Download Disease Immune System

Major Costs in Aquaculture
Major Repeating Costs in Aquaculture Include:
New Seed – Growing or Purchasing – To Make
Effective Decisions – You Need to Know
About Reproduction of the Target Species
Feeds – To Make an Effective Decision You
Need to Know About – Life History Stages
and Their Nutrition Requirements
Disease – To Make Effective Decisions You Need
To Understand The Immune Response of the
Target Species – The Causative Agent of the
Disease – and Optimal Avoidance Strategies
Disease in Aquaculture
Stress
effects of repeated stress responses
Immune System
antibody and cellular responses
Diseases
viral, bacterial, protozoan, parasitic
Types of Treatments
drug, external, sanitation
Biosecurity
controlling disease & vectors
Intensive Husbandry Methods
crowding, handling, vaccinating
Disease in Aquaculture
Disease has Grown Proportionally with Intensive
Aquaculture of Diverse Species – Why?
Increased Stocking Densities
Infected Carriers (eg Broodstock)
Infected Facilities (or Ineffective Sanitation)
Inappropriate or Poor Nutrition
Substandard Water Quality
Biggest Problem: Greater Disease Susceptibility via
Compromise of Native Immune System Under
Stressful Intensive Culture Conditions
Stress Defined
Stress
Any Stimulus Changing Normal Metabolism, Growth,
Immune Function, Reproductive Capacity or Behavior
Stress Can be Acute or Chronic
Stress Response
Primary Response: Change in Circulating Levels of
Cortisol and Catecholamines
Secondary Response: Changes in Glucose, Lactate
Major Ions, Tissue Levels Glycogen & HSPs.
Tertiary Response: Changes in Growth, Disease
Resistance or Behavior
Stress and Illness
Repeatedly turning on the stress-response, or failing to
appropriately turn it off, over time will cause the
stress-response to be as damaging as stressors.
Many Stress-Related Diseases are Disorders of
Excessive Stress-Response.
Response to a Stressor is Dynamic and Measuring
It May Represent Only a Snap-Shot in the Reaction
Stressors can be Physical, Chemical or Biological
Stressors
Chemical Stressors: Poor Water Quality, Pollution
Diet Consumption, Metabolic Waste
Biological Stressors: Population Density, Other Species
Micro-organisms, Macro-organisms
Physical Stressors: Temperature, Light, Sounds
Dissolved gases
Procedural Stressors: Handling, Shipping, Disease
Treatments
Prevention of Stress
Good Water Quality: Minimize Organic Debris and
Nitrogenous Waste, Maintain pH, Temp, O2 Levels
Good Nutrition: Feed High Quality Diets, Species
Specific Essential Nutrients
Proper Sanitation: Implement Biosecurity Procedures
Remove All Debris – Disinfect Equipment Before
Introducing New Groups of Fish.
Hole in the Head Disease
Affects Marine & FW
Fish in Captivity
Only in Cultivated Fish
Never in Wild Stocks
Adjustment to Diet with
Vitamins A, C & D
Sometimes Helps.
Autoimmune Disease
Brought on by Stress?
Disease
Disease Types in Aquaculture
Infectious Diseases
Parasitic Diseases
Non-Infectious Diseases
Most Environmentally Based –
Controlled Via Good Management
Infectious Disease Types
Viral Diseases: Cannot ID Without Lab Tests
Vaccines Do Not Exist for Most
Bacterial Diseases: Infections Often Internal & Unseen
Require Treatment with Medicated Water - Feeds
Parasitic Diseases: Relatively Easily Controlled with
Proper Application of Chemicals – Biosecurity
Fungal Diseases: Most Often a Secondary Problem
Common Viral Diseases in Aquaculture
Channel Catfish Viral Disease
Infectious Hematopoietic Necrosis
Infectious Hypodermal Hematopoietic Necrosis
Infectious Pancreatic Necrosis
Infectious Salmon Anemia
Koi Herpes Virus
Lymphocystic Virus
Midgut Gland Necrosis Baculovirus
Necrotizing Hepatopancreatitis
Spawner Mortality Virus
Spring Viraemia of Carp
Taura Syndrome Virus
Viral Hemorrhagic Septicemia
White Spot Syndrome Virus
White Tail Virus
Yellowhead Virus
Common Bacterial Diseases in Aquaculture
Bacteremia
Chilodonelliasis
Columnaris Disease
Dropsy
Enteric Redmouth
Enteric Septicemia of Catfish (ESC)
Fin Rot
Furunculosis
Hepatopancreatic Rickettsia
Necrotizing Hepatopancreatitis
Ulcer Disease of Goldfish
Vibriosis
Parasitic Diseases in Aquaculture
Anchor Worms
Fish Grubs
Fish Lice
Fish Velvet
Flukes
Henneguya
Ich
Ichthyobodo Disease
Ichthyophoniasis
Nematodiasis
Rust Disease
Tapeworms
Trichodiniasis
Water Molds
Whirling Disease
White Spot
Winter Disease
Foreign Invaders: Three Lines of Defense
Skin: First Line of Defense
Largest Organ in Body
Physical and Chemical Barriers
Physical – Hard to Penetrate
Armor – Scales & Collagen
Indigestible Keratin
Chemical Barrier – Mucus
Second Line of Defense
Innate Immune Response
Defenses No Matter What the Invader
Natural Killer Cells – Cytotoxic Lymphocyte
Macrophages – Amoeboid Phagocyte Engulfers
Dendritic Cells
Inflammation - Leukocyte Histamine Release
Fever – Caused by Histamines. The Fever
Kills Invaders by Denaturing Proteins.
Natural Killer (NK) Cell
Macrophage
Neutrophil
Third Line of Defense: Immune Response
Immune Response
Fish Response Similar to Mammals - Shrimp & Molluscs
Much Less Elaborate
The Immune Response can be Highly Specific
Specific Antibodies In Response to a Specific Antigen
The Immune System Identifies All Foreign Substances
and Differentiates Self from Non-Self
Immune System Works with Different White Blood Cells
In a Highly Integrated Manner
Immune Response System
Two Coordinated White Blood Cellular Systems
1) Humoral or Antibody Immunity (Using B Cells)
2) Cell-Mediated Immunity (Using T Cells)
Both Cellular Systems Work by Identifying Antigens
Non-Self Debris, Cells or Molecules
Auto-Immune Disease – When Immune Cells No
Longer Recognize Self
Macrophages
Are Engulfers
B Cells –
Antibody
Response
T Cells –
Cellular
Response
Antibody Response of the Immune System
B Cells – Create the Antibody Response
B Cells – Effectors – Produce Antibodies
B Memory Cells – Subsequent Antibody Production
Antibodies – Immunoglobulin
2 Heavy Chains, 2 Light Chains
Heavy Chains: Constant Region (types: α, δ, ε, γ, μ)
and Variable Region
Light Chain: Constant Region (types: κ, λ) and
Variable Region
Cellular Response of the Immune System
T Cells – Activated by Antigen Presenting Cells
Helper T Cells – Turn on B Cells - Activate
Killer T Cells
Killer T Cells – Effector – Destroys Antibody
Marked Cells
Memory T Cells – Stimulates Rapid Mobilization
Against Reinfections
Suppressor T Cells – Effector – Maintains
Tolerance of Self
Phagocytosis
Immune Response in Fish
Finfish and Shellfish Account for 25%
World Aquatic Production
With Intensification – Comes Deterioration
Culture Environment & Increased Disease
Poor Water Quality Stresses Fish
Immune Response in Fish Includes
Expansion of Cells for the Response
Expression of Both Responses
Coordination by Signaling Molecules
Response Following Encounter with Pathogen
Fish Contacts Pathogen
Innate Immunity
Success (No Disease)
Failure (Disease and Death)
Initiation and Instruction of the
Specific Immune Response
Humoral Response
(Extracellular
Pathogens and Toxins)
Acquired Immunity,
Immunologic Memory, and
Protection (Survival)
Cell-Mediated Immune
Response (Intracellular
Pathogens and Viruses)
Factors Influencing Disease Resistance
and Immune Response of Fish
Salmon Lice as Chronic Stressors
Stressor - Salmon Louse
Stressors – Salmon Lice
What Are Sea Lice? – Crustacean, Copepod
~ 550 species 3 Genera External
Parasites of Fish
Lepeophtheirus salmonis (salmon louse)
Natural Parasite to Salmonids
Genera: Salmo, Salvelinus, Oncorhynchus
Caligus elongatus (sea louse)
Parasite to Many Marine Fishes
Reported in 73 Different Fish Families
Current Sea Lice Treatment Methods
Chemical Treatment
Drug Bath or Dip
Drug Incorporated in Feed
Biological Treatment
Cleaner Fish
Not Viable in Colder Regimes
Treatment - Bath & Dip Drugs
Organophosphates
Neurotoxins Blocking Acetylcholinesterase
Mostly Kill Mobile Stages
Toxic to Many Crustaceans
Sevin or Carbaryl: Anti-Arthropod Poison
Hydrogen Peroxide
Strong Oxidizer - Effectively Removes But
Does Not Kill Sea Lice
Toxic to Salmon Under High Concentrations
Elevated Temperatures, Exposure Time
Very Temperature Sensitive
Treatment – Drugs in Feed
Ivermectin
Targets Cl- Channels in Arthropods
Effectively Removes Sea Lice
Slow Depuration from Fish Muscle
Can Persists in Feces; Kills Others
Diflubenzuron
Inhibits Chitin Synthesis
Effective on all Stages of Sea Lice
Can Remain in Sediments
May Harm Non Target Species
Cost of Sea Lice & Their Treatments
Loss Factors
Total Loss in Value/Yr
Reduced growth
Reduced FCR
Downgrading
Secondary disease
Mortality
$180,000
$37,500
$6,000
$27,000
$81,000
Treatment 1
Treatment 2
Treatment 3
TOTAL
$12,000
$10,000
$10,000
$363,500
Stress and Illness
Summary
Macrophage defense functions in sea lice infested fish
are impaired, predisposing fish to intracellular
infections with a disease producing microsporidian.
Mustafa, A., Speare, D., Daley, J., Conboy, G., & Burka, J. 2000.
Enhanced susceptibility of seawater cultured Oncorhynchus mykiss
(rainbow trout), to the microsporidian Loma salmonae, during primary
infection with the sea louse, Lepeophtheirus salmonis. Journal Fish
Diseases. 23: 337-341.
Sea Lice Infested Salmon –
Plasma Cortisol Concentration
nmol/l
Continuous Turning-On of Stress Response?
Immune Response in Shrimp
Fish and Shrimp Differ in Their Ability to
Carry Out Immune Response
Capacity to Recognize, Expand Recognition
Express Specific Recognition, and Coordinate
Immune Defense Lower in Shrimp
Often Assumed That Fish and Shrimp Have
Similar Immune Competencies
Inappropriate Decisions Made on How Defense
Mechanisms Might be Enhanced in Shrimp
Specific Response of the Immune System
Glycoprotein Receptors
Macrophage
Macrophage
Step 1
Pathogens eaten by Macrophage
Step 2
Displays portion of Pathogen
on surface
Step 3
Pathogens
Helper-T cell recognizes
Pathogen
Activates Killer T- Cell
Memory T-Cell
Kills Infected Cells
Activates B- Cell
Memory B-Cell
Antibodies
Cellular vs Antibody Immunity
Cellular Immunity Antibody or Humoral Immunity
Carried out by T – Cells
Carried out by B – cells
T – Helper Cells
Activate T – Killer Cells
T – Helper Cells Activate
B – Cells to Produce Antibodies
T- Killer Cells Destroy
Infected Cells
Abs Released in Blood Stream
Antibodies Bind Antigens
Deactivating Them.
Primary vs Secondary Immune Response
Primary Immune Response
Immune Response to a First Time Invader
No Measurable Response for Several Days
Over 2 Weeks, Antibody Production Grows
Secondary Immune Response
Rapid Response on Second Invasion
Antibody Production Quickly Increases
Increase is Dramatic
Immune Response Summary 1
Antigens Exposed to Immune System Cells
Macrophage Ingests Antigen and Displays it
Helper T Cell Recognizes Antigen and Activates
Helper T Cell Activates Killer T & B Cells
Killer T Cells Divide and Proliferate
Killer T Cells Divide
Making Suppressor & Memory T Cells
Killer T Cells Kill Infected Cells
Immune Response Summary 2
B Cells Divide and Proliferate
B Cells Divide
Making Plasma Cells & Memory B Cells
Plasma Cells Produce Antibodies
Memory T & Memory B Cells
Speed Response if Antigen Reappears
Suppressor T Cells Halt Immune
Response when Antigens not Present