Unknown illness affecting kanakana/lamprey in Mataura River

[Zev]

A large number of kanakana, or lamprey, in some Southland rivers have been found sick and dying from a bacterial disease.

The bacteria is not a risk to human health. But, it is recommend that you do not eat kanakana that look unusual or unhealthy.

This disease has not been identified in New Zealand before.

There is a risk that it could spread to other commercial and recreational fish including salmon, trout, eel, whitebait, and native fish such as kokopu.

Further information here: http://www.fnzas.org.nz/?p=2546

Also from MAF: 'If any of your members come across fish that exhibit symptoms they should be encouraged to report the finding to the MAF hotline (0800 809966) as we are interested in getting a better understanding of the disease and how far it has spread. If your members retain the fish to send in for analysis they should be encouraged not to freeze the fish.'

[Zev]

Issue developments

MAF received a report from Environment Southland of sick or dead lamprey in the Mataura River. This had been first noticed around 13 September 2011. On 30 Sept preliminary lab testing of the fish identified the presence of a bacterium, Aeromonas salmonicida. The Aeromonas bacterium occurs in ‘typical’ and ‘atypical’ strains. The ‘typical’ strain causes a range of conditions, including skin lesions, in salmon and trout. The ‘atypical’ strain affects a wider range of fish worldwide (including Australia) with similar symptoms. Neither strain has been previously found in New Zealand, although community information suggests the disease may have been noticed in lamprey populations in earlier years.

A. salmonicida is an unwanted organism and a notifiable organism under the Biosecurity Act 1993 and a new organism under the HSNO Act 1996.

Subsequent to the positive identification of the bacterium in the lamprey, infection with A. samonicida has been confirmed in two juvenile rainbow trout from a hatchery on the Taieri River. MAF is examining two further trout from the hatchery, but our investigations at this stage suggest there is a very low prevalence of the disease at the facility.

We now have a situation where lamprey (from the Mataura, Mokoreta and Waikawa Rivers) and trout from the Taieri River have been confirmed with the bacterium.

Laboratory work continues to identify the particular strain of bacterium at play in this situation. We are awaiting final confirmation of the positive PCR test results received to date through bacterial culture. This could take some weeks yet. Further analysis is required to determine if the bacterium is typical or atypical.

In the meantime we are keen to continue receiving reports of sick or dead fish to our freephone 0800 80 99 66.

In particular we need further specimens of diseased lamprey to help with full identification. As well I encourage reports of any illness in other fish species.

Reporting of new finds

Reports of any affected fish can be made through the 24/7 pest and disease hotline – 0800 80 99 66. The call centre will put you in contact with an investigator who will give you instructions on the best way to collect and preserve samples for analysis.

[Zev]

A further update from the MPI:

MPI has just received reports that some lamprey migrating up the Mataura River in Southland this year appear to have similar skin markings to those present on lamprey last spring.

When we put our activities on hold last year, the intention was to monitor future lamprey migration activity should the issue reoccur. We’re planning to send out a small team of scientists to collect suitable samples to carry out the necessary laboratory testing to once again try to identify what’s going on.

In the coming weeks we plan to work with other agencies, local authorities, tangata whenua and industry groups to identify and manage any biosecurity issues. We aim to provide you updates on our progress as we understand more about the situation. Bear in mind that it may take a number of weeks to gain any useful new information.

In the meantime, we recommend people finding lamprey with skin markings similar to those in the photos below immediately contact our 0800 free-phone – 0800 80 99 66. This will allow us to build up a picture of how widely distributed the problem is.

At this point, we plan to collect all necessary samples for laboratory testing, as the method of collection and processing is crucial to getting suitable samples. We do not need community members to submit dead or affected lamprey.

[Adrienne]

This what I imagined viral hemorrhagic septicemia would look like.

[alanmin4304]

They certainly have that look about them. I would have thought the would be testing for VHS.

[F15hguy]

reminds me of the queensland groper outbreak in Townsville, ended up being a strep infection

Streptococcus agalactiae

[Sheepsnana]

Well if we're guessing... I'm thinking it looks like... fish leprosy.

On a more serious note: Has it affected/infected anything else yet? Or just Lamprey and Trout?

[alanmin4304]

Did they all have a fever, turn scarlet and have sore throats?

[Zev]

Depending on the strain of A. salmonicida a wider range of fish can be susceptible, if anything else in the region turns up with the same or similar markings they would be interested in know about these as well.

[GrahamC]

That white stuff looks like necrotic tissue where the skin is sloughing off. How fresh are these specimens?

[Zev]

No idea sorry Graham.

[GrahamC]

http://microbewiki.kenyon.edu/index.php ... almonicida

Says the bug grows optimally 22-25C ... wonder what other condition is favouring these infections at our low temperatures. Must be a worry ....

[Zev]

Good afternoon all

A further update on the MPI investigation into skin lesions and deaths of kanakana/lamprey in Southland rivers.

Over the weekend and yesterday a field team deployed in Southland managed to collect a number of lamprey with skin lesions and these have been sent to the Animal Health Laboratory in Wallaceville for examination.

In all, 22 kanakana showing unusual skin markings were collected from the Waikawa River over the past two days.

Our labs report that the specimens in the first shipment on Sunday were all in good condition for analysis, and work has begun on testing for viruses and bacteria. The testing is expected to take a couple of weeks for any results to be available. Bear in mind that the results may be inconclusive, or we may be looking at a situation where a range of factors are responsible for the condition of the kanakana.

Our field team reports that while they managed to find a reasonable number of marked kanakana for testing, there were still good numbers of the kanakana that did not have skin lesions.

The MPI team is following up on reports of affected kanakana from other Southland rivers as they come in, and I will continue to keep you updated on this, and other issues, as they come to hand.

[Zev]

Good afternoon everyone

Time for another update on progress in the investigation into red skin lesions presenting on lamprey in some Southland rivers.

To summarise the current situation:

MPI laboratory testing of lamprey samples from the Mataura and Waikawa Rivers has so far found no sign of any known disease-causing organisms.

Our field sampling is continuing with a great deal of help from local iwi who are providing on-the-ground support with sampling locations and in catching the lamprey/kanakana.

The field team has this week been monitoring the Waikawa, Mataura and Oreti rivers for signs of affected lamprey/kanakana.

We are now working to obtain samples for lab testing from the Mokareta River and from lower reaches of the Mataura and Waikawa Rivers.

River conditions – high flows caused previously by rain and now snow melt – are hampering efforts in some places.

There have been no further reports of suspect cases outside of Southland. There were earlier reports of potentially affected lamprey in South Canterbury. Unfortunately no samples could be collected and there have been no further reports.

MPI is currently preparing to put together a Technical Advisory Group (TAG) to assist with the development of ongoing options once the laboratory testing has been completed. A TAG is a team of people with relevant expertise to the issue – it can include, for example, cultural advisors, local government, scientists and potentially affected industries. We’ll keep you posted regarding progress with this.

We did receive a report of an eel with suspicious skin markings. It was decided that the markings were likely due to injuries sustained during capture, rather than the lamprey condition under investigation. Our incursion investigators and laboratory experts determined that lab tests were not required. To be clear, MPI still encourages public reports of suspect cases – even though, from time to time, samples may not be needed, or may not be suitable for testing.

We are currently developing a web page for our biosecurity website for this investigation. This will be active sometime next week and you will be sent the link.

I will be in touch as further information comes to hand.

Regards

Andre