Diagnostic Guide for Marek s Disease and other Tumors

Transcription

1 Diagnostic Guide for Marek s Disease and other Tumors Veterinary Diagnostic Pathology, LLC Frederic J. Hoerr, DVM, PhD fred.hoerr@gmail.com; ; CF TumorHistopathologyDiagnosticGuide.FJH /17 total

2 Resources for Marek s Disease and Tumor Diagnostics - $40 USD CF TumorHistopathologyDiagnosticGuide.FJH Online $0 USD - PDF 2

3 Diagnostic Strategy for Marek s and Tumors History, epidemiology, clinical observations, necropsy Characterization of the tumor cell Characterization of the virus Presence Quantity Absence The pathogenesis and diagnosis viral tumor disease is complicated. A practical diagnostic strategy helps to make the correct diagnosis. CF TumorHistopathologyDiagnosticGuide.FJH

4 Broilers or Young Breeders & Layers Clinical presentation Immunosuppression Skin lesions at slaughter Lymphoma at slaughter Paralysis classic presentation Transient paralysis Causes Errors in vaccine administration Emergence of new challenge strain CF TumorHistopathologyDiagnosticGuide.FJH

5 Broilers or Young Breeders & Layers History and Epidemiology Age of birds affected Date first observed Breeder flock Hatchery source Farm history Necropsy Examine multiple birds Record the incidence and severity of lesions Examine skin, viscera, and nerves Photograph representative lesions cell phone cameras CF TumorHistopathologyDiagnosticGuide.FJH

6 Broilers or Young Breeders & Layers Vagus nerve Histopathology Skin lesions with 1 cm margin Nerves from each chicken, Vagus, brachial plexus, and sciatic Select enlarged nerves if possible Tumors Spleen, liver, kidney, gonad, brain, and proventriculus from each chicken One eye from each affected chicken Use neutral-buffered formalin! 10 formalin:1 tissue Pelvic plexus and sciatic CF TumorHistopathologyDiagnosticGuide.FJH

7 Broilers or Young Breeders & Layers FTA Cards If possible, collect from euthanized affected chicken Label the cards!! Enlarged feather follicle Feather pulp Tumors blot the central portion Whirl-Pak bags (optional) Feather pulp, skin lesions, and tumors in separate bags Ice for transport Freeze to hold for testing. Store in a freezer with no automatic defrost, or on dry ice (CO2), or liquid nitrogen CF TumorHistopathologyDiagnosticGuide.FJH

8 Marek s Disease in Breeders and Layers CF TumorHistopathologyDiagnosticGuide.FJH

9 Tumor diagnosis in breeders and layers Tumor or a non-neoplastic lesion? Lymphoma? Marek s disease, avian leukosis, or reticuloendotheliosis Spontaneous lymphoma with no viral association Not lymphoma but viral etiology? Myelocytomatosis, histiocytic sarcoma, hemangiosarcoma Lymphoma : Common lesion with different etiologies, each requiring different prevention and control responses Diagnosis is possible if the correct specimens are available. CF TumorHistopathologyDiagnosticGuide.FJH

10 Tumor diagnosis in breeders and layers History and Epidemiology Age of birds affected Date first observed Breeder flock Hatchery source Farm history Clinical Examination Select cull or sick chickens With gloved hand, palpate the bursa of Fabricius through the dorsal wall of the cloaca Chickens with enlarged bursa are valuable for necropsy If all bursae are normal, proceed with necropsy CF TumorHistopathologyDiagnosticGuide.FJH

11 Tumor diagnosis in breeders and layers Necropsy Examine multiple birds Record the incidence and severity of lesions Examine skin, viscera, and nerves, brain, bursa of Fabricius, thymus, and eyes Photograph representative lesions cell phone cameras CF TumorHistopathologyDiagnosticGuide.FJH

12 Tumor diagnosis in breeders and layers Histopathology Skin lesions with 1 cm margin Nerves from each chicken, Vagus, brachial plexus, and sciatic Select enlarged nerves if possible Tumors Spleen, liver, kidney, gonad, brain, and proventriculus, bursa, (thymus) from each chicken One eye from each affected chicken Use neutral-buffered formalin! 10 formalin:1 tissue Marek s - ocular lymphoma Avian leukosis bursa intrafollicular lymphoma CF TumorHistopathologyDiagnosticGuide.FJH

13 Lesion distribution Tissue Marek s Leukosis Reticuloendotheliosis Spontaneous Lymphoma Viscera Eye (-) Nerve + - (+) (-) Bursa Interfollicular (initial) Intrafollicular (initial) Intrafollicular (initial) Brain (-) (-) CF TumorHistopathologyDiagnosticGuide.FJH

14 Tumor diagnostics in breeders and layers FTA Cards If possible, collect from euthanized affected chicken Label the cards!! Enlarged feather follicle Feather pulp Tumors blot the central portion Whirl-Pak bags (optional) Feather pulp, skin lesions, and tumors in separate bags Ice for transport Freeze to hold for testing. Store in a freezer with no automatic defrost, or on dry ice (CO2), or liquid nitrogen CF TumorHistopathologyDiagnosticGuide.FJH

15 Tests and Procedures Standard Gross pathology Histology Impression smear cytology Autolysis decreases cytological detail; however, if sufficient tissues are available (eye, nerve, bursa), the lesion distribution can support a diagnosis Advanced Immunohistochemistry DNA Analysis PCR Virus Isolation Serology CF TumorHistopathologyDiagnosticGuide.FJH

16 Tumor virus detection and diagnosis Dual or multivalent infections are common Exogenous and endogenous retroviruses Negative tests = negative Positive tests = Identification of virus by sequencing Marek s disease vaccine virus infects for life Positive tests = expected result (vaccine) Viruses differentiated by specific primers or sequencing Tumors have more virus than normal tissue Tumor viruses MUST be differentiated by exclusion. Dr. Guillermo Zavala CF TumorHistopathologyDiagnosticGuide.FJH

17 Acknowledgements & References Dr. Gregorio Rosales Dr. Guillermo Zavala Dr. Susan Lockaby AAAP Frequently Asked Questions on Tumor Virus Diseases Tumor Diagnosis Manual The Differential Diagnosis of Lymphoid and Myeloid Tumors in the Chicken CF TumorHistopathologyDiagnosticGuide.FJH