Health Assessments of Reptiles: How Do We Know What is Normal?

Transcription

1 Health Assessments of Reptiles: How Do We Know What is Normal? MATT ALLENDER, DVM, MS, PHD, DIPLOMATE ACZM ILLINOIS FALL CONFERENCE 2015 Outline Background Physical Examination Sample Collection Hematology Plasma electrophoresis Pathogen detection Background Traditional means for determining health PE, CBC, Chem, Radiographs What is healthy? Lack of abnormalities on PE, bloodwork Absence of parasites Behaving normal Lack of clinical signs on history Mammalian characteristics of health are not always appropriate for reptiles Temperature

2 Background Common disorders Chelonia Trauma Infectious diseases Mycoplasma, herpesvirus, ranavirus Metabolic diseases Aural abscesses Squamata Serpentes Upper respiratory infections Pseudomonas, OPMV Viral infections - Boids Anorexia Reproductive Sauria Fungal dermatitis Metabolic disease Physical Examination Approach Follow same pattern each time, i.e. head to tail Evaluation of head Symmetry of the eyes, nares (Mycoplasma and ranavirus), tympanum Lack of discharge ORAL EXAMINATION!!! Most important portion of a reptile examination Dehydration, septicemia, anemia, infectious disease, vitamin deficiency

3 Photo courtesy of Matt Allender Photo courtesy of Juergen Schumacher Photo courtesy of Juergen Schumacher

4 Photo courtesy of Mark Mitchell Photo courtesy of Juergen Schumacher

5 Physical Examination Approach, cont. Musculoskeletal Range of motion, response to stimuli Ulcerations, flaking, swelling of the skin Symmetry of the bones, shell Neurological Normal mentation at rest Ability to locomote Lack of opisthotonous, torticollis Integument Swellings, discharge, abnormal scales Lacerations Photo courtesy of Mark Mitchell Photo courtesy of Juergen Schumacher

6 Photo courtesy of Juergen Schumacher Photo courtesy of Mark Mitchell

7 Photo courtesy of Matt Allender Photo courtesy of Matt Allender Photo courtesy of Matt Allender

8 Physical Examination Cardiorespiratory Mucous membranes Doppler for heart rate Auscultate through wet gauze or paper towel for lung fields Evaluate glottis for discharge, increased respiratory effort Coelomic Digital palpation Reproductive, gastrointestinal, and urogenital structures Photo courtesy of Matt Allender Physical Examination Limitations Lack of access Chelonians shell obstructs access, difficulty in opening mouth Snakes ribs cover all but ventral 10-20% Difficulty in assessing heart No true auscultation Changes with temperature, seasonal, species Common disorders are those associated with access, not necessarily true prevalence Many common disorders have subtle or do not have varying degrees of severity, either not at all or really bad

9 Sample Collection Identify the structures, disorders, or diseases that are most likely to help you in assessing health Common tests utilize Blood Radiographs Tissue collection invasive or non-invasive Venipuncture Chelonians Jugular Subcarapacial sinus Brachial vein Femoral Tail sinuses Photos courtesy of Matt Allender and Terry Norton Venipuncture Snakes Cardiac Ventral tail vein Palatine Photos courtesy of Sykes and Klaphake, 2015

10 Venipuncture Lizards Ventral tail vein Ventral abdominal vein Cardiac Photos courtesy of Juergen Schumacher Complete Blood Counts Techniques More laborious than mammal CBCs Different techniques will result in different normals Need to be performed same day Different requirements for anti-coagulant Most turtles: lithium heparin Some lizards and snakes: EDTA Maximum blood volume is 0.8% of body weight 0.8 ml in 100 g animal All techniques to determine reptile WBC are manual Nucleated RBCs CBC techniques WBC Hemacytometer Labor intensive both diff and hemacytometer need to be read $5/sample Gives absolute WBC Blood smear Count #WBC in 40x field (average of 10 fields x 2000) Both techniques might be altered by poor blood smear, inexperience, or staining technique

11 CBC techniques Determination of total protein Manual Refractometer Determines total solids, not true protein, but are highly correlated Automated Chemistry machine Abaxis are historically unreliable for proteins Electrophoresis Most precise Requires special equipment, but will give protein fractions in addition to total CBC techniques Packed cell volume Manual Hematocrit tubes Read on card or dial Can read buffy coat as well Automated istat CBC analyzer CBC Temporal effects Yellow-marginated tortoises Higher PCV in drier/warmer months Lower monocytes in summer Asian yellow pond turtles All WBC cell types varied with season except monocytes Gopher tortoises Higher PCV during dry months Box turtles WBC and PCV are different between years

12 CBC in Box Turtles CBC Spatial effects Very little known about common species Box Turtles Differences in wild species between states Higher TS in northern latitude compared to southern latitude May indicate climatic or other environmental factors play a role in homeostasis CBC Life stage effects Very little known Indian cobra Higher PCV as age increases Massasauga Decreased TS in juveniles Increases in WBC driven by heterophils in juveniles Box turtles No effect of age class on any hematologic variable

13 CBC Sex New Guinea snapping turtles Higher PCV in males Desert tortoises Higher PCV in males Yellow-headed temple turtles Higher WBC in males Yellow-marginated box turtle Higher eosinophils in males Higher monocytes in females CBC Response to disease Ranavirus Red-eared sliders Decreases in TS at last sample before they died Other diseases Only inferences in response to disease Plasma Biochemistries Temporal effects Not an important factor in box turtles from Illinois and Tennessee Indiana Decreasing AST and phosphorus as active season progresses Boa Increase in AST and decrease in UA in summer Spatial effects Box turtles Higher Ca and phosphorus in northern latitudes compared to southern latitudes Age class Higher AST in some juveniles Ca and P more similar to adult males than males

14 Plasma biochemistries Sex Box turtles Higher Ca and P in females No difference in Ca:P ratio Higher BA in females Higher UA in males Massasauga Higher glucose in males Plasma electrophoresis Temporal Box turtles Higher TP and albumin in summer Carpet python Higher albumin and AG ratio in summer Boa Higher alpha globulin in summer Spatial Box turtle Higher TP, albumin, and globulin in northern latitudes Demographic Box turtle Higher TP and globulin in adult females Massasauga Increase gamma globulins in adults Males higher alpha 2 globulins Plasma electrophoresis Response to disease Massasauga Increase gamma globulins with fungal dermatitis Little known in other species Limitations An incredible gap in knowledge of normal response Unknown how disease will affect results Non specific changes could indicate multiple diseases

15 Pathogen detection Methods Pathogen detection PCR ELISA Culture Isolation Pathogen exposure ELISA HI Pathogen detection Presence of a pathogen does not necessarily mean disease Herpesvirus in box turtles Positive May July Pathogen detection Chelonians Determine status of Mycoplasma, herpesvirus, and ranavirus Presence of other pathogens as needed Micro-arrays might be used Snakes Boids Need IBD status Vipers SFD status OPMV not helpful Lizards Adenovirus?

16 Conclusions Assessing health is paramount to determining course of treatment and prognosis A single CBC, plasma biochemistry, result is rarely helpful in identifying disease, but serial samples or comparisons among similarly grouped animals may detect significant changes Differences in species, season, age class, sex A health assessment should involve multiple modalities PE is critical True assessment of health in reptiles is evolving Thank you Matt Allender Clinical Assistant Professor, University of Illinois Director, Wildlife Epidemiology Lab 2001 S. Lincoln Ave. Urbana, IL WildlifeEpi@vetmed.illinois.edu