EWOS sea lice management

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Surviving lice - Lusedata

EWOS sea lice management

www.ewosinnovation.com


Diflubenzuron Releeze ®

• Mode of action is to inhibit deposition of chitin

• Effective against all moulting stages

• MRL and withdrawal period established

• Commercial use Chile and Norway

• Assessing requirements in UK and Canada

• Resistance monitoring and management a key focus

EWOS Norway – product manager Hege Hovland (tomorrow)

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Lice levels

EWOS Releeze ®

14

12

10

8

6

Control

B

C

4

2

0

2 27 32

Days post challenge

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EWOS Releeze ®

• Resistance monitoring – LD 50 test (VESO)

• Cold temperature efficacy

• Egg string / viability of infective stages

• Rotation of compounds (remove adults)

• Development of integrated pest management

• Additional tools to remove lice surviving treatments

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Wadsworth (1998)


Fast M., Ross N., Craft C., Locke S., MacKinnon S., Johnson S. (2004)

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Wadsworth (1998)


Immune suppressants released

• Prostaglandin PGE 2

• Range of proteases

• Phosphatases

• Macrophage inhibitors

Effect on a range of factors

• Reduced respiratory burst

• Lower macrophage activity

• Increased cell death

• Decreased numbers of mucosal cells

• Down-regulation of immune genes (interleukin IL-1ß and MHC-1)

• Local and systemic immune suppression

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Growing understanding of suppression

• Firth K.J., Johnson S.C., Ross N.W. (2000). Characterization of proteases in the skin mucus of Atlantic salmon (Salmo salar)

infected with the salmon louse (Lepeophtheirus salmonis) and in the whole-body louse homogenate. Journal of Parasitology. 86.

1199–1205.

• Nolan D., Raune N., Van Der Heijden M., Quabis E.S, Costelloe J., Wendellar S.E. (2000). Juvenile Lepeophtheirus

salmonis (Kroyer) affect the skin and gills of rainbow trout Oncorhynchus mykiss (Walbaum) and the host response to a handling

procedure. Aquaculture Research. 31. 823–833.

• Kvamme, B.O., Kongshaug, H. & Nilsen, F. (2005). Organisation of trypsin genes in the salmon louse (Lepeophtheirus

salmonis, Crustacea, Copepoda) genome. Gene 352, 63-74.

• Fast M.D., Ross N.W., Muise D.M., Johnson S.C. (2006). Differential gene expression in Atlantic salmon, Salmo salar, infected

with Lepeophtheirus salmonis (Copepoda: Caligidae). Journal of Aquatic Health. 18. 116–127.

• Fast M.D., Johnson S., Eddy T., Pinto D., Ross N. (2007). Lepeophtheirus salmonis secretory / excretory products and their

effects on Atlantic salmon immune gene regulation. Parasite Immunology. 29. 179–189

• Fast, M.D., Johnson S., Eddy T., Pinto D., Ross N. (2008). Cortisol response and immune-related effects of Atlantic salmon

(Salmo salar Linnaeus) subjected to short- and long term stress. Fish & Shellfish Immunology. 24. 194–204

• Wagner G., Fast M., Johnson S.C. (2008). Physiology and immunology of Lepeophtheirus salmonis infections of salmonids.

Trends in Parasitology. 24. 176-183.

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Boost Control

• Can reduce sea lice attachment (38%)

• Improved when combined with medicines

Allow increased immunity against lice

Burrells et al., 2000

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Lice levels

20

18

16

14

12

10

8

6

4

2

0

Surviving lice – slow development

0ppb 1ppb 5ppb

Ch 4 PAM1 PAF1 PAM2 PAF2 AM Total

Lice developmental stages

5

1

0

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Other Control Mechanisms

Some lice survive treatment

Less robust against immune response

Boosted fish remove >50%

Removing resistant population

Reduce effectiveness from

the treated lice

Allow increased immunity against lice

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Wadsworth (1998)


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