Week 14 Protozoa Notes PDF

PROTOZOA 14 class: mastigophora Flagellates Motor component: flagella axonemes kinetoplast: neuromotor apparatus consist of blepheroplast parabasal body UNDULATING MEMBRANE: finlike structure connected to the outer edge of some flagellates AXOSTYLE: ro...

PROTOZOA 14 class: mastigophora Flagellates Motor component: flagella axonemes kinetoplast: neuromotor apparatus consist of blepheroplast parabasal body UNDULATING MEMBRANE: finlike structure connected to the outer edge of some flagellates AXOSTYLE: rodlike support structure found in some flagellates Majority live in the large intestine except for Trichomonas tenax Trichomonas vaginalis  Lumen-dwelling flagellates Parasites Habitat giardia lamblia duodenum & jejunum trichomonas vaginalis vagina & urethra trichomonas tenax mouth trichomonas hominis large intestine (caecum) chilomastix mesnili large intestine (caecum) enteromonas hominis large intestine (colon) retormonas intestinalis large intestine (colon) dientamoeba fragilis large intestine (caecum & colon)  hemoflagellates Parasites Habitat leishmania reticuloendothelial cells trypanosoma brucei connective tissue and blood trypanosoma cruzi reticuloendothelial cells and blood Enteromonas hominis cyst May be oval to elongated On first inspection of these organisms, yeast cells may often be suspected. 1-4 nuclei; binucleated forms are more common A high frequency of binucleated cysts seen on a stained preparation indicates probable E. hominis. trophozoites Pear-shaped or ovoid; may also be seen in the form of a half-circle Exhibit jerky motility; single nucleus No cytostome, undulating membrane, and axostyle 4 flagella: three are directed anteriorly and one directed posteriorly Retortamonas intestinalis cyst Lemon to pear-shaped One nucleus Two fused fibrils resembling a bird’s beak trophozoites Ovoid that exhibits jerky motility Single, large nucleus Characteristic cleftlike cytostome may be seen near the nucleus 2 anterior flagella Chilomastix mesnili cyst Lemon-shaped and possess a clear, anterior, hyaline knob One, large nucleus The well-defined cytostome, with its accompanying fibrils, may be found to one side of the nucleus trophozoites 4 flagella: 3 extend out of the anterior end; the fourth is shorter and extends posteriorly Has a single nucleus and a typical curved cytostomal fibril, called the shepherd’s crook Giardia lamblia Most common cause of intestinal infection worldwide It is the most common protozoan pathogen and is worldwide in distribution. The only protozoan parasite found in the lumen of the human small intestine Man acquires infection by ingestion of cysts in contaminated water and food. Person-to-person contact through oral-anal sexual practices or via the fecal-oral route may also transfer G. intestinalis pathogenesis: Giardiasis: the most common cause of diarrhea in patients with immunodeficiency syndromes Malabsorption/Steatorrhea (also Capillaria philippinensis) Traveler’s Diarrhea (like ETEC) - Gay Bowel Syndrome cyst Ovoid 2 (immature) – 4 (mature) nuclei Median bodies: two in immature cyst or four in fully mature cyst Resistant to routine chlorination procedures troph Pear or teardrop-shaped - Exhibits falling-leaf motility Bilaterally symmetrical (only protozoan) With sucking disk: does not invade the tissue but remains tightly adhered to intestinal epithelium by means of the sucking disc. - Four pairs of flagella: one pair of laterally crossed flagella, one pair of central flagella, a lateral pair of uncrossed flagella, and one pair of posterior flagella Rod-shaped, deeply staining organelle believed to be the parabasal body found in the center 2 nuclei, each with a large karyosome lying within the sucking disk OLD MAN’S FACE/OLD MAN WITH EYEGLASSES APPEARANCE “Someone looking at you” Dientamoeba fragilis Initially classified as an ameba; now an ameboflagellate based on electron microscope study; without external flagella It is seen worldwide and is reported to be the most common intestinal protozoan parasite in Canada. NO CYST STAGE The D. fragilis trophozoite is characterized as having one nucleus or two nuclei (binucleate trophozoite more common). The nuclear chromatin usually is fragmented into three to five granules, and normally no peripheral chromatin is seen on the nuclear membrane.  The cytoplasm is usually vacuolated and may contain ingested debris and some large, uniform granules. Stain of choice for distinguishing the individual chromatin granules in the nuclei is iron hematoxylin Hakansson phenomenon when mounted in water preparations, D. fragilis returns to normal size after swelling unlike the other amebic trophozoites; diagnostic for its identification Trichomonas spp. exist only in the trophozoite stage; no cystic stage pear-shaped Has an undulating membrane: Jerky, tumbling motility Trichomonas Trypanosoma features T. hominis t. tenax t. vaginalis habitat intestinal oral cavity genitalia size medium smallest largest nucleus ovoidal rounded ovoidal undulating As long as the costa 2/3 the costa 1/2 the costa membrane (body) inclusion bodies none none siderophil granules specimen stool oral scrappings urine & secretions Trichomonas vaginalis Infection is acquired primarily through sexual intercourse. Trichomoniasis (Ping-Pong Disease): primary non-viral sexually transmitted disease worldwide Infective stage: trophozoite Trophozoites exhibit rapid, jerky motility brought about by its four to six flagella T. vaginalis trophozoites thrive in a slightly alkaline or slightly acidic pH environment such as that commonly seen in an unhealthy vagina. The most common infection site of T. vaginalis in males is the prostate gland region and the epithelium of the urethra. Parasite causes petechial hemorrhage (strawberry mucosa), metaplastic changes, and desquamation of the vaginal epithelium. Intracellular edema and so called chicken-like epithelium, is the most characteristic feature of trichomoniasis. Asymptomatic cases most frequently occur in men; symptomatic men often experience persistent or recurring urethritis Persistent vaginitis, found in infected women, is characterized by a foul-smelling, greenish-yellow liquid vaginal discharge after an incubation period of 4 to 28 days. The identification of T. vaginalis is often based on the examination of wet preparations of vaginal and urethral discharges, urine, and prostatic secretions (must be performed within 10- 20 minutes after collection) Giemsa or Papanicolaou stain can be used for permanent stained smears. Culture is recommended when direct microscopy is negative and is considered as a 'gold standard' as well as the most sensitive (95%) method for the diagnosis of T. vaginalis infection. PROTOZOA class: CILIOPHORA CILIATA Includes species that move by means of cilia, or short extensions of cytoplasm that cover the surface of the organism. Have two different types of nuclei, one macronucleus and one or more micronuclei. balantidium coli Only human pathogen Rare infection Largest parasitic protozoan Mode of Transmission: Ingestion of infective cysts in contaminated food or water (probably from feces of swine) hosts: Natural Host: Pigs Accidental Host: Man Reservoirs: Pig, monkey, and rat infective stage: Cysts Disease: Balantidiasis resemble amebic dysentery; abscesses and ulcers characterized by up to 15 liquid stools daily containing pus, mucus, and blood. cyst: refractive double wall enclosing cilia trophozoites: Two kinds of nuclei: kidney-shaped macronucleus, dot-like micronucleus parts: Cytostome: Mouth Cytopyge: Anus Macronucleus: Vegetative Function Micronucleus: Sexual Reproduction Motility: Thrown-Ball Motility