Amebae●Flagellate●Coccidia (lumen/tissue/blood) Lumen amebae ==================== Entamoeba histolytica trophozoite , stool smear. A nucleus with a central endosome and a fine peripheral ring of chromatin distinguishes this parasite from E. coli ===================== Entamoeba histolytica cyst, stool smear. Note the presence of four or fewer nuclei. Although all four nuclei may not be visible in the same plane, they can be counted by carefully adjusting the fine focus control (N1- N4, second row). Chromatoidal bars (C), when present in immature cysts, usually have blunt ends, versus splintered ends in cysts of E. coli. ======================= Entamoeba coli trophozoite, stool smear. This species can be distinguished from E. histolytica by the usually eccentric location of the endosome and the relatively coarser, larger granules in the ring of peripheral chromatin ======================= Entamoeba coli cyst, stool smear. Note the presence of more than four nuclei (actually, eight are present in mature cysts). Chromatoidal bars (C) in immature cysts have splintered ends, versus blunt ends in cysts of E. histolytica ======================= Endolimax nana trophozoite, stool smear. Note the small size and prominent endosome ======================= Endolimax nana cyst, stool smear. Note the small size and presence of up to 4 nuclei with prominent endosomes ======================== lodamoeba butschlii trophozoite, stool smear. Note the prominent endosome and numerous cytoplasmic vacuoles ======================== lodamoeba butschlii cyst, stool smear. Note the oval shape, prominent endosome, and large, single, glycogen-filled vacuole ====================== Dientamoeba fragilis stool smear. Specimens possess two nuclei (which are still connected by a mitotic spindle). The cytoplasm usually contains endocytosed material, and while not very obvious in these photographs, the nuclear chromatin typically occurs in 3-5 clumps. In contrast to most intestinal protozoa, there is no cyst, and the trophozoite is the infective stage Tissue amebae ======================= Acanthamoeba culbertsoni trophozoite. Note the spike-likerhizopods.Certain species of this genus of free-living amoebae have been found as opportunistic parasites of immunosuppressed individuals and in immunocompetent persons suffering trauma to the conjunctiva of the eye or using contaminated contact lens cleaning solutions. In immunosuppressed individuals, it forms slowly spreading granulomas in the visceral organs.cyst in soil introduced into eye. trophozoite in tissues ========================== Naegleria fowleri histological section of mouse brain infected a. Low magnification view of brain with central necrotic zone (area within dashed line). b. Individual trophozoites within necrotic zone, each with a prominent endosome. c. Trophozoites in a culture smear. Human infections with this opportunistic parasite are contracted by diving into water containing the infective biflagellated form, which adheres to the olfactory epithelium, transforms into the trophozoite, and invades the brain via the olfactory nerve. The resulting primary amoebic meningoencephalitis (PAM) is rapidly fatal. Cysts are not found in the tissues. cyst is in bottom mud.trophozoite in tissue ======================== Lumen ciliated Balantidium coli trophozoite, stool smear. Note the oval shape, large curved macronucleus (M), cytostome (C), peristomal cilia (P), and food vacuoles (V). The only pathogenic ciliate parasite of humans, B. coli can cause intestinal lesions that result in a disease similar to amoebic dysentery, although this is rare =========================== Balantidium coli cyst, stool smear. Note the smooth round shape, large curved macronucleus, and cyst wall (W), which has separated from the cell in some specimen ========================= Lumen blastocyst Blastocystis hominis cyst, trichrome stain. Although considered a yeast by some, others classify it as an amoeba. Cysts may contain a central vacuole-like inclusion surrounded by a thin rim of cytoplasm with a variable number of granules Lumen flagellate ======================= Giardia lamblia trophozoite, stool smear. Note the pyriform shape, two nuclei, and median bodies (M). The trophozoite stage normally would be found in loose stools. Flagella (which number 8) are not visible in these photographs, although axonemes (A) can be seen in the cytoplasm of some cells as dark lines ======================== Giardia lamblia cyst, stool smear. Note the oval shape, smooth cyst wall, axonemes (A), and four nuclei, usually not all of which are visible in one focal plane. The cytoplasm often is retracted from the cyst wall in fixed specimens, leaving a clear space ========================= Chilomastix mesnili trophozoite, stool smear. Note the pyriform shape, single nucleus, and presence of cytostomal groove (C), visible when the focus is changed slightly (arrow). There are three anteriorly directed flagella (F), and one flagellum that is recurved into the cytostomal groove. Note also the considerable size variation ============================ Chilomastix mesnili cyst, stool smear. Note the lemon shape, single nucleus, and “cap” at one end (C). Axonemes and the cytostomal groove often can be seen within the cyst ======================= Trichomonas vaginalis trophozoite, culture smear. Note the presence of a single nucleus (N), undulating membrane (U), four anterior flagella (F), and axostyle (A). As for all trichomonads, there is no cyst stage, and transmission is direct, usually via sexual intercourse Tissue flagellate لیشمانیوز جلدی مخاطی( برازیاینس و مکزیکانا) لیشمانیوز جلدی( تروپیکا و ماژور) لیشمانیوز احشایی(دنوانی و اینفانتوم) ========================= Leishmania donovani amastigote, liver smear. These are indistinguishable from amastigotes of Trypanosoma cruzi. Note the minute size, and absence of an emergent flagellum or undulating membrane. The kinetoplast (K) is the dark rod- shaped inclusion near the round nucleus (N). Large purple structures are host liver cell nuclei (H). L. donovani is transmitted by Phlebotomus spp. sand flies in the old world (Africa, Asia, Middle East) and by Lutzomyia spp. in the new world (C and S America). ======================== Lutzomyia a genus of phlebotomine sand flies a potential vector of leishmania spp Boold flagellate ========================== Trypanosoma brucei rhodesiense trypomastigote,peripheral blood smear. Note the undulating membrane (U), anterior flagellum (F), and posterior location of the kinetoplast (K) relative to the nucleus (N). These would be indistinguishable from trypomastigotes .of T. b. gambiense ======================= Tsetse fly Glossina spp, the vector of African trypanosomiasis due to Trypanosoma brucei brucei in animals, and T. b. gambiense and T. b. rhodesiense in human ======================== Trypanosoma brucei gambiense trypomastigote , peripheral blood smear. Note the undulating membrane and posterior location of the kinetoplast relative to the nucleus. These would be indistinguishable from trypomastigotes of .T. b. rhodesienese ======================= Kissing bug a potential vector of Trypanosoma cruzi Lumen cocidia ====================== Isospora belli oocyte, wet mount, bright field and Nomarski interference optics. Oocysts are passed out in the feces unsporulated, containing one cell (sporont) or two cells (sporoblasts). Each sporoblast develops outside the host into a sporocyst with 4 sporozoites (8 sporozoites/ oocyst). As with Cyclospora cayetanensis, oocysts of I. belli fluoresce when viewed with ultraviolet light between 340 and 380 nm (top right photographs) ======================== Cyclospora cayetanensis oocyte, wet mount. The oocyst is unsporulated when passed in the feces, producing 2 sporocysts, each with 2 sporozoites. Because the oocyst, like that of Isospora belli, is autofluorescent, diagnosis can be made by scanning wet mounts with a fluorescence microscope ========================= Cryptosporidium parvum oocyte, stool smear. First row, modified acid fast stain; rows 2-5, wet mount Tissue cocidia ========================== Toxoplasmosis .Histological section of liver. showing an infected cell in the center (arrow)(a) . Smear of peritoneal fluid, showing tachyzoites(b). ======================= Sarcocyst spp.Histological sections of muscle cysts . Because the oocyst easily ruptures in the digestive tract of the definitive host, usually only sporocysts (packets of sporozoites) are released in the feces Blood cocidia ======================== Plasmodium vivax trophozite. These can be identified as P.vivax by the following features: enlarged, decolorized infected erythrocytes; prominent Schüffner's dots; and the ameboid shape of the trophozoite. Decolorization is not apparent here. Hemozoin granules may be relatively difficult to identify in this species ======================== Plasmodium vivax schizont. When merozoites invade host erythrocytes, most undergo schizogony to produce 12 to 24 merozoites (average of 16) within approximately 48 hours. These burst out of the cell and immediately infect new cells. Because the infection becomes synchronous in the host, large numbers of infected erythrocytes burst more or less simultaneously, causing a rapid rise in body temperature at 48-hour intervals ========================== Plasmodium falciparum young signet ring trophozoite. Failure to recognize P. falciparum infection in a smear like the one shown here may have fatal consequences. Diagnostic features are: high parasitemia; presence of only signet ring trophozoites; appliqué forms, double chromatin dots, and multiple infections in some cells; and absence of Schüffner's dots ======================= Plasmodium falciparum schizont. This stage usually is not observed in peripheral blood, except in very heavy infections. Each schizont produces from 6 to 32 merozoites, with an average of 20 to 24, every 48 hours. Hemozoin pigment is clumped in the center of the infected RBC. Note that the merozoites are very small, and that the schizont usually does not fill up the RBC ====================== Plasmodium falciparum gametocyte. Some merozoites penetrate erythrocytes and differentiate into gametocytes instead of undergoing schizogony. Although the gametocytes of all four human-infecting species can be distinguished, those of P. falciparum have a unique appearance, and therefore are valuable in diagnosis. Macrogametocytes of this species are elongate, and have a nucleus less than one-half the length of the cell. Microgametocytes may be shorter and more blunt-ended, have a lighter blue cytoplasm, and have a nucleus that is greater than one-half the length of the cell ====================== Plasmodium malariae trophozoite. Occasionally trophozoites form a band shape,stretching across the red blood cell, as shown in these photographs. The cytoplasm of the parasite stains more darkly than in P. vivax, and there are no Schüffner's dots. Hemozoin granules are much more conspicuous in this species than in the other three. Unlike the case with P. vivax, infected erythrocytes are not enlarged ======================== Plasmodium malariae schizont. From 6 to 12 merozoites (average of 8) form in each infected cell at 72-hour intervals. The merozoites are often, but not always, arranged in a rosette around the periphery, with the hemozoin granules at the center ====================== Plasmodium ovale trophozoite. This species has the lowest prevalence among malarial parasites, occurring mainly in tropical Africa. Although sometimes difficult to distinguish from P. vivax, up to 20-60% of infected cells show oval distortion (versus around 5% in P. vivax), as depicted in this plate. Schüffner's dots and hemozoin granules are prominent, as is the large chromatin mass. Also, infected cells are enlarged (although usually not as enlarged as with P. vivax) , and some of the infected cells have fimbriated (ragged) edges ====================== Plasmodium ovale schizonit. This stage shares many diagnostic features with the trophozoite stage: enlarged, ovally-distorted host cells, and prominent Schüffner's dots. From 6 to 14 merozoites (average = 8) are produced by each schizont in 48 hr ===================== Babesia microti trophozoite are pear shaped and often occur in pairs or fours, joined at the tip, a result of binary schizogony. The resulting malaria-like disease There is no exoerythrocytic schizogony in the life cycle, and the vector is a tick گ
