Parasitology - Lecture 4 Flashcards
What order or nematodes has the most significant species of parasites to animals?
Order Strongylida
what are some common names for parasites of the Order Strongylida?
“strongyles”, “bursate nematodes”
Describe the general morphology of parasites of the superfamily Ancylostomatoidea
Anterior end: bent dorsally, buccal capsule with no leaf crowns. has teeth or cutting plate Posterior end (M): have copulatory bursa Eggs: thin shelled, morula stage
What is a common name for parasites of the superfamily Ancylostomatoidea?
hookworms
Where do Ancylostomatoidea parasites locate in the host? What do they feed on?
adults in the small intestine
- feed on blood,mucosa, tissue and fluids
What species of Ancylostomatoidea infect dogs?
A. braziliense
A. ceylancum
Uncinaria stenocephala`
What species of Ancylostomatoidea infect cats?
A. tubaeforme
A. braziliense
A. ceylancium
Uncinaria stenocephala
What species of Ancylostomatoidea infect ruminants?
Bunostomum trigonocephalum
B. phlebotomum
Gaigeria spp.
What species of Ancylostomatoidea infect Pigs?
Globocephalus spp.
Describe the morphology of A. caninum
9-20mm
white or reddish
buccal capsule with 3 pairs of teeth on ventral margin
eggs: oval, thin shelled, morula stage
Describe the morphology of A. braziliense
6-10mm
buccal capsule with 2 pairs of teeth on the ventral margin
Describe the morphology of A. ceylancium
6-10mm
buccal capsule with 2 pairs of teeth on the ventral margin
Describe the morphology of Uncinaria stenocephala
5-12mm
pair of cutting plates on the ventral border of the buccal capsule
eggs: oval, thin shelled, lateral sides almost parallel, morula stage
Describe the pathology and significance of A. caninum
large quantities of blood pass rapidly through the worm, causing mass blood loss from host. host takes bite from host and may change spots 4-6 times/ day.
- host may lose 0.2mL of blood/ day/ adult worm
What is the significance of the Ancylostomatoidea worms on human health?
A. ceylancium can mature in humans. larvae of dog hookworms can cause cutaneous larval migrans (CLM).
- hookworms release chemicals to regulate the immune response of the host
What are the hosts of A. caninum?
dog, fox, wolf,
where does A. caninum locate in the host?
small intestine
describe the lifecycle of A. caninum
- eggs laid and passed in poop
- develop L1 to L3 in environment
- best temp is 25-30C, and wont develop below 15C
- can infect the host through skin,migrate to heart, lungs, trachea, then intestines. PPT = 4-5 weeks
- can infect host orally(environment, milk or paratenic host), mature in intestine. PPT= 2-3 weeks
- some L3 will migrate to somatic tissue and arrest. can be reactivated and migrate to intestine, or during pregnancy will migrate to mammary glands and [ass to puppies.
What factors affect the probability of A. caninum larvae undergoing arrested development?
- age/ resistance of host
- temp the L3 were exposed to before infection
What is the significance of arrested development?
- most anthelmintics ineffective against arrested larvae
- larvae cannot be detected
- acts as a reservoir to replace adult worms that may be killed
What are the hosts of A. braziliese?
dog, cat, fox, etc.
where does . braziliense locate in the host?
small intestine
Describe the lifecycle of A. braziliense
similar to A. caninum. however there is no transmammary transmission
What are the hosts of Uncinaria stenocephala?
dog, cat, fox, etc.
where does Uncinaria stenocephala locate in the host?
small intestine
describe the lifecycle of Uncinaria stenocephala
normally orally, but some through skin.
no transmammary transmission
best temp is 20C
describe the morphology of A. tubaeforme
7-12mm
buccal capsule with 3 pairs of teeth on ventral margin
describe the lifecycle of A. tubaeforme
- eggs from F passed in poop
- L1-L3 in environment
- best temp 20-26C
- infection orally, through skin or paratenic hosts
What species do Bunostomum trigonocephalum infect? where in the host? what does it eat?
small intestine of sheep and goats.feeds on blood
describe the morphology of Bunostomum trigonocephalum
18-26mm
- buccal capsule is large and has pair of cutting plates (ventral margin), dorsal cone/ tooth (dorsal margin), pair of subventral lancets near base.
how can B. phlebotomum be differentiated from B trigonocephlum?
shorter dorsal cone, two pairs of sub ventral lancets,long spicules
What species do Bunostomum phlebotomum infect and where? what do they eat?
small intestine of cattle. feeds on blood
describe the lifecycle of Bunostomum spp.
eggs: thin shelled, morula stage
- eggs develop between 15-34C
- infection of host through skin (migrate to lungs then coughed up and swallowed) or ingestion of pasture (mature in wall of intestine before emerging into lumen to mature to adults)
PPT = 2 months
Describe the general features of the superfamily Metastrongyloidea
anterior end: mouth small or absent. has 6 lips or lips are small.
anterior end: bursa is small.
What is a common name for parasites of the superfamily Metastrongyloidea?
lungworms
What species are not affected by Metastrongyloidea?
cattle or horses
Describe the general lifecycle of Metastrongyloidea
- eggs or larvae passed in poop
- Indirect lifecycle (L1-L3 in gastropods, ingested, migrate to lungs)
- direct lifecycle (L1 infects the host)
Describe the general morphology of the genus Metastrongylus
Body: white, filiform
anterior end: mouth with 2 trilobed lips
posterior end (M): bursa has specific shapes. spicules long and transversally striated
posterior end (F): appears digitiform
Where does Metastrongylus apri locate in the host? what species does it infect?
trachea, bronchi and bronchioles of sheep
describe the morphology of Metastrongylus apri
Eggs: have a corrugated surface and are embryonated when laid
- same as general morphology, but spicules end in a hook (posterior looks like finger with a claw)
describe the lifecycle of Metastrongylus apri
indirect lifecycle
- eggs laid in resp tract, coughed and swallowed, leave in poop.
- eggs MUST be ingested by earthworms to develop to L3
- infective earthworms ingested by pig, and migrate to lungs via SI.
PPT = 3-6 weeks
Describe the lifecycle of Protostrongylus rufescens
- eggs laid and hatch in lungs. coughed up and pooped
- L1 invades snails/ slugs and reaches L3
- host eats snails/ slugs with L3, reach lungs via SI.
PPT = 30-40 days
What is the host and location of Protostrongylus rufescens?
small bronchioles of sheep and goats
What is the host and location of Muellerius capillaris?
terminal bronchioles and alveoli of sheep and goats
What is the host and location of Cystocaulus ocreatus?
terminal bronchioles and alveoli of sheep and goats
What is the host and location of Osleurus osleri?
nodules at the junction of the trachea and bronchi of dogs
What is the host and location of Angiostrongylus vasorum
pulmonary artery and right side of the heart of dogs
What is the host and location of Angiostrongylus cantonensis
Adults in pulmonary artery of rats
Larvae in the brain
What is the host and location of Aelurostrongylus abstrusus?
bronchioli, alveoli and pulmonary artery of cats
What is the morphology of Osleurus osleri?
slender, 4-15mm long worms
M have no bursa, posterior rounded with subequal spicules
F have bluntly rounded tail
eggs: thin shelled, embryonated when laid
larvae have ‘S’ shaped tail
Describe the lifecycleof Osleurus osleri
- no development needed outside host as L1 in saliva or poo is infective.
- infection normally from mum to pups because L1 canot survive in environment for long
- PPT = 10 weeks
What is a common name for Angiostrongylus vasorum?
french heartworm
describe the morphology of Angiostrongylus vasorum
- small reddish worms
- white ovaries coiled around red intestine
- bursa of M is small, spicules are subequal
describe the lifecycle of Angiostrongylus vasorum
indirect (IH = snails and slugs)
- eggs laid in lung capillaries, hatch and penetrate alveoli, coughed and swallowed. shed in poop.
- IH infected with L1
- host infected by ingesting IH, paratenic hosts or food containing slime from IH
- L3 pierce GIT and migrate to pulmonary arteries
PPT = 28-108 days
host can be infected for life
describe the lifecycle of Angiostrongylus cantonensis
IH = slugs and snails
- ingest IH with L3
- ingest slime from IH
- ingest paratenic host
What pathology is cused by infection with Aelurostrongylus abstrusus?
development of nodules in lungs which are firm, raised and greyish in colour
describe the morphology of Aelurostrongylus abstrusus
- tiny (>10mm), slender
- dark brown, black when fresh
- males have small bursa
- female vulva opens near anus
describe the lifecycle of Aelurostrongylus abstrusus
indirect
- F lay eggs that embryonate and hatch in alveolar ducts, coughed and swallowed, shed in poop
- IH = slugs and snails
- PH = rodents, birds, reptiles.
- infection by ingestion of PH or IH
- larvae migrate from stomach to lungs within 24hours
PPT = 4-6 weeks
