Protists (micro) Flashcards
Parasites of veterinary importance
- Kingdom Protozoa / Protista
– Excavates (flagellates)- Phylum Euglenozoa
– Kinetoplastea (Trypanosoma) - Phylum Metamonada
– Diplomonads (Giardia, Hexamita)
– Parabasalids (Histomonas, Trichomonas)
– Phylum Apicomplexa
– Eimeria, Neospora etc.
– Phylum Ciliophora (ciliates)
– Balantidium
– Amoebozoa
– Entamoeba
- Phylum Euglenozoa
Protozoan vs Protist
- Protozoa is a general term for ?-celled eukaryotes, either ?-living or ?, which feed on ? matter
- A protist is any eukaryotic organism that has cells with nuclei and is not an ?, ? or ?. So includes ?, slime molds and dinoflagellates
- Neither form a natural group
- Protozoa “first and animal-like” implies a kinship with ? (metazoans), so the use of the term protozoa is discouraged by many
- For this reason, the terms “protist”, is now typically preferred for the high-level classification of eukaryotic microorganisms.
In 2005, members of the Society of ? voted to change the name of their organization to the International Society of ?.
Protozoan vs Protist
- Protozoa is a general term for single-celled eukaryotes, either free-living or parasites, which feed on organic matter
- A protist is any eukaryotic organism that has cells with nuclei and is not an animal, plant or fungi. So includes algae, slime molds and dinoflagellates
- Neither form a natural group
- Protozoa “first and animal-like” implies a kinship with animals (metazoans), so the use of the term protozoa is discouraged by many
- For this reason, the terms “protist”, is now typically preferred for the high-level classification of eukaryotic microorganisms.
In 2005, members of the ** Society of protozoologists ** voted to change the name of their organization to the ** International Society of protistologists **
Protozoa – classified by locomotion
Phylum: Euglenozoa (Excavates) major supergroup of unicellular organisms belonging to the domain Eukaryota. Include the ? (a group of flagellates, most of which are parasitic) and ?.
Amoebozoa: The amoebozoans include protists that are distinguished by possessing ?.
Protozoa – classified by locomotion
Phylum: Euglenozoa (Excavates) major supergroup of unicellular organisms belonging to the domain Eukaryota. Include the diplomonads (a group of flagellates, most of which are parasitic) and kinetoplasts
Amoebozoa: The amoebozoans include protists that are distinguished by possessing pseudopods.
Stramenopiles: (Heterokonts) Algae, kelp to diatoms & Oomycetes -> Water molds, Aphanomyces etc
Unikonts: amoebozoa and opisthokonts (fungi and animals) -> Amoebozoa; fungi/microsporidia
Excavates: amitochondriate flagellates, amoeboflagellates, Euglenozoa ->
Trypanosoma & Diplomonads
Alveolates: Ciliates, apicomplexans and dinoflagellates -> Many coccidian/apicomplexan parasites. Also ciliates and some parasitic dinoflagellates
Cercozoa: amoeboids and flagellates that feed by means of filose pseudopods, includes Halposporidians -> Ascetosporea (Haplosporidians) shellfish parasites (Marteilia) Mikrocytos ?
Infective stage of a coccidian
a * sporozoite *
Merocystis kathae
Protozoa – terminology
Zoite – ? creature
* Prefixes are added to the term “zoite” to denote a portion of the life history.
* Sporozoite – ? form
* Trophozoite – form which ? and ?
* Tachyzoite – form which ? rapidly
* Bradyzoite – form which divides ?
* Merozoite – ? (can also be infective in the case of two ? being involved)
Protozoa – terminology
Zoite – small creature
* Prefixes are added to the term “zoite” to denote a portion of the life history.
* Sporozoite – infective form
* Trophozoite – form which feeds and grows
* Tachyzoite – form which divides rapidly
* Bradyzoite – form that divides slowly
* Merozoite – many (can also be infective in the case of two hosts being involved)
PROTOZOA (PROTISTS): unicellular, eukaryotic ‘animals’
- Nucleus, endoplasmic reticulum, ?, a Golgi body and ?
- Anerobic or aerobic
- Absorb nutrients or have a “?-mouth”
- Feed on ?, other ?, organic matter or tissues of the ?
(some of the flagellates have lost their mitochondria so not all have mitochondria)
Protozoa may take in food by ‘ ? ’ absorbing nutrients through their cell ?; or they may feed by ?, either by engulfing particles of food with ? (as amoebae do), or taking in food through a mouth-like aperture called a ?.
PROTOZOA (PROTISTS): unicellular, eukaryotic ‘animals’
- Nucleus, endoplasmic reticulum, lysosome, a Golgi body and mitochondria
- Anerobic or aerobic
- Absorb nutrients or have a “pseudo-mouth”
- Feed on bacteria, other protozoa, organic matter or tissues of the host
(some of the flagellates have lost their mitochondria so not all have mitochondria)
Protozoa may take in food by ‘ osmotrophy ’ absorbing nutrients through their cell membrane; or they may feed by phagocytosis, either by engulfing particles of food with pseudopodia (as amoebae do), or taking in food through a mouth-like aperture called a cytostome.
Protozoa – key characteristics
Many are part of the normal ?; do not cause ? (Entamoeba – commensal
intestines; ciliates in sea urchins, Cryptobia stomach lumpfish; gregarines intestinal ‘parasites’)
- Locomotion via ?, ?, gliding movements or cilia
Protozoa – key characteristics
Many are part of the normal microbiota; do not cause disease (Entamoeba – commensal
intestines; ciliates in sea urchins, Cryptobia stomach lumpfish; gregarines intestinal ‘parasites’)
- Locomotion via pseudopods, flagella, gliding movements or cilia (characterised by these as well (flagella - complicated))
- Asexual reproduction = ? exposure = significant damage
- Host(s)
– ?-specific or ?-spectrum
– Zoonotic or non-host specific ( ? ) - Chronic infections; immunity ( ? )
- Many form ? (in the environment or in a host). (Sarcocystis in muscles)
- Asexual reproduction = large exposure = significant damage
- Host(s)
– host-specific or broad-spectrum
– Zoonotic or non-host specific ( Toxoplasma ) - Chronic infections; immunity ( Giardia )
- Many form cysts (in the environment or in a host). (Sarcocystis in muscles)
Protozoa – Asexual reproduction
- ? fission, * ? * / multiple fission (merogony)
- Protozoa that divide asexually have a long or short? generation time
- Schizogony (merogony)
– ? increase in numbers
– Destruction of host cells in proportion to the ?
– Stops after a fixed number of ?
Protozoa – Asexual reproduction
- binary fission, * budding * / multiple fission (merogony)
- Protozoa that divide asexually have a short generation time
- Schizogony (merogony)
– exponential increase in numbers
– Destruction of host cells in proportion to the infection
– Stops after a fixed number of repetitions
Protozoa – binary fission
It is the most ? form of reproduction in prokaryotic organisms and occurs in some ?-celled Eukaryotes like the ? Paramecium.
Protozoa – schizogony a.k.a merogony
- Asexual reproduction of ? characterized by multiple divisions of the nucleus and cell
- Common in many apicomplexans.
** Intermediate host: ? reproduction: Merocystis kathae in scallops ** - Very ?
Protozoa – binary fission
It is the most common form of reproduction in prokaryotic organisms and occurs in some single-celled Eukaryotes like the ciliate Paramecium.
Protozoa – schizogony a.k.a merogony
- ** Asexual reproduction of protozoans ** characterized by multiple divisions of the nucleus and cell
- Common in many apicomplexans
** Intermediate host: asexual reproduction: Merocystis kathae in scallops **
- Very pathogenic
Protozoa – sexual reproduction
Gametogony or sporogony
- Merozoites becomes either a ? (macrogamont) and then a ? OR a Microgametocyte (microgamont) and then several ?
- A microgamete fertilizes a macrogamete forming a ** ? **; a wall forms around this and it becomes an ** ? **
Definitive host: ? reproduction: Merocystis kathae in common whelk
Protozoa – sexual reproduction
Gametogony or sporogony
- Merozoites becomes either a Macrogametocyte (macrogamont) and then a macrogamete OR a Microgametocyte (microgamont) and then several microgametes
- A microgamete fertilizes a macrogamete forming a ** zygote **; a wall forms around this and it becomes an ** oocyte **
Definitive host: sexual reproduction: Merocystis kathae in common whelk
Not pathogenic!!!!
Protozoa - flagellates
SUB-PHYLUM: ‘Mastigophora’ class kinetoplastida (Excavates)
locomotion by flagella
ORDER:
Kinetoplastorida
- haemoflagellates (haemo means blood)
- parasites of the blood
- generally transmitted by biting insects
yes are the ones we went through
Diplomonadorida
Trichomonadorida (YES)
- flagellates
- predominantly of the intestines
PROTOZOA GENERA
Kinetoplastorida: Trypanosoma cruzi (yes)
Diplomonadorida
Trichomonadorida: Giardia (YES), spironucleus, histomonas - poultry (YES), tritrichomonas
Trypanosoma is a genus of ?, a monophyletic group of unicellular ? ? protozoa.
Trypanosomes infect a variety of hosts and cause various diseases, including the fatal human diseases ? sickness, caused by ? ?, and ? disease, caused by Trypanosoma ?.
Protozoa - flagellates - Giardia
Aztec emperor of Mexico
Montezuma’s revenge is a colloquial term for traveler’s ? contracted in Mexico.
Trypanosoma is a genus of Kinetoplastorida, a monophyletic group of unicellular parasitic flagellate protozoa.
Trypanosomes infect a variety of hosts and cause various diseases, including the fatal human diseases sleeping sickness, caused by Trypanosoma brucei, and Chagas disease, caused by Trypanosoma cruzi.
Protozoa - flagellates - Giardia
Aztec emperor of Mexico
Montezuma’s revenge is a colloquial term for traveler’s diarrhea contracted in Mexico.
- cyst (exogenous) -> ingested -> trophozoite usually in duodenum (endogenous - in the body)-> cyst and trophozoite defecated (endogenous) -> cyst by itself (exogenous)
- trophozoites are also passed in stool but they do not survive in the environment.
- contamination of water, food or hands/fomites with infective cysts and then orally into humans
Protozoa – flagellates - Histomonas
- Histomoniasis/osis is a commercially important disease of ?, particularly of ? and turkeys, due to Histomonas meleagridis
- Clinical signs of Histomoniasis/osis include lethargy, yellow ?, appetite/weight ?, discoloration of the ? (blackhead) and death
- Histomonas specifically infects the ? and ?
- Histomonas is transmitted to the bird by the nematode parasite ? gallinarum, usually in the egg or in an ? containing infected eggs
- No current ?
Protozoa – flagellates - Histomonas
- Hi”st”omoniasis/osis is a commercially important disease of poultry, particularly of chicken and turkeys, due to Histomonas meleagridis
s= chicken; t = turkey
- Clinical signs of Histomoniasis/osis include lethargy, yellow diarrhea, appetite/weight loss, discoloration of the head (blackhead) and death
- Histomonas specifically infects the cecum and liver
- Histomonas is transmitted to the bird by the nematode parasite heterakis gallinarum, usually in the egg or in an earthworm containing infected eggs
- No current treatment
Histomonas life cycle
Cecal worm (? gallinarum) life cycle
- deposit eggs in the ? tract
- chicken’s feces contain eggs
- eggs present in soil, feces and/or bedding
OR - eggs are ingested by earthworm
- Chicken ingests earthworm, soil, feces or bedding containing eggs
- eggs hatch, larvae grow into adults
Adult: H. gallinarum
TURKEY
? meleagridis
- infected H. gallinarum egg
- transport host: ?
Histomonas life cycle
Cecal worm (heterakis gallinarum) life cycle
- deposit eggs in the digestive tract
- chicken’s feces contain eggs
- eggs present in soil, feces and/or bedding
OR - eggs are ingested by earthworm
- Chicken ingests earthworm, soil, feces or bedding containing eggs
- eggs hatch, larvae grow into adults
Adult: H. gallinarum
TURKEY
histomonas meleagridis
- infected H. gallinarum egg
- transport host: earthworm
Protozoa – ciliates
balantidum sp., ? ? disease, sp name: ichthyophthirius multifiliis (always comes for NAVLE!),
encystment and division
- tomites in the substrate -> theront -> trophont -> tomont
Protozoa – ciliates
balantidum sp., WHITE SPOT disease, sp name: ichthyophthirius multifiliis (always comes for NAVLE!),
encystment and division
- tomites in the substrate -> theront -> trophont -> tomont
GOUSSIA OOCYST
? oocysts - four sporocysts each with ? sporozoites
Release of the sporozoites from the sporocysts is via a ? suture
2nd slide:
4 ? per oocyst
(2 ? per sporocyst)
GOUSSIA oocysts - four sporocysts each with 2 sporozoites
Release of the sporozoites from the sporocysts is via a longitudinal suture
2nd slide:
4 sporocysts per oocyst
(2 sporozoites per sporocyst)
EIMERIA oocysts - four sporocysts each with two sporozoites
Release of the sporozoites from the sporocysts is via ? body at the apex of a ?
Epieimeria sp. ?
as eimeria but with ? development
Crystallospora sp.
Sporocysts with a regular ? appearance
EIMERIA oocysts - four sporocysts each with two sporozoites
Release of the sporozoites from the sporocysts is via Stieda body at the apex of a sporocyst
Epieimeria sp. ?
as eimeria but with epicellular development
Crystallospora sp.
Sporocysts with a regular crystalline appearance
Common living (Molva molva)
Goussia ?
Swim bladder completely filled with goo
Lungfish (Cyclopterus lumpus)
- breakdown of ? in pyloric ?
- no sporulated oocysts yet seen
- 18S rDNA > 99% identity to
- Groussia ?: silver bream
- Eimeria subepithelialis:
common carp
Common living (Molva molva)
Goussia lumpus
Swim bladder completely filled with goo
Lungfish (Cyclopterus lumpus)
- breakdown of epithelium in pyloric caeca
- no sporulated oocysts yet seen
- 18S rDNA > 99% identity to
- Groussia balatonica: silver bream
- Eimeria subepithelialis:
common carp
Protozoa – Apicomplexa – one host
Many Eimeria and Goussia spp. sporulate ? of the host.
In particular those infecting the ?. Others usually sporulate ?
Protozoa – Apicomplexa – one host
Many Eimeria and Goussia spp. sporulate outside of the host.
In particular, those infecting the intestines. Others usually sporulate endogenously.
Protozoa – Apicomplexa- two hosts
remember the next one!! for this just skim it.
Sarcocystis spp.
ingestion GI tract -> fertilization -> unsporulated cyst -> sporulated oocyst -> excretion -> sporocyst (exogenous) -> ingestion GI tract (exogenous) -> excystation -> intermediate host (prey) -> extra-intestinal (merogony - many) -> saroocyst -> ingestion GI tract
causing
eosinophilic ileitis, fever, abdominal pain, diarrhea or obstruction
Protozoa – Apicomplexa
- ? for survival
- Either ? or in the ? host
Protozoa – Apicomplexa
Toxoplasma gondii is an ? intracellular, parasitic ? that causes the disease toxoplasmosis.
- Can alter the behavior of the true ? host, to facilitate completion of the life-cycle i.e. predation
DH: ? -> ? ? passed in feces -> oocysts in feed, water, or soil and ingested by ? (MANY) -> contaminated food and water consumed by ? (tachyzoites can also be transmitted through placenta)
Protozoa – Apicomplexa
- cyst for survival
- Either environment or in the intermediate host
Protozoa – Apicomplexa
Toxoplasma gondii is an obligate intracellular, parasitic alveolate that causes the disease toxoplasmosis.
- Can alter the behavior of the true intermediate host, to facilitate completion of the life-cycle i.e. predation
DH: cat -> unsporulated oocyst passed in feces -> oocysts in feed, water, or soil and ingested by IH (MANY) -> contaminated food and water OR tissue cysts ingested in infected uncooked meat consumed by humans (tachyzoites can also be transmitted through the placenta) -> this uncooked meat can also be eaten by cat thus cat consumes tissue cysts
