pathology

What are major concerns for culturists in aquaculture?

Diseases and parasites.

What happens when pathogens or parasites appear in open systems?

Offending organisms can be transmitted to wild individuals.

What are the two main parts of fish immune systems?

Protection from physical invasion and internal pathogen handling.

What provides physical protection for fish?

Scales and layers of the dermis and epidermis.

What does the mucus covering on fish do?

Contains bactericides and fungicides, adds additional physical protection, is constantly renewed, sheds off debris, and discourages parasites from attaching themselves to the fish.

How can pathogens enter a fish's body?

Through physical injury or the digestive tract.

What are antiviral chemicals in fish blood called?

Interferons.

What do C-reactive proteins do?

Attack bacteria and viruses immediately after detection.

How does colder water affect the efficiency of a fish’s immune system?

It slows down the immune system.

What behavior do infected fish exhibit in response to sickness?

They exhibit 'fever symptoms' and head for warmer areas.

What do white blood cells do when a pathogen is detected?

They are attracted to the area, pick up foreign bodies, and take them to the spleen and kidney for handling.

What are the functions of antibodies produced in fish?

Detoxify the antigen, attract a complement to destroy the antigen, and deactivate reproduction of the antigen.

What is an antigen?

A toxin or other foreign substance.

Why do most fish respond to primary antigenic challenges by producing specific antibodies?

It allows a faster and greater magnitude response to secondary challenges.

Why can't invertebrates make antibodies?

They cannot be successfully vaccinated.

What is the first line of defense against pathogens for crustaceans?

Their body covered by chitin that is largely calcified.

What happens when a pathogen penetrates the chitin layer of crustaceans?

It triggers recognition by pattern recognition receptors via pathogen associated molecular patterns.

What important mediators are found in the hemolymph of crustaceans?

Prophenoloxidase activating system and associated factors.

What is the proPO-system?

An important immunological mediator in crustaceans.

What does the proPO-activating system lead to?

Melanization of pathogens which then disables them.

With which organisms do mollusks share defense mechanisms?

Arthropods.

What forms the natural immunity process in mollusks?

Anatomical and chemical protective barriers.

What is the main physical barrier of mollusks?

Shell and mucus which cover their soft bodies.

How do the internal defense mechanisms in mollusks work?

Through cellular reactions, including phagocytosis and nodule formation.

What is phagocytosis?

The process where a cell engulfs and destroys foreign substances.

What is nodule formation?

A cellular immune response that destroys large invaders.

What is encapsulation in mollusks?

The process of isolating and walling off foreign materials.

What is the most numerous active blood cell type in mollusks?

Granulocytes.

How are small invaders eliminated in mollusks?

Through phagocytosis.

How are numerous and large invaders eliminated in mollusks?

Through nodule formation or encapsulation.

What are lectins?

Carbohydrate-binding proteins crucial for innate immune responses by recognizing and eliminating pathogens.

What are examples of pathogens?

Viruses, bacteria, fungi, fungi-like organisms, protists, and metazoans.

What are metazoans?

External and internal parasites.

What do true viruses contain?

Nucleic acid, which can be either DNA or RNA, along with protein.

What is the infective, extracellular form of a virus called?

Virion.

What does a virion contain?

At least one unique protein synthesized by specific genes.

What is a capsid?

A protein shell around the viral nucleic acid.

What forms a capsid?

Protein.

What are the types of viruses?

Icosaheral, enveloped, helical, and more complex structures.

How do viruses reproduce?

They do not grow through cell division but use the machinery and metabolism of a host cell.

What happens with a virion after it infects a host cell?

It replicates using the host cell's components.

What are the two methods by which viruses take over host cells?

1. Some RNA viruses are directly translated into viral proteins. 2. Some DNA viruses are first transcribed into viral mRNA before being translated.

What is the main function of ribosomes?

Protein synthesis, translating genetic instructions from mRNA.

What happens after virions form new virions?

They cause the host cell to break down, allowing the virions to burst out.

What are the two pathways for transmission of viruses and other pathogens?

Horizontal transmission and vertical transmission.

What is horizontal transmission?

Transmission of viruses among individuals of the same generation.

What is vertical transmission?

Transmission from parent’s gametes to their offspring.

What causes channel catfish virus?

Herpesvirus

What does channel catfish virus cause?

High mortality and reduced growth.

What are channel catfish virus outbreaks often associated with?

Environmental stress and crowding.

When does channel catfish virus usually occur?

In warm summer months at temperatures of 27℃ or higher.

What are the signs of channel catfish virus?

Convulsive swimming, lethargy, swollen abdomen, exophthalmos, and hemorrhaging.

What is the experimental antiviral agent for channel catfish virus?

Kaempferol.

What is the causative agent of infectious hematopoietic necrosis?

Rhabdovirus

What species does infectious hematopoietic necrosis affect?

Salmon and trout.

What are visible signs of infectious hematopoietic necrosis?

Lethargy, occasional frenzied activity, darkened external surfaces, swollen abdomens.

What does exophthalmic mean?

Eyes protruding.

Is there an effective treatment for infectious hematopoietic necrosis?

No effective treatment; early detection and removal of infected fish are standard practices.

What causes viral hemorrhagic septicemia?

rhabdovirus

What species does viral hemorrhagic septicemia affect?

Over 50 species of freshwater and marine fish.

How does the viral hemorrhagic septicemia virus infect fish?

It is shed in the urine and reproductive fluids of infected fish.

When do most outbreaks of viral hemorrhagic septicemia occur?

In spring when water temperatures are less than 5℃.

What are some signs of viral hemorrhagic septicemia?

Hemorrhages, bulging eyes, swollen abdomens, darkened coloration.

What treatments are effective for viral hemorrhagic septicemia?

There are no effective treatments; early detection and removal of infected fishes is common.

What is the standard detection method for viral hemorrhagic septicemia?

Virus isolation in cell culture followed by identification.

What are examples of other fish viruses?

Infectious salmon anemia virus, tilapia lake virus, viral erythrocytic necrosis.

What is another term for infectious salmon anemia virus?

Hemorrhagic kidney syndrome.

What does Ostreid herpesvirus 1 primarily affect?

Oysters and other bivalves.

How is transmission of Ostreid herpesvirus 1 achieved?

Through water.

What life stage is often lethally affected by Ostreid herpesvirus?

Pacific oyster spat and juveniles.

What are clinical signs of infection with Ostreid herpesvirus?

Slowed growth, weakened condition, circular swimming.

When do infections of Ostreid herpesvirus usually occur in California?

In summer when water temperatures rise above 24℃.

What species does gill necrosis virus affect?

European flat oysters and Portuguese oysters.

What signs does gill necrosis virus typically show in infected oysters?

Ulcerations of the gill and labial palps.

What impact has gill necrosis virus had on oyster culturing?

It is no longer cultured commercially in many areas due to disease severity.

What is white spot syndrome virus?

A virus from the genus Whispovirus, affecting crustaceans.

What signs does white spot syndrome virus show in shrimp?

Lethargy, reduced food consumption, white spots over the carapace.

What does hypertrophied mean?

Thickening or enlargement of cells.

What treatment helps prevent white spot syndrome virus?

Maintenance of good environmental conditions.

What is taura syndrome virus?

An icosahedral, non-enveloped virus with a single-stranded RNA genome.

What tissues does taura syndrome virus infect?

Ectoderm- and mesoderm-derived tissues.

What signs indicate infection with taura syndrome virus?

Irregular black spots, reddish body color.

What should the selection of an antibiotic for disease treatment be based on?

Results of an in vitro sensitivity test.

What is Furunculosis?

A serious, septicemic bacterial disease.

What fish does furunculosis mainly occur in?

Salmonid fishes.

What are symptoms of furunculosis?

Crater-like lesions, hemorrhages, lethargy, loss of appetite.

What is another term for enteric septicaemia of catfish?

Edwardsiellosis.

What are symptoms of enteric septicaemia infection?

Multiple hemorrhages, loss of appetite, abnormal behavior.

What antibiotics can help treat enteric septicaemia infection?

Terramycin, Romet, Aquaflor.

What is vibriosis?

An infection caused by many Vibrio species in fish.

What are common clinical signs of Vibrio infection in fish?

Skin lesions, body discoloration, lethargy.

What are prevention methods for Vibrio infection?

Antibiotics, probiotics, and vaccines.

What causes columnaris?

Flavobacterium columnare.

What are symptoms of columnaris?

Sores on gills and body, ulcers that increase in size.

What are two other important fish bacterial pathogens?

Edwardsiella tarda and Aeromonas hydrophila.

Are bacterial diseases more common in crustaceans or mollusks?

Bacterial diseases are not common, except for Vibrio.

Are fungi eukaryotes or prokaryotes?

Fungi are eukaryotes.

What are some examples of fungi?

Yeasts, molds, and mushrooms.

How do fungi reproduce?

Asexually by fragmentation, budding, or sexually by producing spores.

What are the filaments and bodies of fungi called?

Filaments are called hyphae, and the body is called mycelia.