Chelonians Flashcards
What are the mechanism and clinical signs of acute ransom toxicity in tortoises?
Acute Ramson (Allium ursinum) Toxicosis in Captive Tortoises Hellebuyck T, Simard J, Velde NV, Geerinckx L. Acute Ramson (Allium ursinum) Toxicosis in Captive Tortoises. Journal of Herpetological Medicine and Surgery. 2019;29(1-2):34-9.
Allum spp plants assoc with severe hemolytic anemia.
MOA - Sulfur-containing compounds cause oxidative damage to RBC.
Other plant toxicities in reptiles - lillies, avocado, Digitalis spp, mistletoe.
Heinz bodies NOT observed (hallmark in other spp).
What husbandry/dietary changes mitigated GI perforations in a group of juvenile spiny softshell turtles?
Gastro-Duodenal Perforations and Coelomitis in a Group of Juvenile Spiny Softshell Turtles (Apalone spinifera)
Couture ÉL, Ferrell ST, Desmarchelier M, Lazure L, Lair S.
Journal of Herpetological Medicine and Surgery. 2017;27(1-2):36-43.
Gastroduodenal impaction and perforation from excessive food consumption and large, abrasive foods.
Husbandry Recommendations:
Limited time feeding (remove food after 20-30 minutes)
Invertebrate prey smaller than the width of the reptile’s head
Freeze-dried shrimp less abrasive vs sun-dried
2 day fast per week
Conclusions: Feeding large amounts of abrasive food can cause gastrointestinal impaction, perforation, and fatal coelomitis in juvenile spiny softshell turtles.
What was observed in a study evaluating acupuncture points governing vessels 1 and 26 alone and in combo during anesthetic recovery of EBTs?
EVALUATION OF ACUPUNCTURE POINTS GOVERNING VESSELS 1 AND 26 ON ANESTHETIC RECOVERY OF EASTERN BOX TURTLES (TERRAPENE CAROLINA CAROLINA).
J Zoo Wildl Med. 2018 Dec;49(4):870-874.
Cerreta AJ, Walker ME, Harrison TM.
GV26 - Nasal philtrum
GV 1 - Between coccyx and anus
All tx groups had a shortened time to voluntary movement, response to limb extension, and anesthetic recovery compared to control (no accupuncture). There was no difference among the groups.
HR in the GV-26 group was higher.
Conclusions: GV-26, GV-26 and GV-1, and GV-26 and GV-1 electroacupuncture all shortened recovery times in box turtles anesthetized with an injectable protocol.
What factors were associated with high lactate in EBTs during a canine search adventure?
BLOOD LACTATE CONCENTRATIONS IN EASTERN BOX TURTLES (TERRAPENE CAROLINA CAROLINA) FOLLOWING CAPTURE BY A CANINE SEARCH TEAM
Klein K, Adamovicz L, Phillips CA, Allender MC.
Journal of Zoo and Wildlife Medicine. 2021 Apr;52(1):259-67.
Higher lactate in turtles with Terrapene herpes 1 (no cs), quiet mentation, increased PCV, and increased capture and handling time.
Peak lactate was ~130 min after capture.
What was observed in a comparison of ax with ketamine-medetomidine and S-ketamine-medetomidine in testudo spp?
Preliminary Clinical Comparison of Anesthesia with Ketamine/Medetomidine and S-Ketamine/Medetomidine in Testudo spp.
Monika Bochmann, Sandra Wenger, Jean-Michel Hatt
J. of Herpetological Medicine and Surgery, 28(1):40-46 (2018).
S-ketamine 4x greater affinity for NMDA receptor = inc analgesia and anesthetic effects
Both ketamine and S-ketamine caused decreased HR, RR, muscle relaxation
No loss of response to noxious stimuli
S-ketamine had reduced palpebral at 30 min
No adverse effects
Body temp correlated to environment temp
Conclusions: Ketamine-medetomidine and S-ketamine-medetomidine both produced moderate anesthesia, bradycardia, bradypnea with no analgesia.
Intranuclear coccidian parasite of Testudines (TINC) has a predilection for which type of cell?
EXTENSION OF THE KNOWN HOST RANGE OF INTRANUCLEAR COCCIDIOSIS: INFECTION IN THREE CAPTIVE RED-FOOTED TORTOISES ( CHELONOIDIS CARBONARIA)
Stilwell JM, Stilwell NK, Stacy NI, Wellehan JF, Farina LL.
Journal of Zoo and Wildlife Medicine. 2017 Dec;48(4):1165-71.
TINC has a predisposition for epithelial cells, causes widespread inflammation, necrosis, and epithelial hyperplasia.
Tortoises are the definitive host - Microgametocytes, macrogametocytes, and oocysts have been found.
Conclusions: Intranuclear coccidian parasite of Testudines (TINC) affects a wide variety of tortoises, causing multisystemic disease which was successfully treated in two red-footed tortoises with ponazuril.
Name three upper respiratory tract pathogens that are major causes of disease in chelonians.
CHARACTERIZING THE EPIDEMIOLOGY OF HISTORIC AND NOVEL PATHOGENS IN BLANDING’S TURTLES (EMYDOIDEA BLANDINGII)
Winter JM, Mumm L, Adamovicz LA, Andersson KE, Glowacki GA, Allender MC.
Journal of Zoo and Wildlife Medicine. 2020 Nov;51(3):606-17.
URT infections major cause of dz in chelonians - Mycoplasma, ranavirus, herpesvirus.
Key Points:
Pathogens highest occurrence in adults>>> rare subadults, juveniles
Likely due to behaviors exhibited by age class (ie communicable disease is transmitted with increased contact, like during breeding season)
Emydoidea herpesvirus 1 (EBHV1) 22 animals, no illness, most during MAY, tended to cluster spatially
Tended to be seen in animals with limb abnormalities and absence of leach infestation
Herpesvirus disease may be seen because the limb abnormality has stressed the animal (difficulty foraging, recent injury etc)
May is breeding season, spend more time on land, likely why fewer leeches
Salmonella typhimurium, rarely positive, Causes illness in mammals
Novel mycoplasma identified in turtle w/ nasal discharge
Tortoise intranuclear coccidiosis (TINC) and ranaviruses
Conclusions: Adults more affected by infectious diseases, suspect due to increased horizontal transmission from interactions. EBHV1 had low prevalence and no illness, associated with decreased immune functioning and breeding season.
How does temperature affect ranavirus in juvenile chelonians (RES, MS map turtles, false map turtles, river cooters)?
EXPERIMENTAL TRANSMISSION OF FROG VIRUS 3–LIKE RANAVIRUS IN JUVENILE CHELONIANS AT TWO TEMPERATURES
Allender MC, Barthel AC, Rayl JM, Terio KA.
Journal of wildlife diseases. 2018 Oct;54(4):716-25.
All juvenile turtle spp had 100% mortality rate within 6-16 days. Nearly all died before clinical signs (one turtle was lethargic).
Higher mortality at higher temps in general.
FMT survived the longest.
MMT and RES at higher temp died sooner compared to same spp at lower temp.
No difference in survival time between turtles at higher or lower temp in FMT or RC groups.
Conclusion - Ranavirus kills juvenile turtles, usually without CS other than lethargy, and higher mortality is observed at high temps. MMT and RES died sooner at higher temps.
What type of herpesviruses are all reptilian herpes?
What was observed in a serosurvey of terrapene herpesvirus 1 in EBTs in TN and IL?
PREVALENCE OF TERRAPENE HERPESVIRUS 1 IN FREE-RANGING EASTERN BOX TURTLES (TERRAPENE CAROLINA CAROLINA) IN TENNESSEE AND ILLINOIS, USA
Kane LP, Allender MC, Archer G, Dzhaman E, Pauley J, Moore AR, Ruiz MO, Smith RL, Byrd J, Phillips CA.
Journal of wildlife diseases. 2017 Apr;53(2):285-95.
Background:
Herpesviruses are a large, enveloped viruses with a dsDNA genome
All reptilian herpes virus are Alphaherpesviruses
Terrapene herpesvirus 1 → upper respiratory signs in eastern box turtles
Terrapene herpesvirus 2 → fibropapilloma in a box turtle in FL
Key Points:
Prevalence of TeHV-1 in E box turtles in TN and IL was 31.3%
More positives in July in TN.
PCV, eosinophils, H:L ratio were higher and lymphocyte and monocytes were lower in positive turtles
Overall clinical signs were not associated with positive results.
Signs: nasal discharge, ocular discharge, ocular swelling, oral plaque, and respiratory distress
Conclusions: Eastern box turtles in TN and IL have a high prevalence of terrapene herpesvirus 1, which causes upper respiratory signs.
What copathogens were detected in free-ranging EBTs in IL and TN?
DETECTION OF COPATHOGENS IN FREE-RANGING EASTERN BOX TURTLES (TERRAPENE CAROLINA CAROLINA) IN ILLINOIS AND TENNESSEE
Archer GA, Phillips CA, Adamovicz L, Band M, Byrd J, Allender MC.
Journal of Zoo and Wildlife Medicine. 2017 Dec;48(4):1127-34.
Four pathogens detected:
Ranavirus
Terrapine herpes 1
Mycoplasma
Adenovirus 1
TerHV1/Myco and TerHV1/BT Adv1 coninfection detected
NO occurence of Myco + BT Adv1 together
Adenovirus more common in juveniles.
Mycoplasma found more commonly in fall
TerHV1 more common in summer
What was found in a survey of blanding’s turtles for emydoidea herpesvirus 1 in IL?
Was there an association with clinical signs?
What sample is best for antemortem testing?
Epidemiology of Emydoidea herpesvirus 1 in free-ranging Blanding’s turtles (Emydoidea blandingii) from Illinois
Lindemann DM, Allender MC, Thompson D, Glowacki GA, Newman EM, Adamovicz LA, Smith RL.
Journal of Zoo and Wildlife Medicine. 2019 Sep;50(3):547-56.
Chelonian herpesviruses:
Testudinid herpesvirus 1-4
Emydid herpesviruses (emydid HV-1,2, Glyptemy Hv-1,2, Terrapene Hv-1,2)
Lifelong infections and latency OR persistent infection with recurrent shedding
Newly identified Emydoidea herpesvirus 1 (EBHV1)
Key Points:
In Blanding’s turtles surveyed, EBHV1 qPCR prevalence of 11%
All females
Not associated with clinical signs, county
Positives most common in May, then Sep, then June (different from EBTs which are highest in July)
Sampling with oral swabs is best for antemortem
Conclusions: Emydoidea herpesvirus 1 can be detected in wild Blanding’s turtles with qPCR of oral swabs, especially highest in May.
What amoebic pathogen can cause sudden death in chelonians, lizards, and snakes?
A RETROSPECTIVE ANALYSIS OF AMOEBIASIS IN REPTILES IN A ZOOLOGICAL INSTITUTION
McFarland A, Conley KJ, Seimon TA, Sykes IV JM.
Journal of Zoo and Wildlife Medicine. 2021 Apr;52(1):232-40.
Entamoeba invadens can cause sudden death in reptiles (chelonians, lizards, and snakes)
Direct lifecycle: ingest cyst → trophozoite attach to duodenal mucosa +/- invade wall and spread in blood
Fecal-oral transmission
Chelonians may be asymptomatic carriers or be clinically affected
Crocodilians may be asymptomatic carriers
Snakes develop clinical signs
Entamoeba ranarum causes clinical disease in amphibians (and one snake in this paper)
Entamoeba terrapinae was fatal in on chelonian in this study but is normally commensal in chelonians
Negative PCR in cases with histologic amoeba
Conclusions: Entamoeba spp.can be fatal in reptiles.
Do chelonians have urinary bladders?
What is stored in accessory bladders and how do they fill?
Positive Buoyancy Secondary to Gas Accumulation within the Accessory Bladders in a Florida Cooter (Pseudemys floridana floridana)
Scifo A, DeVoe RS, Goe A.
Journal of Herpetological Medicine and Surgery. 2020;30(1):9-13.
All chelonians have bladders:
Terrestrial tortoises = large, bilobed bladder for fluid storage
Aquatic turtles = smaller bladder for water storage and buoyancy control
Bilateral ureters → urodeum → bladder or proctodeum
Accessory bladders = cloacal bursae = cloacal bladders
Paired, vascular structures in some aquatic and semiaquatic chelonians
Fill and empty through cloaca with water
Do not store urine
In aquatic species, lateral to urinary bladder and small
In semiaquatic species, large, filled with water through vent
Conclusions: All chelonians have bladders, but aquatic and semiaquatic turtles have accessory bladders that can fill with water through the vent.
What was the most common presentation for turtles in NC?
What factors were associated with risk of euthanasia/death?
MORBIDITY AND MORTALITY OF WILD TURTLES AT A NORTH CAROLINA WILDLIFE CLINIC: A 10-YEAR RETROSPECTIVE.
Sack A, Butler E, Cowen P, Lewbart GA.
J Zoo Wildl Med. 2017 Sep;48(3):716-724.
Box turtles most common
Vehicular trauma = most common presentation
Upper respiratory infections +/- aural abscesses were uncommon (5% cases)
URI cases were often eastern box turtles
Fishing hook trauma cases were most often sliders
Head trauma cases were most often snapping turtles
Had a better survival rate for head trauma than other species (maybe because injuries typically on jaws
Cooters were most likely to present as gravid females
Factors that increase the risk of euthanasia/death
Vehicular trauma
Head injuries
Midline injuries (spinal)
Myiasis
Snapping turtles did better with head trauma vs other spp.
Conclusions: Wild turtles present to rehab centers for a variety of reasons, and vehicular trauma, head traum, and open coelomic injuries decrease survival rate.
What was observed in a health assessment of free ranging chelonians in NY?
Health assessment of free-ranging chelonians in an urban section of the Bronx River, New York.
Aplasca AC, Titus V, Ossiboff RJ, Murphy L, Seimon TA, Ingerman K, Moser WE, Calle PP, Sykes IV JM.
Journal of wildlife diseases. 2019.
Environmental contaminants accumulate in different tissues:
Organochlorines, polychlorinated biphenyls: hepatic, adipose
Metals (except Pb): hepatic, renal, +/- others
Lead: erythrocytes, bone
Polychlorinated biphenyls can cause developmental deformities in snapping turtles
Organochlorines inhibits ATP and can cause conjunctivitis, otitis media, aural abscesses, lower lysozyme levels, and abnormal sexual development in chelonians
Lead impairs the activity of aminolevulinic acid dehydratase (part of heme synthesis)
Key Points:
Snapping turtles, compared to red-eared sliders, had:
More Haemogregarina (hemoparasite) and Placobdella parasitica (leech) Placobdella can transmit Haemogregarina
Higher lead levels, higher selenium
Higher PCV
Novel Mycoplasma and novel chelonian herpesvirus
Red-eared sliders also had parasites, lead, Mycoplasma, and herpesvirus
No mercury, ranaviruses, nor adenoviruses detected
Conclusions: Common snapping turtles and red-eared sliders in the Bronx river had OCs, PCBs, lead, Mycoplasma, and herpesviruses with environmental contaminants higher in the snapping turtles.
What is the prognostic values of PCV and BG in chelonians? What combinations were associated with the highest odds of death?
Prognostic value of packed cell volume and blood glucose concentration in 954 client-owned chelonians
Violaine A. Colon, Nicola Di Girolamo
J Am Vet Med Assoc 2020;257:1265–1272
Increased odds of death in chelonians:
Anemia (risk increases with severity)
Hypoglycemia
Hyperglycemia (risk increases with severity)
Categories of risk: chelonians with the highest odds of death:
Severe hyperglycemia + severe anemia
Severe hypoglycemia + severe anemia
Mild hyperglycemia + severe anemia
Moderate hyperglycemia + polycythemia.
Conclusions: Blood glucose concentrations and PCV may be prognostic indicators for chelonian patients.
Which diagnostic tests were considered to be the most useful as a marker of inflammation in gopher tortoises?
DIAGNOSTIC PERFORMANCE OF INFLAMMATORY MARKERS IN GOPHER TORTOISES (GOPHERUS POLYPHEMUS)
Rosenberg JF, Hernandez JA, Wellehan JF, Crevasse SE, Cray C, Stacy NI.
Journal of Zoo and Wildlife Medicine. 2018 Sep;49(3):765-9.
Erythrocyte sedimentation rate was the best marker of inflammation
Followed by mature heterophils, leukocytes, lactate, immature heterophils
Sick tortoises had a lower albumin:globulin ratio
Fibrinogen was NOT helpful in this species
Conclusions: Erythrocyte sedimentation rate was the best marker of inflammation in gopher tortoises.
What blood analytes can be influenced by refrigeration/freezing in RES?
Effects of time and storage temperature on selected biochemical analytes in plasma of red-eared sliders (Trachemys scripta elegans).
Eshar D, Avni-Magen N, Kaufman E, Beaufrère H.
Am J Vet Res. 2018 Aug;79(8):852-857.
Key Points:
There was no difference between 1 and 4 hours at room temperature.
There was increased variability in CK, glucose, and phosphorus when refrigerated or frozen.
There was an increase in AST, uric acid, and potassium when refrigerated or frozen.
Calcium and potassium in frozen samples were outside of the acceptable range for allowable total error.
Total protein increased when refrigerated for more than 24 hours.
Conclusions: Refrigerating and freezing samples for >8 hours may affect biochemical analytes.
What were the most common isolates in a retrospective of bacterial isolates from clinically ill chelonians and what drugs were they sensitive to?
Retrospective Evaluation of Bacterial Isolates from Clinically Ill Chelonians: 155 Cases
Musgrave KE, Mans C.
Journal of Herpetological Medicine and Surgery. 2019;29(1-2):49-54.
Gram-negative bacteria comprised majority of isolates, Pseudomonas and E. Coli most common
Both are part of the normal gastrointestinal flora
Pseudomonas was most sensitive to fluoroquinolones
Escherichia coli was most sensitive to aminoglycosides
Take home message: Opportunistic, Gram-negative bacteria are the most common cause of bacterial infection in turtles.
What population of EBTs in TN and IL had higher rates of antibiotic resistance?
MULTI-DRUG RESISTANCE PATTERNS OF ENTERIC BACTERIA IN TWO POPULATIONS OF FREE-RANGING EASTERN BOX TURTLES (TERRAPENE CAROLINA CAROLINA)
Rasmussen C, Allender MC, Phillips CA, Byrd J, Lloyd T, Maddox C.
J Zoo Wildl Med. 2017 Sep;48(3):708-715
Cloacal swabs and CBC (from subcarapacial sinus) from free-ranging box turtles in TN (urban) and IL (rural) (n=90)
Gram negative isolates:
Citrobacter spp.: 69% resistant to Clavamox, 21% resistant to cefoxitin
No resistance in E. coli
Geography:
IL turtles less resistance to Clavamox, ampicillin, and cefoxitin
TN had higher MIC90 for chloramphenicol
Demographics:
Females had more gram-negative isolates resistant to ceftiofur
Juveniles had more gram-negative isolates resistant to ceftiofur
No differences in health parameters
Gram positive isolates:
Lactobacillales (Vagococcus, Enterococcus, Carnobacterium) isolated
Most isolates resistant to three classes (n=24), followed by two classes (n=12)
Demographics:
Females had more gram-positive isolates resistant to enrofloxacin and cefovecin
Juveniles had more gram-positive isolates resistant to gentamicin
Health Parameters:
WBC and TS had decreasing trend with increasing number of antibiotic classes resistant
Higher TS in turtles with marbofloxacin resistant bacteria
Lower TS in turtles with cefovecin susceptible bacteria compared to cefovecin resistant bacteria
Weight higher in turtles with marbofloxacin resistant Gram positive profile compared to marbofloxacin susceptible
Gram positive
Other studies in sea turtles have shown profiles of resistance in sea turtles
Overall, isolates from rural areas had greater susceptibility than urban turtles
Conclusion: Antimicrobial resistant organisms are present in wild eastern box turtles in Tennessee and Illinois, with higher rates of resistance seen in urban populations and females. WBCs and TS were decreased as Gram positive resistant bacteria increased.
What pathogen was found to have a high prevalence in emydid turtles in Missouri?
A QUANTITATIVE PCR ASSAY FOR A MYCOPLASMA FROM EMYDID TURTLES INDICATES HIGH PREVALENCE IN HEALTHY THREE-TOED BOX TURTLES (TERRAPENE CAROLINA TRIUNGUIS) FROM MISSOURI, USA
Sandmeier FC, Ruiz R, Leonard K, Bayer B, Dowd C, Urban T.
Journal of wildlife diseases. 2019 Jul;55(3):589-96.
Mycoplasma agassizii causes upper respiratory tract disease in Mojave desert, but many carry a low load normally
Eastern box turtles have serologic evidence of M. agassizii exposure but may actually be an unnamed emydid mycoplasma
Emydid mycoplasma also occurs at a high prevalence in three-toed box turtles
Key Points:
Of the wild E box turtles, 61% were positive for emydid mycoplasma
None were PCR positive for M. agassizii nor M. testudineum
Conclusions: Eastern box turtles have a high prevalence of emydid mycoplasma.
Discuss diagnostic testing options for mycoplasma URTD in chelonians.
COMPARISON OF CURRENT METHODS FOR THE DETECTION OF CHRONIC MYCOPLASMAL URTD IN WILD POPULATIONS OF THE MOJAVE DESERT TORTOISE (GOPHERUS AGASSIZII)
Sandmeier FC, Weitzman CL, Maloney KN, Tracy CR, Nieto N, Teglas MB, Hunter KW, DuPré S, Gienger CM, Tuma MW.
Journal of Wildlife Diseases. 2017 Jan;53(1):91-101.
Background:
Mycoplasma (M. agassizii and M. testudineum) can cause chronic upper respiratory tract disease in desert tortoise
M. agassizii is more common in the wild population
Antibody response and are slow in desert tortoises (max titers at 4-27 wks) and long lived (elevated titers >1yr)
Low level infections may not result in an antibody response
Key Points:
Most Mycoplasma-positive tortoises had mild or latent disease
Quantitative PCR (qPCR) appears to be best diagnostic technique to identify low intensity infection
Low agreement between qPCR and antibody likely because of low antibody responses
Conclusions: Mycoplasma URTD is a chronic, intermittent, low mortality disease, therefore don’t rely on one test to say there is no disease.
What diagnostic sample could be valuable for detecting ranavirus in a deceased autolyzed turtle carcass?
DETECTION OF RANAVIRUS USING BONE MARROW HARVESTED FROM MORTALITY EVENTS IN EASTERN BOX TURTLES (TERRAPENE CAROLINA CAROLINA).
Butkus CE, Allender MC, Phillips CA, Adamovicz LA.
Journal of Zoo and Wildlife Medicine. 2017 Dec;48(4):1210-4.
FV3 is diagnosed by demonstrating viral presence in postmortem tissues or oral-cloacal swabs.
In chelonian, mass mortality events, the skeleton and shell are often the only remains, making diagnosis difficult.
Key Points:
Bone marrow was collected from by sterilely drilling into the marginal scutes
FV3 was detected in 14% of postmortem samples.
There was good agreement between the perimortem and postmortem samples in the fourteen turtles.
Two turtles were negative on oral swabs but positive on bone marrow possibly because oral shedding of FV3 is intermittent.
Conclusions: Sampling bone marrow by the drilling method described may be a good method in deceased chelonians to detect FV3 via qPCR.
Compare pros and cons of techniques for sex determination of chelonians (cloacoscopy vs cytoscopy vs anti-mullerian hormone vs celioscopy).
FIELD ANESTHESIA AND GONADAL MORPHOLOGY OF IMMATURE WESTERN SANTA CRUZ TORTOISES (CHELONOIDIS PORTERI).
Emmel ES, Rivera S, Cabrera F, Blake S, Deem SL.
Journal of Zoo and Wildlife Medicine. 2021 Jan;51(4):848-55.
Cloacoscopy - Minimimally invasive, challenging to ID penis vs clitoris
Cystoscopy - Less invasive, light anesthesia, short recovery; Difficult visualizing through bladder, emesis/bladder rupture complications, sometimes poor accuracy.
AMH - Only need small volume, accurate in hatchlings (only found in males); Less accurate in juveniles.
Celioscopy - Accurate; Requires equipment, invasive.
Endoscopic Sexing Technique:
Hold in right lateral recumbency with hind leg extended
Local lidocaine block in the prefemoral fossa
Sharp skin incision with scalpel, followed by blunt dissection with mosquito hemostat
Insert scope and use LRS for insufflation
Suture with 3-0 Monocryl in horizontal mattress
Western Santa Cruz tortoise males’ testicles were oval, red-pink, and tightly adhered to the kidney
Not lobular and yellow like in desert tortoises
Females did not have primordial follicles (seen in other species when immature)
Conclusions: Celioscopy can be used in Western Santa Cruz tortoises in the field, but need to know species anatomy (males = red-pink ovals; females = no primordial follicles).
What parameters were best to predict BCS in EBTs evaluated with CT?
BODY CONDITION OF EASTERN BOX TURTLES (TERRAPENE CAROLINA CAROLINA) EVALUATED BY COMPUTED TOMOGRAPHY.
dePersio S, Allender MC, Dreslik MJ, Adamovicz L, Phillips CA, Willeford B, Kane L, Joslyn S, O’Brien RT.
J Zoo Wildl Med. 2019 Jun 13;50(2):295-302.
Key Points:
Mass alone or mass and carapace width were the best variables to predict body condition score
Previous unvalidated models for chelonian BCS are likely inaccurate
In sea turtles, carapace length and mass are the best indicators of body condition index
Conclusions: Mass and carapace width are the best predictors of body condition index.
How did 25OHVitD3 correlate with UVB in EBTs?
CHARACTERIZING THE 25-HYDROXYVITAMIN D STATUS OF TWO POPULATIONS OF FREE-RANGING EASTERN BOX TURTLES (TERRAPENE CAROLINA CAROLINA)
Watson MK, Byrd J, Phillips CA, Allender MC.
Journal of Zoo and Wildlife Medicine. 2017 Sep;48(3):742-7.
Omnivorous reptiles obtain vit D from diet or secondary exposure to UVB radiation.
Vitamin D3 in skin has a longer half-life than dietary vitamin D3 because it skin D3 is 100% protein bound
Recommended method of measuring Vit D is 25-OHD3.
Key Points:
Vitamin D3 was positively correlated with UVB at time of capture.
No correlation with latitude, calcium, Ca:P, age, or sex
Conclusions: 25-OHD3 levels in wild eastern box turtles were correlated with UVB levels at the time of capture.
Describe how a visual scoring system can be used to ID and quantify anemia in male EBTs.
ASSESSMENT OF A VISUAL SCORING SYSTEM FOR IDENTIFYING AND QUANTIFYING ANEMIA IN MALE EASTERN BOX TURTLES (TERRAPENE CAROLINA CAROLINA).
Cerreta AJ, Mehalick ML, Stoskopf MK, Dombrowski DS, Lewbart GA.
J Zoo Wildl Med. 2018 Dec;49(4):977-982
FAffa MAlan CHArt (FAMACHA) is used in small ruminant species to estimate anemia based on conjunctival color
Male eastern box turtles have an non-pigmented iris, which causes it to have a red hue
Key Points:
There was a strong correlation between eye-color score and PCV. (Lighter = more anemic)
Using 5 or 6 color options resulted in less variable and more specific assessments than 9 color options.
5 or 6 options were highly specific (100%) but not sensitive (30-44%) for anemic EBT
Describe the best approach to the stomach for celiotomy in snapping turtles. What about sea turtles?
SURGICAL ANATOMY OF CELIOTOMY APPROACHES TO THE STOMACH IN THE COMMON SNAPPING TURTLE (CHELYDRA SERPENTINA).
Jimenez IA, Hermanson JW, Childs-Sanford SE.
J Zoo Wildl Med. 2019 Mar 1;50(1):82-88.
Options for surgical removal of GI foreign bodies in chelonians:
Plastron osteotomy; may not have good access to the stomach because of limited organ mobility
Prefemoral celiotomy
Axillary celiotomy
Key Points:
Left axillary approach: 4 cm adjacent to plastron edge
Required transection of superficial muscle bellies to see coelomic membrane
Greater curvature stomach visualized but not easily exteriorized
Left prefemoral: 4 cm adjacent to plastron edge
Fascia excised and coelom penetrated easily
Able to exteriorize duodenum and exteriorize stomach
Simple and atraumatic
Conclusion: Celiotomy to access stomach for surgery in snapping turtles is recommended as prefemoral approach in snapping turtles.
Discuss effects of long-term oral clarithromycin administration in chelonians with subclinical mycoplasma infection.
Long-term Oral Clarithromycin Administration in Chelonians with Subclinical Mycoplasma spp. Infection
Rettenmund CL, Boyer DM, Orrico WJ, Parker SG, Wilkes RP, Seimon TA, Paré JA.
Journal of Herpetological Medicine and Surgery. 2017;27(1-2):58-61.
Mycoplasma agassizii and Mycoplasma testudineum = agents of contagious upper respiratory tract disease (UTRD) in tortoises
Mycoplasma testudinis = asymptomatic infection
M. agassizzi and M. testudienum affect Gopher tortoises
Can find mycoplasma in conjunctival swabs of normal chelonians
Intermittent shedding of Mycoplasma, so PCR can give false negatives
Clarithromycin is macrolide- used to successfully treat M. agassizii in desert tortoises in another paper (took 6 mo)
Good intracellular penetration because it travels in phagocytes to sites of infection
Accumulates in respiratory lining cells and secretions
Conclusions: Long-term clarithromycin PO is safe but does not stop shedding of Mycoplasma in Forsten’s tortoises or Sulawesi forest turtles.
Discuss absorption of ponazuril in red-footed tortoises.
A PRELIMINARY ANALYSIS OF PROLONGED ABSORPTION RATE OF PONAZURIL IN RED-FOOTED TORTOISES, CHELONOIDIS CARBONARIA
Benge SL, Heinrichs MT, Crevasse SE, Mahjoub B, Peloquin CA, Wellehan JF.
Journal of Zoo and Wildlife Medicine. 2018 Sep;49(3):802-5.
TINC (Testudine intranuclear coccidiosis)- first found in radiated tort in 1990
Systemic disease, affects multiple organ systems: GI, resp, endocrine, lymphoid
Coccidia associated with inflammation and necrosis
Similar to Sarcocystis neurona (equine protozoal myeloencephalitis)
High mortality
Ponazuril inhibits all developmental stages of coccidia
Key Points:
Prolonged and variable oral absorption (continual absorption over an entire week!)
20mg/kg did not reach Cmax consistent with effect in mammals
Suspect inadequate dosing of ponazuril reason no documented cases of tortoise clearing TINC
Highest concentration of the drug was at 168 hours
Take Home Message: Red footed tortoises did not reach mammalian Cmax necessary to treat coccidial disease at a dose of 20mg/kg. The hope was that ponazuril could be used to treat TINC
Discuss efficacy of topical emodepside and praziquantel vs nematodes in captive tortoises.
Efficacy of a Topical Formulation Containing Emodepside and Praziquantel (Profender®, Bayer) against Nematodes in Captive Tortoises
Tang PK, Pellett S, Blake D, Hedley J.
Journal of Herpetological Medicine and Surgery. 2017 Dec;27(3-4):116-22.
Oxyurids have a direct life cycle and are host specific
Inhabit lower intestinal tract of tortoises
High levels have been associated with fatal post-hibernation anorexia
Most common ascarid in herbivorous tortoises = Angusticaecum holopterum
Direct life cycle after ingestion of embryonated eggs
Low levels are likely insignificant, but heavy burdens can cause intestinal obstruction and perforation
Fenbendazole is a common oral antiparasitic in tortoises, but can have negative clinicopathologic effects
Heteropenia, transient hypoglycemia, hyperuricemia, and hyperphosphatemia (source below)
Potential for reduced fenbendazole efficacy in chelonians
Emodepside is a cyclooctadepsipeptide with activity against gastrointestinal nematodes
Triggets inhibitory neurotransmitter release from presynaptic membrane → flaccid paralysis in nematodes
Displayed efficacy against a variety of nematodes in a wide variety of species
Praziquantel has anthelmintic activity against trematodes and cestodes
Increases permeability of calcium channels to cause an influx of calcium across muscle/tegumental membranes of parasites
Ivermectin is a parenteral anthelmintic which in chelonians can cause paresis, flaccid paralysis, hepatic lipidosis, nephrotoxicity, and death
Key Points:
Oxyurid were not changed at day 14, but decreased by ~60% at day 33
Delayed, moderate anthelmintic activity
Suboptimal temperatures may have inhibited drug absorption
Ascarids reduced by 67% at day 14 (Not enough samples for day 33)
Conclusion: Profender produced delayed, moderate anthelmintic activity in tortoises and may be an option to reduce but not eliminate oxyurid burden in tortoises when oral medications not a treatment option.
Discuss pros of capillary zone electrophoresis in chelonians.
Buscaglia, N. A., Inman, D. N., Chen, S., Arheart, K. L., & Cray, C. (2021). Partial hematology, biochemistry, and protein electrophoresis reference intervals for captive spotted turtles (clemmys guttata). Journal of zoo and wildlife medicine, 52(2), 704-709.
Protein electrophoresis - semiautomated agarose gel electrophoresis traditionally used.
Capillary zone electrophoresis - Increased precision of fraction quantitation, better resolution of new protein fractions, easier to use, completely automated, faster results, smaller sample can be run.
Discuss pros of capillary zone electrophoresis in chelonians.
Buscaglia, N. A., Inman, D. N., Chen, S., Arheart, K. L., & Cray, C. (2021). Partial hematology, biochemistry, and protein electrophoresis reference intervals for captive spotted turtles (clemmys guttata). Journal of zoo and wildlife medicine, 52(2), 704-709.
Protein electrophoresis - semiautomated agarose gel electrophoresis traditionally used.
Capillary zone electrophoresis - Increased precision of fraction quantitation, better resolution of new protein fractions, easier to use, completely automated, faster results, smaller sample can be run.
It is possible to compare results of CZE using serum and plasma.
Compare and contrast options for venipuncture in tortoises.
COMPARISON OF SUBCARAPACIAL SINUS AND BRACHIAL VEIN PHLEBOTOMY SITES FOR BLOOD COLLECTION IN FREERANGING GOPHER TORTOISES (GOPHERUS POLYPHEMUS)
Journal of Zoo and Wildlife Medicine 52(3): 966–974, 2021 - Neiffer, Dipl ACZM, et al.
Higher brachial vein mean values for most parameters. Attributed to greater hemodilution of subcarapacial samples with lymph.
Subcarapacial prone to lymph dilution. Can collect larger samples, allows for more rapid processing and does not require chemical restraint. Assoc with serious complications i.e. paralysis.
All CBC parameters were higher in brachial vein samples except for lymphocytes (high in lymph, SC). All plasma chem, EPH, and vitamin parameters higher in brachial vein samples except NaCl and BUN.
What organism releases brevetoxins? Symptoms? Treatment?
INTRAVENOUS LIPID EMULSION TREATMENT REDUCES SYMPTOMS OF BREVETOXICOSIS IN TURTLES (TRACHEMYS SCRIPTA). JZWM 50(1): 2019
Cocilova, Flewelling, Granholm, Manire and Milton
Karenia brevis - Brevitoxicosis
Animals treated with IL 30 min after brevetoxin exposure had greatly reduced symptoms within first 2 hrs. Fully recovered within 24 hrs.
Animals receiving ILE first showed little to no clinical signs post exposure.
Increase observed in brevetoxin in bile and feces 24h post ILE tx vs non treatment exposure control.
Describe Chelonian taxonomy.
What taxa are they most closely related to?
What are the two suborders?
When are the terms turtle, tortoise, and terrapin used?
F8 Chelonians; Mader 2019 - Ch. 7 Chelonian Taxonomy, Anatomy, and Physiology
- Chelonians (turtles, tortoises, terrapins)
- Diapsids – have two temporal fenestra
- Sister clade to Archosaurs (crocodilians, birds, extinct dinosaurs)
- Less closely related to Lepidosaurs (lizards, snakes, amphisbaenids, tuataras)
- Most highly endangered of any of the major vertebrate groups.
- Threats – hunting, traditional medicine, pets, intro of invasive spp, disease, anthropogenic trauma, fisheries, habitat degradation, fragmentation.
- Taxonomy: Chelonia
- Suborder Cryptodira (11 families, 250+ spp) - Hidden-neck turtles
- Can retract head and neck straight back into shell, hiding neck
- Includes sea turtles although unable to retract
- Family Carettochelyidae: Pig-nosed turtle
- Family Cheloniidae: Hard-shelled sea turtles
- Family Chelydridae: Snapping turtles
- Family Dermatemydidae: Central American river turtles
- Family Dermochelyidae: Leatherback sea turtle
- Family Emydidae: Box turtles, pond turtles, map turtles, wood turtles, terrapins, sliders, cooters
- Family Geoemydidae: Asian river, lead, roofed, or Asian box turtles
- Family Kinosternidae: Mud and musk turtles
- Family Platysternidae: Big-headed turtle
- Family Testudinidae: Land tortoises
- Family Trionychidae: Softshell turtles
- Suborder Cryptodira (11 families, 250+ spp) - Hidden-neck turtles
- Suborder Pleurodira (3 families, 80+ spp) - Side-necked turtles
- Not fully able to retract neck, fold it sideways
- Family Chelidae: Austro-American side-necked and snake-necked turtles
- i.e. Comon snake-neck turtle, mata mata
- Family Pelomedusidae: Afro-American side-neck turtles
- i.e. African helmeted turtle
- Family Podocnemididae: Madagascar big-headed turtles, big-headed Amazon river turtles, South American side-neck river turtles
- Common names vary:
- Tortoise – typically terrestrial i.e. family Testudinidae; Australians will refer to turtles as tortoises, UK terrapin refers to FW chelonians, turtle refers to marine, tortoise refers to terrestrial.
- North America – terrapin used for single spp (diamondback terrapin), all other aquatic turtles called turtles.
Describe the musculoskeletal anatomy of chelonians.
What are the two parts of the shell?
How do scutes grow? How are they shed? How are they numbered?
What species have soft shells? What makes these shells softer than other turtles?
What are the three parts of the pectoral girdle?
- Musculoskeletal system
- Shell – upper carapace, lower plastron, joined laterally by bony bridges
- Carapace - ~50 bones derived from ribs, vertebrae, dermal elements
- Plastron – 9 bones from clavicles, coracoids, interclavicles, gastralia (ribs)
- Most spp have keratinized epithelium covering a thin dermis layer consisting of collagen fibers, melanophores, vessels, and nerves, beneath which is dermal bone.
- Scutes – superficial layer of keratin
- Staggered, seams between not directly over bone
- New scutes produced with each major growth period
- Terrestrial chelonians retain scutes
- Aquatic/semiaquatic chelonians shed scutes
- Grow outward from central nucleus (areola)
- Each year, new scute forms beneath previous year’s
- Outer edge will form annulus (growth ring)
- Nutritional deficiencies – inversion of annuli
- Counting annuli not accurate for determination of age
- Scute nomenclature – Fig. 7.23
- Shell modifications depending on spp
- Leatherback sea turtles, softshell turtles, Fly River turtles – scutes replaced by leathery skin (alpha keratin)
- All other turtles both alpha and beta keratin
- Hatchling tortoises have fontanelles b/t carapacial bones, fuse with age
- Some spp i.e. pancake tortoises retain fenestrae
- Plastronal hinges i.e. box turtles, spider tortoises, mud turtles
- Caudal carapacial hinge – hinged-back tortoises
- Leatherback sea turtles, softshell turtles, Fly River turtles – scutes replaced by leathery skin (alpha keratin)
- Chelonians = only extant vertebrates with pectoral and pelvic girdles within ribcage
- Tripartite rectilinear pectoral girdle
- Dorsoventral scapula
- Ventromedial acromium process
- Ventrocaudal corcoid (procoracoid)
- Vertebrae are incorporated into the carapace from first thoracic vertebra caudally to coccygeal vertebra.
- Tripartite rectilinear pectoral girdle
- Marine spp and the Fly River turtle have elongated metacarpals and phalanges (flippers)
- Shell – upper carapace, lower plastron, joined laterally by bony bridges
Describe the respiratory system of chelonians.
Where do the nares open into?
Do they have complete or incomplete tracheal rings? What else is important about their tracheal anatomy?
Where are the lungs located? What type of lungs do chelonians have?
What is the peak airway pressure recommended for turtles?
Which phase of respiration is active?
What are some of the factors that make it difficult for turtles to remove secretions, infections, or FB from their lungs?
- Respiratory system
- Obligate nasal breathers – open-mouth breathing is pathologic
- Complete tracheal rings
- Cryptodiran turtles – short trachea, bifurcation is mid-cervical
- Cranial bifurcation and complete tracheal rings enable breathing unimpeded when neck is withdrawn. May be a hazard for intubation.
- Lungs adherent to carapace, dorsal
- Ventrally separated by septum horizontale – attached to liver and GIT
- Pleuroperitoneal/coelomic cavity
- Multicameral (partitioned), saccular, 3-11 chambers dep on family
- Reticular surface, smooth muscle and connective tissue
- Large lung volume, advantage as hydrostatic organ for aquatic turtles
- Three-toed box turtles, relatively small tidal volumes coupled with high respiratory rates.
- Peak airway pressures during anesthesia recommended < 10 cm H20
- Antagonistic muscles decrease or increase lung and visceral volume
- Gular pumping to assist olfaction, not typically ventilation (except some aquatic spp)
- In submerged snapping turtle – active inspiration, expiration passive.
- On land, passive inspiration, active expiration.
- Some aquatic turtles – supplemental cloacal, buccopharyngeal, or cutaneous respiration for prolonged submergence.
- Long periods of apnea make induction of gas anesthesia difficult.
- Open fractures of shell with lung exposure do not typically result in obvious respiratory distress.
- Many factors make removing secretions or FB from lungs difficult:
- Termination of mucociliary elevator outside the glottis.
- Poor drainage through dorsally located bronchi.
- Compartmentalization of lungs.
- Large potential space within the lungs.
- Lack of a complete muscular diaphragm to cough.
- Pneumonia can be difficult to manage and life threatening
- Ventrally separated by septum horizontale – attached to liver and GIT
Zoo Path
- ● Nares open into paired vestibules or nasal passages (no sinuses, turbinates)
- o Mucosa - keratinized epithelium that transitions to multilayered olfactory epithelium dorsally & ciliated epithelium w/ mucus glands ventrally
- ● Trachea short, bifurcates early into bronchi 🡪 open into singular saccular lung lobes (R,L) 🡪 subdivided into multiple variably sized compartments by smooth muscle trabeculae and smaller faveoli
- o Lungs firmly attached dorsally to carapace & separated from coelomic cavity by fibrous membrane (septum horizontale or pleuroperitoneal membrane)
- o No diaphragm - can’t cough; clearance of lower resp. infection/inflammation nearly impossible
- o Some aquatic species use air in lungs for buoyancy control
- o Evidence (controversial) some aquatic spp. have marginal extrapulmonary gas exchange (moving water through oral and cloacal cavities)
Describe the gastrointestinal anatomy of chelonians.
What is unique about the sea turtle esophagus?
Describe their intestinal anatomy.
Why do foreign bodies get stuck in the transverse colon?
How many liver lobes do they have?
What factors affect GI transit time?
- Digestive system
- Most terrestrial spp herbivorous
- Aquatic species carnivorous, omnivorous - Numerous exceptions
- No teeth, swallow bite-sized pieces, saliva is not enzymatic
- Esophagus is ciliated
- Sea turtles – large esophageal papillae
- SI relatively short vs mammals
- LI – primary fermentation site in tortoises, includes cecum, colon
- Cecum lacks mesenteric attachments
- Transverse colon has wider mesenteric attachment to stomach, gives dorsoventral mobility
- Heavy ingested FB sink ventrally in the transverse colon, become entrapped, and accumulate at the descrnding colon.
- FB removal facilitated by milking material anterograde into cecum, easiest to exteriorize.
- Stomach, SI, pancreas produce digestive enzymes
- Liver – two major lobes, envelops GB on right
- May have normal melanomacrophages
- Pale yellow to tan may indicate hepatic lipidosis or normal vitellogenesis in females.
- One study did not detect postprandial increase in bile acids in RES.
- Pancreas directly contacts spleen (cryptodirans) or separate in mesentery with duodenum (pleurodirans)
- Factors affecting GI transit time:
- Temperature, spp, feed frequency, food size, water or fiber content of food.
- Transit time omnivores < carnivores < herbivores.
- Captive diets generally move faster, especially in tortoises.
- Loggerhead sea turtles, GI contrast 2-3 weeks
- Metoclopramide, cisapride, and erythromycin did not significantly reduce GI transit time compared with water in desert tortoises.
- Temperature, spp, feed frequency, food size, water or fiber content of food.
Zoo Path
● No teeth - keratinized horny ridges line the upper (rhamphotheca) and lower (dentary) beak
● Green sea turtles - esophagus lacks mucus glands, Cd-directed conical papillae help retain ingested prey
● Several marine turtle species have a crop to retain food
● GI tract simple, suspended from dorsal midline by a single mesentery
● Liver has 2 main lobes w/ gallbladder w/in or along caudal border of R lobe
o Histo – hepatocytes in discrete trabeculae, but distinct lobular architecture absent
o Melanomacrophages considered normal cellular population in liver
Describe the anatomy of the urinary tract in chelonians.
Where are the kidneys located?
How well do they concentrate urine?
What are the three nitrogenous wastes? What groups excrete which product?
Do chelonians have a bladder?
- Kidneys – retrocoelomic, deep to caudodorsal carapace, posterior to acetabulum.
- Except marine turtles – anterior to acetabulum.
- Metanephric, no loop of Henle.
- Cannot concentrate urine above that of plasma.
- Urine not sterile.
- Ammonia and urea require large amounts of water for excretion.
- Renal portal system – PK studies have shown no significant difference in drug metabolism if injections are given in caudal region vs cranial limbs.
- Differences from mammals markers (BUN, Cr) making detection of kidney disease difficult:
- Amino-ureotelic: Marine and highly aquatic FW turtles excrete more ammonia and urea than uric acid.
- Ureo-uricotelic: Semiaquatic turtles excrete mostly urea.
- Ureo-uricotelic to uricotelic: Terrestrial chelonians produce more insoluble uric acid and urates passed in semisolid state.
- Healthy sea turtles very high BUN vs other chelonians (> 100 mg/dL).
- Healthy herbivorous tortoises have basic urine.
- Tortoises in catabolic state acidic urine, not specific to disease.
- Urinary bladder
- Some spp accessory urinary bladders.
- Terrestrial chelonians – largest, bilobed, thin, membranous distensible, ciliated, mucus secreting wall.
- Used for water storage and K/Na exchange during drought.
- Care should be taken to prevent urination when handling wild tortoises, could result in significant fluid losses for that individual.
- Aquatic chelonians – small bladders, thicker walls.
- Cloaca, colon, UB can reabsorb urinary water.
- Bladder prolapse may occur with uroliths or colonic FB.
Zoo Path:
● Paired lobular kidneys in retrocoelomic space; no distinct cortex and medulla grossly
o Fewer nephrons, no loops of Henle 🡪 chelonians cannot concentrate urine
o Proportion of N waste excreted as NH3, urea, & uric acid varies by spp., habitat, season, diet, age
▪ FW turtles excrete equal amts of ammonia and urea
▪ Sea turtles also excrete uric acid
▪ Tortoises (esp. desert spp.) excrete far more uric acid & K+-urate salts in semisolid state
o Ureters enter dorsal urodeum 🡪 excreted or diverted into urinary bladder
▪ Urinary bladder - ciliated epithelium w/ mucus glands
▪ In some spp. - 2 additional small accessory bladders lateral to urodeum
▪ Bladder - water reservoir, resorptive capacity in some spp.
o BUN has limited utility as marker of renal fxn, except perhaps in aquatic spp.
▪ BUN also ↑ during hibernation in desert tortoises (↓ H2O intake, protein catabolism)
▪ Urea - better for hydration status, water availability than kidney function
Describe the reproductive anatomy of chelonians.
Where are the gonads located?
What stimulates spermatogenesis?
What stimulates vittelogenesis?
What hormone regulates seasonal reproduction in both sexes?
What is the hormone that peaks during oviposition?
What are the two patterns of temperature-dependent sex determination in chelonians?
What are some examples of sexual dimorphisms in chelonians?
- Gonads.
- Paired, anterior to kidney.
- Fertilization is internal.
- Seasonal hormone patterns.
- Spermatogenesis is temp and testosterone dependent.
- Rising in spring/summer, falling in fall/winter.
- Spermatozoa may be retained through winter.
- Sperm may be stored months to years by female in albumin gland within isthmus of oviduct.
- Following fertilization, produces membranes/albumin around ovum.
- Shell gland produces shell membranes and eggshell.
- Ovary/follicles.
- Previtellogenic follicles – secrete estradiol in response to pituitary gonadotropin.
- Estradiol stimulates liver to secrete vitellogenic protein.
- Taken up by maturing follicles.
- Nesting F sea turtles have higher TP, alb, glob, Ca, P, TG, and cholesterol.
- Estradiol stimulates liver to secrete vitellogenic protein.
- Testosterone regulates seasonal reproduction in males and females.
- Follicular testonsterone increases with maturation of follicle.
- Biphasic increase associated with spring and fall mating.
- Falls after ovulation, females become nonreceptive.
- Ovulation occurs after courtship and mating, then within days of nesting.
- Associated with LH and progesterone surges.
- Follicular testonsterone increases with maturation of follicle.
- Single or multiple clutches of eggs dep on spp.
- Arginine vasotocin peaks during first oviposition, baseline within an hour.
- Follicles that have not ovulated undergo atresia.
- Reduces in size, becomes a corpora albicans.
- Repeated folliculogenesis and atresia without production of eggs may lead to coelomitis.
- Thyroxine (T4) peaks in both sexes following hibernation.
- Males undergo second peak in late summer as male combat and spermatogenesis return.
- Temperature dependent sex determination
- Pattern 1a: Typical, produces females at higher temperatures, males at lower temps
- Pattern 2: Females at both high and low temps and males at IM temp.
- Smaller gender typically occurs at cooler temps.
- Some turtles have genetic sex determination:
- Common snake-necked turtle, Wood turtle
- Previtellogenic follicles – secrete estradiol in response to pituitary gonadotropin.
- Phallus
- Spade-shaped.
- Ventral floor of the proctodeum, no urethra.
- Seminal groove for transport of sperm.
- No inversion occurs as it does in squamates.
- Males often vocalize during copulation.
- Typically last part of the turtle to be desensitized under general anesthesia.
- Sexual dimorphism.
- Coloration, tail or claw length, size, shell shape.
- Males have longer, thicker tails, distal vent, curved or concave plastron, anal notch on plastron deeper than female.
- Cryptodiran turtles, most significantly larger - F.
- Males typically larger in larger-sized spp.
- Male aquatic turtles tend to have elongated foreclaws for courting.
- Males of some marine spp have hooked claw on front flipper.
- Female leopard tortoises have elongated rear claws.
- Box turtle males have red iris vs yellow/brown of females.
- Coloration, tail or claw length, size, shell shape.
Describe the reproduction of chelonians.
How big are their clutches?
What biochemical changes are appreciated during vitellogenesis?
How can oviposition be facilitated?
- Reproduction (F8):
- All chelonian lay shelled eggs on land.
- Clutch size may range from 1-100+.
- Size and number of clutches per season may be influenced by nutritional status.
- Incubation times vary.
- Most spp have temp-dependent sex det.
- Generally females produced at higher temps, males at lower temps.
- Plasma Ca may exceed 25 mg/dL during folliculogenesis.
- Globs may > 8 and chol 200+.
- Can place in shallow water and administer oxytocin IM or ICe to try to stimulate laying.
- Retention of shelled eggs in otherwise healthy animal not a concern.
- Anorexic or lethargic, otherwise systemically affected, can administer fluids, Ca gluc, repeat oxytocin with prostaglandin.
- Can assess repro status of wild females with US.
- Don’t have to expose the ovary to multiple radiographic events.
- Presence of mature ovarian follicle does not ensure ovulation will occur.
- Some females are capable of resorbing preovulatory follicles.
- Primary repro issue in males is phallus prolapse.
- Cleanse, manually replace and purse string.
- May require amputation.
Describe the cardiovascular anatomy of chelonians.
How many chambers do they have?
What are their great vessels? What do they each supply?
What physiologic changes occur when the turtle is diving?
- Cardiovascular system
- Four-chambered heart: one sinus venosus (pacemaker), two atria, one ventricle with three subchambers (cavas).
- Segregate oxygenated and deoxygenated blood.
- Deoxygenated blood returns to sinus venosus (receives blood from right and left cranial vena cavas, caudal vena cava, left hepatic vein).
- Right atrium >> left atrium, no auricles.
- Great vessels (from ventricle) – two aortas, common pulmonary artery or trunk.
- Left trunk is pulmonary artery, splits into each lung.
- Middle trunk (left aorta) – supplies viscera
- Right trunk (right aorta) has brachiocephalic trunk arising from base, bifurcates into subclavian arteries.
- Landmarks for thyroid gland.
- Left and right aortae join caudal to heart to form dorsal aorta.
- Located on midline except in Trionychidae – displaced to right.
- Bordered laterally by acromium and coracoid processes.
- More pericardial fluid vs mammals.
- Ligamentous gubernaculum cordis attaches ventricular apex to pericardial sac.
- Ventral midline coelomic mebrane incision can inadvertently enter pericardial sac.
- Apnea and diving
- HR and pulmonary blood flow decreases by 50% and 80%, 150% increase in pulmonary resistance.
- Results in more intracardiac R-L shunting.
- When breathing, HR and pulmonary blood flow increase two and three fold, results in net L to R shunt.
- Renal portal system of unknown clinical significance.
- Segregate oxygenated and deoxygenated blood.
- Four-chambered heart: one sinus venosus (pacemaker), two atria, one ventricle with three subchambers (cavas).
Zoo Path
● Heart - pericardial sac connected to apex of heart via gubernaculum cordis; 4 chambers (sinus venosus, 2 atria, ventricle)
o Ventricle - 3 interconnected chambers (cavum venosum, cavum arteriosum, cavum pulmonale)
o Purkinje fibers absent
o Contractions initiated via sinus venosus, propagated by arrangement of myofibers
o Muscular sphincters in pulmonary arteries of some marine spp.
Describe the anatomy of the chelonian nervous system.
What is unique about reptilian meningeal anatomy?
What structure is homologous to teh neocortex?
How many cranial nerves do they have?
- Nervous system
- CNS – brain and SC
- Brain – olfactory bulb, cerebral cortex, thalamus, hypothalamus, pituitary, optic lobes, cerebellum, medulla.
- Most reptiles lack neocortex, some evidence dorsal cortex homologous in chelonians.
- Traumatic midline carapace injuries may affect the spinal cord.
- Bran and SC surrounded by two meningeal layers – inner leptomeninx and outer dura mater. CSF in between (site of intrathecal injections).
- Reptiles lack subarachnoid space.
- Epidural space is rich in vascular supply, does not contain CSF.
- Extreme tolerance for hypoxia and anoxia.
- 12 cranial nerves.
- Nervous terminalis considered nerve 0.
- PNS
- CNS – brain and SC
Describe the hematology of chelonians.
What do the various cells look like?
What is the size of chelonian red cells?
Hematology
● PCV and most other hematologic/biochemical parameters vary sig. by spp., sex, age, nutrition, reproductive status, hibernation, season
● All circulating blood cells retain their nuclei
● Chelonian RBCs large compared to other vertebrates (except amphibians)
o Length approx. same as heterophils
o May contain basophilic cytoplasmic inclusions, thought to be degenerating organelles or hemoglobin ppts (no pathologic sig.)
● Assessing 1º hemostasis challenging - thrombocytes tend to clump and appear similar to lymphocytes
● Thrombocytes - small amounts of cytoplasm, round to ovoid nuclei
o Activated cytoplasm - vacuolated, +/- magenta granules
● Heterophils - largest WBC w/ numerous linear, pink-orange, refractile granules that “melt” together
o Toxic Δ - increased cytoplasmic basophilia, retention of 1º granules - severe inflamm/infection
● Mature lymphocytes - thin rim of basophilic cytoplasm and round nuclei
● Monocytes - round to amoeboid, blue-gray cytoplasm, ovoid to reniform nuclei w/ loosely clumped to coarsely granular chromatin
o Monocytosis - acute & chronic infections
● Eosinophils - round to ovoid, eccentric nuclei, round, pink-orange granules
● Basophils - smallest granulocyte, fine purple/deeply basophilic granules
Describe secodary nutritional hypothyroidism in chelonians.
What plants is it associated with?
What species are more commonly affected?
What are the lesions?
● Secondary nutritional hypothyroidism (& subsequent goiter)
o In captive animals
o Assoc. w/ diets ↓ in iodine or ↑ in goitrogenic plants (kale, broccoli, cabbage)
o Iodine toxicity can also lead to goiter
o Galapagos, Aldabra tortoises more susceptible
o Exact pathogenesis unclear, but common in sea turtles in artificial salt water aquaria for prolonged periods
o Grossly - gland enlarged, follicles engorged
o Selenium def. in other spp., not described in chelonians
What are some common sequelae to cold stunning in sea turtles?
What is the typical appearance of hepatic lipidosis in chelonians?
Chronic liver disease produces what lesions?
Metabolic
● Hypothermic (cold) stunning
o Free-ranging; abrupt drops in water temps
o Juv. - cool down faster 🡪 smaller bodies, higher surface:volume
o Reduced activity, prone to predation: GI and resp. Dz common
o Sequelae 🡪 fungal/bacterial pneumonia, ulcerative enteritis/gastritis, parasites, related to immune system dysfunction 2º to debilitation
● Hepatic lipidosis
o Physiologic (hibernation, reproduction, etc.) or pathologic
o Cytoplasmic accumulation of triglycerides w/in hepatocytes
o Grossly - enlarged w/ rounded edges, light brown to pale tan
o Early stages of pathologic HL - anorexia, protein malnutrition, hepatic injury, systemic disease; grossly indistinguishable
o Liver may float in fixative, water
● Disseminated hepatic fibrosis and hepatocellular nodular hyperplasia cirrhosis)
o Can be 2º to several chronic disease processes
▪ Hepatic inflamm. or severe lipidosis, heart failure, hepatic/post-hep. biliary obstruction
o Grossly - SQ edema/ascites, small liver w/ pale yellow/tan hyperplastic nodules surrounded and separated by thick fibrous connective tissue septae, often w/ pigmented macrophages
Describe the testudinid herpesviruses.
Which virus affects which taxa?
What are the typical clinical signs?
How is this diagnosed? What are some important differentials to consider?
What treatments are available?
What is the prognosis?
How is this disease prevented?
Viruses
● Herpesviruses
o All reptile herpesviruses belong to subfamily alphaherpesviridae
o 1st herpesvirus isolated in terrestrial chelonians named tortoise herpesvirus 1 (THV-1), has since been ID’d in other spp. of chelonians
▪ Causes necrotizing stomatitis, glossitis, diphtheritic plaques in oral cavity, Cr. esophagus, & trachea (some coinfected w/ Mycoplasma)
▪ Rhinitis, hepatomegaly, enteritis, conjunctivitis also reported
▪ Eosinophilic to amphophilic glassy intranuclear inclusions in mucosal epithelium of oral cavity, tongue, GI tract, resp tract, urinary/genital tract; only during acute phase
o THV-2 - isolated from a CA desert tortoise
▪ Similar clinical and pathologic findings as THV-1
▪ Endotheliotropism 🡪 vasculitis, edema, thrombosis in several cases (unlike THV-1)
Ch. 169 Testudinid Herpesvirus (Mader 2019)
- Definition:
- Herpesviridae; Alphaherpesvirinae.
- Testudinid herpesviruses (TeHVs):
- TeHV3 – Widespread, most pathogenic, any tortoise.
- Group B assoc with worse lesions vs group A.
- TeHV 1 – Russian tortoises.
- TeHV2 – Agassiz’s desert tortoises.
- TeHV4 – African tortoises, Leopard tortoises.
- TeHV3 – Widespread, most pathogenic, any tortoise.
- Transmission y contact +/- vertical. IN and IM inoculation causes dz.
- Testudinid herpesviruses (TeHVs):
- Herpesviridae; Alphaherpesvirinae.
- Clinical presentation:
- Stomatitis, glossitis, oral/nasal discharge, ocular discharge, conjunctivitis, dyspnea, neuro signs, cervical edema, anorexia, wt loss.
- Oral diphtheronecrotic plaques are classic.
- TeHV3 is neurotropic, but inclusions present systemically.
- Virus reactivation unpredictable, shedding common after hibernation.
- Diagnostic confirmation:
- Ddx – Ranavirus, virus X (picornavirus), Mycoplasma.
- Serology – SN and ELISA.
- ELISA validated in Greek and Hermann’s tortoises for TeHV3.
- Minimum 2 ELISAs at least 8 wks apart for definitive TeHV3 infection, and 10 wks apart for SN. Both equally reliable.
- Helpful in chronic infection without clinical disease.
- PCR.
- Specific and pan-herpesvirus protocols.
- Test of choice during acute infection.
- VI, EM, Histo.
- VI definitive proof.
- Tx:
- Acyclovir, ganciclovir reduce viral replication in vitro.
- Effective concentrations could not be reached in vivo.
- Supportive care – fluid therapy, tx secondary infections.
- Vx has been unsuccessful.
- Acyclovir, ganciclovir reduce viral replication in vitro.
- Prognosis and prevention:
- Lifelong infection.
- Quarantine 6+ mos, repeated serology and PCR.
- Separate animals with clinical signs.
- Avoid overcrowding and mixing spp.
Describe fibropapillomatosis in sea turtles.
What is the etiologic agent?
What species and demographics are most commonly affected?
What are the typical clinical signs?
What are the histologic lesions?
-
Fibropapillomatosis (FP)
- Emerging, panzootic infectious dz affecting green sea turtles, documented in all sea turtle spp.; recognized in 1938; pathogenesis and epidemiology not yet elucidated
- Putative agent currently - chelonian herpesvirus 5 (ChHV-5), previously chelonid fibropapilloma-assoc. herpesvirus
- Alphaherpesvirus, genus scutavirus; at least 4 genetic variants
- Has been identified in non-affected animals (suggests not strict viral cause)
- Common in post-benthic juv. migrating to coastal shallow feeding areas
- Both genders; suggests horizontal transmission (aggression, mating)
- Has not been identified in deep ocean-dwelling turtles
- Stressors, new environments, social dynamics may play a role
- Water temp, anthropogenic activity, algal blooms implicated
- Spontaneous regression noted in some location
- External tumors in natural & experimentally induced - identical, pathognomonic
- Tumors - vary, flat, plaque-like lesions to raised exophytic gray to black, verrucous masses over 30 cm in diameter
- Arise from skin around eyes, mouth, limbs; also on cornea, surface of shell
- Localized fibroblast proliferation w/in superficial dermis 🡪 hyperplastic epidermis 🡪 exophytic nodules composed of papilliferous fronds
- Histo – acanthosis, basal cell necrosis, cleft formation along dermo-epidermal jxn
- Eosinophilic intranuclear inclusions are rare/transient
- Internal, well-demarcated, smooth tumors (firm, white, nodular) described in oral cavity, glottis, lungs, kidney, heart, liver, spleen, GI tract; tend to develop late in dz process
- Foreign body granulomas assoc. w/ sprirochiid trematode ova or epidermal inclusion cysts not uncommon in FP lesions of free-ranging turtles
- Ulcerated regions often assoc. w/ bacterial or fungal colonization
Describe the papillomaviruses of sea turtles.
What are the typical lesions?
How do these differ from the lesions of fibropapillomatosis?
● Papillomaviruses
o Caretta caretta papillomavirus (CcPV) – ID’d in a free-ranging loggerhead
o Chelonia mydas papillomavirus (CmPV) – ID’d in in free-ranging green sea turtles
▪ Both developed few to many soft, white raised smooth nodules over head and flippers
▪ Histo – eosinophilic intranuclear inclusions surrounded by clear halo
What iridoviruses affect chelonians?
How do we think this virus is transmitted?
What are the typical lesions?
What are the inclusion bodies?
-
Iridoviridae – diverse group of viruses that infect vertebrates and invertebrates
- Contains Iridovirus and Ranavirus genus (all OIE reportable); implicated in cause of disease and mortality in chelonian populations worldwide
- Mediterranean and gopher tortoises, Eastern box turtles (EBT), red-eared sliders
- Turtle virus -3 (TV-3) (nearly identical to Frog virus-3 (FV-3)) - recovered from EBT
- Enviro. temps may have sig. effect on virus-assoc. morbidity/mortality
- Transmission unknown, but because iridoviral particles can be observed in circulating WBCs; may be by blood-feeding parasites or biting insects
- Other possible transmission modes - consumption of infected animals, enviro. contamination, fomites, amphibian/fish reservoirs
- Lesions (vary some by spp.) 🡪 oral plaques/ulcers, necrotizing glossitis/tracheitis, pneumonia, multifocal gray foci, hemorrhage in liver, hepatic lipidosis, splenomegaly
- Necrotizing splenitis w/ hemorrhage - consistent in red-eared sliders
- raised, often ulcerated abscesses in EBT skin fairly common
- Fibrinoid vasculitis - consistent finding
- Intracytoplasmic basophilic inclusions in epithelial cells (renal, hepatic), although uncommon and difficult to ID
- Contains Iridovirus and Ranavirus genus (all OIE reportable); implicated in cause of disease and mortality in chelonian populations worldwide
What bacteria are most commonly isolated in turtles with septicemic cutaneous ulcerative disease?
What are the risk factors for developing lesions?
What are the typical lesions?
● Ulcerative lesions of skin and shell, 2º infection w bacteria primarily in captive FW chelonians
o Often assoc. w/ suboptimal housing, nutrition, management
o Often start as abrasions or result of conspecific aggression
o If becomes systemic - SCUD (septicemic cutaneous ulcerative disease)
▪ Signs - Lethargy, weakness, limb paralysis, cutaneous abscesses, necrosis of digits or shell
▪ Reported in N. American, Europe; identical presentation in African terrapins
▪ Citrobacter freundii most common; also Serratia sp. & Beneckea sp.
▪ Grossly - cutaneous erosions/ulcers, loosening of scutes; w/ disseminated 🡪 necrotic foci in liver, spleen, kidney, heart, caseous yellow mass in coelomic cavity
▪ Histo - Intense heterophilic and histiocytic inflammation w/ necrosis
o Recent ID of fungi consistent w/ Nannizziopsiaceae in some lesions complicates pathogenesis; not all should be attributed to bacterial infection
Describe mycobacteriosis in chelonians.
What types of chelonians are most commonly affected?
What mycobacteria species are most common?
What are the typical presentations?
What are the the typical lesions?
● Mycobacteria spp.
o Slender, aerobic, acid-fast, and Gram-positive bacilli
o Infections most common in aquatic chelonians
o M. marinum & M. chelonae common; M. kansasii some, few rep. of M. avium - green sea turtles
o More common in free-ranging (can be captive), and can be acute or chronic in nature
▪ Acute – lethargy, limb petechial hemorrhages, bloody nasal d/c, internal hemorrhages
▪ Chronic – more common; granulomatous dz - lungs, coelomic viscera, skin; bones, joints
o Bacterial emboli and disseminated IV coagulopathy reported
o Histo - heterophil aggregates w/ or w/o central liquefied core surrounded by histiocytes, macrophages, multinucleated giant cells
o Typically stain positive w/ acid fast stains such as Ziehl Neelson and Fites method but atypical mycobacteria may not
o Diagnosis - a/f bacteria in exudates, but positive culture and molecular more definitive
Describe the fungal infections of chelonians.
What are three important fungal causes of superficial dermatomycoses?
What lesions are commonly seen with microsporidiosis? What species has been affected?
What are the lesions typiclaly associated with emydomyces? What group of fungi does that belong to?
What fungus is a common cause of pneumonia in cold stunned sea turtles?
What about fungal pneumonia in tortoises?
What fungus is widespread in the GI tract? What lesions are present if it is causing pathogenicity?
Fungi
- Largely considered opportunistic, typically under managed care
- Managed care - suboptimal housing, overcrowding, inappropriate temps, poor hygiene; allow organic debris to build up, promote fungal growth
- Free-ranging - adverse enviro. conditions
- Hyalohyphomycoses and phaeohyphomycoses reported in chelonians
-
Superficial dermatomycoses
- Typically lesions on shell, less commonly on skin
- More common in marine and fresh water turtles than terrestrial
- White to lightly colored blemishes on carapace 🡪 scute necrosis, pitting, can ulcerate
- Fatal infections rare, but outbreaks of Mucor (FL softshell turtles) and Paecilomyces (Fly River turtles) reported
- In terrestrial - 2º fungal pododermatitis can develop (d/t substrate putatively)
-
Necrotizing scute dz (NSD) – caused by Fusarium incarnatum
- Isolated from free-ranging and managed Texas tortoises
- Blemishes on shell confined to superficial epidermal keratin layers
- Differs from SCUD – lesions do not result in systemic dz/death
-
Microsporidiosis
- Reported in Hermann’s tortoises w/ granulomatous/necrotizing hepatitis, pneumonia w/ intralesional basophilic spores
- Stain positive w/ Grocott-Gomori’s methenamine Silver & PAS
-
Phaeohyphomycoses
-
Ochroconis and Exophiala (dematiaceous fungi)
- Granulomatous to ulcerative skin lesions on feet and tail of box turtles
- Exophiala - reported oral granuloma (radiated tort), deep ulcerative shell lesions (Aldabra tort), unilateral ocular infection/systemic disease (Galapagos tort)
- Veronea sp. - obstructive tracheitis in stranded green sea turtles
-
Ochroconis and Exophiala (dematiaceous fungi)
-
Nannizziopsiaceae
- Unique presentation of mycotic shell disease
- Reported in variety of managed and free-ranging aquatic/semi-aquatic chelonians
- Grossly - multifocal to coalescing scute ulceration, keratin discoloration, deformation, necrotizing osteomyelitis (radiographically nodular lytic lesions)
- Cystic - central accumulation of tan/gray caseous material, large lesions may compress coelomic viscera
- Hyphae readily visible w/ GMS stain but may be inapparent w/ routine HE staining
- Phylogenetic analysis 🡪 distinct from related reptile pathogens (Ophidiomyces, CaNV)
-
Systemic mycoses
- Respiratory tract is primary route of infection (usually the lungs), dissemination possible
- Fusarium spp. - assoc. w/ cold-stunning events, causing fungal pneumonias
- Fungal pneumonia assoc. w/ sporulating fungi (Aspergillus, Paecilomyces, Penicillium spp.) relatively common in giant tortoises
-
Aspergillus spp. fungal pneumonias usually involve lower resp tract
- Caseous, firm, nodular masses, fungal plaques on mucosal or coelomic surfaces
- Dissemination to liver, spleen, kidneys, other viscera possible
-
Yeasts, (esp. Candida albicans) - widespread in GI tract; pathologic infections are rare
- Reports include oronasal ulcers (radiated tortoise), pneumonia (Greek tortoise), enteritis and pneumonia (stranded loggerhead sea turtle)
Describe spirorchidiiasis in chelonians.
What is an important intermediate host for these trematodes?
What animals are commonly the most affected?
Where are the adult trematodes found?
What are the gross and histological lesions?
Metazoa
-
Spirorchiid trematodes – at least 10 genera documented in sea turtles
- One of most common/widespread CV parasites in world
- Thought to play a role in sea turtle stranding and mortality
- Life cycle unknown; thought to involve a gastropod and a motile cercarial stage
- Amphiorchis sp. identified as key intermediate host for infection in loggerheads
- Infection extremely common in free-ranging sea turtles, but trematode burden does not always correlate w/ clinical disease or death, however ↑ tissue ova burden may correlate w/ declining BCS
- Spirorchiid infections often colocalize anatomically w/ other dz processes, like FP-assoc. skin & internal tumors, coccidian-assoc. enteritis, systemic Gram-neg bacterial inf.
- Adult trematodes 🡪 cardiac chambers, lumina of great vessels
- Gross - cardiac and vascular lesions 🡪 endocarditis, arteritis, tunica muscularis thickening, mural mineralization, intimal nodular proliferation, thrombosis, aneurysms
- Ova - round to elongated (500 um x 100 um) deposited in vascular lumen, wall, or @ perivascular sites (most commonly spleen), often assoc. w/ granulomatous inflammation
Describe testudinid intranuclear coccidiosis.
What species have been affected?
What are the clinical signs?
What are the typical gross lesions?
What is teh most common histological lesion?
How is this disease confirmed?
-
Intranuclear coccidian
- Reported in confiscated/pet-trade radiated, giant, flat-tailed, spider, bowsprit, and impressed tortoises, E. box turtles, and Arakan forest turtles
- Clinical presentation variable 🡪 clear mucoid nasal/ocular discharge, lethargy, weakness, anorexia, anemia, leukocytosis, hypoNa, hyperuricemia, hyperglycemia
- Life cycle and mode of infection/transmission not been elucidated
- Generally systemic and widespread infections; concurrent mycoplasmosis, amoebiasis, bacterial septicemia possible
- Grossly - severity and distribution vary; mucous membrane pallor, rhinitis w/ oronasal fistulas, generalized SQ edema, coelomic effusion, pseudomembranous enteritis, epicardial and intestinal petechiae, tan liver discoloration, splenic congestion, gray pallor to red mottling in kidneys, urinary bladder distension, pulmonary congestion, skin ulceration
- Intranuclear stages more commonly in renal tubular epi cells, hepatocytes, enterocytes, pancreatic ductular epi, acinar cells, u bladder, ureteral epi, nasal mucosa, tracheal epi, and pneumocytes
- Most common histo lesion 🡪 single cell necrosis assoc. w/ intranuclear (or less commonly intracytoplasmic) stages of organism
- Organisms not ID’d in CNS but inflamm. infiltrates in brain/spinal cord of some affected animals
- Can be difficult to ID on HE stain, do not selectively stain w/ Fite’s acid-fast of PAS methods
- Cytology of nasal exudate w/ Wright-Giemsa may highlight organisms
- qPCR on swabs from conjunctiva, oral, choanal, or cloaca for confirmation in suspect cases
Describe the GI protozoal parasites of chelonians.
What coccidian parasites commonly affect these species?
Which one was associated with a mass mortality events in sea turtles? What lesions were present in those cases?
What are the typical clinical signs of cryptosporidiosis in chelonians?
How does Entamoeba affect chelonians?
-
GI protozoal parasites
- Eimeria spp. most common in chelonians
- Eimeria caretta,
-
Caryospora cheloniae - assoc. w/ mortality in mariculture-raised green sea turtles and mass mortality events in green sea turtles in Australia
- Main lesion - heterophilic to granulomatous meningoencephalitis and fibrinous or fibrinonecrotizing enteritis
- Meronts packed w/ numerous basophilic merozoites - cytoplasm of intestinal epi cells and w/in WBCs in intestinal mucosa & lamina propria, thyroid, brain; also renal tubular epi.
-
Cryptosporidium spp. - at least 2 novel spp. ID’d in GI tract of tortoises (Testudo)
- Signs not always obvious 🡪 diarrhea, pica, weight loss, undigested food in feces, anorexia
- Gastric cryptosporidiosis – stomach dilated and filled w/ fluid, organisms along apical surface of gastric mucosal epithelial cells
- Intestinal cryptosporidiosis – fibrinonecrotic lesions, ulceration, hemorrhage w/ intracellular, extracytoplasmic organisms assoc. w/ apical border of enterocytes
-
Amoebiasis (usually Entamoeba invadens)
- Pathogenesis similar to other reptiles
- Lesions – fibrinonecrotic enteritis/colitis, +/- necrotizing hepatitis via dissemination through portal vasculature or common bile duct
- Amoeba readily apparent on HE stain
Describe the approach to a prefemoral coeliotomy in a chelonian.
What organs can be accessed this way?
How should the tortoise be positioned?
How should the incision be closed?
Ch. 99 – Prefemoral Coeliotomy (Mader 2019)
- Two major approaches to coelom of chelonians: transplastron and prefemoral.
- Prefemoral approach – Through prefemoral fossa.
- Less invasive.
- Can provide unilateral surgical access to caudal lung, liver, small and large intestine, reproductive tract, kidney, and bladder.
- Positioned in lateral recumbency, head down helpful.
- Left prefemoral approach often preferred by right-handed surgeons (with a right approach easier for those who are left-handed).
- Ipsilateral pelvic limb maximally extended and secured caudal.
- Skin incision cranial to extended limb and in a cranial-to-caudal direction, in middle of prefemoral fossa, starting close to skin insertion at plastrocarapacial (bridge) junction and ending just cranial to musculature of limb.
- Blunt dissection cranial to sartorius and ventral to iliacus muscles exposes pale coelomic aponeurosis formed by external abdominal oblique muscle
- Coelomic membrane, musculature, subcutaneous tissues closed with simple continuous pattern using absorbable sutures.
- Skin closed using nylon or polydioxanone and simple, horizontal mattress sutures
- Removed (if still present) 8 weeks postop.
Describe the transplaston approach to a coeliotomy in chelonians.
When is it indicated?
What are the disadvantages?
What are the important landmarks to be aware of?
How is the incision made?
How is closure accomplished?
Compare the transplastron and the prefemoral approaches.
Ch. 100 – Chelonian Transplastron Coeliotomy (Mader 2019)
- Disadvantages:
- Increased surgical trauma, pain and discomfort, and prolonged bone healing.
- Indications:
- Extensive exposure (for large cystic calculus, foreign body, or mass removal) or exploration required.
- Patients with small prefemoral fossae.
- Locations of the heart (usually at midline intersection of pectoral and abdominal scutes), paired abdominal veins (running caudocranially within ventral abdominal musculature), hinges (between abdominal and femoral scutes in Testudo, and between pectoral and abdominal scutes in Terrapene), and plastron thickness (including its expansion toward plastrocarapacial bridge) have to be considered before surgery.
- Access cannot be easily enlarged - ensure initial cuts are sufficient.
- Plastron incision:
- In neonates and young juveniles - scalpel blade can be used.
- Oscillating sagittal saw couples accuracy with reduced collateral damage and minimal soft-tissue trauma needed in most cases.
- Thinner incisions can often be obtained using a fine blade rotary saw but rotating saws are less forgiving on soft tissues, and over-scoring at corners occurs with larger-blade diameters.
- Saw held at 45 to 60 degrees to bevel lateral shell incisions - made first.
- Fine hypodermic needle or scalpel blade can be used to gauge depth.
- Caudal cut and final cranial cut made in a similar fashion, but bevelling not necessary.
- Caudal or cranial cut can be incomplete, with a few millimeters bone thickness left.
- Soft tissues are bluntly dissected free while elevating cranial and caudal margins, staying as close to the shell as possible.
- Paired abdominal veins - closely associated with plastron.
- Soft-tissue attachments at fractured bone line can be left intact, because plastron flap is reflected caudal and covered with moistened, sterile gauze.
- Entry into coelom options:
- Midline incision, between abdominal veins, through poorly defined linea alba.
- Unilateral or bilateral paramedian incision(s) lateral to abdominal veins.
- Even ligation and transection of one abdominal vein to permit an L-shaped flap for removing large structures.
- Ligation of both abdominal veins not recommended, because severe circulatory disturbance would likely ensue.
- Coelomic membrane closed in simple continuous pattern using absorbable suture material.
- Poliglecaprone 25 or polyglyconate can be used for closure of paramedian incisions, but polydioxanone preferred for linea alba.
- 3-4 stabilizing sutures (usually polydioxanone, but wire can be used for large species) placed through drilled holes to anchor bony section to plastron.
- Closure - epoxy resin or acrylic (e.g., polymethylmethacrylate), either at 4 points or around the entire bony incision.
- Common for plastron flap to become a sequestrum that provides temporary protection for new bone growth beneath.
- Plastron typically heals within 12 weeks but can take longer, and therefore the covering is usually left in place for 6 to 12 months.
- Rads seldom helpful in assessing healing - radiolucent lines persist long after healing is complete but, osteolysis may suggest osteomyelitis.
Describe the restraint and positioning of chelonians for radiography.
Ch. 56 – Radiography of Chelonians (Mader 2019); Review images from this chapter.
- Restraint and positioning
o Elevation of chelonian by placement of plastron on an appropriately narrow lucent structure (central plastron stand) encourages head and limb extension.
o Chemical restraint helpful for evaluation of head or limbs (depending on patient) – tape can also be used for limb arrangement.
o Position as close to cassette as possible.
o Shell curvature – structures further away from cassette will be magnified or blurred – right and left laterals recommended for larger chelonians.
o Orthogonal views: Dorsoventral, horizontal beam lateral(s), cranial caudal images.
o Technique adjustments for shell may be needed – increase mAs.
Describe the radiographic evaluation of the cardiovascular and respiratory systems in chelonians.
Where is the heart loacted?
How do various pulmonary diseases appear (focal, multifocal, diffuse)?
- Cardiovascular system
- Radiography not commonly used to assess for heart disease – heart poorly visualized with indistinct borders -> echocardiography.
- Heart located as soft-tissue opaque structure ventral to the tracheal termination.
- Loggerhead – triangle formed by scapula and coracoids is landmark.
Respiratory system
- Lung is arborized – small airways terminating in spongy (edicular) air spaces; dorsal lung adheres to carapace parietal serosa, interspersed muscular fibrous bands.
- Pulmonary vasculature should be visible.
- Limb and head extension are important for lung expansion.
- PPV – less risk of misinterpreting overinflation compared to snakes and lizards.
- Diseases – increased pulmonary soft tissue opacity- focal, multifocal or diffuse.
- Fibrosis is differential for diffuse or multifocal pattern.
- Focal – focal pneumonia, granuloma, abscess, neoplasia.
- Cold-stunned Kemp’s ridleys distribution and pattern of pulmonary infiltrates have not been reported with disease/condition specificity (honeycomb pattern).
- CT optimal
Describe the radiographic evaluation of the chelonian GI tract.
How do transit times differ between barium or iodinated contrast?
- Gastrointestinal
- Temperature, nutrition, time since last meal must be considered.
- DV and HBL, best visualized on DV.
- Stomach in left mid portion, minimal gas should be present (aerophagia, fermentation, obstruction).
- Large intestinal contents – mixed soft tissue and gas appearance or more granular.
- GIT is uncommonly empty in chelonians.
- Barium contrast studies reported for a variety of species – EBT, red-eared slider, leopard tortoise, Geoffroy’s side necked turtle, yellow-spotted river turtle, and Arrau river turtle (dosages vary by species and temperature).
- RES transit time: 72-192 hours.
- Leopard tortoise: 144-166 hours.
- Iodinated contrast studies – red-eared slider, Greek tortoise, faster transit times.
- GT had faster transit times between 27 and 34 deg C.
- Avoid respiratory administration.
- Generalized ileus –progressive accumulation of ingesta or abnormal motility.
- Severe gas distension – obstruction.
- Fish hooks are common.
Describe the radiographic evaluation of the chelonian reproductive tract.
Reproductive system
- Reproductive/dystocia monitoring – evaluate uniformity of shell and size, thickness.
- Ultrasound and CT recommended as second line.
- Dystocia – enlarged eggs, fractured shells, follicular stasis, normal eggs outside of reproductive season.
- Increased but even mineralization and smooth – usually prolonged retention in lower repro.
- Thickened and rough shells can indicate uric acid and mineral deposition of shells that have been retained within urinary bladder.
- Soft tissue mass effect – follicular stasis is differential, soft tissue accumulation can also indicate yolk coelomitis.
Describe the radiographic evaluation of the chelonian urinary system.
How do uroliths appear?
What is severe bladder distension indicative of?
Urinary system
- Expansive in volume, bilobed, can extend to mid cranial coelom close to stomach.
- Commonly evaluated for urinary calculi – urate is most common in chelonians (radiolucent, but can mix with other minerals); more common in left lobe of bladder; irregularly rounded shape; obstruction uncommon.
- Severe urinary bladder distension due to spinal fracture reported.
- Kidneys hard to see and renal calcification is not commonly seen.
Describe the radiographic evaluation of the chelonian musculoskeletal system.
How does a fracture line change radiographically over time?
How does joint disease appear radiographically?
What lesions might be seen with nutritional secondary hyperparathyroidism?
Musculoskeletal system
- Radiography most useful for this in chelonians.
- Long bones have distinction between cortical and medullary regions, but less distinct than mammals.
- The pectoral girdle bones should be clearly visualized with sharp margins, small medullary canal and homogenous cortical radiopacity.
- Shell fractures – help document the degree of displacement and extensiveness of shell trauma and investigate concurrent soft-tissue abnormalities associated with injuries (pulmonary); CT helpful.
- Healing of shell – fibrous callus -> fracture lucent line can persist for years; recommended to repeat rads 10-20 weeks after stabilization, complete healing/remodeling may take 12-18 months.
- If carapace fracture crosses midline, spinal fracture should be expected – further imaging modalities helpful to evaluate spinal cord.
- Orthogonal views of limbs – lateral and craniocaudal/dorsopalmar(plantar) images.
- CTs better define abnormalities- good for surgical planning.
- Osteomyelitis and septic arthritis common – lytic (greater degree than mammals, accompanied by caseous abscessation) and osteoproliferative changes, soft tissue enlargement.
- Gout – soft tissue mineralization, gout tophi, pseudogout.
- Degenerative joint disease common – they live a long time, trauma, resolved septic arthritis.
- Periarticular mineral proliferation.
- Osteophytes.
- Early stages – difficult to distinguish active septic arthritis from degenerative changes.
- Advanced disease – soft tissue mineralization around joint (not common in mammals) – limit range of motion.
Nutritional secondary hyperparathyroidism common.
- Know expected degree of mineralization for species and life stage.
- Juveniles have reduced mineralization for a year; assess pectoral or pelvic girdles.
- Diffusely decreased opacity of bones is primary abnormality.
- Cortical bone thinning, shell and rarely limb thickening, pathologic fractures.
