Ciliates Flashcards
General ciliophora characteristics
- 2 types of nuclei: macronucleus and micronucleus
- ciliated body
- food ingested thru cytostome
- reproduction via binary fission
- majority are free living (facultative)
Ciliates are symbiotic with what 2 animals?
Ruminants, equids
What species of ciliophora are parasitic?
- Balantidium coli
- Ichthyophthirus multifiliis
- Cryptocaryon irritans
What is the largest parasitic protozoan in humans?
Balantidium coli
- only ciliate known to parasitize humans
Balantidium coli hosts
- Pigs*, humans, primates, horses, bovine, rodents
- asymptomatic
Balantidium coli distribution
Worldwide
Balantidium coli location in host
Large intestine
Balantidium coli has a ______ life cycle
Direct
- cysts in host feces –> cysts ingested by host –> trophozoites excyst in SI –> trophozoites colonize LI –> binary fission –> encystation in LI (cyst formation) –> cyst and trophozoites are excreted –> cysts ingested
Balantidium coli infective stage?
Cysts in feces
Balantidium coli completion of life cycle takes ______
4-5 days
Balantidium coli route of infection
Fecal oral
Balantidium coli diagnostics - trophozoites
Horseshoe shaped macronucleus
- ciliated
- fresh fecal sample
- direct smear - motile trophozoites
Balantidium coli diagnositcs - cyst
Shed in feces, detected via fecal float
- zinc sulfate
- large horseshoe shaped macronucleus
Balantidium coli clinical signs
Domestic/wild pigs are usually asymptomatic - diarrhea, colitis Humans: could be mild, chronic - chronic diarrhea, colitis, weight loss - ulcers, perforation of LI - concurrent infection - rule out: amoebic dysentery
Balantidium coli treatment
Swine: not treated
- potential zoonosis
Control: interrupt fecal-oral transmission
What human populations are at risk for B. coli infection?
Rural, institutionalized groups
- immunosuppressed
- pigs are reservoir host
- potential water/food contamination
Ichthyophthirius multifiliis
“Ich” or white spot disease
- largest parasitic protozoan in fish (esp. freshwater)
Marine form of Ichthyophthirius multifiliis
Cryptocaryon irritans
Ichthyophthirius multifiliis parasitic stage
Motile ciliated trophont
- distinct horseshoe nucleus
- trophont: same as trophozoite
Ichthyophthirius multifiliis has high outbreaks and mortality in ________
Aquaculture fish
- problem in public and private aquaria (persistant)
Ichthyophthirius multifiliis - life cycle outline
Development in water
- exiting tomont –> encysted tomont –> tomite –> invading theront –> trophont that grows on skin
Trophont
Parasitic fish stage (feeding stage)
- sites of infection: gills, fins, skin
- protected from chemical treatments
- mature on fish and drop off into the water
- encyst into tomonts
Tomont
Protected and encysted stage in water
- binary fission within tomont = tomites (hundreds)
Tomites
Further development into theronts
- release of theronts
Theronts
Motile, ciliated stage
- emerge from tomont into water column and encounters fish host
- stage of host infection and only stage that is treatable!!! –> manipulate water temperature
- if theront does not contact fish host (can see light) within a few hours it will die
Theront infection
Penetrate epithelium of fish –> develop into trophonts
- at 24-27 C or 75-80 F, theront must contact fish within 48-72 hours –> cooler temperatures increases this window of opportunity
Ichthyophthirius multifiliis completion of life cycle is dependent on ______
Water temperature
- lower temps: tomite development is delayed
- 24-27 C: life cycle is complete in 4-7 days
- <21 C: life cycle takes 5 weeks
- > 30 C: unable to reproduce
Treatment for I. multifiliis targets the ______ stage
Theront
Ichthyophthirius multifiliis - pathology
Small white nodules on skin/gills/fins
- secondary infections
- epithelial erosion, sloughing of epidermis, focal necrosis, ulcerations, excess mucus production
- gills: O2 exchange compromised
- flashing: abnormal swimming behavior
- lethargy, anorexia
- mortalities
I. multifiliis - diagnostics
Need live or freshly dead fish
- use coverslip to collect mucus from suspect area (will not always see white spots)
- direct smear with dechlorinated water
- look for trophont stage (motile)
- wet mount: clip gill filaments, mucus scraping
- histology
I. multifiliis - oriental fish
Treat for at least one week
- gradually increase water temp
- OTC treatments
I. multifiliis - food fish
- copper sulfate
- potassium permanganate
- formalin
- salt
- recheck fish
I. multifiliis - treatment/control
Home aquarium - quarantine - dont add travel water - reduce stress - purchase plants from tanks with no fish - disinfect new items Aquaculture - prevent wild fish from entering - ground vs surface water - pond must remain unstocked 3-4 days after filling (kills tomites due to no fish to hang onto) - disinfect - avoid cross contamination
Cryptocaryon irritans
Marine white spot disease
- problematic in public/private aquariums, and net pen cultured marine species
- life cycle: similar to I. multifiliis
- treatment: similar, hyposalinity
