Question

25         The Entamoeba histolytica life cycle and fecal/oral transmission is an example of  

            ………………………………………………………………………….

26         In a formalin-fixed, mushy stool specimen you see amebae but no cysts: your next step is to

            a          Request a further specimen when the fecal consistency is more formed
            b          Examine a trichrome-stained smear of the current specimen
            c          Report “Amebae present: unable to identify”

            d          Examine an iodine-stained wet preparation of the specimen

27         If you chose   b   in Question #26, according to a still widely held view in parasitology, you could
             identify the parasite as Entamoeba histolytica if you see

            a          Amebae with ingested bacteria

            b          Amebae with nuclei showing large and eccentric karyosomes

            c          Amebae with ingested red blood cells

            d          Amebae with nuclei with both eccentric karyosomes and irregular peripheral chromatin

28         The trophozoite of this flagellate is typically binucleate with no nuclear chromatin and the
              karyosome has 4-8 distinct granules. Some have hypothesized that it is possible that this
            parasite is transmitted via helminth   eggs (e.g., Ascaris, Enterobius spp.).

   

             ………………………………………………………..                        

29.        Which two amebae cannot be distinguished from each other by morphology

            a          Entamoeba coli and Entamoeba dispar

            b          Entamoeba histolytica and Entamoeba coli

            c          Entamoeba histolytica and Entamoeba dispar

            d          Endolimax nana and Iodamoeba butschlii

30.        Diagnosis of Toxoplasma gondii in infection in man is usually determined by  

            ……………………………………………………..

31.        The optimal stain to demonstrate oocysts of Cryptosporidium species in feces is  

……………………………………………………………………..

32.        In the literature on the microscopy of Cyclospora cayetanensis it is often stated that unstained
            oocysts in wet preparations autofluoresce an intense “neon” blue when illuminated with ultra-violet
             excitation (UV light). What would be the reason that, with UV illumination, the fluorescence is seen
             as green.  

              ………………………………………………………………….

33.        A patient presents with a 2 week history of a flu-like syndrome and diarrhea: in an unstained wet preparation of his feces you see numerous spherical structures of 10-11 microns diameter and, on
focusing up and down, the surface of these appear dimpled, resembling that of golf balls. These are most likely

            ……………………………………………………………..

Answer 1

27.  If you chose   b   in Question #26, according to a still widely held view in parasitology, you could
             identify the parasite as Entamoeba histolytica if you see

            b          Amebae with nuclei showing large and eccentric karyosomes

            c          Amebae with ingested red blood cells

            d          Amebae with nuclei with both eccentric karyosomes and irregular peripheral chromatin.

28. The trophozoite of this flagellate is typically binucleate with no nuclear chromatin and the karyosome has 4-8 distinct granules. Some have hypothesized that it is possible that this parasite is transmitted via helminth eggs (e.g., Ascaris, Enterobius spp.). The flagellate is Dientamoeba fragilis.

29. Entamoeba histolytica and Entamoeba dispar are morphologically indistinguishable but can be differentiated by monoclonal antibodies and DNA probes.

30. Diagnosis of Toxoplasma gondii in infection in man is usually determined by isolation of the parasites, PCR, serological tests, histological examination and measurement of IgG.

31.  The optimal stain to demonstrate oocysts of Cryptosporidium species in feces is modified safranin technique (which unifrmly stains all the oocysts).