Ciliates

Question 1

General ciliophora characteristics

Answer 1

• 2 types of nuclei: macronucleus and micronucleus
• ciliated body
• food ingested thru cytostome
• reproduction via binary fission
• majority are free living (facultative)

Question 2

Ciliates are symbiotic with what 2 animals?

Answer 2

Ruminants, equids

Question 3

What species of ciliophora are parasitic?

Answer 3

• Balantidium coli
• Ichthyophthirus multifiliis
• Cryptocaryon irritans

Question 4

What is the largest parasitic protozoan in humans?

Answer 4

Balantidium coli

- only ciliate known to parasitize humans

Question 5

Balantidium coli hosts

Answer 5

• Pigs*, humans, primates, horses, bovine, rodents

- asymptomatic

Question 6

Balantidium coli distribution

Answer 6

Worldwide

Question 7

Balantidium coli location in host

Answer 7

Large intestine

Question 8

Balantidium coli has a ______ life cycle

Answer 8

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

Question 9

Balantidium coli infective stage?

Answer 9

Cysts in feces

Question 10

Balantidium coli completion of life cycle takes ______

Answer 10

4-5 days

Question 11

Balantidium coli route of infection

Answer 11

Fecal oral

Question 12

Balantidium coli diagnostics - trophozoites

Answer 12

Horseshoe shaped macronucleus

• ciliated
• fresh fecal sample
• direct smear - motile trophozoites

Question 13

Balantidium coli diagnositcs - cyst

Answer 13

Shed in feces, detected via fecal float

• zinc sulfate
• large horseshoe shaped macronucleus

Question 14

Balantidium coli clinical signs

Answer 14

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

Question 15

Balantidium coli treatment

Answer 15

Swine: not treated
- potential zoonosis
Control: interrupt fecal-oral transmission

Question 16

What human populations are at risk for B. coli infection?

Answer 16

Rural, institutionalized groups

• immunosuppressed
• pigs are reservoir host
• potential water/food contamination

Question 17

Ichthyophthirius multifiliis

Answer 17

“Ich” or white spot disease

- largest parasitic protozoan in fish (esp. freshwater)

Question 18

Marine form of Ichthyophthirius multifiliis

Answer 18

Cryptocaryon irritans

Question 19

Ichthyophthirius multifiliis parasitic stage

Answer 19

Motile ciliated trophont

• distinct horseshoe nucleus
• trophont: same as trophozoite

Question 20

Ichthyophthirius multifiliis has high outbreaks and mortality in ________

Answer 20

Aquaculture fish

- problem in public and private aquaria (persistant)

Question 21

Ichthyophthirius multifiliis - life cycle outline

Answer 21

Development in water

- exiting tomont –> encysted tomont –> tomite –> invading theront –> trophont that grows on skin

Question 22

Trophont

Answer 22

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

Question 23

Tomont

Answer 23

Protected and encysted stage in water

- binary fission within tomont = tomites (hundreds)

Question 24

Tomites

Answer 24

Further development into theronts

- release of theronts

Question 25

Theronts

Answer 25

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

Question 26

Theront infection

Answer 26

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

Question 27

Ichthyophthirius multifiliis completion of life cycle is dependent on ______

Answer 27

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

Question 28

Treatment for I. multifiliis targets the ______ stage

Answer 28

Theront

Question 29

Ichthyophthirius multifiliis - pathology

Answer 29

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

Question 30

I. multifiliis - diagnostics

Answer 30

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

Question 31

I. multifiliis - oriental fish

Answer 31

Treat for at least one week

• gradually increase water temp
• OTC treatments

Question 32

I. multifiliis - food fish

Answer 32

• copper sulfate
• potassium permanganate
• formalin
• salt
• recheck fish

Question 33

I. multifiliis - treatment/control

Answer 33

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

Question 34

Cryptocaryon irritans

Answer 34

Marine white spot disease

• problematic in public/private aquariums, and net pen cultured marine species
• life cycle: similar to I. multifiliis
• treatment: similar, hyposalinity