PARA 311 Module 3 - Intestinal Flagellates (Week 3 Lecture) PDF

CLINICAL PARASITOLOGY 311 – LECRURE MODULE 3 – INTESTINAL FLAGELLATES SUBPHYLUM MASTIGOPHORA Flagellates Intestinal And Urogenital Flagellates (Flagellates)...

CLINICAL PARASITOLOGY 311 – LECRURE MODULE 3 – INTESTINAL FLAGELLATES SUBPHYLUM MASTIGOPHORA Flagellates Intestinal And Urogenital Flagellates (Flagellates) Flagellates belong to the phylum Giardia duodenalis Generalities Sarcomastigophora and are members of Other names: the subphylum Mastigophora, class All inhabit the large intestine except: ▪ Giardia intestinalis Zoomastigophora. ▪ Giardia lamblia – Small Intestine ▪ Giardia lamblia Flagellates are known to inhabit the: ▪ Trichomonas vaginalis – Vagina/urethra ▪ Lamblia duodenalis ▪ Reproductive tract o Man can also have T. vaginalis ▪ Lamblia intestinalis ▪ Alimentary canal o Can’t be found in stool Causative agent of outbreaks of ▪ Tissue sites and Blood stream ▪ Trichomonas tenax – Mouth / Oral cavity gastroenteritis and Traveler's diarrhea, ▪ Lymph vessels All undergo Encystation except: Giardiasis. ▪ Cerebrospinal canal ▪ Trichomonas Species (No cyst form) Initially known as Cercomonas intestinalis. ▪ Drentamoeba fragilis 1859 by French scientist Dr. F. Lambl and o (CDC – has cyst form (updated)) Dr. Giard. o (Zeibig – no cyst form) Small intestine – Large intestine – Life Cycle Giardia duodenalis (lamblia): All undergo Asexual Reproduction through Binary fission. Some species reproduce sexually by a process called syngamy, the fusion of two gametes produced by meiosis. Mouth / Oral cavity – Vagina / Urethra – Syngamy: 2=1 Sexual reproduction Leishmania Trypanosoma Binary fission: 1=2 Asexual reproduction CLINICAL PARASITOLOGY 311 – LECRURE Anterior MODULE 3 – INTESTINAL FLAGELLATES Flagella Cysts are resistant forms and are and Prevention (CDC), are Metronidazole responsible for transmission of giardiasis (DOC) (Flagyl), Tinidazole (Tindamax) and Both cysts and trophozoites can be found Nitazoxanide (Alinia) in the feces (diagnostic stages). Notes of interest: Central The cysts are hardy and can survive several ▪ Giardia intestinalis was discovered in months in cold water. Infection occurs by 1681 by Anton van Leeuwenhoek the ingestion of cysts in contaminated when he examined a sample of his own Sucking disk / Posterior water, food, or by the fecal-oral route stool. Sucking Grooves Flagella (hands or fomites) ▪ Giardia trophozoites have often been In the small intestine, excystation releases referred to as resembling an old man trophozoites (each cyst produces two with whiskers, a cartoon character, trophozoites) and/or a monkey's face. (Acc to Zeibig) Trophozoites multiply by longitudinal ▪ G. intestinalis and Trichomonas binary fission, remaining in the lumen of the vaginalis are both known to be carriers proximal small bowel where they can be free of double-stranded RNA viruses or attached to the mucosa by a ventral (Reovirus). sucking disk Giardia duodenalis Encystation occurs as the parasites transit toward the colon. The cyst is the stage found most commonly in non-diarrheal feces. Giardia lamblia Pathogenesis: “Gay Bowel Syndrome” (foul smelling stool or Explosive diarrhea) Steatorrhea (Excess fat in stool) “Failure to Thrive Syndrome” alters mucosal intestinal cells/cytoskeleton. Diagnosis: Stool examination for trophozoite and cyst duodenal aspirates Direct Immunofluorescence Assay (DFA) (Gold Standard). Treatment: The primary choice of treatments for G. intestinalis infections, - Energizing structure - Structure where the flagella according to the Centers for Disease Control is attached. - Used for attachment to absorb nutrients in the Small Intestine. CLINICAL PARASITOLOGY 311 – LECRURE MODULE 3 – INTESTINAL FLAGELLATES Chilomastix mesnili Clinical Symptoms: ▪ Infections with C. mesnili are typically Asymptomatic. Treatment: ▪ Treatment for persons infected with C. mesnili is usually not indicated because Nipple Shaped - this organism is considered to be a Nonpathogenic. - Support CLINICAL PARASITOLOGY 311 – LECRURE MODULE 3 – INTESTINAL FLAGELLATES Dientamoeba fragilis 1. Trophozoites are found in the lumen of Clinical Symptoms the large intestine, where they Multiply D. fragilis was initially classified as an via binary fission, and are shed in the Asymptomatic Carrier State. amoebas because this organism moves by stool. It is estimated that most people with D. means of pseudopodia and does not have 2. Historically, only the trophozoite stage fragilis infection remain asymptomatic. external flagella. of D. fragilis had been detected. Further investigation using Electron However, rare putative cyst and pre- Symptomatic. microscopy studies has suggested that D. cyst forms have been described in fragilis does have flagellate characteristics. Diarrhea, abdominal pain, bloody or mucoid human clinical specimens; whether and Under Mastigophora (Has flagella inside stools, flatulence, nausea or vomiting, in what settings transmission to humans and only seen by electron microscope). weight loss, and fatigue or weakness. occurs via ingestion of such forms in Some patients experience diarrhea contrast or in addition to other fecal-oral Discovered by Wenyong in 1909 alternating with constipation, low-grade transmission routes is not yet known. Use of iron Hematoxylin-stained films. eosinophilia, and pruritus. 3. Transmission via helminth eggs (e.g., (Stain of choice) via Enterobius vermicularis and Treatment Rosette Shaped nuclei Ascaris eggs) has been postulated. Coinfection with Enterobius vermicularis / The treatment of choice for such infections is Ascaris egg. Laboratory Diagnosis Iodoquinol. Multiple leaf-like pseudopodia. Tetracycline is an acceptable alternative Based on CDC, D. fragilis has a Cyst form.\ 80% have 2 nuclei treatment. Examination of stool samples for the Pathogenesis: Irritable Bowel Syndrome Paromomycin (Humatin) (Last resort) may presence of trophozoites is the method of like, excess mucus and hypermotility. be used in cases when the treatments listed choice for the laboratory diagnosis of D. Non-commensal / Pathogenic earlier, for whatever reason, are not fragilis. Life Cycle of Dientamoeba fragilis: appropriate. (Neprotoxic and ototoxic) A recent study evaluated methods of detection for D. fragilis and RT – PCR was Notes Of Interest shown to be the most sensitive of all diagnostic methods. When placed in water, the trophozoite swells and then returns to normal size. In the swollen Epidemiology state, numerous cytoplasmic granules exhibit Brownian movement. The exact mode of D. fragilis transmission remains unknown. One unproven theory This feature, called the "Hakansson suggests that D. fragilis is transmitted via the phenomenon” is peculiar to D. fragilis; it is a - encystation outside the body eggs of helminth parasites such as feature diagnostic for the identification of D. Enterobius vermicularis and Ascaris fragilis. lumbricoides. CLINICAL PARASITOLOGY 311 – LECRURE MODULE 3 – INTESTINAL FLAGELLATES Trichomonas Species Trichomonas tenax Trichomonas hominis Commensal / Laboratory Diagnosis: Trichomonas tenax/bucalis Non pathogenic ▪ The specimen of choice for diagnosing T. Trichomonas vaginalis - Pathogenic tenax trophozoite is mouth scraping. ▪ Tartar between the teeth and gingival Trichomonas hominis margin of the gums are the primary There is no known cyst form of T. hominis. areas of the mouth that may also T. hominis is considered to be a potentially harbor this organism. nonpathogen. Treatment, therefore, is ▪ There is no known cyst stage of T. usually not indicated. tenax. Infections with T. hominis are generally Mode Of Transmission: asymptomatic. ▪ Using of contaminated dishes and utensils, Introducing droplet Stool examination is the method of choice contamination through kissing. for the recovery of T. hominis trophozoites. ▪ The trophozoites appear to be durable, surviving several hours in drinking water. ▪ Infections with T. tenax occur throughout the world almost exclusively in patients with poor oral hygiene. Clinical Symptoms: ▪ T. tenax is considered to be a nonpathogen and no chemical treatment is normally indicated. ▪ The T. tenax trophozoites seem to disappear in infected institution of proper oral hygiene practices. Treatment ▪ Practicing good oral hygiene is the most effective method of preventing and controlling the future spread of T. tenax infections. CLINICAL PARASITOLOGY 311 – LECRURE MODULE 3 – INTESTINAL FLAGELLATES Trichomonas vaginalis Life Cycle of Trichomonas vaginalis 1. Trichomonas vaginalis resides in the female lower genital tract and the male urethra and prostate. 2. Where it replicates by binary fission. 3. The parasite does not appear to have a cyst form and does not survive well in the external environment. Trichomonas vaginalis is transmitted among humans, its only known host, primarily by sexual intercourse. Laboratory Diagnosis: ▪ Most common pathogenic protozoan of humans in industrialized countries (Developed countries) CLINICAL PARASITOLOGY 311 – LECRURE MODULE 3 – INTESTINAL FLAGELLATES ▪ There is no known T. vaginalist cyst Clinical Symptoms: Treatment: stage. ▪ Asymptomatic cases of T. vaginalis ▪ The treatment of choice for T. vaginalis ▪ T. vaginalis trophozoites may be most frequently occur in men. infections is Metronidazole (Flagyl). recovered using standard processing ▪ Persistent: Urethritis (aka lower UTI) Because this parasite is sexually methods in spun urine, vaginal ▪ Persistent: Vaginitis transmitted, treatment of all sexual discharges, urethral discharges, and o Persistent vaginitis, found in infected partners is recommended. prostatic secretions. women, is characterized by a foul- Note of Interest: ▪ Although permanent stains may be smelling, greenish-yellow liquid ▪ There is evidence to suggest a performed, examination of saline wet vaginal discharge after an connection between T. vaginalis preparations is preferred in many incubation period of 4 to 28 days. infections and cervical carcinoma. cases. ▪ Cervical cancer – Caused by Human Additional Diagnosis: Papilloma Virus. 1. Phase contrast microscopy - Clinical microscopy 2. Papanicolaou (Pap) smears 3. Fluorescent stains 4. Monoclonal antibody assays 5. Enzyme immunoassays 6. Cultures Epidemiology: ▪ The primary mode of transmission of the ▪ Strawberry cervix is almost always a T. vaginalis trophozoites is sexual sign of trichomoniasis. This is often intercourse considered to be the most common ▪ These trophozoites may also migrate curable sexually transmitted infection through a mother's birth canal and around the world. infect the unborn child. ▪ Under optimal conditions, T. vaginalis is known to be transferred via contaminated toilet article or underclothing. ▪ T. vaginalis trophozoites have been known to survive in urine, on wet sponges, and on damp towels for several hours, as well as in water for up to 40 minutes. CLINICAL PARASITOLOGY 311 – LECRURE MODULE 3 – INTESTINAL FLAGELLATES Enteromonas hominis Retromonas intestinalis CLINICAL PARASITOLOGY 311 – LECRURE MODULE 3 – INTESTINAL FLAGELLATES CLINICAL PARASITOLOGY 311 – LECRURE MODULE 3 – INTESTINAL FLAGELLATES Trichomonas vaginalis Trichomonas hominis Trichomonas tenax Habitat Females: Urogenital Area Colon or Large Intestine Mouth (Tartar of teeth) Males: Prostate Mode of Transmission Intimate contact, Infant delivery, Ingestion Direct contact (Kissing) Contaminated Underwear and Towels Using contaminated utensils Size Largest Medium Smallest Nucleus Ovoidal Rounded Ovoidal (No peripheral chromatin) Undulating membrane ½ of the body Full body Length 2/3 or ¾ of the body Inclusion Bodies Siderophil granules (Contains IRON) NONE NONE Motility (Wet Smear) Jerky, Tumbling motility Jerky Jerky Specimen Urine Stool Tartar and Cavities Disease Trichomoniasis, Vaginal Pruritis Commensal Commensal Illustration CLINICAL PARASITOLOGY 311 – LECRURE MODULE 3 – INTESTINAL FLAGELLATES Parasite Flagella Trophozoite Cyst Disease Giardia lamblia 4 pairs (8 flagella) 2 Young – 2 Gay bowel syndrome 1 pair – Anterior Failure to thrive 1 pair – Posterior Mature – 4 2 pair – Central, extending laterally Chilomastix mesnili 4 1 1 Commensal 3 – extending from the anterior end 1 – extending posteriorly from cytosome region Dientamoeba fragilis Has flagella (undiscovered) 2 No Cyst Irritable-bowel Syndrome, Excess mucus & hypermotility Enteromonas hominis 4 1 1-4 Commensal 1 – directed anteriorly 3 – directed posteriorly Retromonas intestinalis 2 1 1 Commensal Located into anterior portion Trichomonas vaginalis 3-5 1 No Cyst Male: Asymptomatic All originating anteriorly Female: Strawberry Cervix 3-5 extending anteriorly 1 extending posteriorly Trichomonas homins 3-5 1 No Cyst Commensal All originating anteriorly 3-5 extending anteriorly 1 extending posteriorly Trichomonas tenax 3-5 1 No Cyst Commensal All originating anteriorly (poor oral; hygiene) 4 extending anteriorly 1 extending posteriorly