"Grey Lady" SIGNALMENT: 4 years old spayed female Weimaraner Geographic location: Kingsville, TX Weimaraner, "Grey Lady" HISTORY • decreased activity several weeks • occasionally appears reluctant to move • decreased appetite • owner thinks dog "has a fever" "Grey Lady" Weimaraner PHYSICAL EXAM • quiet but alert • slightly underweight body condition (BCS 3.5-4) • submandibular, prescap, popliteal LNs somewhat enlarged • few petechial hemorrhages on oral membranes • vague reluctance to move, ? lameness ? • T= 102.8, well hydrated • heart rate, respiration within normal limits preliminary differential diagnostic list? D degenerative A autoimmune A anomalous M metabolic virus ? N neoplastic bacteria I infectious fungus T traumatic protozoa helminth T toxic preliminary differential diagnostic list? INFECTIOUS: intracellular bacteria intracellular hemoprotozoa AUTOIMMUNE: immune mediated disease? multisystemic disease Diagnostic plan? CBC Chemistry panel Aspirate LN - cytology coagulation panel urinalysis ? Laboratory Results CBC: RBC within normal limits WBC within normal limits Platelets 128,000 (200,000 - 900,000) Laboratory Results Chem panel abnormals: ALT: 244 (10-130) Alk Phos: 284 (24-147) Tot protein: 6.4 (5.7-7.8) albumin: 2.5 (2.4-3.6) globulin: 3.9 (1.7-3.8) Diagnostic Results Cytology - lymph node aspirate reactive hyperplasia plasmacytoid characteristics moderate degenerative neutrophils no bacteria visualized Laboratory Results coagulation panel: normal urinalysis: normal Problem List: generalized lymphadenopathy intermittent fever physical findings ? lameness thrombocytopenia slight hyperglobulinemia laboratory findings borderline hypoalbuminemia Additional Diagnostic Testing? • 'tick panel' serology • examine stained blood film Diagnostic Results SEROLOGIC "tick panel" RMSF 1:64 Ehrlichia canis positive 1:1024 Bartonella neg < 1:16 Babesia neg < 1:16 No pathogens seen on stained blood films Additional Diagnostic Testing? OTHER CHOICES NOW AVAILABLE: 'tick panel' real-time PCR point-of-care rapid immunodiagnostic tests Ehrlichia Family Tree alpha-proteobacteria obligate intracellular bacteria Order: Rickettsiales • Family: Anaplasmataceae Genus: Anaplasma Genus: Ehrlichia Genus: Neorickettsia • Family: Rickettsiaceae Genus: Rickettsia Rickettsiaceae Name Changes E. platys Anaplasma platys E. phagocytophila A. phagocytophilum E. equi A. equi Anaplasma Neorickettsia E. risticii E. sennetsu Rickettsiaceae Family Tree Grouped according to cell trophism • monocytotrophic (monocyte, macrophage) • granulocytotrophic (neutrophil, eosinophil) • thrombocytotrophic Canine Ehrlichiosis Monocytotropic species *Ehrlichia canis Neorickettsia risticii Ehrlichia chaffeensis Granulocytotropic species Ehrlichia ewingii Anaplasma phagocytophilum Thrombocytotropic species Anaplasma platys Ehrlichia canis • worldwide geographic distribution • vertebrate hosts • domestic dog, coyote, fox, jackal • tick hosts • Rhipicephalus sanguineus • Dermacentor variabilis (experimental) TICK REVIEW Rhipicephalus sanguineus • one host or three host tick? • host feeding preferences? • define transstadial • define transovarial TICK REVIEW Rhipicephalus sanguineus Fig 5.42 Zajac & Conboy text TICK REVIEW Rhipicephalus sanguineus - 3-host tick diagram from Foreyt lab manual TICK REVIEW Rhipicephalus sanguineus - 3-host tick https://www.cdc.gov/ticks/geographic_distribution Ehrlichia canis - transmission Rhipicephalus sanguineus (brown dog tick) • all tick stages feed preferentially on dogs • transstadial transmission in tick Ehrlichia spp. Pathogenesis • infect leukocytes – remain in phagosome & replicate morula: multiple organisms in cell vacuole • hematogenous spread • multisystemic disease lysosome nucleus http://kroun.ulmarweb.dk/micrococ.htm Ehrlichia spp. Diagnosis • history • clinical presentation / physical exam • laboratory testing • specific diagnostic testing – antigen (evidence of organism) – serology (antibody as host response) – molecular (evidence of organism) – microscopic ID of agent/pathogen Ehrlichia spp. Diagnosis HISTORY • Ehrlichia - endemic location (including travel) • likely tick exposure Ehrlichia spp. Diagnosis CLINICAL SIGNS Acute: Chronic: • fever • weight loss • anorexia • bleeding disorders • lethargy • polyarthritis • lymphadenopathy • +/- seizures • +/- uveitis • multisystemic signs • +/- CNS signs • +/- bleeding disorders Ehrlichia spp. Diagnosis LABORATORY ABNORMALITIES: • anemia • thrombocytopenia • hypergammaglobulinemia • +/- hypoalbuminemia • +/- pancytopenia • +/- proteinuria Ehrlichia spp. Diagnosis: Agent Detection • stained blood film: morula in leukocytes: rarely seen in clinical cases Ehrlichia spp. Diagnosis: Serology point of care tests Idexx Laboratories SNAP 3DX™ Heartworm Ag, Lyme & E. canis antibodies SNAP 4DX™ adds Anaplasma phagocytophilum Ab SNAP 4DX plusTM adds E. ewingii, A. platys Ab Ehrlichia spp. Diagnosis: Serology - send out NCSU: "tick panel" http://www.cvm.ncsu.edu/vhc/csds/ticklab.html other state vet diagnostic labs Ehrlichia spp. Diagnosis: Serology Indirect Fluorescent Antibody Test (Titers) • detects antibodies (exposure) • cross-reactive with most Ehrlichia spp. • titers more common than disease Ehrlichia spp. Diagnosis: Molecular PCR, quant PCR, RT-PCR increasing commercial choices • NCSU • IDEXX • ANTECH • some state vet diagnostic labs Ehrlichia spp. Diagnosis: Agent Detection PCR • can differentiate cross-reactive Ehrlichia species or co-infection with 2 species • expensive • variable turn-around time for results Nicholson et al., Trends in Parasitol. 2010 IDEXX decision tree 2013 Ehrlichia Predisposing Conditions • Exposure to Ticks • Endemic Geographic Areas • Ehrlichia : German Shepherds ? – more susceptible more severe course – appear to have poor cell-mediated immune response Ehrlichia Therapeutic Considerations Doxycycline (tetracycline, minocycline) high levels within cells! 28 days (ACVIM recommendations) but response in 7-10 days Agents may still persist monitor hematology, serologic titers (?) relapse not uncommon Treat patients with disease Do not treat patients with antibody titers Ehrlichia Therapeutic Considerations • Imidocarb (ImizolJ) – standard Babesia treatment – effective against Ehrlichia – single injection, repeat in 2-3 weeks Tick-Borne Pathogens • Polymicrobial infections involving 2+ tick- borne pathogens are now recognized. • Clinical signs: combinations & usually BAD. • if you detect one of these agents, consider testing for others, especially if response to treatment is limited. Lyme Borrelia, Ehrlichia & Babesia Preventive Measures • Tick avoidance, tick removal Ehrlichia - Public Health • Human Ehrlichiosis • usually other species in USA – E. chaffeensis, Venezuelan E. canis? • dogs bring owners into potential contact with tick vectors Human E. chaffeensis data from CDC http://www.cdc.gov/ehrlichiosis/stats/ accessed 3/15 Ticks Geographic Distribution Western blacklegged tick Blacklegged tick Lone star tick (Ixodes pacificus) (Ixodes scapularis) (Amblyomma americanum) Borrelia burgdorferi Ehrlichia ewingii Lyme disease source: CDC Anaplasma Ehrlichia phagocytophilum, chaffeensis, Ixodes Amblyomma Rickettsia rickettsii, Dermacentor RESOURCES North Carolina State Univ. CVM tick lab: http://www.cvm.ncsu.edu/vhc/csds/ticklab.html CDC website: http://www.cdc.gov/ticks/diseases http://www.cdc.gov/ehrlichiosis/stats/ Companion Animal Parasite Council website: http://www.capcvet.org/capc-recommendations/ .