1.1. Learning Objectives

This section on Reptile Medicine will give you a good review of the major husbandry challenges, diseases, and clinical approaches to reptile health issues. At a minimum, you will be expected to be familiar with the following:

• Basic husbandry requirements/concerns for captive reptiles
• Common bacterial agents that affect reptiles
• Common sites for bacterial infection of reptiles
• Preferred antibiotics used to treat gram negative infections in reptiles
• Common parasitic agents that infect reptiles
• Significance of the renal portal system of reptiles
• Inclusion body disease of boid snakes
• Reproductive disorders of the green iguana
• Commonly used reptile anesthetics
• Reptile anesthetic monitoring
• Important parameters in reptile plasma biochemistry
• Nutritional secondary hyperparathyroidism
• Vitamin A deficiency

1.2. Recommended review

It is recommended that you review your reptile anatomy notes from 1st Year Comparative Anatomy, and reptile husbandry and restraint notes from 2nd year Clinical Skills prior to attending the lectures.

For more anatomy review, visit http://www.reptileallsorts.com/anatomy.htm

2.1. Taxonomy

A good review/access to reptile taxonomy can be found at:

http://www.embl-heidelberg.de/~uetz/LivingReptiles.html

http://www.naherpetology.org/nameIntro.asp

2.2. Threats to reptile populations

• Habitat loss, degradation, and fragmentation
• Food, skin, and traditional medicine trade
• Pet trade
• Disease

Asian flower box turtle

2.3. Legal issues

• Local: mainly focus on "dangerous species"
• State: native species, exotic species, pet store laws, breeding permits, etc.
• Federal: U.S Endangered Species

  Some species may require interstate health certificates for transport due to concerns with exotic diseases (e.g. heartwater disease).

• International: CITES

3.1. Ecological Husbandry

• Tropical forests: hot, humid
• Savannah: varying seasonal rainfall conditions, generally hot
• Desert: dry, hot days, cool nights, cool winters in some areas
• Temperate: e.g. Northeastern U.S.
• Montane: cool, humid
• Importance of microclimate

3.2. Cage options

• Indoor vs. outdoor: outdoor always best if conditions allow and safety ensured
• Glass tanks, Neodesha cages (fiberglass)
• Rack systems (allow stacking for breeding facilities, efficient)
• Homemade (may be least expensive)
• Pools ("kiddie pools", aquaculture tanks)
• Semi-free range (e.g. tortoise corrals, greenhouses, etc)
• Screen enclosures (important for chameleons, good ventilation)

3.3. Heat options

• Incandescent lights (effective, inexpensive)
• Infrared ceramic elements (useful for night background heat, no light produced)
• Heat tape, heat pads (generally most suited for snakes)
• Aquarium heaters (for aquatic species, be careful of breakage)
• Central heating (may be best for large collections)
• "Death rocks" (hot rocks may cause lethal thermal burns and provide inadequate usable heat for most reptiles)

Thermal burn in a snake

3.4. Ultraviolet light

• Metabolic needs (UVB stimulates Vit D3 synthesis in skin, deficiency may cause nutritional secondary hyperparathyroidism)
• Behavioral needs (UVA may be important for illuminating sexually dimorphic colors or femoral gland secretions in some lizards).
• Natural, unfiltered sunlight provides best UV spectrum
• Zoomed, Energy Savers, UVHeat.com: commercial lights for indoor use that provide good UV spectrum
• Vitalite, Chroma 50, GE BL: also produce some UV for indoor use but less than those above
• Decline of UV output with time (over 6-12 months), distance (over 12-18 inches), and by filtration (glass or plastic eliminate much usable UV). So replace bulbs frequently and position them effectively.

3.5. Substrates

• Newspaper (cheap, easy to clean, easy to monitor, non-toxic, very useful)
• Carpet (harder to clean, but OK)
• Alfalfa pellets (useful for small desert species like young bearded dragons)
• Large size bark mulch (must be big enough to prevent ingestion)
• Sphagnum moss (useful for humid conditions to allow burrowing, e.g. young semiaquatic turtles)
• Sand (caution due to ingestion, including "calcisand")
• Gravel, corn cob, walnut shells, etc. (often cause GI obstructions)

3.6. Water

• Fresh water as appropriate for the size and ecology of the animal
• Presentation of water (bowls, mist, drip systems) is important as some species will not recognize or utilize water unless it is properly presented, e.g. chameleons prefer a drip or mist system to a bowl of water.
• Water quality (important for aquatic systems where ammonia and other toxins may accumulate)
• Water availability for desert species, may not be necessary if a high-water-content diet is provided, but can be offered periodically, and is often utilized.

3.7. Filtration

• Manual water changes (labor intensive, often not done enough)
• Tropical fish filters (may not be effective for messy turtles)
• Homemade (pond pumps used to run water through large buckets of cotton, gravel, charcoal)
• Pool filters
• Sump pumps (to allow easy, frequent full water changes, well worth the cost)
• Complete water change at least monthly is still generally needed

4.1. Carnivore nutrition

• Snakes, crocodilians, tuatara, amphibisbaenians, many lizards, many chelonians
• Rodents, rabbits, birds often used for snakes and crocodilians and large lizards
• Fish: OK for water snakes, garter snakes, many turtles
• Insects and other invertebrates: most lizards, turtles, and some snakes
• Prepared diets: useful, convenient, be careful to provide a well balanced diet.

4.2. Herbivore nutrition

See useful Table of Nutrient Content.

• Many chelonians, some lizards
• High fiber, low fat, low protein, adequate calcium
• Predominantly green leafy vegetables, forage plants: kale, collards, dandelion, clover, chicory, escarole, turnip tops, beet greens, alfalfa, timothy, endive, etc.
• Thiocyanates: may be found in moderate quantities in the cabbage family. Proposed theoretical but not likely real danger of hypothyroidism if fed exclusively.
• Oxalate: found in many greens including spinach, beets, rhubarb. May cause calcium imbalances or oxalate uroliths in theory, but little evidence. OK to feed in moderation.
• Commercial diets: caution that well-balanced and well-researched

4.3. Nutritional diseases

Thiamin deficiency (thiaminase in frozen fish, neuro signs) Vitamin A (squamous metaplasia of various epithelial tissues including eye, respiratory tract, causes classic puffy eye syndrome in aquatic turtles) Vitamin E/ Selenium (not well documented, steatitis seen in crocs fed fatty rodents) Nutritional Secondary Hyperparathyroidism (calcium, vitamin D3, or UV deficiency) Hepatic lipidosis (common in ill reptiles, pathogenesis unclear, may be nutrition related due to excess dietary fat/obesity) Pyramiding (abnormal "lumpiness" of tortoise's shells, cause unclear, nutrition may contribute) Other nutritional syndromes undoubtedly exist but have not yet been described.

4.3.1. Nutritional Secondary Hyperparathyroidism

• Deficiency in calcium, Vit D3, UV light, and excess phosphorous. Genetic component?
• Fibrous osteodystrophy
• "Popeye" long bones, soft shell, pathological fx, "rubber jaw"
• Correct diet, specific supplements
• UV light. Calcitonin?

5.1. Bacterial diseases

• Often opportunistic normal flora, most commonly Gram negative rods
• Anaerobes in up to 50% of cases
• Respiratory, (sub)cutaneous, intestine, liver, bone most common
• Sepsis is common

5.1.2. Diagnosis of bacterial infection

• Wheezing, mucous, casseous debris
• Erythema of skin, shell
• Subcutaneous masses
• Aspirate and cytology
• Aerobic and anaerobic culture (blood)
• Tracheal wash, coelomic wash, etc
• Consider mycoplasma and mycobacteria

Moderate stomatitis in a snake

5.2. Parasites

Do not Use Ivermectin in turtles and tortoises

• Mites and Ticks: (Ophionyssus natricis, Trombiculids, Amblyoma)
• Nematodes (Strongyloides, Rhabdias, Angusticaecum)
• Cestodes and Trematodes (Spirochids in chelonians)
• Protozoans (flagellates, amoebae, cryptosporidium, isospora)
• Hemoparasites (hepatozoon, hemogragarine)

5.3. Viral diseases

Major known viruses as follows. Many others likely such as recently documented reovirus of boids

5.3.4. Adenovirus

• Pogona spp.
• Fatal in young dragons

7.1. Hematology

• Coccygeal veins, cardiac stick, cervical and post-occipital sinuses, axillary, jugular, ventral abdominal. Lymph contamination often occurs curing blood draw. Lymph contaminated samples will yield inaccurate CBC results but may be used for generally accurate chemistry results (some values not accurate, e.g. lower albumin in lymph than whole blood)
• Heparinized sample is recommended to decrease the chance of serum clotting, prevent clotting of cells for the CBC, and provide slightly more volume of plasma for the chemistry profile.
• EDTA may cause hemolysis of some reptile samples and is not generally recommended as an anticoagulant. Recent research has shown that this may not apply to some species of snakes.
• PCV, WBC, differential count, parasites, inclusions
• Generally safe to take 0.5 to 1% of the body weight of the animal for a single blood draw
• CBC is specific but not sensitive. PCV is useful indicator of anemia and dehydration.

Blood sampling in an iguana

7.2. Chemistry

• Newer analyzers require as little as 0.1cc of blood or plasma.
• BUN (only generally useful in chelonians)
• Uric acid (indicates renal function, not always sensitive)
• AST, LDH (non-specific locations)
• CPK (heart, skeletal muscle)
• Ca, PO₄ (nutritional and renal status)
• Na, K, Cl (as in other species)
• Alb, Glob, TP (liver, antigenic stimulation, dehydration, starvation, etc.)
• Glucose (no true diabetics, may elevate with hepatic disease, low in sepsis and starvation)
• Trig, Cholest (may be high with folliculogenesis)
• Bile acids (likely useful indicator of liver disease, needs research)
• Mg, Ammonia, Heavy metals, Biliverdin, Creatine, protein electrophoresis: may be found to be useful in future

7.3. Radiology

Browse through the Reptile Image folders for examples of reptile radiographs

• Lateral, DV, AP
• Horizontal beam if possible
• Consider mammography or dental film
• GI contrast
• IVP- recently described, usefulness needs to be determined.

8.1. Sexing reptiles

• Snakes: physical exam
  • "popping" (manual eversion of hemipenis)
  • probing (depth of post-cloacal sulcus deeper in males)
• Chelonians in general male has longer, thicker tail and concave plastron, but species variation. Color variations in some species. Longer nails on front feet of males of some American aquatic species (Pseudemys, Trachemys, and Chrysemys).
• Lizards: physical exam (femoral pores often larger in males), radiology, other
• Alternatives such as ultrasound, endoscope, DNA evaluation (Zoogen offers blood test to determine gender of Iguana iguana), or plasma steroid levels

Prolapsed snapping turtle penis

8.2. Reproductive diseases

• Penile prolapse - since penis has no urinary function can be amputated easily.
• Delayed oviposition generally due to lack of suitable nest site.
• Follicular stasis
  • Failure of mature follicles to ovulate
  • Common in lizards
  • Follicles prone to necrosis and rupture
  • Ovariectomy necessary
• Dystocia
  • Often abnormal eggs, physical obstruction, exhaustion
  • Obstetrical procedures may be needed
• Egg yolk coelomitis
• Neoplasia
• Nest site, calcium, oxytocin, vasotocin, PGF_2α, PGE gel, propranolol, ovocentesis

9.1. GI obstruction

Corncob impaction in an iguana

9.2. Renal failure

Common syndrome in adult middle age to old iguanas

9.2.2. Diagnosis

• Palpate large kidneys
• Often hyperphosphatemic, uric acid may be normal
• Definitive diagnosis by biopsy
• Generally interstitial fibrosis, not reversible

Kidney of an iguana

9.3. Gout

Often secondary to dehydration, feeding excessive protein to herbivores, or nephrotoxic antibiotics.

• Renal
• Articular
• Visceral : cardiac, etc.

Renal gout due to gentamicin overdose in a snake

9.4. Cystic calculi

Cystic calculi in an iguana

9.5. Retained shed, spectacles

• "Dysecdysis" is often due to low humidity
• Generally treated by bathing and gentle manual removal

9.6. Tail and digit necrosis

Causes include bacterial infection, trauma and vascular compromise.

9.7. Subspectacular abscesses in snakes

Bacterial infection ascends the lacrimal duct Abscess forms between the spectacle and cornea Surgical removal of spectacle necessary but exposes cornea to desication Requires long term, frequent corneal protective ointments until new spectacle grows (months)

11.1. Inhalant anesthesia

• Isoflurane
• Non-rebreathing systems for small patients
• Intubation
• PPV often required, 5-10 mmHg, exact frequency unknown: 1-4 bpm? Most reptiles apneic at surgical plane.
• What's the best carrier gas? ... Recent evidence shows faster recovery with room air than 100% oxygen, possibly due to inhibitory effect of O₂ on respiratory drive.
• Judging anesthetic depth
  • Palpebral
  • Withdrawal
  • Righting reflex
  • Spontaneous respiration

11.2. Anesthetic monitoring

• Observation
• ECG: only shows electrical activity. Reptile hearts can beat after removal from the body!
• Doppler
• Esophageal stethoscope
• Pulse oximetry

11.3. Surgical principles

• Sterile technique as per mammals
• Electrocautery useful
• Knowledge of anatomy critical: e.g. midline abdominal vein in lizards
• Microsurgical tools, magnification
• Hemoclips
• Avoid cat gut
• Evert skin closure: generally 6-8 weeks for skin healing.

Skin incision into the body of a snake

Coeleotomy in a desert tortoise

13.1. Green Iguana, Iguana iguana

Tropical, diurnal, arboreal herbivore. Farm raised in Central America.

13.2. North American Box Turtles Terrapene carolina spp.

Temperate, diurnal, terrestrial omnivore.

13.2.3. Common Problems

• Rhinitis
• Vitamin A deficiency
• Ear abscess
• Conjunctivitis
• Overgrown beak and nails
• NSHP
• Bot fly larvae
• GI parasites

Surgical debridement of an ear abscess in a box turtle

13.3. Red Eared Slider Turtle Trachemys scripta elegans

Temperate, diurnal, aquatic omnivore.

13.4. Sulcata, Leopard, Testudo Tortoises

Sulcata and Leopard are tropical terrestrial African species.

Most Testudo are temperate to subtropical European, Asian, and North African species.

Note: need interstate permit for movement of Leopard Tortoises due to possible tick/Heartwater threat. See more at APHIS http://www.aphis.usda.gov/lpa/news/2001/07/TORTRULE.HTM on this problem.

Leopard tortoise

13.5. Redfoot, Yellowfoot, Hingeback Tortoises

Tropical, omnivorous, terrestrial, humid savannah and forest species.

Captive Yellow Foot Tortoise

13.6. Leopard Gecko

Subtropical, terrestrial, diurnal, insectivore; small, alert, good 'starter' pet.

13.7. Bearded Dragon

Australian, subtropical, terrestrial, diurnal omnivore.

13.8. Snakes in general

Carnivorous, temperate to tropical, terrestrial to arboreal to fossorial, diurnal or nocturnal.

Ball Python

14.1. Readings

• Lecture 3: Descriptive Epidemiology
• Gout and Other Crystal Diseases
• Gout and Other Crystal Diseases
• Rabbit Medicine
• LU1:Yellow Submarine-PDF tutorial
• Farm Animals