Lab Exercises
Ciliophora - The Ciliates
Balantidium coli: domestic animals
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Balantidium coli trophozoite
The red arrows indicate the cilia and the green arrow is pointing at the macronucleus. |
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Sarcomastigophora - The Amoebae and Flagellates
Entamoeba histolytica: domestic animals, humans, primates
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Entamoeba histolytica
Trophozoite: note the characteristic nucleus. |
Giardia sp.: birds and mammals
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Giardia sp. trophozoite |
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Cysts (about 12 µm): low power (left) and high power (right)
red arrow = nucleus; blue arrow = remains of the flagella; yellow arrows = median bodies |
Click here to link to the Giardia life cycle.
Click here for a video of Giardia moving under a microscope.
Trichomonas spp.: birds and mammals
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Trichomonas sp.
Note the undulating membrane (red arrows) along the surface of this flagellate.
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Click here for a video of Trichomonas under a microscope
Trypanosoma brucei: domestic animals (Africa and South America); birds (North America - occasionally pathogenic)
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Above: Diagram of the trypomastigote form of Trypanosoma gambiense. Note the undulating membrane and the single free flagellum.
Left: Life cycle of the African trypanosomes. Half the life
cycle is spent in the Tsetse fly and half in the mammalian host.
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The trypomastigote form of Trypanosoma gambiense
in a blood smear. |
The trypomastigote form of Trypanosoma equiperdum
in a blood smear.
This parasite causes a venereal disease ("Dourine") in horses and donkeys. |
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Leishmania donovani: dogs, rodents, humans
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Life cycle: L. donovani lives as a promastigote within the sandfly vector and as an amastigote within the macrophages of its mammalian host. |
Drawing of a L. donovani amastigote. |
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Leishmania donovani amastigote
(white arrow) in lymph node impression smear. |
L. donovani tissue smear of the spleen of an infected rodent.
The red arrows point to some of the amastigotes
which have broken out of the splenic macrophages when the smear was made.
The green arrows point to the remains
of the nuclei of the host macrophages.
Note
the kinetoplast and nucleus within each amastigote.
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Click here to link to the Leishmania donovani life cycle.
Apicomplexa - The Piroplasma, Haemosporidia, and Coccidia
The Piroplasma
Babesia canis: dogs
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Babesia canis trophozoites (red arrows) in the red blood cells of a dog |
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The Haemosporidia
Haemoproteus sp.: birds and reptiles
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Haemoproteus sp. in red blood cells
Note the gametocytes (red arrows) in the red blood cells of this bird. Remember that bird rbc's are nucleated. |
Leucocytozoon smithi: birds
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Leucocytozoon smithi
A gametocyte
(red arrow) within a leucocyte of a turkey. |
The Coccidia
Cystoisospora spp.: mammals
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Cystoisospora felis oocyst (blue arrow, unsporulated, about 40 µm) and a sporulated Cystoisospora rivolta oocyst (red arrow, about 20 µm). The oocyst of C. canis (dog) looks like that of C. felis (cat) and the oocyst of C. ohioensis (dog) is similar to that of
C. rivolta (cat). |
Eimeria spp.: birds and herbivores
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Eimeria stiedae oocysts from rabbit feces. These oocysts (and many oocysts of species of Eimeria from livestock) have a micropyle
(a thinning of the shell) at
the narrow end. |
Eimeria sp. in the intestine of a goat. Many macrogametes (blue arrows) can be seen. |
Eimeria tenella oocysts from chicken feces
blue arrow = unsporulated;
red arrows = sporulated (infectious) This species has no micropyle. |
Click here to link to the Eimeria bovis life cycle.
Sarcocystis spp.: dog - cattle
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Sarcocystis sp. sporocysts (blue arrows)
The oocysts of Sarcocystis spp. sporulate within the host's intestine and then rupture, releasing the sporocysts, which are thus found on a flotation of the feces. |
Sarcocystis sp. Sarcocyst in the muscle of a cow (the intermediate host). This cyst contains many bradyzoites which, when eaten by the definitive host, will initiate the infection. |
Sarcocystis sp. A sarcocyst (blue arrows, note the internal septum in the center of the cyst of this species) in the muscle of a rodent. Note the Trichinella spiralis larva (red arrow) in the adjacent muscle cell. |
Toxoplasma gondii : cats
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Toxoplasma gondii An unsporulated oocyst (blue arrow) and a sporulated oocyst (red arrow) seen at high power (40 X). It takes 2 to 3 days for the oocyst (10 µm) to sporulate. |
Click here to link to the Toxoplasma gondii life cycle.
Cryptosporidium sp.: birds and mammals (including humans)
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Cryptosporidium sp. oocyst
These oocysts measure about 4 to 5 µm in diameter. |
| This fecal smear was stained by a cold Kinyoun acid-fast technique. Cryptosporidium oocysts stain red (i.e. are acid fast), whereas yeast stains blue or green. This staining technique is normally used for Mycobacterium, but it also has great utility in confirming cryptosporidiosis. |
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