Chagas Disease Flashcards
Chagas disease
-caused by hemoflagellate protozoan= Trypanosoma cruzi
-transmitted by feces of triatomine bug (kissing bug)
-affects dogs and people
Trypanosoma cruzi lifecycle
-feed at night
-attracted to mouth and nose heat
-bug defecates and deposits infection… human rubs into mouth or wound
-epimastigotes develop inside bug into trypomastigotes which infect human
-amastigotes common in heart tissue
-amastigotes transform to trypomastigotes bursting out of cell into blood
Distribution of kissing bug
South america and mexico
South USA
Transmission of chagas
-ingestion of bug
-feces rubbed into mouth and wounds
-ingestion of infected animals
-ingestion of acai/fruit juice infected with bugs or their feces
Clinical signs in humans and dogs
-lethargy, decreased appetite, weight loss
-fainting, exercise intolerance, vomiting, diarrhea
-cardiomegaly, heart failure, arrythmias, organomegaly (spleen, liver), sudden death
Acute chagas disease
-usually no signs,
-lymph nodes and spleen enlarged, pale gums
Indeterminate/latent chagas disease
-dog enters this stage after seroconversion
-asymptomatic and amastigotes in tissues
**dog can stay in this stage its whole life
Chronic Chagas disease
Symptoms
amastigotes continue to replicate in the dog and develop heart failure
Acute stage Diagnosis
-uncommon
-PCR
-direct exam with microscopy= blood smears but not reliable because parasite load may be low
**if animal progressed out of acute stage, then detection in blood low
Diagnosis in indeterminate/chronic stage
-also uncommon
-serological assays (at least 2, 3rd to confirm)
**ELISA, IFA, IHA, immunochromatographic qualitative assay
Most common Chagas disease diagnosis
-clinical presentation: cardiomegaly, organomegaly
-can use ECG
Epidemiology of Chagas disease
-if dog and owners from Canada, then not Chagas disease BUT if animal travelled or lived in Central America then Chagas potential
**remember DCM linked with Dobermans, great danes, boxers, cocker spaniels, AND gluten free diets
Chagas treatment
Humans: benzimidazoles and Nifurtimox
Dogs: Benzimidazoles, Ravuconazole, Albaconazole
*best to use antiarrythmics and pacemaker implants
Drugs best in acute stage, chronic sees 50% decrease
Zoonoses of Chagas
-no vaccine and poor treatment
-millions of people infected; many undiagnosed
