Exotics 2 Flashcards
In terms of population level effects from disease what are the main ones and what lead to and what are the 2 main individual level
Population 1) reproductive rate 2) mortality 3) behaviour/migration -> effect population size -> ecosystem flow on effects (top-down to bottom-up) Individual 1) mortality 2) sub-lethal effects at host level
Ecosystem flow-on effects (Tropic cascades) what are the topic levels in the ecosystem
BOTTOM - producers - plants - primary consumers - herbivores - secondary consumers - carnivores that feed on herbivores - tertiary consumers TOP
Give examples of disease that cause trophic cascades top-down control and bottom-up control
Top-down control: Devil facial tumour disease and effects on small marsupials (increase feral cats as competition with Tassie devils result in decrease in quolls)
- Problems start at the top with carnivores
Bottom-up control: Rabbit haemorrhagic disease and effects on Iberian lynx (iberian lynx dependent on rabbit numbers, crash correlated)
- Problem start at the bottom with producers or herbivores
Chlamydia in koalas what does the lack of disease mean for individual and population levels
- Lack of disease, can lead to overabundance, especially if other controlling factors are missing
○ Present -> body condition worse and reproductive less
○ French Island (Chlamydia free) -> overabundance of koalas - RESULT -> increase in primary consumers (koalas) but also decrease in other animals as decreasing the producers (their feed)
○ Will eventually lead to a crash
What are 7 main factors the predispose rare species to extinction due to disease
- Multiple disease outbreaks in clumped distribution, or very small population in one area
- Slow but lethal -> facial tumour
- Reservoir hosts
- Changes in susceptibility or new pathogen
- Host behaviour
- Other threats already present, stochastic events
○ Fragmentation -> increase inbreeding and therefore population susceptibility as well as possibly resulting in an immunologically naïve population that then when exposed leads to high levels of infection - Disease may also have significant impacts on ex-situ conservation efforts - captive breeding
White Nose Syndrome (Pseudogymnoascus destructans) what is the pathogen, the effect on the bat, location, population and individual level
- Fungus introduced into Norther American -> invades body systems, wings, fur but not the lesions that cause the issue
○ During hibernation in winter -> kept waking up during winter, cannot find food -> maceration -> starvation
§ If survive through winter can then control when warmer weather (fungus prefers colder temperature) - Endemic in Europe but mortality is not found as high there -> possible co-evolution
- Bats -> primary consumers, important for control of insects which is important for agriculture
- HIGH mortality - 90-100% cave dwelling bats
White Nose Syndrome (Pseudogymnoascus destructans) what are the 4 main disease influencing factors and main effect
a. naïve population
b. Population density
c. Hibernation/resource availability is low in winter
d. Temperature - low in winter when cause most issue
CONSERVATION THREAT
Chytrid disease - Batrachochytrium dendrobatidis what species important for, what occurs, what are important factors with individual, population, environment effects
- Southern gastric-brooding frog - NOW EXTINCT due to this
- Extinction of 250 frog species world wide
- Tadpoles become infected, once becomes frogs covers the skin and then they die
- Multiple strains -> highly virulent strains causing the extinction events
○ Thought to come from east asia - Ways for recovery
○ Individual -> innate immune response, adaption to faster maturation, innate or adaptive behavioural fever
○ Population -> disease impact variable across life-stages,
§ BAD -< if reservoir hosts
○ Environment -> environmental refugia - more access to sun when bask, heat tends to kill fungal spores
§ BAD -> environmental optimal conditions for growth of the fungus
Chytrid disease - Batrachochytrium dendrobatidis treatment and main effect
- Treatment
○ Individual -> itraconazole (antifungals for individuals)
○ Population -> biosecurity, increased salinity, lots of invertebrates within the water (ciliates - gobble up fungus)
CONSERVATION THREAT
Toxoplasmosis what is the definitive host, intermediate host and effects
- Cats definitive host
- Intermediate host -> eating animal with cyst OR eating something contaminated with cat faeces
- Can affect ANY warm-blooded but marsupials more susceptible possibly due to not co-evolving with felis
- Accumulate in marine environments in filter feeders - molluscs can affect otters
CONSERVATION THREAT
Tasmanian devil facial tumour when does it first appear, effects and epidemiology
- First appeared in 2005 in Tasmania -> contagious cancer from single female cell
○ Antigens aren’t presented on MCH class I and II - invades immune system - 6+months to live once infected then die
○ Inability to feed due to cancers around the mouth as well as metastasis - SECOND facial tumour now found -> unsure on relationship seems to be different
Tasmanian devil facial tumour what is the main effect and epidemiology
CONSERVATION THREAT
- Epidemiology
○ Affects generally more dominant and healthy animals as generally more aggressive so bite (transmission)
○ Decline in 80-90% in Tasmanian devils
§ Not total crash in the populations -> possible selective pressure resulting in evolution of the population to become more resistant
○ Frequency dependent disease
Sarcoptic mange what species important with, what leads to, prevention and the main concern
- Wombats -> smaller populations can become extinct through this -> can be a conservation threat
- Severe hyperkeratosis as other species but also HIGH levels of numbers - systemic disease, organ failure, maceration
- Earlier stages of disease feasible to treat
- Prevention? -> challenging at the moment only option is flaps on the burrows but need high labour and isolated populations for high effectiveness
○ Need to eliminate every mite -> cannot know how effective the treatment is without skin scraping
ANIMAL WELFARE
Beak-and feather disease (psittacine circovirus) what species found in, how spread, main effects
- Acute death in young birds, older become chronic infections - die or become carriers
- Lots of species of carriers -> rainbow lorikeets
- Generally doesn’t lead to conservation issue UNLESS other pressures on that population
○ Orange belly parrots -> very low numbers less in the wild so loss of a few individuals is significant
Human and livestock health what are the 3 main effects need to consider and describe a disease that effects this one health approach
1) animal health 2) human health 3) ecosystem health
Nipah virus
- South east asia -> people infected straight from pigs - pigs infected from flying foxes that drop half eaten fruit within the piggeries
- Why occur -> move into closer contact with pigs because
○ Habit loss, environmental diseases result in migration towards these areas
What are 3 important ecosystem effects that affect rate of emerging disease
- Changes in biodiversity -> Species richness
○ Dilution effect -> range of host pathogens can choose from but only a few are the best carriers - others will eliminate
○ Amplification effects -> more different hosts and all are good at transmitting disease - INCREASE?
○ Which is it? -> depends on the situation - Increased human/livestock/wildlife interfaces -> greater likelihood of pathogens moving into different hosts
- Indirect effects on disease susceptibility
Give an example of a disease where dilution effect from changes in biodiversity affects rates of emergence
lyme disease carried by a tick -> birds, possums, mice are hosts
□ Mice is the best at carrying the virus -> if have multiple species/hosts then tick go onto that and be eliminated
□ In fragmentated environments increase mice and decrease other species -> increase survival of tick and prevalence
What are 4 main differences in an aquatic environment
- Oxygen availability
- Exposure to waste products and nitrogen cycle
- Temperature and effect on animals
- Exposure to salinity and pH
What are important structures in aquatic animals
- Gills and buccal/opercula pump
- Skin -> living cells, can heal rapidly, IMPORTANT BARRIER TO OUTSIDE WORLD
○ Salt water -> immediately water pulled out will rapidly dehydrate and VICE VERSA in fresh water
§ Will need to work overtime to maintain internal osmotic environment - Swim bladder
- Lateral line -> vibrations in water
- GIT -> very different between species
- Immune system and haemopoietic tissue -> no bone marrow
What is important about poikilotherms and how do tuna and salmon deal with it, what temperature is stressed and why - what to do in this situation
- Metabolism related to water temperature
○ Cannot regulate temp due to Gills -> large surface area for heat exchange straight in contact with water - Tuna -> red muscle on the inside of white muscle (insulated) able to regulate their temperature
- Salmon -> get stressed when temperature above 19 degrees
○ Increase Temperature -> oxygen concentration decrease AND will require more oxygen due to increased stress - DON’T FEED AND DON’T STRESS THEM
Gills function, how achieve what are the 2 main parts of the gill and their structure and function
- Extract oxygen from within the water -> lower concentration generally than air
- Tiny blood vessels -> blood comes into contact with water via membranes and oxygen comes across to haemorrhage
- Gill arch -> has primary filament comes down with secondary lamellae (channel where blood flows through and where capillaries are located) - GAS EXCHANGE SURFACE -> once comes out of water these channels collapse (cannot breathe)
○ Blood flows opposite to the flow of water to optimise gas exchange
○ TUNA -> fusion between primary filaments and tops of secondary lamella - Gill rakers -> protect the gill (act as a sieve water moves through)
- Sit under operculum cover
What are the 3 main types of ventilation with fish gills and the type of fish present within
1) Ram ventilation -> must keep their mouth open and kept moving to get water flowing over gills
○ EG - tuna
§ WHY DOESN’T IT HAVE BOTH -> buccal pump mechanism takes a lot of energy (why tuna doesn’t have) ALSO need space for this muscle so tuna just have bigger gills
2) Pump mechanism -> can sit still and pump water through gills
○ EG - goldfish
3) Combination of both depending on whether moving or not
○ EG - salmon
What leads to disease within a tank/ closed ecosystem
Ecosystem - has a bearing capacity -> temperature, salinitiy, plants, animals, micro-organisms
Added pressure - farming activities, unrelated water activies, land based activities, climate change can change the capacity
RUPTURE
- changes in biotic and abiotic parameters - induced changes in these parameters -> STRESS -> DISEASE
What are 7 common causes of added stresses on aquatic animals
- Temperature -> optimal temperature and quick changes
- Dissolved oxygen -> FIRST THING TO LOOK AT - emergency
- Salinity -> salmon and barramundi need both marine and fresh water
○ Change in salinity can be used to treat amoebic gill disease in Atlantic salmon - Ammonia -> NH3 can become toxic at certain levels (ionised)
- pH -> amount of ionised (toxic) and non-ionised ammonia varies with this
- CO2 -> can affect pH
- Currents
What are 7 additional causes of added stresses on aquatic animals
- Predators - fish not feeding, poor feed conversions
- Suspended solids - river system with flood - dirt wash into the system
- Pollutants/toxins
- Overcrowding
- Handling
- Nutrition
- Treatments - formaldehyde, copper
What are 8 main steps in the examination of a fish health problem on a fish farm and what looking for within
- History
○ Mortality -> rate, is it increasing in rate, are all tanks involved
○ Duration, system, fish (how many, rate), species (if two species on farm are both being affected), clinical signs, water quality
○ Feeding (changes?), handling/grading, any treatments (vaccination) - Site visit
- Examination of a fish as a group
- Examination of individual fish
○ Eating, schooling (fish), colour, alert, gill movements, mortalities, circling, spiralling, flashing
○ Growth rate, food conversion rate, feed storage, smolt quality - Sampling of fish
- Sampling of water
- Laboratory
- Advice +/- treatment
Abalone disease outbreak what species within, mortality, disease agent and transmission
- Abalone are snails -> shallow troughs live within
- Mortality -> 5-90%, significant cumulative mortality, one year old stock appeared worst affected
○ One year old stock appeared worst affected
○ Another pump ashore farm affected - destroyed stock immediately after seeing high mortality
§ No further signs until months later
○ Two other sea based farms affected - Disease agent found to be a herpes like virus
○ Transmissible through water
○ Highly virulent
○ Diagnostic lesions - ganglioneuritis
○ Abalone viral ganglioneuritis - Wild abalone affected in the vicinity of one farm - now spread through wild (or is it simply that we are now LOOKING)
What is important with aquarium environment and what is needed to help with that
The aquarium environment
- Closed environment has consequences -> accumulations of waste, organics, nutrients
- Water is a culture medium - add fish or add nutrient = microbial growth
The aquarium environment
- Aquarium filtration
○ Mechanical -> will get clogged -> need to clean
○ Biological - converts
○ Chemical - absorbs -> certain amount can absorb after this need to change
- Aquarium filter is an expanded aerobic environment for colonisation by Nitrifying bacteria
Describe the ammonia cycle and which ones are toxic and what occurs during detoxification process
Ammonia is broken down by nitrosomonas to Nitrite
Nitrite is broken down into nitrate into nitrobacter
Ammonia and nitrite are toxic
Nitrate isn’t toxic but acts as food for bacteria -> over population so still need to remove
H+ accumulates during detoxification -> pH drops as filter starts to work
Biological filtration what occurs, what can add to it, how to test
- Conditioning period for enough nitrifying bacteria to develop varier (2-6 weeks)
- Can be shortened by inoculating with live gravel -> will already have the bacteria present
- Test kits for ammonia, nitrite, nitrate are available
- Acid shift occurs due to H+ production
- Filters must be kept healthy, clean and aerobic
The new tank syndrome what is involved, how develops and when know that it has been established
THE NEW TANK SYNDROME
- NH3 ammonia
- NO2 nitrite
- NO3 nitrate
New biofilters take several weeks to establish
- NH3 levels rise until Nitrosomonas spp begin to reduce NH3
- As NH3 levels decrease, NO2 levels increase until Nitrobacter establish
- As Nitrobacter spp begin to convert NO2 to NO3 the levels of NO2 begin to decrease and the levels of NO3 increase
TANK THAT HAS GONE THROUGH THE CONDITIONING PERIOD NO AMMONIA OR NITRITE
Ammonia toxicity what varies with, what increases toxicity, why is ammonia more toxic than ammonium and the clinical signs in the fish
- Varier with pH and temperature (need to drop pH with ammonia toxicity)
- High temperature increase toxicity (reduce temperature)
- High pH increases toxicity (at first the tank is often alkaline due to water added so need to wait)
- Ammonia NH3 crosses cell membrane easily and enters cells - more toxic
- Ammonium NH4+ does not cross membrane easily - less toxic
Signs in the fish - Depression, anorexia, dull colours, inflammation, excess slime, cloudy eyes
- Blindness, secondary bacterial disease and death
List some ways to reduce ammonia toxicity
- Stop feeding until have no ammonia
- Dilute -> remove and add new water
- Reduce temperature (reduce gill inflammation -> increase O2 consumption)
- Reduce the pH
- Monitor the ammonia levels
- Conditioned gravel
- Ammonia absorbers (carbons, ion exchange resins) - DO NOT RELY ON THIS BY ITSELF
Nitrite toxicity when occurs, clinical signs in fish and ways to reduce
- generally when filters go anaerobic -> stop producing oxygen -> goes backwards in ammonia cycle
Signs in fish - Gulping for air on the surface -> gills are also brown due to methaemoglobin
- Death - rapid mortality
Strategies to reduce nitrite levels - Water changes daily
- Stop feeding
- Add 0.3% salt NaCl - 3 heaped teaspoons to 10L) - FIXES
- Decrease temperature (increase oxygen concertation in the water)
- Chloride is the antidote
- Conditioned gravel
Nitrate overload what level does it need to be below and what does it result in when gets above it
- Not toxic but need to keep below 50ppm
- Changes water to a microbial broth -> opportunistic infections
- Causes immunosuppression due to high organic loads
○ Nitrates, phosphates, bacteria, debris, protozoa, fungi - High organic levels reduce growth rates and suppress the immune system
○ Many fish diseases are associated with high organic levels
What are 7 causes of ammonia and nitrite problems in the established tank
- Increase in fish size or fish numbers -> can overcome the filters ability to break down the ammonia and nitrite
- Medications
- Acid shift -> if correct pH too much (over 7 for ammonia will lead to toxicity)
- Cleaning or replacing filter beds -> if too aggressive can remove all biological filter
- Debris and detritus
- Cessation of water flow through filter -> leads to anaerobic filter
- Anaerobic filter -> leads to backwards flow of cycle -> production of nitrite - nitrite
List the main types of aquarium filters
internal filters, canister filters, ungravel filters, pre-filter (collects the muck on the intake of the filter before hits the filter -> don’t need to clean the filter as commonly)
Marine aquariums what is present in fish only and reef environments and the pH and temperature in each
Fish only - Can contain dead coral, lava rock, coral rubble and shell grit ○ Temperature 24-27 degrees ○ pH - 8-8.4 - IMPORTANT Reef environments - Can contain live coral, live rock, crabs, shrimps ○ Temperature 24-17 degrees ○ pH - 8-8.4
pH what are the preferred rangers for acidophile, most fish, alkalinophiles, marine and community tanks, how to control the pH
- Acidophile - 6.5-6.8 (tetras, discus)
- Most fish - 6.8-7.4
- Alkalinophiles - 7.4-8 (livebearers)
- Marine - 8.1-8.4
- For community tanks and most shop tanks best to maintain a pH of 6.8-7.0
Acid shifts - pH drops with time
- Must be controlled
○ Partial water changes
○ Filer cleaning
○ Water buffers
○ Neutralizing blocks
○ Shell grit, crushed coral
○ KH-up
General hardness how measured, what increase and decrease with, what levels are considered soft, medium and hard
- Measure of calcium and magnesium
- Increased with
○ Conditioning salts
○ Neutralizing blocks
§ Shell grit, crushed coral - Higher general hardness generally higher pH
- Decreased with
○ Dilution
○ Ion exchange resins
○ Peat moss
○ Remove shell grit, crushed coral - Soft - 50-100ppm (tetras, discus)
- Medium - 100-200ppm (livebearers)
- Hard - 200-500ppm (africans)
What are 7 important aspects of approaching an aquarium problem
1) history
2) water testing
3) fish symptoms
4) faecal exam
5) diet
6) gill biopsies and body scraping
7) post mortems
In terms of approaching an aquarium problem what is involved with history and asking about fish symptoms
- History
○ Aquarium environment must be assess, skill and experience of the client as a fish keeper - Fish symptoms
○ Details symptoms in the fish
○ Which fish are affected and any recent additions - any biosecurity
○ Closure examination of the fish can be achieved in a bag or small tank - however generally very non-specific
○ Microscopic examination of scraping or gill biopsy -> BEST
§ Wet preps are examined immedaitely under the microscope at low, medium and high power
§ Gill inflammation, hypertrophy, hyperplasia and deformity are all easily assessed
§ Parasites, fungi, some viral lesions and bacteria identified
In terms of approaching an aquarium problem what is involved with faecal exam and gill biopsy and body scraping
- Faecal exam
○ Faecal samples may be gently expressed directly onto a microscopy slide or collected at post mortem
○ Fresh wet preps are examined - Gill biopsies and body scraping
○ BEST
○ NOT SPONGE -> place within the net then safe
a. Need someone to handle the net with fish within (will survive for 5 mins within a wet net)
b. Hold fish, net and slide in one hand
c. Gentle scrape with closed scissors
d. Gill biopsy - same closed scissors, lift the operculum and then cut transversely (not feel and will grow back)
e. Removing the filaments from scissors -> tweezers with water to scrap off onto slide
f. Cover slip and look under microscope QUICKLY
In terms of approaching an aquarium problem what is involved with post mortem what occurs straight after death, what needs to be taken and what is important about parasites
○ Undergo rapid autolysis after death therefore PM only for fresh dead or euthanised fish
§ Samples can be taken for wet preps, and microscopic examination
○ For further testing diagnostic laboratories can be used for microbiology and histopathology
○ External parasites do not stay on dead fish for long, so for parasite investigation it is best to take gill biopsies
Anaesthesia and surgery for fish, what tanks are needed, medication, sedation and anaesthesia dosages
Induction -> induction tank
- Alfaxan anaesthetics injection - 10mg/ml
- Sedation 1-2mg/L
- Anaesthesia 1.5-4mg/L
Recovery tank -> water moving within and generally recover within 10mins
What are the 3 main options for fish euthanasia and which is the best
- Cutting with scissors at the back of the fish head just behind the eyes - BEST WAY
- Larger fish are stunned hitting on the back of the head with a club or waddy and then dispatched by cutting their throats
- Intramuscular or intraperitoneal injections of lethabarb and can be given to euthanize fish
○ If do this cannot send to the lab
FIsh post mortem what are the 3 main cuts
- Cut along the ventral abdomen
- Cut along dorsal abdomen wall
- Cut remove flap
What are the 8 main nutritional fish diseases
- Overfeeding
○ Need to observe the fish eating the food -> should be gone within 30 seconds - Starvation
○ Small fish may not get the food, less dominant
§ Feed a mix of sinking and floating food -> enable others to get food
○ Could be nocturnal feeders -> catfish only feed in dark - Saturated fats
○ Fish fats are unsaturated
○ Mammalian fats are saturated fats therefore if feed fish red meat will accumulate - Vitamins
○ Vit E disappears first within the food
○ Fish food needs to be fresh -> at most 3 months - Minerals
○ If too much calcium stops zinc from being absorbed -> too high general hardness - Spoiled food
○ Mycotoxins (fungal spoilage) of the food - Indigestible food
○ Blood worms -> exoskeletal is indigestible -> discus bad - Freezing food
Gas bubble disease when occurs, why and signs
- Super saturation of dissolved gas in water
- Faulty power filters
- Signs include
○ Gas bubbles in the eyes
○ Frantic darting
○ Sudden death
○ Erosion of fin tips
Parasitic disease in fish what are factors favoring parasitic disease within a fish farm
- High population density
- High organic loads
- Cannibalism - if see fish about to die remove from the tank
- Live foods
- Immunosuppression
- Stress
- Young fish
Parasitic disease in fish symptoms and diagnosis
Symptoms - Scratching - Slime changes - White spots - Erosions - Ulcers - Increased gill rates - Swollen inflamed gills - Colour changes - Anorexia - Lethargy - Death - NON-SPECIFIC Diagnosis - Based on gill biopsy and body scraping
ICHTHYOPHTHIRIUS MULTIFILIIS - white spot what species present in, where infect, results and diagnosis
- Multiplies rapidly
- Infects skin and gills
- Tissue damage, erosions, ulceration
- Irritation and itching
- May die before white spots develop
- Wet prep under microscope - distinctive rolling, creeping movement and rapidly beating cilia are seen
- Spherical, fully covered with cilia, horse show nucleus
CRYPTOCARYON IRRITANS - marine white spot lifecycle, results and effects on tissues
- Lifecycle similar to ICH
- Usually produces erosions and ulcers rather than white spot
- Microscopically similar to ICH
Drill into the tissues -> penetrate and grow and ultimately they burst out - about 1mm in size
Temperature dependent - warm takes 3-4 days and in cool take can stop
Spiracle, rotates and penetrates - Can see it moving
Parasites in fish what are some treatments
- Formalin and malachite green
- Copper
- Protozin
- Water change, gravel and filter cleaning
- Increasing water temperature -> treatment only works before penetration (want lifecycle moving along and repeat treatment based on lifecycle time at the temperature)
- Salt bath -> removal external protozoa
- Commercial white spot cures
- Hyposalinitiy for marines
Ichthyoboda necator “costia” what is it, what result in and diagnosis
- Fresh and marine fish parasite
- Increased inflammation and slime production, skin and gills
- Erosions and ulcers
- Itching and rubbing
- Diagnosis by gill biopsy and body scraping
- Wet prep under the microscope - parasite flickers, vibrates and has jerky movements
- Very small, same size as RBC
Ichthyoboda necator “costia” treatment
- Formalin and malachite green ○ Water change, gravel and filter cleaning - Salt - Copper - Protozin - White spot cures
Chilodonella (fresh water), brooklynella (marine) what is it, what results in, diagnosis and treatment
Fish parasites - Irritation, inflammation of skin and gill - Excess slime - Wet prep under the microscope - characteristic creeping, gliding movement - quite flat - Has a flattened shape Treatment - Change water before treat - F/Mg - Copper - Salt - Commercial white spot cures
Trichodinids what is it, when occur, diagnosis and treatment
- Fresh and marine systems - fish parasites
- Occurs with high organic load
- Wet prep under the microscope - darts and zooms
Treatments - F/Mg
- Salt bath (fresh)
- Freshwater bath (marine)
- Improved water quality
Tetrahymena (fresh water) Uronema (Marine) what is it, what leads to, diagnosis and treatment
- Free living opportunist ○ Induced by high organic loads - Some can be invasive - penetrate - Wet prep under microscope - motile and fast Treatment - Improved water quality - CLEAN FIRST - F/Mg - Protozin - White spot cures
Dinoflagelates oodinium “velvet” what systems present within, what results in and treatment
- Fresh and marine systems fish parasite
- Gill damage, excessive slime
- +/- fine dusting of spots
- Highly infectious - droplet transfer very quickly
- Lethargy
Treatment - Copper
- Acriflavin and quinine
- Salt
- Remove dead fish - multiplies like crazy on dead fish
- Salt baths/freshwater baths
Monogenetic trematodes Gyrodactylids (body fluke), dactylogyrids (gill flukes) what results in and treatment
- Fresh and marine systems parasite ○ Non-symptomatic carriers are common ○ Occurs with high organic load ○ Itchy inflamed body and gills Treatment - Clean the tank - reduce organic loads - Organophosphates - generally resistance is high - Praziquantel - very effective Salt baths/fresh water baths - very effective
Digenetic trematodes species, what results in, lifecycle, diagnosis, how common and treatment
- Produce cysts embedded in the body tissues and gills
- Complex lifecycle requiring intermediate hosts
- Wet prep under the microscope
○ See fluke in the cysts -> differentiate from white spot - Uncommon
Treatment - Praziquantel
Nematodes in fish, name 2 that cause disease, clinical signs and diagnosis
- Most don’t cause disease
- The following two are common and are pathogenic
a. Camallanus -> small red worm protruding from anus
§ Other fish will think that worm is food -> direct lifecycle this way
b. Capillaria
§ Cause anorexia, wasting and death
§ Diagnosis on post mortem gut preparation - see eggs under microscope
Nematodes in fish what are the 2main treatments to use and which one you don’t use
- Ivermectin (Ivomec liquid for sheep) 0.8g/L = 800mcg/ml
○ Add water at 0.05ml/20L and repeat in 48 hours - DO NOT USE IVOMEC FOR CATTLE
- Fenbendazole (panacur 100) 2.5ml/100gm of food for 3-5 days, repeat in 2 weeks
Crustacean parasites in fish name the 2 common ones
1) Argulus (fish lice)
2) lernaea (anchor worm)
Argulus (fish lice) what are they, effects, transmit and treatment
- Crab like parasites visible to the naked eye
- Irritation, ulcers secondary infections
- May transmit bacteria, viruses and blood parasites
Treatment - Ivermectin (IVOMEC FOR SHEEP 0.8gm/L, dose at 0.05ml per 20 L and repeat in 48 hours)
- Organophosphates
- Salt baths
Lernaea (anchor worm) what fish found in, diagnosis, effects and treatment
- Occurs in freshwater, marine fish and axolotls
- Seen embedded and protruding from the fish
- Raised bleeding ulcers
Treatment - Ulcers with melafix
- Ivermectin in the tank (IVOMEC for sheep) - 0.05ml per 20L repeat in 48 hours
- Trichlorofon tablets
What are the 3 main internal protozoa of fish
1) Hexamita
2) Myxosporidia and microsporidia
3) amoebic gill disease
Hexamita what are they, what lead to, diagnosis, how common and treatment
- Part of normal gut flora but can over grow
- Wasting, slimy trailing faeces, death
- Wet prep under the microscope will see flagellated protozoa
- Uncommon -> if only see 1 or 2 normal
Treatment - Metronidazole - in feed at 1% for 7-10 days
○ Dose in water 20mg/L repeat in 7 days
Myxosporidia and microsporidia what are they, diagnosis, how spread and treatment
- Common parasites in the wild
- Cysts, lumps, white muscle patches, milky fresh
- Wet preps of lesions under microscope - see refractile bodies
- Spread by cannibalism
Treatment - None effective
- Control by removing dead and diseased fish
- Gravel and filter cleaning
Amoebic gill disease what caused by, what locations occur, effect on host, predisposing factors, diagnosis and treatment
- Neoparamoeba perurans
- Occurs in marine aquariums and in farmed salmon.
- Produces inflammation and necrosis of the gills.
- Opportunistic Infection.
- Predisposing factors
○ warm water and high stocking rates : Immunosuppression
○ high organic loads - Diagnosis
○ gill biopsy - Treatment
○ Fresh Water Bath
○ Reduce organics.
Fish bacterial disease what are some predisposing factors and diagnosis
- Predisposing causes of bacterial disease
○ High organic loads
○ Parasites
○ Poor nutrition
○ Poor water quality
○ Handling, transport,
○ Extremes of temperature - Diagnosis through ruling out other causes
- Obtaining bacteria for culture and sensitivity testing
- Swabs are taken from kidneys of fresh killed fish for analysis by a veterinary laboratory service
Fish bacterial disease what are some common symptoms
○ Ulcers, fin erosion ○ Haemorrhage and inflammation ○ Distended abdomen ○ Exophthalmia (pop eye) ○ Colour changes ○ Lumps ○ Wasting ○ Buoyancy problems
Columnaris disease what species, what caused by, in what environment, effects, diagnosis and treatment
Fish - Caused by Flavobacterium columnare - Fresh and marine fish - Causes necrosis of skin, gills and mouth - Can produce ‘saddle patch’ lesions - Lesions may have filaments –‘cotton wool’ - Rapidly fatal - Can be confused with fungal infection - Wet prep under the microscope ○ rule out fungal infection Treatment - Antibiotics - Salt - Improve water quality - Melafix
Neon splitting disease what is it caused by, effects on host and treatment
- A specific form of Flavobacterium columnare infection in Neons ○ The bacteria is already in the tank - Rapidly spreading and fatal disease - Pale midbody patch that expands and may cause the fish to split in two - Death occurs in 1-3 days -> clean tank and make sure all dead removed before antibiotics as act as a reservoir - Lesions are characteristic Treatment - Improve water quality - Soft acid water, pH 6.5 - Melafix may help - Doxycycline 5mg/litre - Repeat in 5 days
Fin rot what caused by, predisposing factors, diagnosis and treatment
- Caused by many bacteria including Aeromonasand Pseudomonas
- Predisposed by poor water quality, high organic load
- Could be scratching there
- Diagnosis by ruling out protozoa and fungi with microscope wet preparations
Treatment - Improve water quality -> FIRST OPTION (generally occurring with an old tank)
- Melafix
- Salt bath -> GREAT
Antibiotics in feed or water
Fish tuberculosis what is it caused by, effects on fish, diagnosis and treatment/control
Mycobacteria
- Weight loss
- Lumps -> diagnostics via microscope
- Internal nodules
- Death
- Wet preps of lesion under the microscope
○ see granulomas
- Lab tests required to confirm diagnosis
Treatment & Control
- Granulomas will not respond to treatment -> need to cut them out
- Kill affected fish and clean up environment -> will be in the tank
- Avoid cannibalism
- Keep water temperature below 27 Celsius
- IS ZOONOTIC
Septicaemia in fish what age common in, prediposing factor, effects, diagnosis and treatment
- Common in young growing fish
- High organic loads
- Sudden death, haemorrhagic inflammation of body and fins, bloated abdomen, protruding eyes, ulcers
- Post mortem kidney swabs sent for bacterial identification
Treatment - Improved environment
- Antibiotics
- Melafix, Melafix/Pimafix
Ulceration in fish where can occur and cause
- Ulcers can occur at the site of sensory canals and pores, located on the head and the lateral line
- When this occurs on the head the lesion is called ‘hole-in-the-head’
Cause: - Opportunistic bacteria are the main cause -> when nitrates are too high -> overgrowth of the bacteria
○ High organic loads (high nitrates) - Vitamin C and E deficiency
Ulceration in fish prevention and treatment
Prevention
- Maintain water quality -> DECREASE NITRATES
- Good nutrition
- Low nitrates
Treatment
- Improve water quality -> if nitrates around 20 ulcers will often heal (long duration)
- Antibiotics and metronidazole in food - need to use for 30 days
○ Try this last
- Melafix, Pimafix, Black Water Extract can help
What is the main fungal disease in fish, look on fish, associated with, diagnosis and treatment
Saprolegnia
- Ubiquitous
- Woolly filaments on the skin.
- Associated with high organic loads, injury and stress.
- Post mortem -> fluffy around dead fish
- Wet preps of lesion under the microscope
○ see broad, non-septate hyphae
Treatment
- Improved environment
- Salt baths
- Salt in tank
- Pimafix - will kill fungus, will not hurt the plants
- Fungal Cures
What are the 2 main viral diseases of fish, what result in terms of appearance, effects and diagnosis
- Lymphocystis
- Iridovirus: produces massive cytomegaly
- White firm rough nodules up to 1cm across on fins, body and mouth
○ Generally not an issue unless obstructive (eye, mouth, cloaca)
- Can be non-symptomatic carriers
- Lesions may regress and fall off
- Wet preps of lesion under the microscope –see very large cells with large nuclei
What are important government services that work with quarantine/biosecruity for fish and what is important
- Australian Quarantine and Inspection Service working with Biosecurity Australia are doing PCR testing.
- Cost, and numbers tested per batch, are major concerns for the Ornamental Industry.
- They are doing Random Testing for Gourami Iridovirus, Spring Viraemia, and Aeromonas Salmonicida.
- Tests are done in Sydney. They are also reviewing quarantine.
- Recent Import Risk Analysis has led to Revised Quarantine Measures.
- Cichlids, Gouramis and Poeciliids (livebearers) must be batch tested negative for Iridovirus (Megalocytovirus) prior to export. Begin 1/ 3/ 2016.
What are the 2 ways to medicate feed with fish
- medicate feed
1) using oil to “lock in” medication - locks treatment into the food
2) oil coating the feed - in water medication
List the steps in using oil to lock in medication when medicating fish
○ Mix good quality flake and/or pelleted fish food with water. Work into a `putty-like’ consistency.
§ Flour at 5% may also be added
○ Add 5% vegetable oil or cod liver oil or a combination of both.
§ Cod liver oil increases palatability and acceptance.
○ Add medications and mix well
○ The food can be fed by breaking into pieces or rolling into balls.
§ It can also be frozen and then be grated directly into the aquarium
List the steps in using oil to coat the feed for medicating fish
○ Add 5% cod liver or vegetable oil to a measured amount of food and mix
○ Medication is mixed with the oil first
○ Freeze and use within 3 months
§ Works well with Crumble and Pellets
○ The food is coated with medicated oil and retains its shape and size
List 4 things that can be used as an antibiotic for fish
- Melafix®
- Pimafix®
- Black Water Extract®
- Salt
○ 0.15-0.2% in tank
○ 1.5-2.5% Salt Bath (Up to 10 mins, aerate &observe, remove if roll or very stressed)
In terms of salt (sodium chloride) at concentrations of 1. 0.1-0.25, 2. 0.3, 3. 2-2.5 what are the effects on fish
- 0.1-0.25%
○ general tonic
○ antibacterial and antifungal
○ aids osmoregulation
○ adverse effect on many protozoa
○ long term exposure at greater than 0.15% is not tolerated by most plants. - 0.3%
○ to treat nitrite poisoning - 2.0-2.5%
○ Salt baths for 2-10 mins with strong aeration, must observe fish closely and remove quickly if they roll or are very stressed.
○ Will remove all external parasites except Lernaea
○ Destroys external fungi
○ Can use fresh water baths for marine fish (2-5mins)
in terms of grams how much is 1 heaped teaspoon, level teaspoon, cup and 2.5%
1 Heaped Teaspoon = 10 gm
1 Level Teaspoon = 5 gm
1 Cup = 250 gm
2.5% = 250 gms/10 litres -> 1 cup
In terms of using antibiotics what is important and which products don’t you need a vet for
Diagnose first! - Rule out environmental factors first - Parasites? Use the right products! - Nutrient Carriers? - Dose? Label must have full directions. - Tetracyclines and Triple Sulpha are open sellers - Biological filter is unaffected - Other Antibiotics are Veterinary prescribed and labelled
Paint pigments in fish what does it lead to and what has resulted from
Immune system, renal and hepatic system issue
- NOW BANNED FROM ENTERING AUSTRALIA -> painted glass fish (paint is toxic)
List the 5 main differences between farm and wild population outbreak investigations
1) is there an outbreak
2) determining who is affected
3) finding out when the outbreak started/finished/recurring
4) what is the infectious cause
5) management of that disease
in terms of is there an outbreak with outbreak investigation what is the differences between farm and wild populations
○ FARM -> Know herd size, mortality rate and production rate
§ Able to examine the live animals -> clinical examination
○ WILD -> don’t know population size, mortality rate, duration of signs -> may not know the mortality is occurring until large mortality is present
§ Much more difficult to clinical examine the live wildlife
in terms of determining who is affected with outbreak investigation what is the 2 main differences between farm and wild populations
1) Scavenging rate varied significantly with wild -> may not find the dead
§ FARM -> scavenging not an issue for larger cattle, sheep etc.
§ WILD -> passerine or small animals are scavenged within the day -> mortality rate would be lower than
2) Detection rate varies significantly
§ FARMS ->have access to all animals AND KNOW THE NUMBER AFFECTED
§ WILD -> being able to find the wild animals affected is not very sensitive -> ecology and habitat
in terms of finding out when outbreak finished/started and management of disease with outbreak investigation what is the main differences between farm and wild populations
Finding out when the outbreak started/finished/recurring?
○ FARM -> farmer observing the herd can tell from the day when started, if still finding deaths if this occurred before
○ WILD -> generally no one observing population daily so
Management of that disease
○ FARM -> have access and CONTROL over the animals, money provided by farmer
○ WILD -> may not have access
in terms of finding the infectious cause in outbreak investigation what is the main differences between farm and wild populations
○ FARM -> generally have more information surrounding history, clinical signs, duration, experience with species and diseases
§ BOTH DO POST MORTEM
○ WILD -> lack of reference values with diagnostic tests, lack of experience with the species, lack of knowledge of normal for individual species
§ DO POST MORTEM -> but quality could be reduced as done in the field and been dead for longer
Outbreak detection what are the 6 main important features
1) mortality events (mass vs small scale) OR sub-lethal disease
2) who
3) when
4) where
5) what
6) why
In terms of who with outbreak detection what are the 3 main questions and how to answer in wild populations
○ Species -> single vs multiple
○ How many animals are affected
§ Detection of wild animals is not very sensitive -> will miss some animals
○ What is the prevalence, i.e -> impact?
§ Counts
□ Animal -> often a sample and extrapolate that for the total area
□ Index -> count trails, faeces
§ Mark/capture technique
□ Go out and capture and mark all you catch
□ Come back later and re-catch and then see how many you caught were marked
□ Use this to find population size = n (number caught second time) x M (number marked)/ m (number marked that recaptured)
□ Assumption -> equally likely to capture all animals in the area, that population size doesn’t change between captures
In terms of when with wild outbreak investigations what are the 4 main questions and what to construct that would answer some
○ When did the outbreak start?
○ Has the outbreak finished
○ Is it single or recurring, seasonality?
○ Can we construct epidemic curves?
§ Clue to transmission
§ Significance for longer term management
§ Point sources -> large spike and then decline
§ Bi-modial curve -> incubation area
In terms of where with wild outbreak investigations what are the important questions, what need to combine with
○ Geographical location § How do you find out? § Small vs large scale □ Small -> walk around with GPS □ Large -> helicopter/ fly over § Mud map vs GIS § Active vs passive surveillance ○ May need to be combined with “When” § Travelling waves vs diffuse transmission § What population got infected when? ○ Which and how many populations are affected? § Clues to aetiology □ Point source □ Transmission characteristics ® E.g. Presence of vectors/reservoirs/intermediate host □ Environmental factors - Important conservation implication
In terms of what with wild outbreak investigations what is the main questions, how to answer and limitations for wildlife
WHAT is the cause of the outbreak?
§ Infectious vs non-infectious
§ Pathogen?
○ Necropsy and sample collection are Essential AND don’t forget your PPE!!
§ consider carefully what samples and how to store
○ Limitations in wildlife:
§ time since death
§ knowing what’s normal
§ diseases affecting that species
§ validity of diagnostic tests
§ interpretation?
○ TALK TO PEOPLE
§ Local government vet - agriculture victoria
§ Wildlife health australia -> government
§ Talk to clinical pathologist -> know samples needed
In terms of why with wild outbreak investigations what is important factors to consider
§ Environment, host and pathogen interaction
§ Changes in host, pathogen, environment
□ Habitat loss -> immunologically depressed, climate change, urbanisation
□ Pathogen -> pathogenicity - virulence change, mutation, host changes
□ Host -> co-infection, added stresses
