Mucosoflagellates Flashcards
Mucosoflagellates
Live in the GI or genital tract, in close association with mucous membranes; transmitted in feces or genital secretions
Family Retortamonadidae
Chilomastix mesnili
Retortamonas intestinalis
Family Hexamitidae
Giardia sp. – (5 recognized) – in humans, G. lamblia, G. intestinalis, G. duodenalis
Spironucleus (Hexamita) meleagridis
Family Trichomonadidae
Trichomonas tenax Trichomonas vaginalis Pentatrichomonas hominis Tritrichomonas foetus Trichomonas gallinae
Family Monocercomonadidae
Histomonas meleagridis (Blackhead/Histomoniasis) Dientamoeba fragilis
Chilomastix mesnili
Hosts: Humans, non-human primates, pigs, other mammals, birds, etc.
Morphology: Trophozoite pyriform/4 flagella; cyst – pear-shaped/single nucleus
Transmission: Ingestion of cysts (contamination of drinking water)
Pathology: non-pathogenic
Retortamonas intestinalis
Hosts: Similar to Chilomastix sp.
Morphology: Trophozoite – smaller/2 flagella; Cyst – smaller/1 nucleus
Pathology: non-pathogenic
Giardia sp
History: Described in 1681 in diarrheic stools by Leeuwenhoek
Hosts: Human, beavers, dogs, cats, sheep, etc.
Giardia sp (morphology)
Trophozoite – rounded anteriorly; pointed posteriorly; 2 equal nuclei; 4 pairs flagella
Cyst – ovoid; 2 nuclei when newly formed 4 nuclei when older (stage most commonly seen in stools
Giardia sp (life cycle)
Trophozoites live in small intestine, adhering to epithelial cells divide by binary fission multiply rapidly as feces enter colon and dehydrate, encysting occurs flagella shorten/ wall is secreted pass out in feces ————– cyst is swallowed excyst in duodenum flagella grow out
Giardia sp (pathogenesis and treatment)
Pathogenesis:
Vary from asymptomatic to mucoid diarrhea with intestinal pain.
Pets generally asymptomatic after 6 months of age.
Diagnosis:
Trophozoites or cysts in stained fecal smears – requires 1000X magnification. Zinc sulfate flotation best.
Direct smear technique should be performed on animals < 6 mo./when diarrhea is a problem.
Treatment: Metronidazole (Flagyl™) Drontal Plus Panacur Treat all family members/pets
Prevention: High degree sanitation Water supplies Food handlers Day care centers
Spironucleus (Hexamita) meleagridis
Hosts: Galliform birds, esp. turkey
Morphology: similar to Giardia, smaller
Life Cycle: live in small intestine, similar to Giardia
Pathogenesis: Disease of young birds; mortality up to 80% - survivors may serve as source of infection for new birds
Treatment: None successful
Prevention: Management – separate young from older birds
There is some association of a Spironucleus organism with “Hole in the Head Disease” in fish (most common in Oscars)
Trichomonas tenax – worldwide
Hosts: Humans
Morphology: only trophic stage – oblong; 4 anterior free flagella/undulating membrane; axostyle
Life Cycle: Live only in mouth – transmission is direct by kissing, sharing drinking utensils, etc
Pathology: harmless
Diagnosis: smear from mouth
Trichomonas vaginalis (morphology)
Distribution: Worldwide – 189,000,000/yr infected
Hosts: Human
Morphology: larger than T. tenax
Trichomonas vaginalis (life cycle)
Life Cycle: Lives in vagina, urethra of female / prostate, seminal vesicles, urethra of male – transmission STD; to newborns from mother; soiled cloths, etc. (possibly by AI??)
Pathogenesis: Men usually asymptomatic; women vary from asymptomatic to severe vaginitis with leukorrhea
Diagnosis: Organisms in secretions or culture
Treatment: Metronidazole – tx partners as well
Pentatrichomonas hominis
Hosts: Human, primates, domestic animals
Morphology: 5 anterior flagella
Life Cycle: Lives in large intestine/cecum – transmission by fecal contamination
Pathology: Harmless
Tritrichomonas foetus in cattle (morphology)
Hosts: Cattle and related animals
Importance: A leading cause of early abortion
Morphology: 3 anterior flagella; 4th from posterior
Tritrichomonas foetus in cattle (life cycle and pathology)
Life Cycle: Live in preputial cavity of bull; vagina/uterus of cow – transmitted by breeding or AIPathology: Early abortion/infertility in cows; no signs in bulls
Diagnosis: Direct ID from smear/culture – need 2-3 neg/PCRTreatment: Usually self-limiting – cows – affects only one pregnancy
Bulls – current regulations require that positive bulls be sold for slaughter within 30 days
Bulls must be tested before interstate shipment if over 24 months old; if under 24 months of age, must be certified to be virgin bulls or tested
Tritrichomonas foetus in cats (and dogs)
Recently identified as a cause of chronic diarrhea in cats
Can be tested by culture or by PCR
Treatment is available from compounding pharmacies (Ronidazole)
Trichomonas gallinae
Necrotic ulcerations in upper GI tract
Pigeons, turkeys, chickens
Histomonas meleagridis (Blackhead/Histomoniasis) (final host and life cycle)
Hosts: Gallinaceous fowl
Morphology: No cyst; pleomorphic trophic stages
Life cycle: Live in cecum/liver, etc. ingested by nematode (Hetarakis gallinarum) IH develops in tissues and may be incorporated in nematode eggs, which pass out in bird’s feces survive at least 2 yrs. In soil
Histomonas meleagridis (Blackhead/Histomoniasis) (IM and pathology)
If worm eggs are eaten by birds, they hatch in intestine, and Hetarakis (worm) moves to cecum, where protozoan exits the worm
Paratenic Host: Earthworm
Reservoir Host: Chickens
Pathology: Young turkeys – mortality up to 100% - typhlitis, hepatitis
Diagnosis: Cecal/liver lesions organism
Treatment/Control: Dewormers break life cycle; several drugs available
Dientamoeba fragilis
Host: Human – trophozoites in large intestine
Pathology: Usually harmless – may be associated with intestinal problems in some
Transmission: Unknown
