Protozoan Parasites (34-35) Flashcards
How do protozoan parasites cause disease?
feed on solid tissues directly or after liquefying them (amoebas)
What are the major protozoan groups?
flagellates - intestinal; blood-lymphatics & tissue
coccidia - intestinal, tissue, blood
What are giardia sp. characteristics?
single cell, flagellate protozoan parasite
Where is giardia spp. associated with - outbreak-wise?
waterborne outbreaks
- swimming pools
- waterslides
- municipal water supplies ;/ sewage
What is the lifecycle of giardia spp.?
direct
How do trophozoites of giardia live in the host?
free - extra-cellular
attach via ventral sucking disk in lumen of proximal small intestine
How is giardia re-infected?
via fecal-oral contamination and ingestion of immediately infective cysts
What are the symptomatic infections of giardia spp. in dogs and cats?
water diarrhea in acute phases
voluminous, malodorous stools with mushy consistency
gas, flatulence
cysts appear in stools 7 to 14 days post-infection
What are symptomatic infections in humans regarding giardia spp.?
What are the genotypes of giardia?
Assemblage A-F
What kinds of animals are at risk for giardia?
shelters, boarding kennels, etc
multi-animal situations facilitate spread from infected asymptomatic animals to susceptible hosts
How do you manage giardia infections in companion animals?
A dog presents with greasy stools and anorexia. Upon a ZnSO4 fecal flotation, these organisms were found. What is the likely organism?
giardia spp.
What is tritrichomonas blagburni?
flagellate protozoan parasite in large intestine in cats
What is the causative agent for diarrhea in cats? (protozoan parasite)
tritrichomonas blagburni
How do you treat and prevent tritrichomonas blagburni?
A cat has had chronic diarrhea and was revealed to have lymphoplasmacytic colitis. What likely caused this?
tritrichomonas blagburni
A cow spontaneously had an abortion in her 1st trimester and was diagnosed with bovine genital trichomoniasis. What likely caused this?
tritrichomonas foetus
What are the blood and tissue flagellates?
broadly classified as trypanosomes
What is a trypomastigote?
flagellate trophozoite stage circulating in blood/lymph
- infective for the vertebrate host
- other stages are developmental in the arthropod IH
What is the anterior station of blood and tissue flagellates?
salivarian
bite of infected “teste fly”
What is the posterior station of blood and tissue flagellates?
sectorian
feeding rejuvidae bugs defecate and pass parasites
What is the general lifecycle of blood and tissue flagellates?
arthropods IH infected during blood meal
develop into trypomastigotes in IH
What is the scope of disease for trypanosomiasis?
african trypanosomiasis
T. brucei & T. gambiense
What is trypanosoma cruzi?
causative agent of “Chaga’s disease” or American trypanosomiasis
A human becomes ill with symptoms of mega-esophagus and myocardial disease. How did the parasite infect the host?
through contact with feces of an infected triatomine bug (or “kissing bug”), a blood-sucking insect that feeds on humans and animals
- vector borne: active defecation by IH, ingestion of IH
- non-vector borne: blood transfusion, organ/tissue transplantation, congenital, laboratory exposure, fecal contamination of food items
(this parasite is trypanosoma cruzi)
What is Romana’s sign?
edema and inflammatory response resulting from trypomastigotes defected on host and rubbed into eye
How do trypomastigotes proliferate, and where do they spread?
proliferate asexuality in histocytes as amastigote stage organisms
spread via the lymphatics enter tissues and continue to proliferate
What do trypomastigotes cause in dogs?
lymphadenopathy
myocarditis
pale mucous membranes
tachycardia
splenomegaly
What are leishmania sp.?
parasites infecting macrophages of vertebrate hosts
What stage is only in the host for leishmania sp.?
amastigote
developmental stages occur in Sand flies
How are leishmania sp. transmitted?
by fly bite
How do leishmania sp. cause disease in dogs?
significant hosts for the parasite in endemic localities
severe cutaneous manifestation of disease
proliferation in visceral tissue in advanced cases
visceral and muco-cutaneous disease in people and pets
A dog comes into a South American clinic and had severe cutaneous issues and lymphadenopathy. Microscope examination showed the following structure. How did the host become infected?
sand fly takes a blood meal —> promastigotes are phagocytized by macrophages —> change to amastigotes
(this parasite is leishmania sp.)
What symptoms do dogs with T. cruzi have?
presenting with symptoms of cardiac disease (proliferate in cardiac muscle and infection including):
- lymphadenopathy
- tachycardia
- ascites
- hepato/splenomegaly
What symptoms do dogs with leishmania have?
presenting with symptoms of dermatologic disease and infection including:
- lymphadenopathy
- hepato/splenomegaly
