]'''. |
| − | '''Antibodies''' to ERM can be detected using '''[[Agglutination| | + | '''Antibodies''' to ERM can be detected using '''[[Agglutination|latex agglutination]]''' and can also detect subclinical infections.<ref>Romalde, J. L., Magarinos, B., Fouz, B., Bandín, I., Núnez, S., Toranzo, A. E (1995) '''Evaluation of BIONOR mono-kits for rapid detection of bacterial fish pathogens'''. ''Diseases of Aquatic Organisms'', 21(1):25-34; 32</ref> |
| − | The most recent method is '''PCR''' and is capable of detecting very low levels of Y. | + | The most recent method is '''PCR''' and is capable of detecting very low levels of ''Y. ruckeri'' but is insensitive and not commercially available. |
At '''necropsy''', there is '''congestion of blood vessels''' throughout the peritoneum and white-grey patches of necrosis and '''petechial haemorrhages''' are found in the liver, swim bladder, pancreas, lateral muscles and adipose tissue. '''Serosanguinous fluid often accumulates''' in the body cavities and muscle which become yellow and mucoid within the intestinal tract. There may also be severe damage of the haematopoietic renal tissues. | At '''necropsy''', there is '''congestion of blood vessels''' throughout the peritoneum and white-grey patches of necrosis and '''petechial haemorrhages''' are found in the liver, swim bladder, pancreas, lateral muscles and adipose tissue. '''Serosanguinous fluid often accumulates''' in the body cavities and muscle which become yellow and mucoid within the intestinal tract. There may also be severe damage of the haematopoietic renal tissues. | ||
| − | '''Acute anaemia with a haematocrit as low as 23%''' has also been noted<ref>Lehman, J., Sturenberg, F. J., Mock, D (1987) '''The changes in haemogram of rainbow trout (Salmo gairdneri, Richardson) to an artificial and natural challenge with Yersinia ruckeri'''. Journal of Applied Ichthyology, 3:174-183 </ref> and is thought to be due to '''endotoxic effects'''.<ref> Miller, T (1983) '''Blood coagulation in ERM infected trout: role of bacterial endotoxin'''. In: Proceedings of the 8th Annual FHS/AFS Workshop, ''Kearneysville, West Virginia, USA'',48</ref> | + | '''Acute anaemia with a haematocrit as low as 23%''' has also been noted<ref>Lehman, J., Sturenberg, F. J., Mock, D (1987) '''The changes in haemogram of rainbow trout (''Salmo gairdneri'', Richardson) to an artificial and natural challenge with ''Yersinia ruckeri'''''. ''Journal of Applied Ichthyology'', 3:174-183 </ref> and is thought to be due to '''endotoxic effects'''.<ref> Miller, T (1983) '''Blood coagulation in ERM infected trout: role of bacterial endotoxin'''. In: Proceedings of the 8th Annual FHS/AFS Workshop, ''Kearneysville, West Virginia, USA'',48</ref> |
==Treatment== | ==Treatment== | ||
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'''Good husbandry and water quality are key to minimising the stress''' that precipitates disease. | '''Good husbandry and water quality are key to minimising the stress''' that precipitates disease. | ||
| − | '''Two very effective vaccines''' are also available but may not provide comprehensive cross-protection in all situations.<ref> Erdal, J. I (1989) '''Vaccination against common infectious disease of fish'''. Norsk Veterinærtidsskrift, 101(6):489-495; 4</ref> | + | '''Two very effective vaccines''' are also available but may not provide comprehensive cross-protection in all situations.<ref> Erdal, J. I (1989) '''Vaccination against common infectious disease of fish'''. ''Norsk Veterinærtidsskrift'', 101(6):489-495; 4</ref> |
{{Learning | {{Learning | ||
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Animal Health & Production Compendium, '''Yersinia ruckeri datasheet''', accessed 13/07/2011 @ http://www.cabi.org/ahpc/ | Animal Health & Production Compendium, '''Yersinia ruckeri datasheet''', accessed 13/07/2011 @ http://www.cabi.org/ahpc/ | ||
| − | [[Category: | + | |
| + | {{review}} | ||
| + | [[Category:Fish Diseases]] | ||
| + | [[Category:CABI Expert Review]] | ||
Revision as of 14:14, 18 July 2011
| Yersinia ruckeri | |
|---|---|
| Kingdom | Bacteria |
| Phylum | Proteobacteria |
| Class | Gammaproteobacteria |
| Order | Enterobacteriales |
| Family | Enterobacteriaceae |
| Genus | Yersinia |
| Species | Y. ruckeri |
Also Known As: ERM — Redmouth — Redthroat — Yersiniosis
Caused By: Yersinia ruckeri
Introduction
Enteric redmouth disease is a disease of fish caused by the gram negative, rod shaped, slightly curved bacterium, Yersinia ruckeri. Most of the bacteria are motile due to having seven or eight flagellae, although they only function at temperatures above 9⁰C and below 35⁰C .
There are six known serovars of Y. ruckeri. Many fish species involve a carrier state and are only detected when stressed, becoming a significant source of disease.
ERM can be acute or chronic. Economic losses due to the disease can be significant.
The disease is not zoonotic and no isolates can initiate growth at 37⁰C.
Distribution
Europe, North and South America and Australia.
ERM can be transmitted via water and it is poorly understood whether this is due to saprophytic function or merely prolonged survival in the presence of sediment and organic matter facilitating transmission and infection.[1] The bacterium is shed in the faeces of infected fish and the quantity increases exponentially with stress. Once infected, a population can maintain the disease indefinitely.
Signalment
ERM is particularly associated with intensive fish culture and poor water quality. Fish appear able to withstand exposure to large numbers of bacteria without developing disease in the absence of stress. Poor feeding routine and nutrition can contribute, but poor water quality is the primary concern, usually relating to high ammonia, poor flow, high temperatures or lots of organic matter/sediment. Handling fish can also exacerbate/trigger disease.
The disease is primarily of cultured salmonid fish but a number of other fish families have been found to be infected leading to the belief that its host range is quite diverse.
Young fish 1-5 months old are more susceptible to ERM than adults and brook trout appear to be most vulnerable.[2]
Infections have not been reported below 10⁰C.
Clinical Signs
The reddening of the throat and mouth that give the disease its name are caused by subcutaneous haemorrhage and are common but not always present. This can progress to erosion of the jaw and palate if untreated.
Affected fish also have generally darkened skin and fins with haemorrhagic lesions around the gill tips, vent and fins and are lethargic and inappetant. They may have a distended abdomen leading to a “pot-bellied” appearance. Fish are often pale around the gills and may demonstrate exopthalmos with periorbital oedema. They may be seen to be swimming close to the surface.
Mortalities are frequent and variable. They may occur in small fry with virtually no preceding signs.[3] Losses of 15% over a cycle are not uncommon and can reach 90% on small scale units.
Diagnosis
Diagnosis is often presumed from history at a site and clinical signs but these are not specific and represent many other gram negative septicaemic diseases.
Confirmation is most easily made by culture from tissue samples of the spleen, heart and kidney. Media, such as tryptone soya, are widely available and very effective. They can be supplemented with 5% blood to increase success. The bacterium can then be serologically diagnosed by traditional methods, monoclonal or polyclonal antibody testing and antigen ELISA.
Antibodies to ERM can be detected using latex agglutination and can also detect subclinical infections.[4]
The most recent method is PCR and is capable of detecting very low levels of Y. ruckeri but is insensitive and not commercially available.
At necropsy, there is congestion of blood vessels throughout the peritoneum and white-grey patches of necrosis and petechial haemorrhages are found in the liver, swim bladder, pancreas, lateral muscles and adipose tissue. Serosanguinous fluid often accumulates in the body cavities and muscle which become yellow and mucoid within the intestinal tract. There may also be severe damage of the haematopoietic renal tissues.
Acute anaemia with a haematocrit as low as 23% has also been noted[5] and is thought to be due to endotoxic effects.[6]
Treatment
ERM responds well to antibiotic treatment with oxolinic acid, oxytetracycline, sulphamerazine and tribrissen.
Vaccines can also be used as treatments for infected fish.
Control
Good husbandry and water quality are key to minimising the stress that precipitates disease.
Two very effective vaccines are also available but may not provide comprehensive cross-protection in all situations.[7]
| Enteric Redmouth Disease Learning Resources | |
|---|---|
 Test your knowledge using flashcard type questions |
Enteric Redmouth Disease Flashcards |
References
- ↑ Romalde, J. L., Barja, J. L., Magarinos, B., Toranzo, A. E (1994) Starvation-survival processes of the bacterial fish pathogen Yersinia ruckeri. Systematic and Applied Microbiology, 17:161-168
- ↑ Good, C. M., Thorburn, M. A., Stevenson, R. M. W (2001) Host factors associated with the detection of Aeromonas salmonicida and Yersinia ruckeri in Ontario, Canada government fish hatcheries. Preventive Veterinary Medicine, 49(3/4):165-173
- ↑ Kawula, T. H., Lelivelt, M. J., Orndorff, P. E (1996) Using a new inbred fish model and cultured fish tissue cells to study Aeromonas hydrophila and Yersinia ruckeri pathogenesis. Microbial Pathogenesis, 20(2):119-125; 12
- ↑ Romalde, J. L., Magarinos, B., Fouz, B., Bandín, I., Núnez, S., Toranzo, A. E (1995) Evaluation of BIONOR mono-kits for rapid detection of bacterial fish pathogens. Diseases of Aquatic Organisms, 21(1):25-34; 32
- ↑ Lehman, J., Sturenberg, F. J., Mock, D (1987) The changes in haemogram of rainbow trout (Salmo gairdneri, Richardson) to an artificial and natural challenge with Yersinia ruckeri. Journal of Applied Ichthyology, 3:174-183
- ↑ Miller, T (1983) Blood coagulation in ERM infected trout: role of bacterial endotoxin. In: Proceedings of the 8th Annual FHS/AFS Workshop, Kearneysville, West Virginia, USA,48
- ↑ Erdal, J. I (1989) Vaccination against common infectious disease of fish. Norsk Veterinærtidsskrift, 101(6):489-495; 4
Animal Health & Production Compendium, Enteric Redmouth Disease datasheet, accessed 13/07/2011 @ http://www.cabi.org/ahpc/
Animal Health & Production Compendium, Yersinia ruckeri datasheet, accessed 13/07/2011 @ http://www.cabi.org/ahpc/
 |
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