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31
October 2002 :
Vol 1 : No 6
CONTENTS
-
Do not make Sushi from you Koi
- Online Aquaculture Dictionary
- Survey Toolbox
- WAS for Cheap by e-mail
- Carp Pox
EXPERTS WARN: DO NOT MAKE SUSHI FROM KOI
The recent outbreak of KHV (Koi Herpes Virus) in Indonesia that decimated the Koi and carp populations of Java Island, prompted an expert to warn against the consumption of raw carp and Koi.
Under the headline Fish consumers 'should eat their carp (and koi) well-done', Debbie A. Lubis, reported in the The Jakarta Post of 27 July 2002:
Fish consumers in Jakarta and other parts of Java are advised to take precautionary measures before consuming carp due to a recent discovery of the spread of herpes virus in carp and koi breeding fishponds across Java.
Director of the Centre for Food and Nutrition Studies at the Bogor Institute of Agriculture Adil Basuki Ahza explained on Friday that the virus that attacked the carp and koi -- referred to as cyprinid herpes virus (CHV) -- could also attack the human immune system if people ate them without their being cooked properly.
Therefore, he suggested that anyone preparing the fish for the dining table had better assume that all carp were infected by herpes and consequently would have to cook them thoroughly to kill the virus.
He explained that the virus could not withstand a temperature exceeding 60 degrees Celsius.
"Thus, they would be safe to consume if the infected carp were fried, roasted or cooked in boiling water," Adil told The Jakarta Post.
Carp are widely consumed in Indonesia, while koi are kept purely as ornamental fish.
Meanwhile, Jakarta-based veterinarian Fidiya Haya suggested that consumers carefully check the state of any carp they might wish to buy.
Fidiya explained that herpes-infected carp would have extensive white patches on the gills and produce excessive mucus, sometimes accompanied by bleeding or ulceration.
If consumers buy live carp, Fidiya added, they must observe the behaviour of the fish. Usually, infected fish have sunken eyes and swim erratically. Fish affected by herpes will die within two days to four days, she said.
Meanwhile, director general of communicable disease control and environmental health at the Ministry of Health Umar Fahmi said that the herpes virus found in the fish was not the same as that found in the human body.
"We do not yet know whether the virus is transferable from animals to humans, like anthrax.
"Although there is no study on it, the public should know that the virus is not contagious to humans. No virus can withstand high temperatures," Umar told the Post.
Adil explained that anyone eating herpes-infected fish that had not been cooked thoroughly could experience symptoms on their skin such as itching or swellings, black spots, blistered skin, or even suffer nausea or headache.
He suggested that a person suffering from such symptoms had better consult a doctor.
In a bid to prevent the virus from spreading from Java to other parts of the country, the Ministry of Maritime Affairs and Fisheries has banned exports of the fish from the island.
The ban will be effective for three months, during which a team of experts will have to find ways to eradicate the virus.
"This is a complicated problem; therefore all stakeholders should sit together to find a holistic solution," Adil suggested.
The above may be confusing. The disease reported earlier by the Authorities in Indonesia was KHV and not CHV, which is certainly different according to the work done by Dr Ronald P. Hedrick as reported in Diseases of Aquatic Organisms Vol. 48, No. 2 (2002):
ABSTRACT: Since 1998, episodes of mass mortality have occurred in populations of common carp Cyprinus carpio carpio in Israel and in populations of koi Cyprinus carpio koi in Israel and the USA. A herpesvirus isolated from infected fish has been shown in experimental studies to induce disease and mortality similar to those observed in outbreaks at infected farms. Initial characteristics of the virus show that it is clearly different from Herpesvirus cyprini (CHV), the most commonly known herpesvirus from cyprinid fish. The koi herpesvirus (KHV) has 31 virion polypeptides. Twelve of the virion polypeptides of KHV have similar molecular weights to those of CHV and 10 are similar to those of channel catfish virus (CCV). Both virion polypeptide and restriction fragment length polymorphism analyses of genomic DNA showed that the first KHV isolates from Israel and the USA were identical. In contrast, the genomic DNA restriction fragments clearly distinguish KHV from CHV and CCV. A polymerase chain reaction (PCR) assay to detect the virus in koi tissues was developed with sequences obtained from 1 restriction fragment of KHV DNA. The PCR assay effectively detected a 484 base pair sequence from KHV but did not amplify genomic DNA from either CHV or CCV. The PCR assay detected as little as 1 pg of KHV DNA mixed with 100 ng of host DNA. Viral sequences were amplified from koi obtained from field collections and from koi that were experimentally exposed to 102 TCID50 ml-1 of KHV via the waterborne route. All KHV exposed fish dying of infection between 8 and 10 d post exposure or surviving to 14 d post exposure were found to be positive by PCR, while unexposed control koi were all negative. The assay also showed the presence of KHV DNA in tissues of koi obtained from farms in Israel. The PCR assay should assist virus isolation procedures and histologic and electron microscopic analyses now commonly used to detect KHV infection. Current studies are examining the possibility of using the PCR to detect KHV DNA in live fish and the relative sensitivity and specificity of the KHV PCR assay compared with other diagnostic tests.
Fine, so lets just assume that it's really KHV that is referred to.
I do not want to sound like an alarmist, but the potential hazard it is worth noting. In an industry where mortalities and cullings of the day are often taken home for supper, management should warn workers to cook the fish properly.
No matter how unlikely, our industry do not need any incident that will raise suspicions that our Koi may not be safe to have around the home.
Producers beware.
AQUACULTURE
DICTIONARY
Anyone had a look at the Aquatext online Aquaculture Dictionary?
Claiming "over 2 500 definitions, including 280 tables, 250 pictures and 120 calculations", it sure is a worthwhile site to find your aquaculture game questions answered.
SURVEY
TOOLBOX
According to the NACA website The Survey toolbox for aquatic animal diseases: A practical manual and software package [377 pages, PDF 2.87MB] is a must-have for health specialists. As a result of demand from aquatic animal scientists, ACIAR (the Australian Centre for International Agricultural Research) commissioned Dr Angus Cameron to produce a version of his Survey Toolbox, target specifically at aquatic animal diseases. The new book deals with the particular problems of undertaking rapid, cost-effective, and reliable surveys of aquatic animals. Aimed primarily at those working in developing countries, and using English as a second language, the book will also have considerable appeal to many developed country scientists. Its predecessor, the Survey Toolbox for Livestock Diseases has been translated into four languages. All of these documents have been kindly made available for free download. A printed version is also available from ACIAR.
WAS
FOR CHEAP BY EMAIL
The World Aquaculture Society has launched an "e-subscription". This subscription is intended to allow people from least developed countries to access some of the benefits of the WAS at a special rate. For more details, visit the WAS web site
The e-subscription costs only US$10 per year and includes access to the members area of the WAS web site, inclusion in the WAS membership directory, access to WAS meeting abstracts and members rates in the WAS store. E-subscription does not include members rates for WAS meetings or the right to vote in WAS elections.
CARP
POX
The following concocted from various sources but mostly from the very pleasant site of the Goldfish Girls:
One
of the oldest known fish diseases, carp pox has been recognized since the Middle
Ages. It was first described in 1558 by Conrad Gessner. It is referred to
under a variety of names, from carp papillomatosis to epithelioma papillosum to
fish pox, none are clinically correct. It is neither a pock nor is it
caused by a poxvirus. Herpesvirus epidermal proliferation in carp (HEPC)
is a more appropriate term and will be used instead of "pox"(4).
The etiology of HEPC has been attributed to a herpesvirus and occurs principally
in common carp and crucian carp, but also in barbel, bream, golden ide, pike-perch,
rudd, smelt, tench, carp x goldfish hybrid, and various aquarium fish (2).
Although HEPC causes a reduction in adult fish growth, by far the greatest
economic damage occurs as a result of aesthetics, since clinical signs are
unsightly and render the fish unmarketable for food or display. Juvenile
fish are adversely affected, exhibit high mortality, and survivors may develop
tumors within a year, while morbidity is rare in adult fish (1). Skin
tumors are transient, usually desquamating after some time and forming a scar
(4).
Herpesvirus cyprini is a DNA virus and has an envelope, which makes it
sensitive to ether, pH 3, 50° C for one hour, and iododeoxyuridine. The
carp herpesvirus genome has been detected in the cranial nerve ganglia,
subcutaneous tissue, and spinal nerves in both the papillomatous and latent
phase (1).
Epidemiology
and Pathogenesis
The prevalence of HEPC is influenced by environmental and host-associated
factors. Crowding, inbreeding, and water temperature are critical. Lesions
disappear as water warms in the summer and appear during periods of low to
moderate temperatures (2). Monogenetic trematodes, leeches, copepods, and
myxosporidans have been proposed as possible or probably vectors (3).
Evidence shows that the disease can be transmitted by cohabitation, especially
by rubbing lesions against abraded epithelium. Cells of the epidermis
become hyperplastic and proliferation obliterates the normal strata.
Intranuclear inclusion bodies can be seen with light and fluorescent microscopy
(2).
Gross
Lesions
Lesions typically develop first on the fins, later growing thicker and appearing
as paraffin drops on the skin. Further proliferation results in
irregularly shaped papillomatous formations, having a warty surface and milky to
greyish white in colour. These lesions are generally small, though may
increase in size and cover large areas of the body surface (4). In adult
fish, the lesions eventually regress and disappear. Retarded growth and
emaciation are consistently noted in advanced stages of HEPC. The fish
become "flabby" with reduced muscular tone and osteomalacia.
Two-week old common carp fry show loss of appetite, have distended abdomens,
exophthalmia, darkened pigmentation, and hemorrhage of the the operculum and
abdomen (1).
Control
Effective treatment is unknown, yet several management strategies can be applied
to avoid development of HEPC. Replacement of inbreeding with
cross-breeding can significantly diminish the incidence and severity of disease.
Sloughing of lesions can be enhanced by raising the temperature of the water
above 20° C. Liming of pond water in the spring in European carp culture
seems to accelerate recovery (4).
We had limited success with a repeated scraping off of the lesions, rubbing Zovirax or Activar cream (active ingredient; acyclovir) into the wound and sealing with friar's balsam. However, the tedious nature of this regime can only be justified if it is a valuable fish. Best practice is to remove and terminate all fish that does not exhibit a resistance for carp pox, and don't eat them either. (sdk)
References
1. Plumb, JA Health Maintenance and Principal Microbial Diseases of Cultured Fishes.1999. Iowa State University Press. Ames, Iowa. Pages 81-84.
2. Stoskopf, MK Fish Medicine. 1993. W.B. Saunders Co., Philadelphia, PA. Pages 478-480.
3. Wolf, K Fish Viruses and Fish Viral Diseases. 1988. Cornell University Press. Pages 65-68;253-263.
4. Woo, P.T.K. & D.W. Bruno. Fish Diseases and Disorders. 1999. CABI Publishing. Oxon, UK. Pages 212-216.
Totsiens
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OUR MISSION: This free Newsletter is intended to share information of interest to the Breeders, Exporters, Importers and Dealers of Koi internationally. It is not intended for the average hobbyist. Your feedback or criticism of whatever kind will be valued. If you want to update me on whatever is happening in your part of the world, I will be delighted. The idea is to serve the Koi industry and keep commercial content out. If I make mistakes, well, correct me if you can substantiate your claim. Please forward this to anyone you think might be interested in our subject matter.
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