canine chagas - vida pharmacal...chagas disease clinical symptoms in feline and humans 9 feline...
TRANSCRIPT
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Heartworm Disease Of the 21 st Century
Canine Chagas
Chagas DiseaseAmerican Trypanosomiasis
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Chagas Disease
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T. cruzi Trypomastigote, 15-20um T. cruzi Amastigote, 2-4um
Chagas DiseaseLouisiana
5.3% Shelter/Companion animals
Tennessee
6.4% Companion animals
Texas (~630,000 infected)
9% Shelter dogs
13.1% Companion animals San Antonio region
8% U.S. Military Working dogs
Oklahoma
3.6% Companion animals
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Preva lence
Chagas Disease
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Chagas DiseaseCl in ica l Symptoms Canine
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Acute Collapse
Arrhythmias
Lymphadenopathy/Splenomegaly
Fever
Neurological signs
Chronic Arrhythmias
Ascites
Congestive heart failure
Weight loss
Lethargy
Acute death
ASYMPTOMATIC
Chagas Disease
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Chagas Disease
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Chagas DiseaseCl in ica l Symptoms in Fe l ine and Humans
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FelineCardiovascular and gastrointestinal symptoms
In Mexico, urban domestic cats were determined to be important peridomestic reservoirs
No studies have assessed the epidemiology of Chagas disease in cats in the US
Currently assessing cohorts of Texas cats presenting to the TAMU Teaching Hospital for T. cruzi-associated cardiac disease
HumansCardiac
DCM#1 cardiomyopathy in Latin America
GastrointestinalMegaesophagusMegacolon
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Atrial arrhythmiasVentricular arrhythmias
Chagas Disease
Chagas Disease
ECGRange of arrhythmias
Arrhythmogenic antibodies
Autonomic denervation
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Diagnostic ImagingRadiographs
Echocardiogram
PathologyBlood smear
Troponin
White blood cell count
Lymph node aspirates
Necropsy
Chagas Disease
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Diagnostics• Serology (21 day post infection)
• IFA GOLD STANDARD
• Lifelong persistence likely
• Texas Veterinary Medical Diagnostic Laboratory
• ELISA
• Not FDA approved
• Western Blot
• Not commercially available
PCR• Kinetoplast DNA 121/122
• 99%+ Acute sensitivity, 100% specificity
• 51% Chronic sensitivity, 100% specificity
• Decreased parasitemia with chronicity of infection
• Serial PCR - Good for monitoring treatment efficacy
Blood Culture• Slow (2-20 weeks)
• Limited
Chagas Disease
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Case Study
Molly9 Yr Spayed Labrador Retriever
Indoor / Outdoor
200 acre ranch East Texas
Weakness
Collapse
Panting
Weight loss
Ascites
Hyporexia
Chagas Disease
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Case Study
MollyRadiographs
ECG
CBC/Chemistry
Chagas IFA
1:640PCR
Positive
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Chagas Disease
Benznidazole• Targets T. cruzi DNA via free
radical generation
• Not FDA approved in dogs
• Difficult to obtain
• Good efficacy in Acute phase (>90% efficacy)
• Poor efficacy in Chronic phase (BENEFIT study)
• Side effects common
• Efficacy is highly strain dependent
Allopurinol• Xanthine oxidase inhibitor (reduces
uric acid)
• Humans 62% reduction in parasitemia
• Unknown efficacy in dogs via purine inhibition
Other Azoles• Ketoconazole
• Fluconazole
• Posaconazole
• Ravuconazole
Chagas Disease Treatment
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Amiodarone• Class III antiarrhythmic
• Disrupts calcium homeostasis/Cruzipain
• Loading dose: 15mg/kg PO BID x 7 d,
7.5mg/kg PO BID x 14 d then….
• Maintenance: 7.5mg/kg PO SID
• Adverse events: ALT/SAP elevations,
lethargy, anorexia
Itraconazole• Triazole antifungal
• Interferes with ergosterol synthesis
• 10mg/kg PO SID with food
• Adverse events: anorexia, vomiting,
weight loss, cutaneous eruption,
ALT/SAP elevations, lethargy
Target 2-3 ug/mL
Treatment is for 12 months
Chagas Disease
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Case Study
MollyAbdominocentesis
Quadruple therapy
Itraconazole 300mg PO SID
ITZ #1: 8.2 ug/mL (2-3ug/mL)
Reduce itraconazole 100mg PO SID
ITZ #2: 2.2 ug/mL (2-3ug/mL)
Amiodarone 250mg PO SID
PCR negative @ 1 and 6 months
Chagas Disease
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Case Study
MollyQuadruple therapy
1. ACEi
Enalapril or Benazepril 0.5mg/kg PO SID
2. Pimobendan
2-3 mg/kg PO BID
Dose escalation q 8 hrs
3. Furosemide
1-3 mg/kg PO BID; caution for ascites
4. Spironolactone
RAAS inhibition, reduction of fibrosis
2 mg/kg PO SID
Chagas Disease
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Case Study
Molly
Reduction in cardiomegaly
Minimal ascites
No pleural effusion
Normal appetite
Weight gain
Normal activity
Begging for table food (again!)
Monitor PCR 1 and 2 months post tx
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