1. Balantidium coli, Giardia lamblia, and trichomonas.
Continue in protozoa

2. Balantidium coli: It’s uncommon parasite of humans.
It commonly infects pigs and has a worldwide distribution.
Trophozoite and cyst can be seen.
Usually we see the cyst “in lab”: large, round, thick walled.
Cilia is common but not clearly seen in cyst.
A large macronucleus may be seen. A very small micronucleus lies close to the macronucleus but not clearly appear.

3. One of two contractile vacuoles may be visible.
Macronucleus stains well with iodine and other stains.
Nucleus seen as kidney shape.
Trophozoite: large, easily seen oval shaped ciliate with a rapid revolving motility, not seen in the lab here.
Often contains ingested red cells, not clearly appears.

4. Balantidium coli:
Cyst
Trophozoite

5. Cyst
Trophozoite

6. Giardia Lamblia: In tropical and subtropical areas.
Seen in children more than adults.
Have 2 stages: cyst and trophozoite.
Cyst: oval in shape, with central Axostyle, and 2 nuclei. In direct method may seen without nuclei at 40X.
Trophozoite: pear shape, “monkey face” fragile stage not seen clearly during processing.

7. Giardia lamblia:

8. Giardia lamblia:
Cyst
Trophozoite

9. Giardia lamblia:
Cyst
Trophozoite

10. Trichomonas: Either trichomonas vaginalis or tichomonas hominis.
No cystic form in trichomonas, there is trophozoite stage, and so it considered as the infective stage.
Trophozoite is ovoid or pear-shaped.
Has a short undulating membrane.
Has 4 anterior flagella and a fifth running along the outer margin of the undulating membrane.
Has a big vesicular nucleus.

11. Specimens:
To differentiate between trichomonas vaginalis and hominis this is by the specimen.
Stool sample is for trichomonas hominis.
And urine or vaginal swab is sent in case for trichomonas vaginalis.

12. Trichomonas vaginalis:

13. Trichomonas vaginalis: