Amphibians Flashcards

(53 cards)

1
Q

amphibian skin
- what can they do through their skin

A
  • They breathe through their skin!
  • They drink through their skin!
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2
Q

amphibians use their eyes to help with what physiological function?

A
  • swallowing
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3
Q

many amphibians can change their colour to match…

A

their surroundings!

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4
Q

amphibian RBC size

A

They have the largest red blood cells in the animal kingdom!

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5
Q

some amphibians can do what with their stomach if they eat something bad

A

Some amphibians evert their stomach to clean it if they eat something toxic or undesirable!

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6
Q

Amphibian Taxonomy
- how many
- categories

A
  • Over 7,000 species
    <><>
  • Gymnophiona (caecilians)
    > More common in zoological collections, not usually pets
    <><>
  • Caudata = Urodela (salamanders, newts, sirens)
    > Metamorphosed adults of salamanders are highly terrestrial
    > Adult newts are aquatic
    > Neotony = mature sexually despite the external
    <><>
  • Anuran (frogs, toads)
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7
Q

Common amphibian Species in Practice

A

Axolotl
Pixie frog
African clawed frog
Fire belly toad
American bullfrog
Treefrog
Northern leopard frog
Poison dart frog

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8
Q

External Anatomy
* Caecilians:

A

snake-like body with a short tail (or no tail)

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9
Q

External Anatomy
* Salamanders:

A

lizard-like body, covered in glandular skin, lack claws on their digits, laterally flattened tail, have four limbs (except for sirens)
* External gills may or may not be present

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10
Q

External Anatomy
* Anurans:

A

tail-less as adults, glandular skin may be smooth or have protuberances, absent external gills, webbed/unclawed digits, longer pelvic limbs than forelimbs

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11
Q

Normal Things that Appear Abnormal
External anatomy features:
- parotid glands
- Nuptial pads
- Mental glands
- Swollen cloacal lips
<>
- what are these things?

A

-Parotid glands: caudal to the eyes, can contain toxins
- Nuptial pads: on males, more prominent in the breeding season
- Mental glands: underneath the chin of males in some species
- Swollen cloacal lips: in male salamanders, more prominent in the breeding season

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12
Q

Amphibian skin is unique and one of the most important organs
* Functions:
<>
- drink patch?

A
  1. Respiration
  2. Water balance
  3. Communication
  4. Defense
    <><>
    * Drink patch = modified area of the pelvic ventrum where up to 70-80% of the water intake in anurans occurs
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13
Q

Digestive tract feautures
- length
- teeth
- tongue
- feces
- stomach

A

Digestive tract – short and simple
* Teeth: variable by species
> Caecilians – multiple rows
> Anurans – only some species have them
* Tongue – attached rostrally (caudal in most mammals) and flips out
* Feces often contain undigested parts (chitin, keratin, bones)
* Some anurans can evert their stomach and wipe the mucosal surface with their forelimb to remove toxic or indigestible substances

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14
Q

Cardiovascular system
- contains what type of hearts?
- typical amphibian heart structure

A

Lymph hearts
* Multiple beat in synchrony at ~50-60 beats/min
* Composition is the same as blood without red blood cells
<><>
Typical amphibian heart
* 2 atria, 1 ventricle
* In larval form – 1 atria, 1 ventricle > during metamorphosis a septum forms to create 2 atria

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15
Q

amphibian modes of respiration?

A

Multiple modes of respiration – main are cutaneous, pulmonic, and buccopharyngeal; some species also branchial (gills)

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16
Q

amphibian Anatomy and Physiology
- renal portal
- RBC
- Kidneys and nitrogen excretion

A
  • Renal portal system (like reptiles)
  • Very large red blood cells in small
    numbers
  • Kidneys and nitrogen excretion
    > Aquatic: typically, ammonia
    > Terrestrial: urea (ureotelic) or uric acid (uricotelic)
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17
Q

Physiology of amphibians - how do they maintain body temp

A

Poikilotherms = rely on a combination of environmental heat and adaptive behavior to maintain a preferred body temperature

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18
Q

amphibian hisbandry
- temp
- humidity
- water loss

A

Preferred optimal temperature zone (POTZ)
* Require a “temperature gradient” to allow normal thermoregulation
<><>
* Permeable skin = desiccation a threat to survival
<><>
Activities and ranges are limited due to greater evaporative water loss compared to other terrestrial vertebrates
* Most captive species require a relative environmental humidity of > 70%
* Remember this in the clinic, and during exams!

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19
Q

Husbandry of amphibians
- lighting

A

Full-spectrum UV light
* Position ~25-45 cm from amphibian
* Gradual dimming if possible
* In general, use a 12hr/12hr day/night cycle

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20
Q

Husbandry of amphibians
- water quality, toxins

A
  • Essentially the same as for fish
  • Toxins: high levels of ammonia, nitrites, heavy metals, pesticides, disinfectants, chlorine, chloramine can lead to cutaneous and systemic signs
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21
Q

amphibian nutrition and eating habits
- adults?
- larvae
- BCS?

A

In general, all adult amphibians are carnivorous, and usually swallow their prey whole
* Challenging to feed insects in captivity due to a lack of variety
* Most invertebrates have a markedly inverse Ca:P ratio
> Exceptions: soldier fly larvae, pinhead crickets, earthworms
* Gut loading AND dusting (vit A supplementation, etc.) is essential
* Don’t leave prey items in the enclosure
<><>
* Larval amphibians vary – some are herbivorous
<><>
* Assess body condition score (BCS) and weight regularly

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22
Q

amphibian physical exam
- considerations, cautions for handling

A
  • Remember their unique skin – use caution when handling
  • Safest choice for handling is nitrile gloves, NO powder
  • Can use a moist paper towel to wrap the patient for short manual restraint or medication administration
23
Q

Physical Examination
- how to assess skin, etes, mouth, heart

A
  • Evaluate skin and eyes carefully – can use a guitar pick or old credit card to open the mouth
  • Doppler to assess heart rate
24
Q

what parameters to look at for water quality during amphibian physical exam

A

pH Ammonia (un-ionized) (<0.01 mg/L) Alkalinity (20-100 mg/L)
Nitrite (<0.1 mg/L)
Nitrate (0-5 mg/L)
Hardness (75-100 mg/L)
Dissolved oxygen (> 5 mg/L)

25
Clinical Techniques for fluid admin in amphibians
* SQ route effective in anurans only > Skin tightly adhered in caecilians and salamanders * Intracoelomic is an alternative option * Oral fluids: absorption of water from GI tract negligible in most species * Shallow water soaks are effective – utilizes the drink patch
26
Clinical Techniques - osmolarity - fluid recipes - renal portal?
* Osmolality is lower than in mammals, so typical fluid types are not appropriate * Amphibian Ringer’s recipes > 2 parts 5% dextrose + 1 part 0.9% NaCl > 7 parts 0.9% NaCl + 1 part sterile water * Injections and effects of the renal portal system??
27
Venipuncture - site - anticoagulants - lymph contamination?
* Site depends on species/size * Lithium heparin: anticoagulant of choice due to EDTA hemolysis in some species * Lymph contamination possible from many sites <><><><> * Femoral: may require sedation or anesthesia * Ventral abdominal: large in size, but challenging to hit (rolls); forms hematomas * Lingual: limited to large amphibians * Ventral coccygeal: readily accessible in salamanders * Jugular: lies between the tympanic region and the shoulder * Facial, musculocutaneous: recently described, no lymph contamination
27
Radiographs for amphibians - sedation - positioning methods - view
* Often performed without sedation or anesthesia * Plastic bags or moistened foam blocks for positioning * Use horizontal beam for lateral view
28
Ultrasouns for amphibians - quality - relaxation
* Improved image quality if the patient is placed in water (like fish) * Placing a branch in the water may help arboreal species to relax
29
CT/MRI in amphibians - useful?
Can utilize, but may need them to be micro due to patient size
30
Anesthesia for amphibians - drugs, route - what shouldnt be used?
* Alfaxalone IM (variable results), MS-222 immersion (works great), sevoflurane topically <><> * Mixed results with propofol IM, sevoflurane/isoflurane immersion * Not recommended: eugenol IM and immersion, propofol immersion, isoflurane jelly mixture
31
Anesthesia in amphibians * Assessing planes of anesthesia
* Righting reflex * Loss of withdrawal reflex, corneal reflex, superficial pain, deep pain, limb adduction
32
Anesthesia * Intubation and intermittent positive pressure ventilation > considerations
Intubation and intermittent positive pressure ventilation * Short, small trachea that bifurcates quickly into main bronchi = careful intubation * Delicate pulmonary tissue = use caution not to overinflate the lungs
33
Analgesia for amphibians * Pain responses
* Decreased activity, swiping of back with pelvic limb, decreased appetite, skin color change, hunched posture, eyes held closed
34
Analgesia in amphibians - options
* Options – evaluated in very few species * Dexmedetomidine SC – provides analgesia as in mammals, but without notable sedation (VERY high doses) <><> Opioids – most studies evaluate μ receptors, VERY high doses * Morphine 100 mg/kg * Buprenorphine 50 mg/kg * Butorphanol 0.5 mg/L also appeared to provide analgesia <><> * NSAIDs – most studies evaluate meloxicam, shown to have some efficacy
35
Amphibian Infectious Diseases: Viral – Ranavirus > type of virus > geographic spread, effects >when susceptible > transmission
* Large, double-stranded DNA virus; OIE reportable disease * Found on most continents, but the majority of mortality events have occurred in North America > Die-offs in wild populations of frogs, toads, tiger salamanders > Inbred populations have higher mortality * Most susceptible to disease during, and immediately after, metamorphosis * Transmission: water, sediment, cannibalism of morbid/dead individuals, direct transmission
36
Infectious Diseases: Viral – Ranavirus - clinical signs
CS: erratic swimming, lethargy, anorexia, buoyancy problems, erythema of limbs/ventrum, swelling of limbs/body, cutaneous erosions
37
Infectious Diseases: Viral – Ranavirus - Dx - Tx
* Dx: not possible from clinical signs alone – use PCR on liver, kidney, skin * Tx: supportive care only – decrease stress, increase the temperature to the high end of POTZ
38
Infectious Diseases: Bacterial General - most common types that cause issues? - normal flora? - typically assoc with?
* Gram-negative aerobic or facultative anaerobic are the most common * Normal flora in healthy captive amphibians = Aeromonas sp., Proteus sp., Escherichia coli <><> Typically associated with immunosuppression secondary to * Stress – poor husbandry, shipment, hibernation * Concurrent diseases – iridovirus, Batrachochytrium dendrobatidis
39
Infectious Diseases: Bacterial General - clinical signs > general > Bacterial dermatosepticemia > Mycobacteriosis
CS: erythema, ulceration, hemorrhages, edema * Bacterial dermatosepticemia = “red leg syndrome” = any generalized bacterial infection in amphibians * Mycobacteriosis = military lesions, gray nodules of skin and internal organs
40
Infectious Diseases: Bacterial General - Dx - Tx
* Dx: culture (blood and coelomic fluid, if present), CBC, PCR * Tx: systemic AND topical antibiotics, soaking in amphibian Ringer’s
41
Infectious Diseases: Bacterial Mycobacteriosis - bacterial species - cause disease in what anatomical locations - found where in environment
* Species: Mycobacterium avium, M. marinum, M. fortuitum, M. xenopi, M. ranae, M. chelonae, M. liflandi, M. ulcerans * Often disease of the integument, secondary to dermal wounds * Ubiquitous bacteria
42
Infectious Diseases: Bacterial Mycobacteriosis - clinical signs
Miliary lesions/ multiple gray nodules of * Skin: digital tips, digital webs, lips, mouth, +/- hindlimbs * Internal organs: liver, spleen, respiratory tract (mucopurulent nasal and oral secretions), intestines, and kidney (if lesions on hind limbs secondary to lymphatic spread) <><> * +/- weight loss despite good appetite, emaciation
43
Infectious Diseases: Bacterial Mycobacteriosis - Dx - Tx - Humans?
* Diagnosis: culture, acid-fast,PCR * Treatment: euthanasia of infected individual + cage mates * Zoonotic
44
Infectious Diseases: Fungal Batrachochytrium dendrobatidis - significance - life cycle
* OIE reportable disease, aka chytrid * Responsible for widespread amphibian die-offs around the world > Amphibians are the only vertebrate group affected by this organism * Life cycle: motile zoospores (infective stage) attach to the epidermal layer and penetrate the stratum corneum > forming zoosporangium with a discharge tube that allows escape of the zoospores when the cap is lost > Complete in 4 days at 62-72 F, dies at 90 F > Transmission: contact water with zoospores
45
Infectious Diseases: Fungal Batrachochytrium dendrobatidis - clinical signs
CS: excessive shedding, hyperemia of skin * Digits and drink patch are FIRST – contact substrate the most * Affects keratin
46
Infectious Diseases: Fungal Batrachochytrium dendrobatidis - Dx - Tx
* Dx: unstained skin smears, histo, PCR * Tx: no one treatment fits all – itraconazole, increased temperature, terbinafine, chloramphenicol
47
Infectious Diseases: Fungal Batrachochytrium salamandrivorans - significance? - infects what cells? vs Bd? - effects? - thermal range?
* Emerging disease * Infects epidermal cells  skin ULCERATION with significant destruction of the epidermis * Contrast to Bd – causes hyperplasia and hyperkeratosis * Mass mortality and population decline in European salamanders * Thermal range 10-15C (lethal 25C)
48
Trauma in amphibians - most common? - other common ones? Tx? - amputations, strategy?
* Rostral abrasions most common * Lacerations, foot abrasions also common > Acute Tx: debride, topical antibiotics > Chronic Tx: aggressive debridement, culture * Traumatic amputations, skeletal fractures > May require debridement, external coaptation, amputation (in the case of fractures)
49
Edema Syndrome - what is it, what is it often due to - Dx - Tx
* Often due to an infectious process that affects water homeostasis, but also ovarian neoplasia, hepatic failure, renal failure, malnutrition, osmotic imbalance, hypocalcaemia * Dx: evaluate fluid microscopically, perform chemistry on fluid, blood work, culture * Tx: antibiotics, supportive care, focus on underlying cause (when possible)
50
Nutritional Secondary Hyperparathyroidism in amphibians - how common? - etiology? - clinical signs - Dx - Tx
* Second most commonly reported nutritional disorder * Etiology: imbalance of dietary Ca, P, D3 * CS: mandibular deformity, abnormal posture, scoliosis, reluctance to move, fractures, SQ edema, prolapses (gastric, rectal, cloacal) <><><> Dx: radiographs, +/- blood work * Thin long bone cortices, angular limb deformity, pathologic fractures * Calcium and phosphorus can vary a lot, but if they are both low, it is supportive <><><> * Tx: calcium, vitamin D3
51
Short Tongue Syndrome - etiology - clinical signs - whats the name from? actual cause
* Etiology: hypovitaminosis A * Clinical signs: able to sight and target prey, but unable to prehend the food * The name comes from the old belief that the tongue was too short and that was why they could not eat their prey * ACTUAL cause – squamous metaplasia of the lingual glands > lack of sticky mucous on the tongue > unable to pick up prey
52
Corneal Lipidosis - what is this? etiology?
Lipid keratopathy * Cholesterol is required in the diets of many insects * Domestic crickets have high cholesterol content * Etiology: suspect that cholesterol in a diet composed of domestic insects is too high for amphibians to metabolize