The Fish Vet's Blog

Going through veterinary school, there was always rivalry between the medical students and the veterinary students. You might be familiar with the bumper sticker, “Real doctors treat more than one species.”

The animals that line up in a row under that banner include the traditional dog, cat, horse, cow, sheep, pig and maybe rabbit and mouse.

Now as an aquatic veterinarian, I’m taking that further. “Aquatic Veterinarians treat more than one Phyla!”

The Phyla I’d like to be represented include:

• Coelenterates (e.g. coral, jellyfish, anemone),
• Arthropods (e.g. crab, prawn, lobster),
• Echinoderm (e.g. starfish, sea cucumber),
• Mollusc (e.g. abalone, octopus, cuttlefish, oyster),
• Vertebrates (e.g. Fish, Amphibia, Reptiles [crocodile, turtles, sea snake] and Marine mammals [dolphin, orca]).

Perhaps for the aquatic animals, we might even need to have 2-3 lines of animal pictures!

Check out the idea for my design here and feel free to contribute by design and vote if you can –
99designs.com.au/t-shirt-design/contests/t-shirt-design-required-251104/brief

The audience for the T-shirt design is aquatic veterinarians; for us to wear, to help increase awareness within our veterinary profession and to the outside world.

—
Yours sincerely,

Dr Richmond Loh
DipProjMgt, BSc, BVMS, MPhil (Pathology) Murdoch, MANZCVS (Aquatics& Pathobiology), Cert AqV.
The Fish Vet, Perth, Western Australia.
Veterinary Medicine for fish.
W: http://www.thefishvet.com.au
E: thefishvet
P: +61 (0)421 822 383

It seems that molecular techniques (PCR) are over taking the traditional methods for making diagnoses. It can be much more sensitive and have a much quicker turn around time. But, as a trained veterinary pathologist, I would tread with caution. The technique detailed below talks about how they used it to identify Mycobacteria in CLINICAL CASES. This means that they already knew they had the bug and was just testing for the fact. I have no qualms about using PCR to confirm a diagnosis because we regularly use multiple lines of evidence to arrive at our conclusions. But to use it as the sole means to make a diagnosis can be very dangerous.

Recently I’ve had a case where two animals in the collection was destroyed based on PCR detection of the pathogen. A full necropsy and thorough histopathology examination actually showed the animals had a clean bill of health! How could it have gone so wrong? This is because PCR tests only needs to detect a small portion of the DNA of the bug to give a positive result. So here are two simplified scenarios. The first is that the living bug is not present, but only components of the bug is present which is detected by the test. The second scenario is that the bug may be present in whole, but it may not be causing disease. It’s only an incidental findings.

There’s much to be said about studying the whole animal rather than relying on a test on alphabet soup!

The other great advantage of histopathology is that you can spot many other things that might be going on in the animal.

 

Aquaculture
Volume 411, Number 1-2 (October 2013)
	Use of restriction enzyme fragment length polymorphism (RFLP) of the 16S–23S rRNA internal transcribed spacer region (ITS) for identification of fish mycobacteria
	Authors:	Fazel Pourahmad, Randolph H. Richards
	Author Affiliations:	no affiliations available
	Source:	Aquaculture, Volume 411, Number 1-2 (October 2013)
	Page Numbers:	184 – 189
	Available Full Text:	Full Text: Subscription Required to view full text Format: PDF Size: Unknown Location: Publisher’s Site Authentication: Publisher’s Site
	Abstract:	PCR targeting the 16S–23S rRNA gene internally transcribed spacer (ITS) region has been proposed as a rapid and reliable method for the detection of Mycobacteriumspecies in human clinical specimens. Because of variation in ITS sequences amongst Mycobacteriumspecies, a single PCR amplification can be used to differentiate slowly growing and rapidly growing species within this genus. In the present study, analysis by ITS-PCR and ITS-restriction fragment length polymorphism (RFLP) was found to be a useful, simple and rapid method compared to current molecular and phenotypic techniques. The ITS was amplified from 13 reference strains and 59 fish isolated mycobacteria using a set of published PCR primers. After PCR, the banding patterns generated allowed slowly growing mycobacteria to be differentiated from all other rapidly growing species, with the exception of Mycobacterium conceptionense. HaeIII was selected as one of two restriction enzymes that, together with the knowledge about amplicon sizes, would produce an acceptable level of discrimination in the resulting RLFP patterns, especially in the rapidly growing group of mycobacteria. After digestion with Sau96I, the amplified products of most isolates of Mycobacterium fortuitum, including subtypes II and V and those 2 isolates with new patterns (220, 100bp), presented identical or very similar patterns as obtained by HaeIII digestion. All isolates of Mycobacterium marinum, Mycobacterium chelonaeand Mycobacterium gordonae, whose PCR products were not digested with HaeIII, produced two well-defined fragments with the Sau96I restriction enzyme.
	Citation:	Fazel Pourahmad, Randolph H. Richards . Use of restriction enzyme fragment length polymorphism (RFLP) of the 16S–23S rRNA internal transcribed spacer region (ITS) for identification of fish mycobacteria. Aquaculture, Volume 411, Numbers 1-2 (October 2013), pp. 184-189, <http://ejournals.ebsco.com/direct.asp?ArticleID=483BA7BA8D76F091EC97&gt;
	URL:	http://ejournals.ebsco.com/direct.asp?ArticleID=483BA7BA8D76F091EC97

Be careful what you eat!  see below:

 

PARALYTIC SHELLFISH POISONING – AUSTRALIA: (WESTERN AUSTRALIA) ALERT

********************************************************************

A ProMED-mail post

<http://www.promedmail.org>

ProMED-mail is a program of the

International Society for Infectious Diseases <http://www.isid.org>

 

Date: Wed 18 Sep 2013

Source: In My Community, Mandurah Coastal Times report [edited] <http://www.inmycommunity.com.au/news-and-views/local-news/High-algae-levels-prompt-estuary-shellfish-warning/7650575/>

 

 

High levels of potentially toxic microscopic algae have been recorded in shellfish in South Yunderup [Western Australia] in recent testing.

 

The Shire of Murray is urging residents and visitors to avoid eating all wild shellfish from the Peel-Harvey Estuary.

 

Filter feeding shellfish absorb the algae, which are capable of producing toxins.

 

*****Cooking cannot destroy the toxins and the shellfish could cause poisoning if consumed.

 

Symptoms of shellfish poisoning include nausea, cramping, vomiting, and diarrhoea.

 

“The Shire continues to work closely with the Department of Water and Health to monitor algae levels in the estuary,” chief executive Dean Unsworth said.

 

Anyone who has consumed shellfish from these waters and experiences poisoning symptoms should seek medical attention.

 

Wild shellfish from inland water sources should not be eaten, as water quality and safe consumption can not be guaranteed. These species include oysters, mussels, clams, pipis, scallops, cockles, and razor clams.

 

Shellfish purchased in supermarkets are not affected as these products must adhere to food quality assurance programs to ensure they are safe for consumption.

 

For more information contact the Shire of Murray on 9531 7777 or visit the Department of Health website for further details regarding wild shellfish collection.

 

[Byline: Rachel Fenner]

 

—

Communicated by:

ProMED-mail from HealthMap Alerts

<promed@promedmail.org>

 

[Paralytic shellfish poisoning (PSP) is a public health risk worldwide, resulting from the consumption of seafood that has bioaccumulated toxins produced by microalgae. Bivalve shellfish (such as mussels, clams, oysters, and scallops) pose a particularly high risk as they feed by filtration, providing a method of toxin accumulation. Algae responsible for causing PSP include several species of the genus _Alexandrium_, _Pyrodinium bahamense_ and _Gymnodinium catenatum_. Paralytic shellfish toxins (PST) have been recorded in shellfish from Victoria, South Australia, New South Wales, and Tasmania.

 

PSP is often caused by several closely related species in the genus _Alexandrium_. PSP toxins are responsible for persistent problems due to their accumulation in filter feeding shellfish, but they also move through the food chain, affecting zooplankton, fish larvae, adult fish, and even birds and marine mammals.

 

It is likely that seasonally recurring outbreaks of PSP are linked to the existence of a dormant cyst stage in the _Alexandrium_ life history. This strategy allows the species to deposit dormant cells in sediments where they survive through harsh winter conditions and then germinate to initiate new outbreaks in subsequent years. Long-term climatic variability, which affects temperature, upwelling, and currents, or allows cysts to survive in areas where they did not before, may be factors in extensions.

 

Shellfish that have caused this disease include mussels, cockles, clams, scallops, oysters, crabs, and lobsters. Symptoms begin anywhere from 15 minutes to 10 hours after eating the contaminated shellfish, although usually within 2 hours. Symptoms are generally mild, and begin with numbness or tingling of the face, arms, and legs. This is followed by headache, dizziness, nausea, and muscular incoordination.

Patients sometimes describe a floating sensation. In cases of severe poisoning, muscle paralysis and respiratory failure occur, and in these cases death may occur in 2 to 25 hours.

 

Reference

———

Food and Agriculture Organization of the United Nations. Marine Biotoxins. Food and Nutrition Paper 80; 2004.

 

Portions of this comment have been extracted from <http://aquaticpath.umd.edu/toxalg/psp.html> and from <https://www.health.gov.au/internet/main/Publishing.nsf/Content/cdi3701e>.

 

Maps of Australia can be seen at

<http://www.ga.gov.au/image_cache/GA4073.jpg> and <http://healthmap.org/r/8txX>. Peel-Harvey Estuary is located 80 km

(49.7 mi) south of Perth in Western Australia. – Mod.TG

 

Photos of pipis (_Paphies australis_): <http://tinyurl.com/oo2eoyv>. – Mod.JW]

 

Q: What did one clown fish say to the other?

A: “Keep your friends close.
Keep your anemones closer.”

Pictured below are the bony structures of the Synodontis catfish. Checkout the long bony first ray of the dorsal fin. It’s like a lance and can penetrate any soft tissue readily.

Checkout the serrated first ray of the pectoral fins! Looks like a spear that only goes in one direction!

All these bony structures can be locked in place and provides the gentle fish a defence mechanism. This is the reason many predators leave them well alone; and this is why we must take care when handling them.

Check out the thorough list my colleague out together on her blog:
http://avsnca.com/aquatic-veterinary-medicine-resources/

Q: Which airline company do fish use to fly?

A: Fin-Air.

This is the plane I took to come to Prague.

Cool idea by an artist, the human-algae symbiont suit.

Check out the full article here.

What I gathered from this article email alert is the wide ranging impacts a disease could have on the nation.

For example, this one shrimp disease does not only call on bans on exports of all shrimp products, but also prohibited to import aquaculture inputs (artemia cysts and biomass, polychaetes, prebiotics and probiotics) and algae from these countries, and from those nations where this syndrome is present.

This is why each country remains vigilant to prevent diseases entering the country; and if it does, to detect and eradicate the disease at the earliest. This is the gist of biosecurity.

From: “Dr. David Scarfe”
Date: 8 September 2013 21:16:07 AWST
Subject: AquaVetMed e-News: Ecuador calls for OIE shrimp EMS/AHPNS listing

September 8, 2013
Shrimp disease requested to be included in OIE official list

Ecuador – The National Fisheries Institute (INP) of Ecuador requested the acute hepatopancreatic necrosis syndrome (AHPNS) to be included in the official list of diseases, infections and infestations of the World Organization for Animal Health(OIE). INP representatives claim that this inclusion can help to intensify an animal disease surveillance agent.

Institute delegates made this request during the 6th Meeting of the Inter-American Committee on Aquatic Animal Health, which was held on 22 and 23 August 2013, in Mérida, Mexico. After learning about the crisis faced by the Asian shrimp industry due to AHPNS, the Ecuadorian government took preventive measures in the country. Therefore, since 25 July it decided to ban imports of various live shrimp species at any stage of their life cycle, their products and by-products in all presentations from China, Vietnam, Thailand and Malaysia for a year.

According to the Ministerial Agreement No. 043, it is also prohibited to import aquaculture inputs (artemia cysts and biomass, polychaetes, prebiotics and probiotics) and algae from these countries, and from those nations where this syndrome is present. The INP will initiate a training campaign for the shrimp sector in order to take the necessary precautions.

The AHPNS emerged in 2010 in shrimp farms located in southern China and in Hainan Island, and in early 2011 it was seen in Vietnam and Malaysia, the Ministry of Agriculture, Livestock, Aquaculture and Fisheries (Magap) reported. The first signs of the disease may occur between 7 and 10 days after the pool stockings, and the mortality can reach 100 per cent in the first 30 days of culture.

See the source (http://www.agricultura.gob.ec/author/agricultura/page/2/) for more information.
___________________________
AquaVetMed e-News provides information to veterinary and veterinary-allied subscribers concerning aquatic animal medicine, health, welfare, public health and seafood safety, obtained from a variety of sources (largely AquaVetMed subscribers). While provided by the American Veterinary Medical Association’s, Aquatic Veterinary Medicine Committee and are for public distribution, they do not necessarily reflect the opinion of the AVMA or the veterinary profession. See the AVMA Terms of Use (http://tinyurl.com/29h2rf) for further information.

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________________________________

Dr Loh, The Fish Vet, in Perth, Western Australia is unavailable until 21st September 2013. I am travelling to Prague, Czech Republic to deliver lectures on fish medicine at the World Veterinary Congress as an invited speaker.

Please check the Aquatic Veterinary Directory at www.AquaVetMed.info for a list of veterinarians in your area.

If you require a response from me please resend your e-mail on or after I return if I haven’t already responded. Thank you for your patience and understanding.

In the meantime, please check my blog for information on your topic at www.thefishvet.com

You can also follow me on: Facebook “Fin Page” – YouTube – Blog – Linkedin – Twitter

Thank you for your patience and understanding.

—
Yours sincerely,

Dr Richmond Loh DipProjMgt, BSc, BVMS, MPhil (Pathology) Murdoch, MANZCVS (Aquatics & Pathobiology), CertAqV.
Veterinarian | Adjunct Lecturer Murdoch University | President-elect WAVMA |
Secretary Aquatic Animal Health Chapter – ANZCVS.
The Fish Vet, Perth, Western Australia, AUSTRALIA. Mobile Veterinary Medical & Diagnostic Services for fish and other aquatic creatures.
http://www.thefishvet.com.au
Ph: +61 (0)421 822 383