Canine/Feline Protozoa Flashcards
Giardia intestinalis-Hosts
Dogs, cats, humans Different "assemblages" which vary in infectivity for animals Assemblage C/D: dogs Assemblage F: cat Assemblage A or B: human, dog, cat
Giardia intestinalis-Identification
Trophozoites: 21um long, teardrop, 2 nuclei, 8 flagella
Cysts: 12um long, ovoid, 4 nuclei
Giardia intestinalis-Life Cycle
Trophozoites adhere to microvilli of epithelial cells of SI→multiply by binary fission or budding→ trophozoite encyst→cysts pass in feces and are the infective form
Cysts may survive 2-4wks
PPP = 1-2wks
Giardia intestinalis-Site of Infection
Small intestine
Giardia intestinalis-Pathogenesis and Lesions
Attach to microvilli of proximal small bowl to feed, occasionally cause duodenal ulcerations, malabsorption common
Giardia intestinalis-Clinical Signs
Often asymptomatic
Acute or chronic diarrhea
Giardia intestinalis-Diagnosis
Zinc sulfate to find cysts in feces, trophozoites in fresh diarrhea, double centrifugation, ELISA and IFA assays for antigens
Giardia intestinalis-Treatment and Identification
No treatments approved in USA for dogs/cats, prevention with sanitation and disinfection, filters with 10um aperture prevent transmission
Trypanosoma cruzi-Common Name
Chagas’ disease
Trypanosoma cruzi-Hosts
Dogs, cats, humans
300,000 infected, 300 prenatal infections/yr in USA
Trypanosoma cruzi-Identification
Trypomastigote: elongated, spindle/leaf shaped, 20um long with nucleus near middle, single flagellum
Trypanosoma cruzi-Life Cycle
Infected reduviid bug takes blood meal and releases trypomastigotes in its feces near site of bite wound→ trypomastigote enters host through wound→ invades cells and differentiates into amastigotes→ multiply by binary fission→devel. into trypomastigotes and released into bloodstream (cannot replicate)→ reduviid bug takes blood meal ingesting trypomastigotes→ transform into epimastigotes in midgut→ multiply and differentiate into trypomastigotes
Trypanosoma cruzi-Site of Infection
Cardiac and smooth muscle
Blood
Trypanosoma cruzi-Pathogenesis and Lesions
Amastigotes cause pathology of cardiac muscle
Chagas’ disease in humans and dogs
Puppies and kittens most susceptible
Trypanosoma cruzi-Clinical Signs
Acute and chronic cardiac disease
Pale mucous membrane, lethargy, ascites, hepatomegaly, splenomegaly, tachyarrhymia, lymphadenopathy
Trypanosoma cruzi-Diagnosis
Trypomastigote in blood smear
Xenodiagnosis or serological tests
Trypanosoma cruzi-Treatment and Prevention
None
Cystoisopora (Isopora) canis-Common Name
Coccidia
Cystoisopora (Isopora) canis-Hosts
FH: dogs
PH: rodents
Cats have their own species, Cystoisospora felis/rivolta
Cystoisopora (Isospora) canis-Identification
Largest species, 50 um
Sporolated oocysts are spherical, 2 sporocysts with 4 sporozoites, oval
Unsporolated oocysts are a single cell
Cystoisopora (Isospora) canis-Life Cycle
Sporulated oocysts are infective form
Sporulation, infection and schizogony (or merogony), and gemetogony and oocyst formation
Cystoisopora (Isospora) canis-Site of Infection
Small Intestine
Cystoisopora (Isospora) canis-Pathogenesis and Lesions
Small intestinal cells are destroyed leading to enteritis
Cystoisopora (Isospora) canis-Clinical Signs
Typically asymptomatic
Diarrhea may be severe, watery, profuse and bloody (young most susceptible)
Cystoisospora (Isospora) canis-Diagnosis
Fecal flotation
oocyst smaller than ascarid eggs (80-100um) and larger than Sarcocystis (18um)
Cystoisospora (Isospora) canis-Treatment and Prevention
Management is critical
Overcrowding and poor sanitation leads to heavy contaminated environ with oocysts
Antiprotozoal
Toxoplasma gondii-Hosts
Cats
*Zoonosis
Toxoplasma gondii-Identification
Oocysts small, 12um sporulated oocysts have 2 sporocysts with 4 sporozoites
Toxoplasma gondii-Life Cycle
Unsporulated oocysts shed in feces→sporulate in environ.→IH ingests sporulated oocyst→tachyzoites in muscle and neural tissues→ bradyzoites→cat ingests infected IH Or by direct transmission of oocysts HUMAN INFECTION -Foodborne -Animal to human -Mother to child
Toxoplasma gondii-Site of Infection
Intestinal and extraintestinal tissues (muscle, liver, lung, brain etc.)
Toxoplasma gondii-Pathogenesis and Lesions/Clinical Signs
Typically asymptomatic.
Depends on the organs involved and extent of cells infected
Acute toxoplasmosis
Severe signs seen in cats with FIV. Pneumonia
Toxoplasma gondii-Diagnosis
Oocysts in fecal exam
Serological tests, modified direct agglutination test, ELISA and IFA tests
Toxoplasma gondii-Treatment and Prevention
Avoid contact with feces and eating uncooked meat
Pregnant woman should be especially careful.
Nonsulfonamides and sulfonamides
Sarcocystis spp.-Hosts
FH: dogs, cats, humans
IH: cattle, herbivores, omnivores and birds
*Zoonosis
Sarcocystis spp.-Identification
Sporulated oocysts with 2 sporocysts with 4 sporozoites, 18um
Sarcocystis spp.-Life Cycle
Gametogony in FH and schizogony and sarcoocyst formation in the IH
Infection caused by ingestion of mature sarcocysts with bradyzoites in muscles of IH
Sarcocystis spp.-Site of Infection
Muscles of IH
Sporocysts in GI tract of FH
Sarcocystis spp.-Pathogenesis and Lesions/Clinical Signs
No illness in FH.
Schizogony in endothelium of herbivore may result in fatal illness.
Can cause abortion
Sarcocystis spp.-Diagnosis
Sporocysts in FH
Bradyzoites in muscle tissue of IH
Sarcocystis spp.-Treatment and Prevention
Avoid raw meat and prevent fecal contamination
Hepatozoon spp.-Hosts
Dogs
Hepatozoon spp.-Identification
Gamonts in blood cells of peripheral blood
Hepatozoon spp.-Life Cycle
Dogs become infected by ingesting infected tick
Hepatozoon spp.-Site of Infection
Schizonts in various tissues
Gamonts in white blood cells
Hepatozoon spp.-Pathogenesis and Lesions/Clinical Signs
H. canis-subclinical infection
H. americanum-severe disease, neutrophilic leukocytosis, joint pain, myositis
Hepatozoon spp.-Diagnosis
Gamonts in peripheral blood
Muscle tissue biopsy or necropsy
Hepatozoon spp.-Treatment and Prevention
No satisfactory treatment
Tick control
Babesia spp.-Condition
Canine babesiosis, canine piroplasmosis
Babesia spp.-Hosts
Dogs
Occasionally humans
Babesia spp.-Identification
Trophozoites in RBCs, round, ovoid, elongate, amoeboid, pyriform, club-shaped
Babesia spp.-LIfe Cycle
Infected by inoculation by a tick
Babesia spp.-Site of Infection
Erythrocytes
Babesia spp.-Pathogenesis and Lesions/Clinical Signs
Erythrocyte destruction leads to depression, anorexia, anemia and splenomegaly
Babesia spp.-Diagnosis
Trophozoites in peripheral blood smear using Giemsa stain
Serology, PCR
Babesia spp.-Treatment and Prevention
Antiprotozoal but not approved in USA
Tick control
Theileria (Cytauxzoon) spp.-Hosts
Cats
Theileria (Cytauxzoon) spp.-Identification
Merozoites 1-2um in RBCs
Theileria (Cytauxzoon) spp.-Life Cycle
Transmitted by A. americanum tick
Theileria (Cytauxzoon) spp.-Site of Infection
Blood
Theileria (Cytauxzoon) spp.-Pathogenesis and Lesions
Rapid and fatal disease, die within 9-15 days after infection,
Developing schizonts cause enlargement of infected cells.
Occlusion of blood vessels to heart, liver and lungs
Theileria (Cytauxzoon) spp.-Clinical Signs
Pyrexia, anemia, icterus, dehydration, death
Theileria (Cytauxzoon) spp.-Diagnosis
Wright’s or Giemsa stained blood smears reveal merozoites, PCR
Theileria (Cytauxzoon) spp.-Treatment and Prevention
No satisfactory treatment
Tick control
