Practical considerations for veterinary care in closed containment systems

Transcription

1 Practical considerations for veterinary care in closed containment systems Grace A. Karreman, VMD, Adv Dip GIS App Salmon Containment Workshop St Andrews, NB April 29-30, 2014 The Aquatic Life Sciences Group 1

2 Disclosure/Disclaimer Aquatic Life Sciences Syndel Labs (CDN) Western Chemical (US) International Approved fish health products in US and CDN The Aquatic Life Sciences Group 2

3 Background RAS technology coming to the forefront Food fish Conservation/stocking facilities, large public aquaria or medical research fish RAS facilities Emerging diseases in RAS s Customer/client inquiries Emerging recognition that system design, production practices and fish health must work together The Aquatic Life Sciences Group 3

4 Emerging Diseases in RAS s Pathogens - Recent examples Saprolegnia ( fungus ) in Atlantic salmon Francisella spp in Tilapia Mycobacteria spp in Zebrafish Chlamydia-like organism in Artic char Emerging non-infectious (production) issues Off flavor cyanobacterial products Geosmin Contributes earthy flavor 2-Methylisoborneol (MIB) Contributes musty flavor The Aquatic Life Sciences Group 4

5 Fish health actions/interventions Anesthesia/sedation Monitoring/observations, pathogen detection, diagnosis Record keeping, review and interpretation Vaccination Treatments (in feed, in-water, injectable, immersion etc) Handling movement, grading, health sampling etc Humane harvesting Euthanasia The Aquatic Life Sciences Group 5

6 Production question What can I use to treat Saprolegnia in Atlantic salmon in an RAS? Eggs Pre-smolt after intraperitoneal (IP) vaccination Broodstock held in freshwater The Aquatic Life Sciences Group 6

7 Why are diseases emerging in RAS s? Prevention not sufficient Failure of bioexclusion Most likely comes in or on the fish (gills, GI, skin). Possibly inadequate treatment of ambient water. No in vivo disinfectants (except Ovadine for fish egg surfaces) Don t test for resident organisms (e.g., Saprolegnia) The Aquatic Life Sciences Group 7

8 Bioexclusion keep pathogens out! Route of introduction Physical barriers Functional barriers Incoming Fish** Water Fomites Vectors Feed Quarantine facility Treat ozone, UV, filtration; Equipment storage Physical barriers Secure feed storage Use certified or proven reliable source, disinfect eggs SPF water source; Dispose of transport water Clean & disinfect, SOPs, dedicated equipment Pest control programs; dedicated staff; staff & visitor protocols Heat/other treated feed, or certified or proven reliable source 8

9 Emerging RAS diseases /2 RAS and flow through water quality are not the same Microbial communities Physical and chemical water characteristics 24x7 production promotes persistence No down time unless catastrophic issue Fish stress response Treatments more complicated than in flowthrough systems The Aquatic Life Sciences Group 9

10 RAS - what do the fish experience? Life support in a hostile medium Constantly recirculating air (pumps, filters) Air quality (O2, CO2, temperature, stale etc) Noise Inputs of food, water, fuel Waste management Medium for spread of pathogens, once introduced Decontamination showers Hospital treatment and isolation areas Possibility of catastrophic failure The Aquatic Life Sciences Group 10

11 24x7 Operations No terminal disinfection or down time Cleaning and Disinfection (C&D) Virkon Aquatic approved in both US and Canada 90% of the work is in the cleaning step Measuring effectiveness of C&D (e.g., ATP luminometers) Lack of accessibility to all parts of the system Buried plumbing, hard-to-reach places What happens to the biofilter media? Pumps Biofilms formation and circulating organisms The Aquatic Life Sciences Group 11

12 Biofilms in water systems Genomics, to characterize populations Dynamics biofilm formation, maturation, senesence Multi layered and sequestering BUT beneficial organisms! The Aquatic Life Sciences Group 12

13 Vaccination and fish stress response Skin is the target of the stress response Sparolegnia capable of penetrating skin once mucus is reduced Topical protectants may help IgT The Aquatic Life Sciences Group 13

14 Now, add the in-water treatment Include biofilter and biofilm in the epidemiological triad Host Treatment And/or Management Environment Pathogen 14

15 In-water treatments Drug Parasite-S (37% Formalin) PeroxAid (35% Hydrogen peroxide) Halamid-Aqua (Chloramine-T) Bronopol Label indications US + CDN: Saprolegnia on eggs* US + CDN: Saprolegnia on eggs* US (pending): not labeled for Saprolegnia CDN: Saprolegnia on eggs* *treatment of fish/broodstock is extra label ****Salt (not approved) *** US (GRAS) The Aquatic Life Sciences Group 15

16 RAS s and approved drugs Drugs currently approved in the US and Canada Efficacy and safety (human food, handling; fish; environmental) US: CDN: Drugs authorized under investigational exemption (INAD, ESC) GRAS, LRP etc (e.g., salt) US: New approvals require a statement about use in RAS s Accumulation (environmental, human food safety) Merck received approval for Florfenicol use in RAS s (March 2014) The Aquatic Life Sciences Group 16

17 In-water treatments - application Calculating the proper dose AADAP calculator (US) dap/afs%20fcs%20guide%20to %20Drugs.htm Syndel calculator (CDN)- aspx The Aquatic Life Sciences Group 17

18 Treatment delivery systems High Tech Systems Pumps, metering, monitoring, proper emitters, flush residuals between treatments, equipment tolerant of treatments Expensive, maintenance Low tech systems Manual delivery, time consuming Closer observation of treatments Worker safety The Aquatic Life Sciences Group 18

19 Static baths Keep the tank volume to a minimum during treatment Need additional O2 Monitor WQ closely Evaluating treatments Getting to the therapeutic level Rapid detection tests (colorimetric) Multiple locations in the tanks (hot spots) The Aquatic Life Sciences Group 19

20 if must use inwater treatments Managing the residuals Salt Formalin Hydrogen peroxide Chloramine-T Bronopol Mode of action + end use Hard surface disinfectant Water sanitizer Drug The Aquatic Life Sciences Group 20

21 Formalin (37% Formaldehyde) degradation H 2 C=O + H 2 O H 2 C-(OH) 2 Formaldehyde + water Formaldehyde hydrate (Formalin) 2H 2 C=O + O 2 2 HCOOH Formaldehyde + oxygen HCOOH + O 2 Formic acid + oxygen Formic Acid CO2 + H2O Degradation rates: in sediment>biofilters>>in water. Carbon dioxide + water Dose: 1,000 to 2,000 μl/l (ppm) x 15 minutes. The most widely used concentration is approx. 1,670 μl/l (1.67 ml/l). The Aquatic Life Sciences Group 21

22 Formalin and microbial adaptation From Pederson (2010) Fig. 1 (above). Formaldehyde removal rates in mg/l per hour derived from formaldehyde spiking experiments in pilot-scale systems. Formaldehyde (C0 = 10 mg/l) was added as formalin with different intervals in duplicate systems either weekly ( ) or twice a week ( ) during the first experimental trial. From Day no formalin was applied to any of the systems. Weekly or daily ( ) treatment with formaldehyde equivalent to 10 mg/l were applied in the second experimental trial, where the final two treatment episodes includes double dosages equivalent to 20 mg/l. Values shown represent mean ± S.D. The Aquatic Life Sciences Group 22

23 Hydrogen peroxide (35%) Dose: 500 ppm x 60 mins 500 ppm = 1.43 ml of Perox-Aid per litre of water treated Caution in RAS s Ultralow levels tolerated US: benchmark is 0.9mg/L Rapid detection methods Look at the gap in nitrite levels immediately up- and downstream of the biofilter!! The Aquatic Life Sciences Group 23

24 Hydrogen peroxide degradation Enzymatic degradation H2O2 + H2O2 2H2O + O2 Very rapid in the presence of organics In sediment >biofilters>>in water New product catalyzes rapid degradation of high levels The Aquatic Life Sciences Group 24

25 Halamid (Chloramine-T) Dose: ul/l US: Benchmark established Chloramine, not chlorine, is the active ingredient Can be neutralized with thiosulfate Stagger treatments One tank, flush, next tank, flush etc. Alternate days Whole system 3 days on, 6 days off The Aquatic Life Sciences Group 25

26 Predicting the system post-treatment concentration that will reach the biofilter Predictive model under development Chronology of treatments Target treatment concentrations Takes into account dilution due to system volume The Aquatic Life Sciences Group 26

27 Managing the treatment effluent Depends on: Which drug or compound Concentration Volumes Temperature Bypass and discharge Expensive (heated, chilled water) Make-up water required Dilution Few tanks and low doses The Aquatic Life Sciences Group 27

28 Managing the treatment effluent /2 Degradation Enzymatic (expedited) Due to sunlight/uv, heat, organic material etc Time required Safety to the fish and biofilter Inactivation Thiosulfate Filtration Ineffective at high volumes Small particles very important The Aquatic Life Sciences Group 28

29 Treatments design implications Delivery systems Properly engineered Easy to maintain Rotation of products Treatment systems Reserve space (tanks etc) Treatment systems for degradation and inactivation of treated water in-line Consider treatment product characteristics (e.g., corrosion) Cleaning and disinfection design considerations All parts of the system must be accessible Easy maintenance Access to biofilter media The Aquatic Life Sciences Group 29

30 Longer term thinking More complex treatment regimes Rotating treatments Long term low dose Smaller and redundant component loops within one system Allows part of the system to be taken off line Multiple biofilters reduces risk of catastrophic event Quick isolation if an outbreak, minimize losses Flexibility in production scheduling Capital costs vs. savings in operations and fish health costs The Aquatic Life Sciences Group 30

31 Making use of newer technologies Develop products that work in vivo (while the system is live) Autogenous fish vaccines Vaccination of the biofilm/biofilter Monitor using time lapse photography Fish behavior System performance Biomedical engineering Dialysis/ biological membranes for in-line filtration and water treatment Circulatory system - medical uses of ozonation The Aquatic Life Sciences Group 31

32 Questions? Grace A. Karreman, VMD, Adv Dip GIS App Aquatic Life Sciences Inc McCullough Road Nanaimo, BC, V9S4M9 Canada Acknowledgements: Images from internet sources; Pedersen et al (2010) The Aquatic Life Sciences Group 32