Mucosoflagellates

Question 1

Mucosoflagellates

Answer 1

Live in the GI or genital tract, in close association with mucous membranes; transmitted in feces or genital secretions

Question 2

Family Retortamonadidae

Answer 2

Chilomastix mesnili

Retortamonas intestinalis

Question 3

Family Hexamitidae

Answer 3

Giardia sp. – (5 recognized) – in humans, G. lamblia, G. intestinalis, G. duodenalis

Spironucleus (Hexamita) meleagridis

Question 4

Family Trichomonadidae

Answer 4

Trichomonas tenax 
Trichomonas vaginalis
Pentatrichomonas hominis
Tritrichomonas foetus 
Trichomonas gallinae

Question 5

Family Monocercomonadidae

Answer 5

Histomonas meleagridis (Blackhead/Histomoniasis)
Dientamoeba fragilis

Question 6

Chilomastix mesnili

Answer 6

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

Question 7

Retortamonas intestinalis

Answer 7

Hosts: Similar to Chilomastix sp.
Morphology: Trophozoite – smaller/2 flagella; Cyst – smaller/1 nucleus
Pathology: non-pathogenic

Question 8

Giardia sp

Answer 8

History: Described in 1681 in diarrheic stools by Leeuwenhoek
Hosts: Human, beavers, dogs, cats, sheep, etc.

Question 9

Giardia sp (morphology)

Answer 9

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

Question 10

Giardia sp (life cycle)

Answer 10

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

Question 11

Giardia sp (pathogenesis and treatment)

Answer 11

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

Question 12

Spironucleus (Hexamita) meleagridis

Answer 12

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)

Question 13

Trichomonas tenax – worldwide

Answer 13

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

Question 14

Trichomonas vaginalis (morphology)

Answer 14

Distribution: Worldwide – 189,000,000/yr infected
Hosts: Human
Morphology: larger than T. tenax

Question 15

Trichomonas vaginalis (life cycle)

Answer 15

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

Question 16

Pentatrichomonas hominis

Answer 16

Hosts: Human, primates, domestic animals
Morphology: 5 anterior flagella
Life Cycle: Lives in large intestine/cecum – transmission by fecal contamination
Pathology: Harmless

Question 17

Tritrichomonas foetus in cattle (morphology)

Answer 17

Hosts: Cattle and related animals
Importance: A leading cause of early abortion
Morphology: 3 anterior flagella; 4th from posterior

Question 18

Tritrichomonas foetus in cattle (life cycle and pathology)

Answer 18

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

Question 19

Tritrichomonas foetus in cats (and dogs)

Answer 19

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)

Question 20

Trichomonas gallinae

Answer 20

Necrotic ulcerations in upper GI tract

Pigeons, turkeys, chickens

Question 21

Histomonas meleagridis (Blackhead/Histomoniasis) (final host and life cycle)

Answer 21

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

Question 22

Histomonas meleagridis (Blackhead/Histomoniasis)
(IM and pathology)

Answer 22

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

Question 23

Dientamoeba fragilis

Answer 23

Host: Human – trophozoites in large intestine
Pathology: Usually harmless – may be associated with intestinal problems in some
Transmission: Unknown