Flagellate Infection Flashcards
(19 cards)
Organisms that have one-to-many flagella; occur on the skin ,gills, intestinal organs, and blood of fish.
Flagellates.
Examples of Flagellates.
Amyloodinium ocellatum, Trypanosoma spp,. Cryptobia spp., Ichthyobodo spp.
Infection that is extremely dangerous and sometimes lethal for hosts. Promotes secondary bacterial infections.
Marine Velvet Disease.
Causative Agent for Marine Velvet Disease.
Amyloodinium ocellatum.
Amyloodinium ocellatum description.
Cosmopolitan ectoparasite DINOFLAGELLATE*, lives in brackish and seawater environments.
- Unicellular, two dissimilar flagella from ventral cell side.
Species affected by Marine Velvet Disease.
Mullet, siganid, grouper. All life stages susceptible if naive to A. ocellatum.
Life Cycle of Amyloodinium ocellatum.
Divided in 3 phases that can be completed in 5 - 7 days, when:
Temperature = 23 - 27C.
Salinity = 30 - 35 ppt.
1.) Sessile TROPHONT = Parasitic stage; pear-shaped. Rhizoids to adhere to epithelia. @ Eyes, fins, oropharyngeal cavity. Detaches after 2 - 3 days, encysts on substrates.
2.) TOMONT = Reproductive stage; round and encapsulated in a cellulose wall. Reproduces asexually.
i. Longitudinal division.
ii. Regular at right angles.
3.) DINOSPORES. 1 Tomont = 256 Dinospores.
Pathogenesis of Marine Velvet Disease.
Pathogenicity is associated with trophont attachment to host tissues.
1.) Trophonts twist and turn, killing host cells.
2.) Moderate to intense tissue reactions:
- Gill hyperplasia.
- Inflammation.
- Hemorrhage.
- Necrosis.
3.) Subsequent death <12 hours (Heavy Infections).
Clinical Signs of Marine Velvet Disease.
Jerky movements (Flashing). Pruritus. Dyspnea - Gathering at the surface. Dusty appearance.
Lesions of Marine Velvet Disease.
Gill hyperplasia. Inflammation. Hemorrhages. Necrosis. Reduced or absence of mucus cell.
Diagnosis of Marine Velvet Disease.
Microscopic Examination: Skin scrapings - Gill filaments.
- Pear or ovoid-shaped trophonts with elongated red stigma near attachment site.
Prevention and Control of Marine Velvet Disease.
Use of sand filters. Ultraviolet irradiation. Disinfection - LIME.
Freshwater Bath = Cause parasite to drop off the gills.
0.75 ppm CuSO4 = 5 - 6 days.
0.25 ppm Formalin + 0.1 ppm Malachite Green = 1 day.
100 - 300 ppm Formalin = 10 mins.
Other Flagellates.
Trypanosoma spp., Cryptobia spp,. Ichthyobodo spp.
Species affected by other Flagellates.
Snakeheads, carps, mullet, milkfish.
Clinical Signs from other Flagellate infections.
Greyish-white film on fins and body surface. Frayed or destroyed fins. Rubbing of body.
Pathogenesis of other Flagellate infections.
Ichthyobodo spp. = Attachment on dorsal fins and gills.
Trypanosoma spp., Cryptobia spp. = Parasite on the blood of fish.
Flagellate Life Stages.
INVERTEBRATE / VECTOR:
1.) EPIMASTIGOTE = Infective stage, undergoes multiplication.
2.) METACYCLIC TRYPOMASTIGOTE = Infective, non-diving. Transmitted to host.
VERTEBRATE / HOST:
3.) AMASTIGOTE = Present inside host, undergoes multiplication. Most commonly seen in in T. cruzi.
4.) BLOODSTREAM TRYPOMASTIGOTE = Proliferative stage, circulates in blood, spreads infection.
Diagnosis of other Flagellate infections.
Microscopic Examination.
1.) Ichthyobodo spp.: Mucus - Body surface, gill filaments.
2.) Trypanosoma spp., Cryptobia spp. = Sample fixed in METHANOL, stained with GIEMSA under 100x magnification.
Prevention and Control of other Flagellate infections.
Drying of culture facilities. Use of filters.
Vector control for blood protozoans.
2 - 5 ppm or 10 ppt KMNo4 = 15 - 30 mins.
