Intestinal  Flagellates
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Intestinal Flagellates

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Intestinal  Flagellates Intestinal Flagellates Presentation Transcript

  • Intestinal Flagellates
    • Old Taxonomy: Phylum Sarcomastigophora Subphylum Mastigophora
    • New Taxonomy: Flagellates are placed in 4 PHYLA
    • 2 groups of parasites:
      • intestinal flagellates (Chapter 6)
      • blood and tissue-dwelling flagellates (Chap. 5)
    •  
  • Phylum Retortamonada Giardia lamblia = Giardia duodenalis
    • Discovered in 1681 by ______________________ in his own stool.
    • Most common intestinal flagellate of humans and most common water-borne disease.
      • cosmopolitan (worldwide) distribution; 2 million cases estimated
      • in U.S. each year - responsible for 5000 hospitalizations/year
      • endemic in the Midwest - __________ in WI in 1987 (this is an increase from 2.9% in 1976)
      • children under 5 and mothers with young children have the highest rates of infection
      • name of disease caused by parasite is ______________________
  • 2 Stages of Giardia lamblia
    • TROPHOZOITE - actively moving and feeding stage
      • Habitat:________________________________
      • M ay invade the common bile duct.
      • Trophozoites may also be found in watery stools associated with _____________________
    • Shape: rounded anterior end, posterior end pointed
    • Size: 12 to 15 µm long x 5 to 9 µm wide
    •  
  • Morphology of Giardia lamblia trophozoite Each trophozoite has ____________________ (looks like monkey face) Ventral surface bears _______________________ to adhere to surface of intestinal cell 8 flagella (2 anterior, 2 posterior, 2 ventral, and 2 caudal) - all arise from ________________________ ________________________ occur behind adhesive disk - function is unknown  
  • Morphology of Giardia lamblia trophozoite Scanning EM view of trophozoite surface showing the adhesive disk (text photo on p. 92) ventral dorsal
  • Morphology of Giardia lamblia trophozoite Light microscope photos of trophozoites
  • Morphology of Giardia lamblia trophozoite Trophozoite attaches to surface of epithelial cells with its adhesive disk and feeds on _____________________________________________
  • 2 nd Stage is Giardia lamblia cyst
    • The cyst forms as trophozoites become dehydrated when they pass through the large intestine
    • Morphology:
      • ovoid in shape; 8-12 µ m long x 7-10 µ m wide
      • thin cyst wall
      • _________________________ present, often concentrated at on end (indicates that a nuclear division occurs during encystment)
      • flagella shorten and are retracted within cyst
      • ________________________ provide internal support
    • Cyst may remain viable in the external
    • environment usually water) for many months.
    • When ingested: ____________________________
  • 2 nd Stage is Giardia lamblia cyst
  • Giardia lamblia life cycle DIAGNOSIS ? INFECTIVE STAGE? PRIMARY DIAGNOSTIC STAGE?
  • Pathology of Giardia lamblia infections
    • ___________________________________ accompanied by nausea, flatulence, and weight loss occurs in most cases
      • Diarrhea caused by the production of a watery mucus in response to the trophozoites
    •   2. Numerous trophozoites cover and shorten microvilli of intestinal cells causing ______________________________________________ 
    • Numerous trophozoites may ______________________________
    • interferes with ______________________________
  • Epidemiology of Giardia lamblia infections  
    • 4 general methods of infection:
    • 1. _____________________________________________________
      • many cases in hikers, fishermen, and canoeists in Wisconsin
      • recent problems with giardiasis in Boundary Water Canoe Area of Minnesota
      • Textbook suggests that beavers may be an important source of Giardia for transmission to humans - A ZOONOSIS.
      • Recent studies at the University of Minnesota suggest that giardiasis is of human origin - thus, it is an ANTHROPONOSIS.
  • Epidemiology of Giardia lamblia infections  
    • 2. _______________________________________________________
    • _______________________________________________________
    • 3. _______________________________________________________
      • mothers changing diapers and contaminating fingers
      • use of wading pools by diaper-age children  
    • 4. _______________________________________________________
      • about 5% of giardiasis is food-borne; thus, 95% is water-borne
  • Prevention and Treatment of Giardia lamblia  
    • PREVENTION:
      • filtration of water (be sure filter is fine enough to trap the cysts)
      • boiling water from stream or lake
      • addition of a tincture of iodine are effective in killing cysts (chlorination of water does not effect the cysts)
      • avoid use of wading/swimming pools by diaper-age children
    •  
    • TREATMENT: ___________________________________________
    • _______________________________________________________
  • Other species of Giardia 5 species of Giardia occur in other birds and mammals; They are not thought to be transmissable to humans Giardia muris Giardia canis Giardia felis Giardia equi
  • Phylum Retortamonada Chilomastix mesnili
    • Habitat: __________________________________
    • Hosts: ___________________________________
    • Cosmopolitan distribution:
        • 6% prevalence in the world
        • 3.5% prevalence in the U.S.
        • 0.3% in Wisconsin in 1987
  • Chilomastix mesnili life cycle stages
    • 1. TROPHOZOITE - 6-24 µ m long by 3-20 µ m wide 
    • -shape: __________________________
    • ________________________________
    • nucleus: ________________________
    • ________________________________
    • 4 flagella arise from kinetosomes at anterior end; 3 flagella extend anteriorly, 1 extends into the cytostome (flagella are difficult to see in stained trophozoites)
    • - commonly seen in fecal smears especially from watery stools
  • Chilomastix mesnili life cycle stages 2. CYST is lemon-shaped; 6 to 10 µm in diameter - anterior end: __________________ - contains single nucleus, cytosome, and retracted flagella - common diagnostic stage in feces
  • Chilomastix mesnili life cycle 1. Trophozoites live in the human large intestine and multipy by _____________________________ 2. ___________________________ in the large intestine stimulates encystment. Cyst is released in the feces. 3. Cyst survives in water in the external environment. 4. When cyst is ingested, it excysts in the small intestine and moves to the large intestine. Transmission involves ingestion of cysts primarily from _____________________________ contaminated with feces.
  • Chilomastix mesnili life cycle PATHOLOGY:   IMPORTANCE:
  • Phylum Parabasalia Trichomonas spp.
    • Common flagellate parasites of many vertebrates.
    • I will discuss 5 species:
      • Three species infect humans
      • One important species infects cattle
      • A common species in mice in laboratory
    •  
    • Why is Trichomonas unusual?
    •  
  • General Morphology of the Trichomonas trophozoite Shape: Nucleus: 3 to 5 flagella extend anteriorly 1 flagellum extends posteriorly along the cell membrane to form an _______________________________ _______________________________attaches the undulating membrane to the cell membrane and gives the undulating membrane support  
  • General Morphology of the Trichomonas trophozoite Internal support provided by: _______________________________ is a Golgi apparatus located near the nucleus (not generally seen in most specimens)  
  • 3 species of Trichomonas occur in humans
  • Trichomonas tenax
    • Host and habitat:
    • Pathology:
    • Food:
    • T rophozoite is small - usually between 5 and 10 µm in length
      • possesses 4 anterior flagella; undulating membrane is 3/4 the body length
    • T ransmission:
    •  
    • (We do not have any slides of this species to examine in lab, but know of its presence.)
    •  
  • Trichomonas hominis = Pentatrichomonas hominis Host and habitat: Pathology: Food:  
  • Trichomonas hominis = Pentatrichomonas hominis Trophozoite is usually between 8-12 µm in length ID characters: Often is placed in genus Pentatrichomonas due to presence of 5 anterior flagella Undulating membrane and 6th flagellum runs length of parasite but are not seen in most smears  
  • Life Cycle of Trichomonas hominis 1. Trophozoites live in the human large intestine and multipy by binary fission . 2. Dehydration of the feces in the large intestine caused the trophozoite to round up and become dormant. No cyst is formed. 3. Trophozoites are released in the feces and survive in water in the external environment. 4. When trophozoite is ingested, it passes down the digestive tract to the large intestine.
  • Life Cycle of Trichomonas hominis PATHOLOGY: IMPORTANCE:
  • Trichomonas vaginalis Host and habitat: Food: Common in 30-49 year old women; a recent study in California indicated a prevalence of 30% in childbearing women
  • Trichomonas vaginalis Morphology:  Size: ID characters: - all structures show in stained specimens
  • Life Cycle of Trichomonas vaginalis 1. Trophozoites occur in the urogenital system. 2. Trophozoites multiply by binary fission. 3. Trophozoites are transmitted from one person to another by ____________________________________________________________________________________ (washcloths, towels, etc.). Fomites
  • Pathology of Trichomonas vaginalis infections Pathology in men: ________________________________ _______________________________________________ Pathology in women – causes _________________ infection: (1) (2) (3) These symptoms disappear in women as the infection becomes chronic; she becomes asymptomatic. Parasite is often sexually transmitted from an asymptomatic person to his/her partner.
  • Diagnosis & Treatment of Trichomonas vaginalis
    • DIAGNOSIS:
      • ___________________________________________________
      • culturing techniques increase diagnostic frequency in asymptomatic cases as numbers of trophozoites are usually low in these cases
    • TREATMENT:
  • Two non-human species of Trichomonas Trichomonas (=Tritrichomonas) foetus Parasite of veterinary importance in _____________________________ Habitat: PATHOLOGY in cows: PATHOLOGY in bulls: Treatment is expensive and not always effective
  • Two non-human species of Trichomonas Trichomonas muris - common parasite in _____________________________________ - nonpathogenic - occur in uncountable numbers
  • Dientamoeba fragilis Parasite was originally thought to be an ameba but recent EM and immunological studies indicate it is more closely related to Trichomonas HABITAT - ___________________________________________________  - it is cosmopolitan and infects 4% of the world's population
  • Dientamoeba fragilis MORPHOLOGY - Trophozoite is round in shape - 6 to 12 µm in diameter   - nucleus: cyst?
  • Dientamoeba fragilis LIFE CYCLE - parasite does not form cysts and trophozoites cannot survive passage through the small intestine TRANSMISSION: Transmission through eggs of pinworm and whipworm
  • Dientamoeba fragilis
    • PATHOLOGY
      • Food:
      • Considered to be nonpathogenic and infections are asymptomatic
      •   Some infections have been reported as causing diarrhea but most parasitologists now believe that other parasites were the cause, as Dientamoeba fragilis is usually never found alone
  • Histomonas meleagridis
    • Cosmopolitan parasite of _________________________________
    • Causes a severe and often fatal disease called _________________
    • Only a trophozoite stage present; no cyst:
      • trophozoite is irregular in shape
      • may appear as an ameboid form with pseudopodia or a flagellated form with a single flagellum
    •  
  • Histomonas meleagridis life cycle Transmission is within the egg of the cecal nematode of chickens and turkeys ( Heterakis gallinarum ) - trophozoites from the cecum of an infected bird are ingested by the nematode and invade the eggs - infected eggs of the nematode are released onto the soil where they are eaten by young birds during pecking activities - as nematode eggs hatch in small intestine, Histomonas trophozoites are released to invade cecum and liver
  • Histomonas meleagridis pathology Habitat of trophozoites: Pathology: Young turkeys are more susceptible to the infection than are chickens Mortality can reach 100% in young turkeys - millions of dollars worth of turkeys are lost to this parasite    
  • Termite Flagellates Trichonympha and Holomastigotes are common genera inhabiting the intestine of termites. This is an example of ___________________________   Trichonympha Holomastigotes
  • CILIATES (Chapter 10 – p. 175-179) The Phylum Ciliophora contains a single species of medical importance.   Balantidium coli  
    • Hosts and habitat:
    • Prevalence in humans is ______; in pigs _____________
    • Pigs appear to be the source of most human cases; thus, this is a _________________________________
      • See case report in lab that describes a fatal infection in a Venezuelan pig farmer.
    • Cosmopolitan in distribution but more common in the tropics
  • Balantidium coli – Morphology of 2 stages
    • 1. TROPHOZOITE - large ovoid ciliate; 30 to 150 µm in length (largest protozoan parasite of humans)
      • ID characters:
      • Reproduction:
    •  
  • Balantidium coli – Morphology of 2 stages
    • 2. CYST - formed as feces dehydrate in the rectum
      • round shape; 40 – 60 µm in diameter; cyst wall is transparent
      • transmission:
      •   cyst is the diagnostic stage in a fecal smear
  • Balantidium coli life cycle 1. Trophozoites live in the human large intestine and multipy by binary fission . Conjugation may occur but it is rare. 2. Dehydration of the feces in the large intestine stimulates encystment. Cyst is released in the feces. 3. Cyst survives in water in the external environment. 4. When cyst is ingested, it excysts in the small intestine and trophozoite moves to the large intestine.
  • Balantidium coli Pathology Trophozoites are tissue invaders. They secrete proteolytic enzymes which digest the epithelium of the large intestine. __________________________________ are formed in the mucosa of the large intestine and extend into the submucosa. Ulceration results in bleeding and secondary bacterial infection. Perforation of the large intestine has occurred in some fatal cases. Disease is primarily _________________ _________________________________ Secondary infections in other organs such as liver and lungs are rare.
  • Balantidium coli TREATMENT: PREVENTION:
  • Ichthyopthirius multifiliis
    • This ciliate causes a problem called _________________________ in aquarium and wild freshwater fish
    • Trophozoites attack the epidermis, cornea, and gill filaments of fish
      • grayish pustules occur in the skin
      • destruction of ___________________________causes death by asphyxiation
  • Ichthyopthirius multifiliis Trophozoites are released into water when skin pustules rupture Cysts are formed and _____________________________occurs within the cyst Trophozoites are formed and are infective to a new fish when it comes into contact
  • Ichthyopthirius multifiliis Treatment: