Protozoa I: Intro, Giardia Flashcards
What is the basis of classification for protozoa?
Morphological similarities
Animal hosts
List some protozoa that are important in animals and zoonoses and the diseases associated
Eimeria spp.: Coccidiosis in chickens and other hosts
Toxoplasma gondii, Tritrichomonas foetus, Neospora caninum, Sarcocystis cruzi: reproductive failure in various hosts
Sarcocystis neurona, Toxoplasma gondii: CNS disease
What are general characteristics of protozoa?
Unicellular/multicellular stages Eukaryotes with organelles Aqueous environment to feed/reproduce Life cycles vary (direct or indirect) Reproduction includes asexual and sexual stages
What is the genus and species of Giardia?
Giardia duodenalis
What is the significance of the geographical distribution of Giardia?
It is the most common flagellate of birds, mammals, reptiles, and amphibians
What is the host of G/ duodealis Assemblage A?
Humans and other primates, dogs, cats, livestock, rodents, and other wild mammals
What is the host of G. bovis Assemblage E?
Cattle and other hoofed livestock
Not zoonotic
How long is the direct life cycle of Giardia?
PPP: 5-7 days
What is the reproduction of Giardia?
Asexual: binary fission
What are the stages in the life cycle of Giardia?
Trophozoite
Fecal cyst
What is the infective stage of Giardia?
Cyst stage in feces that can survive for months
What are the routes of infection for Giardia?
Fecal-oral
Carnivorism
What are the sites of infections for Giardia?
Small intestine
Trophozoites encyst in large intestine and the cyst stage is excreted in the feces
Intermittent shedder
Are Giardia trophozoites mainly in the small intestine or large intestine?
Small intestine
What is the motile stage of Giardia?
Trophozoites
Describe Giardia trophozoites
Size range: 4-10 μm x 10-20 μm
2 nuclei
Flagellated
What is the best way to find Giardia trophozoites?
Fresh sample (diarrgeic) Direct smear
Describe the direct smear for Giardia trophozoites
Look for motile trophozoites
Lugol’s iodine stain
Describe Giardia fecal cysts
Size range: 4-10 μm x 6-15 μm
4 nuclei
No flagella
What is the best way to find Giardia fecal cysts?
Flotation with zinc sulfate and Sheather’s solution (main test)
Antigen test
Direct FA test
PCR
What are the clinical signs of Giardia?
Small bowel diarrhea Usually young animals Diarrhea; often intermittent Malabsorption, weight loss Mucus, fluid in small intestine Often associated with concurrent infections
Describe Giardia in ruminants
Primarily Assemblage E
High prevalence worldwide
Young are more susceptible to acute infections
Adults are chronically infected
Periparturient rise in Giardia cyst excretion in ewes
What is used to treat Giardia?
Metronidazole
Albendazole
Fenbendazole*
How can Giardia be controlled?
Environmental control
What are the epidemiological factors of Giardia?
Cysts immediately infective
Water-borne, food-borne, mechanical/transport hosts
Population density/poor hygiene/fecal contamination
Immune status/concurrent infection
Age/passive immunity-colostrum
Host specificity/reservoir hosts
What is the definitive host of Histomonas meleagridis?
Turkeys*, chickens, pheasants, guinea fowl
What are the primary sites of Histomonas meleagridis?
Liver and ceca
What is the type of life cycle for Histomonas meleagridis?
Direct life cycle, but Heterakis gallinarum is usually required as transport host
How is Histomonas meleagridis transported?
Via H. gallinarum eggs into bird host
What is the infective stage of Histomonas meleagridis?
Motile trophozoites
What is the primary route of infection for H. meleagridis?
Ingestion of infected embryonated H. gallinrum egg
What is the life cycle of H. meleagridis?
After ingestion, H. gallinarum egg hatches, Histomonas is released in the intestine. It goes systemic via blood vessles, then moves to the liver/ceca and the trophozites undergo binary fission. In the ceca, Histomonas infects Heterakis gallinarum female and is incorporated into nematode eggs
What are alternate infection routes of Histomonas meleagridis?
Paratenic host
Bird to bird transmission: cloacal drinking
What is the most susceptible bird species to Histomonas meleagridis?
Turkeys
What is Histomonas meleagridis the causative agent of?
Blackhead
What are the clinical signs of Blackhead?
Lethargy Stilted gate Cyanosis 7-12 days PI Mortality- 17 days PI
What are the liver lesions associated with Histomonas meleagridis?
Circular depressions of necrosis, enlarged
What are the ceca lesions associated with Histomonas meleagridis?
Cecal core, ulceration leading to perforation and then peritonitis
What is the treatment for Histomonas meleagridis?
Currently no approved drugs
Control of cecal worm: Heterakis gallinarum
Avoid cohabitation of bird species, problems with free-range birds
What are the hosts for Trichomonads?
Wide range
Vertebrates: amphibians, birds, mammals, fish, and invertebrates
What are the two categories of species of Trichomonads?
Parasitic and commensal
Commensals are used to rule out if it is parasitic or not
What are the trophozoite characteristics of Trichomonads?
3-5 anterior flagella Undulating membrane Axostyle Single nucleus No cyst stage 4-30 μm Most species are not pathogenic
What is the host of Tritrichomonas foetus?
Cattle
What is the location of Tritrichomonas foetus in the female?
Reproductive tract
Vagina/uterus
What is the location of Tritrichomonas foetus in the male?
Sheath of penis
Sometime seminal vesicles and testicles
What is the location of Tritrichomonas foetus in the fetus?
Fluids from abortion
Stomach of aborted fetus
What kind of life cycle does Tritrichomonas foetus have?
Direct life cycle
What is the direct life cycle of Tritrichomonas foetus?
Flagellated trophozoites introduced during coitus— trophozoites reproduce asexually in reproductive tract via binary fission— mature trophozoites in 14-20 days PI
No cyst stage
What are the symptoms of Tritrichomonas foetus in males?
Males are asymptomatic
What are the signs of Tritrichomonas foetus in females?
Repeat breeders Infertility Vaginitis Cervicitis Chronic inflammation of vulva and vagina
What are signs of Tritrichomonas foetus in the fetus?
Usually aborted in first 16 weeks
Describe Tritrichomonas foetus trophozites
Motile Flagellated Undulating membrane 3 anterior flagella Presence of trophozoites on wet mounts Sample from reproductive tract ---Physiological saline ---The "no-no's"
How do you culture Tritrichomonas foetus?
InPouch TF System
What is the treatment for Tritrichomonas foetus?
No drugs approved/available
Metronidazole has shown some efficacy
Vaccine
How can you control Tritrichomonas foetus?
Management strategies evolving and vary Control animal movement; test before introduction of bull/cows AI Test bull annually Use younger bulls Cull positive cows; vaccinate females
What does Tritrichomonas blagburni (foetus) cause in Felids?
Feline Trichomoniasis
Intestinal trichomoniasis in cats (large intestine)
What is the transmission of Tritrichomonas blagburni (foetus) in Felids?
Likely: trophozoites transmitted fecal-oral
Breed/age susceptibility (young, pure-bred domestic show cats; group housed)
What is the pathogenesis of Feline Trichomoniasis?
Large bowel inflammation
- –Chronic diarrhea/relapses
- –Stools hemorrhagic/mucoid
What is the diagnosis of Feline Trichomoniasis?
History of diarrhea: Problem
—FIV, corona virus, FeLV, Cryptosporidium, Giardia
Motile trichomonads in feces
Culture (InPouch); PCR
How is Feline Trichomoniasis controlled?
Isolation of cats, repeat testing, + cattery
What is the site and pathology of Tritrichomonas foetus in swine?
Site: stomach, colon, nasal passages
Pathology: none
What is the site and pathology of Tritrichomonas foetus in dogs?
Site: Large intestine
Pathology: Diarrhea
What is the host of Trichomonas gallinae?
Wide range of avian species
What is the location of Trichomonas gallinae in the host?
Primarily upper GI tract
Extraintestinal
What is the Trichomonas gallinae trophozite like?
4 anterior flagella
Undulating membrane, axostyle
Single nucleus
No cyst stage
What is the Trichomonas gallinae life cycle?
Trophozoites introduced orally—- divide (longitudinal binary fission)— passed to next host orally
What are the routes of infection for Trichomonas gallinae?
Mother—offspring (regurgitation)
Water/feed contamination
Predator/prey
Courtship
What is the pathology for Trichomonas gallinae?
"Canker", roup, frounce, trichomoniasis Upper GI tract Invade mucosal surface Caseous lesions Secondary infection Strain differences
What is the diagnosis of Trichomonas gallinae?
Gross lesion
Direct smear
Histopathology
What is the treatment of Trichomonas gallinae?
Dimetronidazole
Environmental control
What has been found to cause infections in a T-Rex?
Trichomonas sp.
