Babesia canis: Merozoites
Blood smear
Cryptosporidium baileyi oocysts
On the ciliated cell surface of the trachea
Babesia canis merozoites
Blood smear, Giemsa-stained
Unsporulated Eimeria oocysts from a lamb
Eimeria acervulina macrogamonts & developing oocysts
Eimeria maxima: Sporulated oocyst
Iodine stain
Eimeria bakuensis: Unsporulated oocysts
Floatation method, methylene-blue stain
Eimeria: Unsporulated oocyst
E. robusta, methylene-blue stain
Eimeria stiedai: Oocysts
In destroyed biliary epithelium
Leishmania donovani: Promastigotes
Giemsa stain
Toxoplasma gondii: Tissue cysts
Mouse brain, HE stain
Trypanosoma equiperdum: Trypomastigotes
Giemsa stain
Encephalitozoon cuniculi: Focal encephalitis (see macrophages)
Rabbit brain, HE stain
Encephalitozoon cuniculi: Interstitial nephritis
Rabbit kidney, HE stain
Encephalitozoon cuniculi: Interstitial nephritis + CT proliferation
Rabbit kidney, HE stain
Eimeria bovis (larger) & Eimeria zuernii (smaller): Oocysts
Floatation, native
Leishmania donovani: Amastigotes in macrophages
Giemsa stain
Sarcocystis tenella: Tissue cyst
Sheep oesophagus, HE stain
Eimeria stiedai: Biliary hyperplasia
Rabbit liver, HE stain
Trypanosoma cruzi: Pseudocyst
In a section of heart muscle, HE stain
Trypanosoma equiperdum (Dourine): Dollar-spots on the horse
Giardia intestinalis: Cyst
Faecal smear, Lugol solution (iodine)
Giardia intestinalis: Trophozoite
Engorged tse tse fly
Responsible for the transmission of African Trypanosomes E.g:
- T. vivax
- T. congolensis
- T. brucei brucei
Histomonas meleagridis: Ameboids
Liver tissue, PAS stain
Kissing bug: Biological vector
Transmission of Leishmania chagasi (Chagas disease)
Leishmania: Amastigotes
Inside a macrophage
Cutaneous Leishmaniosis
Clinical signs of Nagana (African Trypanosmosis)
Transmitted by the Tsetse fly
Trichomonas infection (Hepatic form)
Pigeon head & liver
Sandfly: Biological vector
Transmission of Leishmania
Trichomonas: Trophozoites (Most likely: poultry)
Giemsa stain
Trypanosoma brucei: Trypomastigotes
Blood smear, Giemsa stain
Trypanosoma cruzi: Trypomastigote
+ a large kinetoplast, Giemsa stain
Lesions in the caeca & liver associated with Histomona meleagridis
Samples from a turkey
Lesions in the surface of the duodenum associated with Eimeria acervulina
Sample from a chicken
Eimeria brunetti: Bloody mucus in the lumen of the hindgut
Sample from a chicken
Macrogamonts with granular cytoplasm
One-nucleated oocysts surrounded by a wall in the destroyed wall of the intestinal mucosa
Eimeria maxima: Small haemorrhages & whitish spots of schizonts in the mucosa of the small intestine
Not to be confused with “salt & pepper” spots in E. necatrix infections
Eimeria necatrix: Haemorrhages in the jejunal wall
Nests of schizonts
Destroyed intestinal mucosa of chicken, HE stain
Eimeria tenella: Lesions of the caeca
Sample from a domestic chicken
Eimeria tenella: Lesions of the caeca
Sample from a domestic chicken
Eimeria truncata: Macrogamonts
Goose kidney tissue, HE stain
Eimeria: Sporulated oocyst
Stained with iodine
Three schizonts & free merozoites in a native mucosal smear
Coccidium spp.: Thick-walled, unsporulated oocysts
Eimeria stiedai: Biliary hyperplasia
Rabbit liver, HE stain
Clinical signs of acute bovine coccidiosis
Either E. zuernii or E. bovis
Clinical signs of Isosporosis of piglets (Isospora suis)
Eimeria stiedai: Unsporulated oocysts
These are often stained yellow by the bile
Eimeria bovis (large) & E. zuernii: Unsporulated oocysts
Section of a globidium
Located in the top layer of interstitial mucosa
Bovine coccidiosis (E. zuernii or E. bovis)
- Pinhead-sized white spots in the thickened mucosa of the intestine
- Covered with bloody mucus
Eimeria flavescens: Dilated caecum of a rabbit
Eimeria intestinalis: Thickened wall of small intestine
Sample from a rabbit
Eimeria magna: White groups of macroschizonts
Wall of the small intestine, rabbit
Eimeria piriformis: Thickened & whitish wall of large intestine
Sample from a rabbit
Eimeria stedai:
- Broadened parts of biliary ducts
- Yellowish nodules can be seen on the surface
Rabbit liver sample
Isospora: Sporulated oocyst
Isospora: Oocyst from:
- A dog
- A cat
Cryptosporidium baileyi:
- Thick-walled oocysts (red)
- Thin-walled oocysts (colourless)
Mucosal cell debris of bursa fabricus, Kinyoun stain
Neospora caninum: Thick-walled tissue cyst
Brain tissue, HE staining
Sarcocystis: Haemorrhagic diatheses on visceral serosa
Dalmeny disease (bo. only), Calf
Besnoitia besnoiti: Large cysts
Subcutaneous tissue of bo., HE stain
Sarcocystis gigantea: Cysts
Muscle layer of the oesophagus, sheep
Sarcocystis: Cyst (longitudinal section)
Skeletal muscle, HE stain
Besnoitia besnoti: Clinical symptoms
- Top row: “Anasarca” stage
- Bottom row: “Scleroderma” stage
Sarcocystis: Cyst (cross-section)
Skeletal muscle, HE staining
Sarcocystis: Cyst
Compressed skeletal muscle, native
Sarcocystis: Thin-walled oocyst
Faecal debris
Toxoplasma: Cysts
Brain tissue
Toxoplasma gondii: Tachyzoites
Giemsa stain
Toxoplasma: Cysts
Brain tissue, HE stain
Toxoplasma gondii: Oocysts (Sporulated & unsporulated)
Theileria annulata: Enlarged lymph nodes
(Bovine theileriosis)
Babesia canis: Clinical signs
Dermacentor reticulatus (brown dog tick/kennel dog tick)
The vector of Babesia canis
Hepatozoon canis:
- In a mononuclear cell
- In a polymorphonuclear cell
Encephalitozoonosis: Clinical sign
Interstitial nephritis
- Babesia bigemina (large)
- Babesia divergens
In blood cells
Theileria annulata: Schizonts
Taken from bovine lymphocytes
Theileria equi: Merozoites
Blood smear
Encephalitozoon cuniculi: Torticollis (clinical sign)
Rare occurance
Histomonas meleagridis: Amoeboids
Liver tissue, PAS stain
Giardia intestinalis: Trophozoites
Eimeria truncata: Macrogamonts
Goose kidney tissue, HE stain
Trypanosoma brucei: Trypomastigotes
Blood smear, Giemsa stain
Entamoeba histolytica: Trophozoite
Faecal smear + Saline + Lugol
Entamoeba histolytica: Cyst
Floatation method
