Exam 3 Flashcards
Structure
Strobila
-Made up of many individual proglottids (segments)
-Older proglottids at the posterior end of the worm
Stabilization–takes place at the anterior end of the worm
Structure pt.2
The tegument and muscle fibers of the tapeworm are continuous there for cestodes are not segmented like annelids or arthropods
End of the tapeworm
-Detach
Dissintegrate–apolysis
Be released via pores
The head is a scolex which has holdfast organs that allows the worm to attach to the GI tract
-suckers
-grooves
-hooks
-spines
-glands
-tentacles
Anterior forms of attachment
suckers/acetabula
-usually 4 or present
Example
-taenia
–in acetabular worms
bothria
-shallow pits or long grooves
-muscular
usually 4
project from scolex
leaf-like margins
Diphyllobothrium spp.
marine mammals–sea lion
Tegument
Important in its absorptice capacity
Remember, tapeworkms have no digestive tract
Structure and function of body covering has long been of great interest
-Living tissue with high metabolic activity
Tegument pt.2
Tapeworms possess a basic tegument like the trematodes
Outer membrane projects numerous fingerlike projections called microtiches
In the groups–tetraphullideans and trypanorhynchs ‘-highly ornate
have 4 kinds of microtriches existing on the scolex
Reproduction
Monecious
usually each segment has a complete set of male and female reproductive structures
Segments mature as they move down posteriorly
Cestodes
All tapeworms of humans belong to the groups cyclophyllidea also formerly known as pesudophyllidea
Usually no medical or economical impact
Morphological diversity is astonishing
Diphyllobothriidea
Genital pores may be lateral
Life cycle includes crustacean 1st IH and fish 2nd IH
Hexagonoporus physeteris
Species in sperm whales
30 meters long
4-14 sets of genetalia
has 45,000 segments (stobula)
Caryophyllidea
Most are intestinal parasites of freshwater fishes
Monozoic
-Very simple–scolex has depressions called loculi
- lack a scolex in some species
Anterior end is very motile
Earthworm has intermediate host
Spathebothriidea
Parasites of marine and freshwater fish
Complete absence of segmentation
possess a linear series of internal proglottids
Scolex unarmed
No life cycle known
Tetraphyllidea
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Order cyclophyllidea
Generally tapeworms of birds and mammals
Possess four symmetrically arranged cup suckers or acetabular
Rosrellum may or may not possess hooks
Most species small
Genital pores usually lateral
Non ciliated embryo
Non-operculate shell
Taenidae
larval stages are called metacestodes
mammals serve as intermediate hosts
Taenia solium
Humans can be the DH or IH host
metacestode(larval) form: cysticercus
If DH will have long worms in the GI tract
Dipylidiidae
Dipylidium caninum
-each proglottid has two sets of reproductive organs
Rostellum is armed
Proglottids are active
Cosmopolitan and also found in cats and wild cats
Anatomy dipluidiidae
In each uterine pocket, there’s 8-15 eggs
eggs are spherical
hooklets are small
the disintegration of proglottids leads to the release of eggs, usually found intact with the mother envelope
Life cycle continued diplidiidae
Eggs are ingested by larval stages of ectoparasitic insects, especially fleas, lice have also been implicated
A larval stage is found in a cystecercoid is found in the arthropod intermediate host (hyperparasitism example)
When ingested the cysticercoid is liberated and attaches to the DH intestine, to complete development
Anoplocephalidae
Monezia
- Hooved animals serve as DH
-Large tapeworms up to 6 meters
-Proglottids are more wise than long
-Two sets of reproductive organs
Scolex is unarmed
monezia Anatomy
Sheep cattle and goats,
Monezia benedeni
eggs are square in shape
Monezia expanse
-eggs are more triangluar
Eggs possess a pyriform apparatus and an embryophore with hook, or horn like extensions
IH is a mite
Mesocestoides
widespread in carnicores
wordwide distribiton
some consider this group a distinct order
Morphology
Medioventral position of genital pores
-diagnostic of the genus
Soclex has 4 simple suckers
no rostellum
each proglottid has a single set of reproductive organs
Mesocestoides life cycle
The complete life cycle is not known but many have a rodent or reptile intermediate host
has a larval tapeworm form is known as an [terathyridium] it is a characteristic of this genus
unusual in that it may undergo asexual reproduction in a definitive host. Not by budding but by longitudinal fission.
Nematodes
Among the most abundant animals on earth
Nematodes are free living or parasitic
75 percent live in marine , freshwater, or soil habitats
Many s[ecies parasitize plants or insects
Nemtodes antonmy
Bilaterally symmetrical
Elongated
Tapered at both ends
Possess a pseudocel
Complete GI tract
Body is covered in non-cellular cuticles secreted by the hypodermis underneath
Cuticle sheds a number of times during development.
Muscles
Secretory and excretory system
Most are dioecious
Considerable sexual dimoprhosem
Females larger
vary in size from 1mm to 10 meters
Form and Function Nematodes
(Look at Slides)
Dioctophyme renale
in a lot of mammals
Morphology of dioctophyme
Morphology, large nematode
blood red in color with blunt ends
Life cycle
Few weeks to three months to embryonated
temperature dependent
Epidemiology
Any large mammal may serve as a definitive host
fish diet
herbivoes
Pathology of kidney worm
loss of kidney finction
worms may penetrate renal capsule and wander the coelomic cavity
Calodium hepatica
A parasite of the liver
predomitnly rodents
eggs deposited in liver
Transmission depends on eggs being released from liver
Consumption by a predator
decomposition of liver tissue after crath
eggs can not develop in the liver
Calodium hepatica
Eggs released from definitive host or pass through GU treat of predator
Wandering adults through liver causes damage
losses of liver cells
loss of liver function
large areas of parenchyma
hepatomegaly
host immune response
granulomatous tissue
infilitration of eosinophils and leukocytes
Capillarids
lung parasite of dogs, cats, cand other carnicores
-eucoleus aeophilus
Eucoleus annulata
requires earthworm as a host, affects esphogus and crop of birds
Tylencha
Strongyloidses
- infects humans, dogs, cats, non-human primates, other mammals
in many cases stronglyoides has a remarkable ability to maintain homogonic, parasitic. lifecycles, or repeat free living generation, depending on conditions
Stronglyoides morphology
both sexes have a rhabditiform esophagus
Parasitic females can burrow in small intestine
produce a thinshelled partially embryonotic egg
-eggs typically hatch as they pass through the GI tract
Usually L, s in the feces of mammals
juveniles can develop in the feces
Strongloides stercolralis
Free licing addults produce generations of free living
infects birds
homogonic heterogonic
- some humans have been infected with this
usually infected through contacting juveniles in contaminated soil and water
transmammary infection can occur in dogs
predominantly a tropical disease
prevalent in poor sanitary conditions
pathology
- worms may migrate into skin
destructions of tissues by adults and larval forms
fibrosis in chronic cases and septicema can lead to death
diagnosis–baermann and serodiagnosis by ELISA for antigens
Phylum nematomoprha–hairworms
parasites of arthropods
beetles and crickets
elongated active worms
known for occurring in tangled masses resembling a gordian knot
Life cycle nema
occurence in water is a normal part of the life cycle
Occur as juveniles in arthropods
develop to near maturity befotr leaving host
transition to adult occurs in water quickly
Nematompoprpha
Phylum has 300 species
Nectonematida
-contains 5 marine species
Gordiida
-freshwater
Nematom morphology
Females larger than males
have dorsal and ventral rows of bristles
body wall
-thick cuticle
homogenous outer layer
several inner fibrious layers
cuticle ornate with areoles
raised polygon shaped areas
papillae
bristles
digestive
simplistic as an adult
locomation
0 many coiling movements
body form
-separate sexes
-most of adule body cavity filled with water
little is known about physiology
- worms unable to be rated in a laboratory
