Quaglio - Introduction and Diagnostic Overview

Question 1

What is the importance of studying fish pathology?

Answer 1

Ensures the health of fish in aquaculture and ecosystems

Identifies and manages diseases caused by physical, chemical, and biological agents (viruses, bacteria, parasites, fungi)

Question 2

What are the main causes of fish diseases?

Answer 2

Physical agents, Chemical agents, Biological agents

• Physical agents: Temperature, UV radiation, turbidity
• Chemical agents: Toxic substances, pH changes, ammonia
• Biological agents: Viruses, bacteria, parasites, fungi

Question 3

What are the key diagnostic steps in fish pathology?

Answer 3

Anamnesis, Signaling, Clinical examination, Sampling, Necropsy and histopathological analysis, Laboratory investigations, Differential diagnosis, Definitive diagnosis

Question 4

What is anamnesis in fish pathology?

Answer 4

A detailed collection of information about the fish’s environment, history, and health status to determine potential causes of disease

Includes environmental, collective, individual, past, and present anamnesis

Question 5

What is environmental anamnesis?

Answer 5

Study of water characteristics, Analysis of farming management, Assessment of natural and anthropogenic factors

• Water characteristics: depth, flow, temperature, pH, oxygen, salinity, turbidity
• Farming management: stocking density, hygiene, feeding practices

Question 6

Why is stress an important factor in fish pathology?

Answer 6

Stress disrupts homeostasis, making fish more susceptible to diseases

Common stressors include poor water quality, overcrowding, and sudden temperature changes

Question 7

What are common signs of gas bubble disease (GBD)?

Answer 7

Protruding eyes, abnormal swimming, emboli in tissues

• Acute GBD: rapid mortality
• Chronic GBD: embolism in cutis, cornea, and mouth with secondary infections

Question 8

How does UV radiation affect fish?

Answer 8

Causes sunburn and lesions in areas like the head, back, and dorsal fins

Leads to acute epidermal necrosis in very clear water

Question 9

What are the impacts of turbidity on fish health?

Answer 9

Affects behavior, respiration, and gill function

• Reduces oxygen levels by warming water
• High turbidity can harm juvenile fish by impairing prey capture

Question 10

What are the main diagnostic observations during a clinical exam?

Answer 10

Nutritional state, Behavior, Respiratory activity, Skin/eye condition

• Nutritional state: Emaciation, concave abdomen
• Behavior: Erratic swimming, lethargy
• Respiratory activity: Gulping, rolling motion
• Skin/eye condition: Ulcers, exophthalmos

Question 11

What is signaling in fish pathology?

Answer 11

Records species, purpose, and characteristics

• Species type (warm water or cold water)
• Purpose (fry, ornamental fish, broodstock)
• Age, sex, size

Question 12

What abnormalities in swimming behavior indicate disease?

Answer 12

Spiral swimming, Swimming near surface, Corkscrew motion

• Spiral swimming: neurological issues
• Swimming near surface: oxygen deprivation
• Corkscrew motion: Whirling disease (caused by Myxobolus cerebralis)

Question 13

What clinical signs suggest respiratory issues in fish?

Answer 13

Gulping at the surface, Lethargy, Rolling or bell-up motion

Question 14

How is water quality assessed in fish pathology?

Answer 14

Temperature, pH, Oxygen levels, Turbidity

• Temperature: Cold or warm water species tolerance
• pH: Neutral to slightly basic preferred (6.5–8)
• Oxygen levels: Essential for respiration
• Turbidity: Must be low to avoid stress

Question 15

What are the lethal temperature limits for fish?

Answer 15

Optimal, Suboptimal, Incipient lethal, Critical thermal

• Optimal: Ideal for growth
• Suboptimal: Outside preferred range but survivable
• Incipient lethal: Near death
• Critical thermal: Causes mortality

Question 16

How do temperature changes impact fish health?

Answer 16

Higher temperatures reduce oxygen levels and increase pathogen replication, Lower temperatures suppress immune responses, Sudden changes cause stress and vulnerability

Question 17

How does pH affect fish health?

Answer 17

Optimal pH, Low pH, High pH

• Optimal pH: 6.5–8 for most species
• Low pH (<6): Causes acidosis and gill damage
• High pH (>8.5): Leads to alkalosis and increased ammonia toxicity

Question 18

What is the significance of dissolved oxygen (DO) for fish?

Answer 18

Critical for respiration and metabolism

Decreases with high temperatures and turbidity; Signs of low DO: surface gulping, lethargy, poor feeding

Question 19

What are the signs of ammonia poisoning in fish?

Answer 19

Lethargy, gasping at surface, red gills, loss of appetite

Toxicity increases with higher pH and temperatures

Question 20

What is the importance of biosecurity in fish pathology?

Answer 20

Prevents disease spread within and between aquaculture systems

Includes quarantine, sanitation, and monitoring of water quality

Question 21

How is sanitation achieved in fish farming?

Answer 21

Removal of organic and inorganic material, Use of drying, sunlight, and chemical disinfectants

Question 22

What is the purpose of sampling in fish pathology?

Answer 22

Diagnoses diseases based on tissue and organ analysis

Identifies pathological changes early to prevent outbreaks

Question 23

What is the ideal method for sending samples to the lab?

Answer 23

Transport live fish in aerated plastic bags, Refrigerate dead fish, Fix tissue in formalin

Refrigerate dead fish within 6–12 hours; Fix tissue for histopathology

Question 24

Why is tricaine methanesulfonate (MS-222) used?

Answer 24

Euthanizes fish humanely during necropsy

Lethal dose: 50–250 mg/L

Question 25

What are the limitations of clinical exams in fish pathology?

Answer 25

Many symptoms are nonspecific, Chronic conditions and multifactorial diseases are harder to diagnose

Question 26

What is the role of external examination in fish pathology?

Answer 26

Detects deformities, lesions, and parasites

Observes mucus production and skin abnormalities

Question 27

What is kyphosis in fish?

Answer 27

An exaggerated outward curvature of the spine

Causes: trauma, genetics, nutritional deficiencies (e.g., Vitamin C)

Question 28

What is the impact of predators on fish health?

Answer 28

Cause injuries, Stress fish

Leading to secondary infections, reducing feeding and immunity

Question 29

What are the main stress factors in aquaculture?

Answer 29

Overcrowding, Poor water quality, Sudden environmental changes

Question 30

How do environmental factors contribute to multifactorial diseases?

Answer 30

Poor conditions weaken fish immunity

Combined effects of stressors and pathogens exacerbate disease outbreaks