Parasitology - Lecture 7 Flashcards
Describe the general features of the superfamily Filaroidea
- long, thin and slender
- anterior and posterior are simple
- eggs contain larvae or microfilariae
- locate in blood and lymph nodes, body cavities, CT, etc.
- indirect lifecycles (IH = arthropods)
What 2 families are under the superfamily Filarioidea?
- Filariidae
- Onchocercidae
What is the general feature of he family Filariidae?
locate in skin/ subcut tissue, cause skin lesions that attract IH to take eggs and larvae
What is a common name for the pathology caused by Parafilarioa multipapillosa?
‘bloody sweat’ or ‘summer bleeding’
what species and where does Parafilaria multipapillosa infect?
coiled in nodules in subcut and muscular CT of horses
describe the morphology of Parafilaria multipapillosa
large number of papilliform thickening at anterior end
describe the lifecycle of Parafilaria multipapillosa
IH = fly
- skin nodules open and blood containing eggs or larvae flows onto skin of host
- IH ingests eggs, L3 develops in IH, infected flies transfer L3 when they feed again.
- disease appears in spring/ summer and disappears in winter. will reoccur annually for 3-4 years before resolving
What species and where does Parafilaria bovicola infect?
- subcut and intermuscular CT in cattle
What species and where does Stephanofilaria spp. infect? how is it transmitted?
skin of cattle. transmitted by buffalo fly
What is the significance of Dirofilaria immitis to humans?
can infect humans, but wont mature
describe the morphology of Dirofilaria immitis
- elongated, filiform worms, females 25-30cm long
- circular mouth with no lips
- female (viviparous) vulva located near anterior end
- male posterior end is curled
What species and where does Dirofilaria immitis locate in the host?
dogs, cats, humans
- adults in pulmonary artery, right ventricle, right atrium. caudal vena cava in heacy infections
- microfilaria in blood
describe the features of microfilaria
- found in blood
- on blood smear with anticoagulant: show nonprogressive motility
- have a tapering cephalic end and a straight caudal end
decribe the lifecycle fo Dirofilaria immitis
IH = mosquitoes
- microfilariae mature to L3 in mosquito after infection by taking a blood meal
- L3 migrate to head and mouth parts of mosquito and pass into DH on next feed via puncture wound.
- PPT = 6-9 months
- Dirofilaria immitis host intracellular bacteria, “Wolbachia pipientis”. essential for survival and reproduction of worms, so this is target of control of worms
What species and where does Onchocerca cervicalis infect?
funicular portion of nuchal ligament of horses
describe the morphology of Onchocerca cervicalis
- white, filariform, striated cuticle with spiral thickening
- vulva located anteriorly, unequal spicules
- have microfilaria
What pathology is caused by Onchocerca cervicalis?
hypersensitivity reaction to microfilaria cn cause alopecia, scaling, crusting, lichenification, etc.
what species and where does Onchocerca reticulata infect?
CT of flexor tendons and suspensory ligament of fetlock, especially front legs
- horses
What species and where does Onchocerca gutterosa infect?
nucal ligament and scapular cartilage of cattle and horses
What species and where dos Onchocerca lienalis infect?
gastrosplenic ligament of cattle
What species and where does Onchocerca gibsoni infect?
tightly coiled in nodules around brisket, stifle and hip of cattle (and sheep)
What species and where does Setaria equina infect?
peritoneal and pleural cavities, eyes, etc. of horses
What species and where does Setaria labiatopapillosa infect?
peritoneal cavity of cattle
Describe the general features of Suborder Trichinellina (Order Enoplida)
- anterior end more slender than posterior
- oesophagus very slender tube embedded wih one or more rows of glandular cells
- M have 1 or 0 spicules
- eggs with polar plugs (except Trichinella spp.)
What two families are under the suborder Trichinellina?
Family Trichinellidae
Family Trichuridae
describe the general features of Genus Trichinella (Family Trichinellidae)
- wide range of hosts
- most widespread zoonotic pathogens
- no exogenous stages
- 2 generations in the same host
- depends on carnivorism to transfer from one host to another
What are the two different types of species of Trichinella? Whats the main differences?
encapsulated
- thick collagen capsule around larvae, infects mammaps
non-encapsulated
- thin collagen capsule around larvae (only visible with electron microscope), infects mammals, birds, reptiles
What species of Trichinella spp. is the only one found in Australia?
Trichinella pseudospiralis, and only in wildlife
What is unique about the morphology of Trichinella spiralis?
- smallest nematode infecting humans
- world’s largest intracelular parasite
What species and where does Trichinella spiralis infect?
wall of small intestine of pigs, humans, rodents
describe the lifecycle of Trichinella spiralis
- host ingests meat with infective larvae
- L1 invades stomach wall and moults to adult in 28 hours
- female begins to lay larvae
- larvae enter lymphatic vessels, then blood vessels, which take them to striated muscle cells
- infected cell undergoes 3 cell modifications; becomes “nurse cell”, encapsulates larvae and development of capillary network around cell
- L1 can arrest and stay viable for all of host’s life
- most active muscles harbour highest % of worms
What is a common name for the genus Trichuris?
Whipworms
describe the morphology of the genus Trichuris
- anterior end: thin. posterior end: thick. abrupt transition from thick to thin.
- eggs: brown/ yellow and have clear plugs at either end. lemon shaped, thick and smooth shell. very resistant
- direct lifecycle
- posterior (M): coiled with one spicule
- posterior (F): curved
describe the lifecycle of Trichuris vulpis
- F lays eggs that are pooped out
- L3 develops inside egg
- host ingests embryonated egg
- hatches in SI, develop and then invade mucosa of LI
PPT = 70-100 days
What species is infected by Trichuris suis?
pigs
What species is infected by Trichuris vupis?
dogs
What species is infected by Trichuris ovine?
ovine (sheep)
describe the general features of genus Capillaria
- small and slender (hairlike), similar to trichuris
- eggs similar to Trichuris
- hosts: birds and mammas
- location: GIT and resp tracts, liver, urinary bladder, etc.
- direct or indirect lifecycles
describe the features of Capillaria annulata
hosts: chickens, turkeys, ducks, etc.
location: oesophagus, crop
eggs: bipolar plugs, thick shell
lifecycle: IH = earthworms
PPT = 3-4 weeks
What species and where does Capillaria contorta infect? what is the IH?
chicken, turkey, phesants, etc.
oesophagus, crop
earthworms
What species and where does Capillaria cudinflata infect? what is the IH?
chicken, turkey
small intestine
earthworms
What species and where does Capillaria obsignata infect?
chicken, turkey, pigeon
small intestine
What are the features of Capillaria/ Eucoleus aeorphilus/ aerophila?
hosts: dogs, cats, foxes
location: trachea, bronchi
eggs: bipolar plugs
- direct and indirect lifecycles (IH = earthworms)
What species and where does Capillaria/ Pearsonema plica infect?
dogs, cats, wolves, etc.
urinary bladder
