Other imp taxa (micro) Flashcards
The Monogenea
The acanthocephala The Myxozoa
Parasites of veterinary importance
Helminths: parasitic worms, large and multicellular
The term “helminth” includes a number of phyla, many of which are unrelated (phylogenetically) but they have superficial similarities:
-they are vermiform or “worm-like” in form-
Phylum Nematoda (roundworms)
Phylum Platyhelminthes (flatworms)
– Class Cestoda (tapeworms)
– Class ? (flukes: endoparasites)
– “Class ? (skin flukes: ectoparasites)”
– Class Turbellaria (free-living flatworms, some parasitic forms)
Phylum Acanthocephala (thorny-headed worms)
Phylum Annelida (segmented worms) not parasitic (leeches)
– “Class Monogenea (skin flukes: ectoparasites)”
- Class Trematoda (flukes: endoparasites)
Class: Monogenea – ectoparasitic flatworms
most imp characteristic:
1. attach via hooks
2. direct life cycle !!!!!
▪ Part of the Phylum ?
▪ Ectoparasites: especially on the ?, fins and gills of fish, also in exotics like ? and reptiles and ?! (in the eye)
▪ No true body ? or coelom
▪ Can be quite large 2-3 cm or microscopic e.g. ?
▪ Simple ? system: mouth ? and intestine, no ? (flame cells are specialized excretory cells found in the simplest freshwater invertebrates, including flatworms)
▪ Poorly developed ?, attachment is via ? (classification)
▪ ?, mostly producing eggs, some are viviparous
▪ Ancestrally related to ? (free-living flatworms) and closest to modern ?
Class: Monogenea – ectoparasitic flatworms
most imp characteristic:
1. attach via hooks
2. direct life cycle !!!!!
▪ Part of the Phylum Platyhelminths
▪ Ectoparasites: especially on the skin, fins and gills of fish, also in exotics like frogs and reptiles and hippos! (in the eye)
▪ No true body cavity or coelom
▪ Can be quite large 2-3 cm or microscopic e.g. Gyrodactylus
▪ Simple digestive system: mouth pharynx and intestine, no anus (mo”no”genea) (flame cells are specialized excretory cells found in the simplest freshwater invertebrates, including flatworms)
▪ Poorly developed suckers, attachment is via hooks (classification)
▪ Hermaphrodites, mostly producing eggs, some are viviparous
▪ Ancestrally related to turbellaria (free-living flatworms) and closest to modern cestodes
Class: Monogenea – ectoparasitic flatworms
** Direct life cycle ** leads to significant ? in cage culture of fish
- direct life cycle thus only 1 host - FH, is involved
Adult on fish gill or in the urinary bladder of frog or turtle -> egg shed into the water -> (hatches) -> free swimming (ciliated, opisthaptor distinct; 2 eyespots, digestive tract & protonephridia present) -> attaches to host (** ONCOMIRACIDIUM **) -> adult on fish gill or in urinary bladder of frog or turtle
Class: Monogenea – ectoparasitic flatworms
?: viviparous monogeneans and some species are extremely pathogenic
viviparous: bringing forth live young that have developed inside the body of the parent
Monogena: ? seriolae of amberjacks
- Feeding on epithelial cells of the skin
Monogenea
Pseudorhabdosynochus sp. of a grouper = feeding ? cells
Class: Monogenea – ectoparasitic flatworms
gyrodactylus: viviparous monogeneans and some species are extremely pathogenic
viviparous: bringing forth live young that have developed inside the body of the parent
Monogenea
Pseudorhabdosynochus sp. of a grouper = feeding epithelial cells
Phylum Nematoda (roundworms)
Phylum Platyhelminthes (flatworms)
– Class Cestoda (tapeworms)
– Class Trematoda (flukes: endoparasites)
– Class Monogenea (skin flukes: ectoparasites)
– Class Turbellaria (free-living flatworms, some parasitic forms)
” Phylum Acanthocephala (thorny-headed worms) “
Phylum Annelida (segmented worms) not parasitic (leeches)
Phylum Acanthocephala– thorny-headed worms
The earliest recognizable description of Acanthocephala – a worm with a proboscis armed with ? – was made by Italian author Francesco ? (1684)
- Acanthocephalans are highly adapted parasites, and have lost many organs and structures through evolutionary processes, making direct comparative taxonomy difficult.
- No ? or ? system, as in cestodes but they are not related
- Nutrient are absorbed from hosts’ digested gut contents, via the integument
- Can be quite large over 10 cm
Phylum Acanthocephala– thorny-headed worms
The earliest recognizable description of Acanthocephala – a worm with a proboscis armed with hooks – was made by Italian author Francesco redi (1684)
- Acanthocephalans are highly adapted parasites, and have lost many organs and structures through evolutionary processes, making direct comparative taxonomy difficult.
- No mouth or digestive system, as in cestodes but they are not related
- Nutrient are absorbed from hosts’ digested gut contents, via the integument
- Can be quite large over 10 cm
Phylum Acanthocephala– thorny-headed worms
- Recent genomic data suggests sister group to rotifers: freshwater zooplankton
- Invertebrate ? host
- Adult stage almost always in the digestive tract, ** not usually ? **
- Acanthocephala are sexually ? (an individual organism is either male or female)
- All have ? life cycles
- Many not ? specific
- Infect
- ? * Birds
- Amphibians * Fish
- ?
Diagnosis by observation of ? in feces
Phylum Acanthocephala– thorny-headed worms
- Recent genomic data suggests sister group to rotifers: freshwater zooplankton
- Invertebrate IH
- Adult stage almost always in the digestive tract, ** not usually pathogenic **
- Acanthocephala are sexually dioecious (an individual organism is either male or female)
- All have complex life cycles
- Many not host specific
- Infect
- invertebrates * Birds
- Amphibians * Fish
- mammals
Diagnosis by observation of eggs in feces
PIC:
1. eggs shed in feces
2. eggs are ingested by an IH
3. The definitive host becomes infected by ingestion of infected IH
4. adult in small intestine of ih
5. then into humans
Phylum Acanthocephala– thorny-headed worms
Recent case study at RUSVM
* Unusual cysts were found in the skeletal muscle of mongoose used in a leptospirosis trial
* Unusual morphology and were not readily identifiable by parasitologists or pathologists
* Used light microscopy to look for microscopic detail
* Amplify DNA from various rRNA gene regions to try to identify
* Later similar cysts were seen in monkeys
Phylum Acanthocephala– thorny-headed worms
The cystacanth is a resting stage, where the parasite lies encysted
No further development occurs in this host, normally an invertebrate
The cystacanth must be ingested by its definitive host, usually a vertebrate
Help….DNA
Problem, mongoose and monkey are vertebrates!! So why is this not in the intestine and an adult stage??
ITS sequencing provided the information needed
Cystacanths from both mongoose and monkey are the same species
Also we had a direct hit in the DNA databases almost 100% identity
“Oncicola venezuelensis”
- In Brazil, the intermediate host of Oncicola venezuelensis is unknown.
- Cystacanths have been recovered (birds eating small lizards and birds beig eaten by a cat) and described in Caribbean termites, in subcutaneous nodules of lizards Anolis cristatellus, in the Indian mongoose Herpestes auropunctatus and in pearly- eyed thrashers Margarops fuscatus
- ** For final development to the adult stage in St Kitts, a cat is probably required to eat the cystacanths, so some hosts are probably a dead end **
3 taxa - exam questions; big msgs
Acanthocephala
- ?-headed worms, worm-like but not related to the other taxa like ? and Platyhelminthes
- Actually related to rotifers
- They are sexually ? (an individual organism is either male or female)
- Have simple or complex? life cycles, adults almost always in the ?, can be quite large
>10 cm (not usually pathogenic) - Many not ? specific especially in the ? hosts
- Highly adapted parasites, no ?, absorb via cuticle
- Example Oncicola venezuelensis (final host a felid (ocelot) in native range)
- In St Kitts, some hosts are likely to be ?-end hosts, such as the mongoose and
monkey - Mongoose and monkey are not final hosts as the cystacanth stage is found ? in the muscle and not developing into an ? in the intestine
3 taxa - exam questions; big msgs
A”c”anthocephala (cuticle -no mouth)
- thorny-headed worms, worm-like but not related to the other taxa like nematodes and Platyhelminthes
- Actually related to rotifers
- They are sexually dioecious (an individual organism is either male or female)
- Have complex life cycles, adults almost always in the intestines, can be quite large
>10 cm (not usually pathogenic) - Many not host specific especially in the intermediate hosts
- Highly adapted parasites, no mouth, absorb via cuticle
- Example Oncicola venezuelensis (final host a felid (ocelot) in native range)
- In St Kitts, some hosts are likely to be dead-end hosts, such as the mongoose and
monkey - Mongoose and monkey are not final hosts as the cystacanth stage is found encysted in the muscle and not developing into an adult in the intestine
Parasite of veterinary importance
- Kingdom Protozoa (Protists)
– Phylum Mastigophora (flagellates)
– Phylum Apicomplexa
– Phylum Ciliophora (ciliates) - Kingdom Fungi
- Kingdom Animalia
– Phylum Arthropoda (insects/arachnids, copepods)
– “ Phylum Cnidaria (Myxozoa) “ - DOING THIS NOW
Polar capsule/filaments are used in ? release ‘evolved/derived nematocyst’
mytacosts, fire out on the left but they don’t sting anymore; sporoplasm escaping on the right
Polar capsule/filaments are used in sporoplasm release ‘evolved/derived nematocyst’
Myxozoa (Class: Myxosporea): Phylum Cnidaria
Indirect life-cycle
Myxozoa are highly adapted ? cnidarians
** ? ** host -> myxospore -> ** ? host (oligochaete / polychaete) ** -> actinospore -> fish host
IMP!!
? cerebralis and ? disease
* Disease first described in Germany in 1898 (Hofer)
* Destruction of ? (especially spinal column and cranium) in juvenile ?; massive infection leads to ? of fish or life-long skeletal deformities.
* Characteristic erratic ? chasing behaviour (“whirling disease”) and ? caudal area due to damage of the CNS due to infection of the cartilage.
* ? trout are considered the most susceptible of 11 salmonid hosts; losses may reach 90%;
* Parasite has been spread by movements of live or frozen fish from presumed origins in ? to many countries in central and western Europe, Australia / New Zealand and the USA.
* Life-cycle elucidated; programs to minimize infection in hatchery-reared rainbow trout now active.
Myxozoa are highly adapted parasitic cnidarians
** fish ** host -> myxospore -> ** annelid host (oligochaete / polychaete) ** -> actinospore -> fish host
IMP!!
Myxobolus cerebralis and whirling disease
* Disease first described in Germany in 1898 (Hofer)
* Destruction of cartilage (especially spinal column and cranium) in juvenile salmonids; massive infection leads to death of fish or life-long skeletal deformities.
* Characteristic erratic tail-chasing behavior (“whirling disease”) and blackened caudal area due to damage of the CNS due to infection of the cartilage.
* rainbow trout are considered the most susceptible of 11 salmonid hosts; losses may reach 90%;
* Parasite has been spread by movements of live or frozen fish from presumed origins in eurasia to many countries in central and western Europe, Australia / New Zealand and the USA.
* Life-cycle elucidated; programs to minimize infection in hatchery-reared rainbow trout now active.
The Hepatic biliary group of myxosporeans: reveals infection with myxospores in other groups
Reptiles: FW ?
Mammals: shrew/?
Birds: ducks/?
Amphibians: ?
morphology and eyeballing is imp.!
Representatives of genera of major myxospore morphotypes
The presence of ? is still the defining diagnostic feature for myxosporean infection
Finding a myxospore is diagnostic: it is not useful for species ?
The Hepatic biliary group of myxosporeans: reveals infection with myxospores in other groups
Reptiles: FW turtle
Mammals: shrew/moles
Birds: ducks/waterfowl
Amphibians: frogs
Representatives of genera of major myxospore morphotypes
The presence of myxospores is still the defining diagnostic feature for myxosporean infection
Finding a myxospore is diagnostic: it is not useful for species identification
Class: Malacosporea, Tetracapsuloides bryosalmonae
Tetracapsuloides bryosalmonae
is a ? parasite of salmonid fish. It causes Proliferative Kidney Disease (PKD), one of the most serious ? diseases of ? populations in Europe and North America.
Collapse of arctic char population in Iceland due to this parasite, as water temperatures have risen about 13C, and the parasite becomes ?
Class: Malacosporea, Tetracapsuloides bryosalmonae
Tetracapsuloides bryosalmonae
is a myxozoan parasite of salmonid fish. It causes Proliferative Kidney Disease (PKD), one of the most serious parasitic diseases of salmonid populations in Europe and North America.
Collapse of arctic char population in Iceland due to this parasite, as water temperatures have risen about 13C, and the parasite becomes pathogenic
The Multivalvulida
- Order of * ? * marine myxosporeans (Kudoidae & Trilosporidae)
- Typically found in skeletal muscles of ? fish but have also been found in other organs such as brain, heart, gills, kidney, gall bladder, ovary and intestines, often still associated with muscle tissues.
- Have 3 or more shell valves, with apical ? capsules
- Mostly pathogenic as develop inside tissues (* ? *) unlike many myxozoans that are ‘Coelozoic’ developing in coelom-like spaces, e.g. the gallbladder
thus problematic as they develop inside tissues!
The Mul”ti”valvulida
- Order of * histozoic * marine myxosporeans (Kudoidae & Trilosporidae)
- Typically found in skeletal muscles of marine fish but have also been found in other organs such as brain, heart, gills, kidney, gall bladder, ovary and intestines, often still associated with muscle tissues.
- Have 3 or more shell valves, with apical polar capsules
- Mostly pathogenic as develop inside “ti”ssues (* histozoic *) unlike many myxozoans that are ‘Coelozoic’ developing in coelom-like spaces, e.g. the gallbladder
