parasitology- Nematodes (unit 15+16)

round

nematodes are commonly called _____worms

Adenophorea (aphasmidea)

Secementea (phasmidea)

what are the 2 main nematode subclasses?

yes

do nematodes have a complete digestive tract?

dioecious

(and have sexual dimorphism)

are nematodes hermaphrodites or dioecious?

yes

(sexual dimorphism)

can you tell female and male nematodes apart?

covers external surface, including mouth, anus, vagina, and excretory pore; has papillae and alae

describe the cuticle of a nematode

contractile myofibrils

what type of musculature do nematodes have?

they have 1 dorsal and 2 lateral lips,

Ancylostomids have ventral lips that are modified into teeth/plates

describe the lips of a nematode

chitinous organs of male nematodes, inserted into female genital opening

what are spicules?

small, chitinous structure of male nematodes, acting as a guide for the spicules

what is gubernaculum?

structures of male nematodes used to embrace and hold the female during copulation

what is the copulatory bursa and bursal rays?

alae

what are these 2 structures called?

inflations of the cuticle around the mouth and near the esophagus

what are cervical/cephalic papillae?

leaf crown

what is the name for the rows of papillae surrounding the rim of the buccal capsule?

a buccal capsule

at the mouth of some nematodes

what is this?

rhabditiform

what type of esophagus is this?

strongyliform

what type of esophagus is this?

filariform

what type of esophagus is this?

oxyuriform

what type of esophagus is this?

stichosome/moniliform

what type of esophagus is this?

cloaca

in males, the genital tract opens up into a _____

primitive, with canals ("lateral cords"), and an excretory pore, located ventrally, near the esophagus

describe the excretory system of nematodes

2 ganglions, connected by fibers in the esophageal ring, giving rise to 6 nervous cords

describe the nervous system of nematodes

phasmids

amphyds

cervical+caudal papillae

genital papillae

what sensitive organs do nematodes have?

sensory organs for chemorrepulsion, located caudally next to the anus

what are phasmids?

amphyds

what sensory organs are next to the mouth and are for chemoreception?

tacticle sensory organs

what is the purpose of cervical and caudal papillae?

tactile and chemorreceptor organs

nect to the cloaca

what are genital papillae?

1 testes

vas deferens

terminal vesicle

muscular ejaculatory duct

cloaca

1-2 spicules

gubernaculum

copulatory bursa

what structures are included in the reproductive system of a male nematode?

male- it has spicules, a copulatory bursa, and bursal rays

is this a male or female nematode? why?

spicules

what is 1?

copulatory bursa

what is 2?

bursal ray

what is 3?

the vulvar flap

what is the arrow pointing to?

2 ovaries (except Aphasmidea)

oviduct

uterus (1 or 2)

ventral and medial genital pore

vulvar flap

seminal receptacle

describe the reproductive tract of a female nematode

reproductive organ of female nematodes, it is a uterine expansion where fertilization occurs

what is a seminal receptacle?

DH

nematodes always mate in the _____

both

do nematode eggs hatch in the host or the environment?

they can lay:

unembryonated eggs (oviparous)

embryonated eggs (ovoviviparous)

live larva (viviparous)

do nematodes lay embryonated or unembryonated eggs?

larval development involves 4 moults/ecdysis

what is Maupa's theory?

1. free L3 ingested by DH

2. free L3 crosses through DH's skin

3. Ingestion of eggs with L2/L3

4. Ingestion of IH with L3 inside

5. Ingestion of paratenic host with L3 inside

6. Active inoculation of L3 by vectors

what are the different options for L3 to infect a host?

Enoplida

Dioctophymatida

what 2 orders are included in subclass Adenophorea?

stichosome

what type of esophagus does order Enoplida have?

L1

what stage of order Enoplida is infective?

NO

does order Enoplida have phasmids?

Trichinellidae, Trichuridae, Capillarridae

which is the main families belonging to Enoplida?

small

male has 2 claspers at the end

viviparous

L1 has a stylet to penetrate blood vessels

describe the morphology of nematodes belonging to the family Trichinellidae

penetration of blood vessels

L1 of family Trichinellidae has a stylet- what is this for?

direct

autoheteroxenous- same host as IH and DH

L1 is ingested, then it penetrates enterocytes, where it goes through 4 moults and becomes adult. Then, they copulate, the male dies, and the female lays L1 (viviparous), which travels via lymph and blood vessels to striated muscle, where it creates cysts, encapsulated by a thick collagen capsule. The muscular fibers that the L1 is encysted in become "nurse cells" (big nucleus, more mitochondria and ER, no myofilaments, anaerobic metabolism).

what type of life cycle does family Trichinellidae have?

host cells that support and nourish the larva phase of the nematode. it has a large nucleus, many mitochondria and ER, no myofilaments, and does anaerobic metabolism.

what is a nurse cell?

no, they are bad hosts and the nematode's cycle cannot continue inside of them

are humans good hosts for the family Trichinellidae?

they get clinical signs in 1-2 days after infection, including a cutaneous rush during the migration of the nematode and periocular edema. nurse cells are formed in 2-8 weeks

what happens to humans if they are infected by a nematode of family Trichinellidae?

family Trichinellidae (Trichinella)

this describes the life cycle of which nematodes?

ingestion of parasitized animals

herbivores are sometimes infected if larva is eliminated in feces or if carcasses with the parasite contaminate the environment. this is rare

how do animals/humans get infected by family Trichinellidae?

feeding animals with swine remains from the slaughterhouse or hunting

the main source of infection by family Trichinellidae is....

whip worms

genus Trichuris are commonly known as...

Trichinella

what important genus included in family Trichinellidae?

family Trichuridae

genus Trichuris

what genus and family?

long and narrow anterior end, short and thick posterior end

males with a curled tail, 1 spicule, and a spicular sheath

females with a straight posterior end

describe the morphology of genus Trichuris. how can we differentiate between males and females?

lemon shaped

brown/yellow

2 polar plugs

resistant to environmental conditions

unembryonated

describe Trichuris eggs

Trichuris

this egg belongs to the genus _____

unembryonated

does genus Trichuris lay embryonated or unembryonated eggs?

T. ovis

T. skrjabini

which species in genus Trichuris affects the caecum of cattle, sheep, and goats?

caecum and colon of swine

what animal and organ does Trichuris suis infect?

T. vulpis

which species in genus Trichuris infects the caecum of dogs, wolves, and foxes?

T. trichiura

which species of genus Trichuris infects humans?

T. spiralis

T. britovi

T. pseudospiralis

all have adults that infect the small intestine of mammals (ex- humans, swine, horses, rats) and in all, the L1 is in the striated muscle. BUT, T. spiralis and T. britovi form intramuscular collagen cysts and T. pseudospiralis does not

what are the 3 important Trichinella species, and what is the difference between them?

direct

is the life cycle of Trichuris direct or indirect?

eggs are shed with feces, then L1 develops, and then the animal ingests L1

how are animals infected by Trichuris?

Trichinella

which Enoplida genus has L1 that develops in striated muscle of the host?

Trichinella

which genus is this?

direct

host ingests L1 that has been shed out as eggs in feces. it penetrates intestines and goes through 4 moults and then emerges as adults in the large intestine.

describe the life cycle of genus Trichuris

Capillaria

which genus?

Capillaria

this egg belongs to what genus?

C. caudinflata- duodenum and ileum of poultry, pigeons, wild birds

C. contorta- crop, esophagus, oropharyngeal cavity of ducks and turkeys

what species of genus Capillaria infects birds?

Capillaria caudinflata

which nematode infects the duodenum and ileum of poultry, pigeons, and wild birds?

crop, esophagus, oropharyngeal cavity of turkeys and ducks

what species and organ does Capillaria contorta infect?

C. feliscati

C. hepatica

C. aerophila

which Capillaria species infect mammals?

bladder of cats

what species and organ does Capillaria feliscati infect?

Capillaria feliscati

which species infects the bladder of cats?

liver of rodents, rabbits, dogs, and humans

what species and organ does Capillaria hepatica infect?

Capillaria hepatica

what species of nematode infects the liver of rodents, rabbits, dogs, and humans?

trachea and bronchi of carnivores

what species and organ does Capillaria aerophila infect?

Capillaria aerophila

which nematode infects the trachea and bronchi of carnivores?

unembryonated eggs eliminated in feces

mammal-infecting Capillarias have a direct life cycle, with earthworms as their paratenic host

bird-infecting Capillarias have an indirect or direct life cycle, with earthworms as their IH (if indirect)

describe the life cycle of genus Capillaria

earthworms

Capillaria uses _____ as their paratenic host

Trichinellidae

Capillarridae

Trichuridae

what families are included in order Enoplida?

Dioctophyma renale

what one species do we study in order Dioctophymatida?

kidneys (parenchyma and renal pelvis) of ichthyophagus carnivores

what species and organ does Dioctophyma renale infect?

yes, although their main host is ichthyophagus carnivores, Dioctophyma renale can also infect horses, swine, cattle, and humans

can Dioctophyma renale infect humans?

Dioctophyma renale

which is the longest nematode?

Dioctophyma renale

this bell-shaped bursa and 1 spicule belongs to what species?

Dioctophyma renale

this is the egg of what nematode?

barrel shape

yellow/brown

unembryonated

thick-pitted shell

describe the eggs of Dioctophyma renale

Trichinella- it is viviparous

which Enoplida nematode does not lay eggs?

1. eggs eliminated with urine and develop in water

2. eaten by IH (parasitic annelids of crayfish) and hatch and develop until L4 is formed

3. DH eats annelid or parasitized crayfish

4. L4 penetrates the intestinal wall and reaches the kidney

- can use fish/frogs as a paratenic host

describe the life cycle of Dioctophyma renale

frogs and fish

what can act as a paratenic host for Dioctophyma renale?

parasitic annelids of crayfish

what is the IH of Dioctophyma renale?

Dioctophyma renale

which species performs hyperparasitism (infects a parasite)?

Dioctophyma renale

this is the life cycle of what nematode?