Protozoa I & II

IN PROGRESS

Trophozoite

increased metabolic & reproductive activity

Cyst

decreased metabolic & productive activity

Homoxenous

uses one host species

Heteroxenous

uses more than one host species

Faculative Heteroxenous

may use more than one host species

Class Amobae

move via pseudopodia

• Entamoeba histolytica

Entamoeba histolytica

Host: K9, Fel, primates

Transmission: cyst ingested from food or water contaminated with large animal feces

Signs: LI D in K9, amebic dysentery in humans, 3rd leading parasitic cause of death

ZOONOTIC

Class Flagellates

fiber propels protozoan

• Giardia spp.

• Leishmania

• Trypanosoma cruzi

• Trypanosoma evansi

Giardia intestinalis

Host: all vertebrates

Transmission: Ingestion of cyst from contaminated food, water, or fomites

Signs: malabsorptive D w/ normal appetite

Diagnostics: ZnSO₄ Float, ELISA, Direct Smear

ZOONOTIC, most common protozoal D

Reproduce via binary fission

Leishmania

Host: K9, Fel, humans

Transmission: sandflies

Signs: mucocutaneous skin sores or visceral form affecting spleen, liver, & bone marrow (anemia & immunocomp)

ZOONOTIC, vx exists for dogs, infected dogs are euthanized

Trypanosoma cruzi

“Chagas Disease”

Host: K9 & humans

Transmission: kissing bug feces entering bite wound or ingested

Signs: hemoprotozia found in cardiac muscle → heart failure

ZOONOTIC

Trypanosoma evansi

“Surra”

Host: K9, Fel, cattle, equine, camelids

Transmission: mating, ingestion of infected tissue or milk

Signs: fever, edema, neuro, weakness, death

Sub-Phylum Apicomplexa

spore-producing protozoa that move via undulations & gliding, w/ a distinct banana shape.

• intestinal coccidia

  • Eimeria

  • Cystoisospora

  • Cryptosporidium parvum

• tissue cyst-forming coccidia

  • Toxoplasma gondii

  • Neosporum caninum

  • Sarcocystis neuroa

• hemo-protozoa

  • Babesia bigemina

  • Babesia canis

  • Babesia equi, Babesia caballi

  • Cytauxzoon felis

  • Hepatozoon spp.

  • Plasmodium spp.

  • Haemoproteus

  • Leucocytozoon

Apicomplexa Reproduction

Oocyst = cyst stage containing sporozoites

Sporogony = zygote → oocyst; outside host

Schizogony = asxual repro w/in host

Gametogony = sexual repro w/in host

Coccidia

Eimeria - 4 sporocysts, 2 sporozoites each

• Calves, scours

Cystoisospora - 2 sporocysts, 4 sporozoites each

• K9, Fel, Swine, young D

Cryptosporidium parvum

Host: mammals, birds, reptiles

Transmission: contact w/ calf D, immediately infective

Signs: watery D, cryptosporidiosis, scours

Diagnostics: direct smear (stain red), antigen testing

Toxoplasma gondii

Host: definitive → Fel, many other intermediate hosts

Transmission: Ingestion of sporulated cysts

Signs: asymptomatic in cats unless immunocompromised, if during pregnancy → abortion, stillbirth, neuro defects

Diagnostics: fecal float

Neosporum caninum 

Sarcocystis neuroa

Babesia bigemina

Babesia canis

Babesia equi, Babesia caballi

Cytauxzoon felis

Hepatozoon spp.

Plasmodium spp.

Haemoproteus

Leucocytozoon