Parasitology Flashcards
What are the two phylums of endoparasites?
What are the classes that come off of these?
(remember endo- means internal)
Nemat-helminths (‘thread-worms’)
- Nematoda (roundworms)
Platy-helminths (‘flat-worms’)
- Cestoda = segmented (tapeworms)
- Trematoda = non-segmented (flukes)
Define the following,
parasitism
mutualism
commensalism
parasitism - one organism benefits from the interaction to the detriment of the other
mutualism - both organisms benefit
commensalism - only one benefits but no harm comes to the other
What are the 4 types of parasites?
Facultative - may survive in host absence (opportunistic)
Obligate - can never survive without host
Endo-parasite - live within host
Ecto-parasite - live on outer bodily surfaces of host
What are the two main types of hosts?
Definitive
- parasite sexual reproduction occurs here
Intermediate (mature)
- parasite asexual reproduction occurs here (immature)
What are the two types of vectors?
Mechanical
- mechanically spreads parasite and is not utilised in the parasites life cycle
Biological
- needed by the parasite to complete part of lifecycle
What is the…
phylum
class
super-family
… of the true lungworm?
phylum = nemathelminths
class = nematoda
super-family = metastrongyloidea OR trichostongyloidea
What are the 2 types of parasitic lifecycle?
Direct life cycle
- all stages occur in/on 1 host
Indirect life cycle
- at least 1 intermediate host needed for development of some stages
What is the name of the bovine lungworm?
What is its lifecycle?
Dictyocaulus viviparus
Direct
- adult parasite live in trachea and bronchi
- lay eggs in airways
- first-stage larvae pass out through feces
- once in environment develop to infective third-stage
- then ingested 3rd stage larvae from pasture (common in cattle on permanent pastures)
- larvae migrate from vasculature to the lungs
What is the name of the mosquito canine heartworm?
What is its lifecycle?
Difrofilaria immitis
Indirect
- microfilariae stage 1 larvae in dog blood
- bitten by female mosquito (vector)
- larvae develop from stage 1 - 3 in mosquito (intermediate host)
- mosquito bite dog and inject stage 3 larvae whilst feeding
- larvae develop in dog (definitive host) from stage 3 - 4 -5 and then to adults in the right heart and pulmonary vessels
- adults sexually reproduce
What is the name of the French canine heartworm?
What is its lifecycle?
What’s the main wildlife host and therefore spreader of this parasite in Europe?
Angiostrongylus vasorum
Indirect
- adults in pulmonary artery of dog (definitive host) heart
- eggs in pulmonary capillaries
- 1st stage larvae penetrate the capillaries and then move in the alveolar wall, they’re then coughed up, swallowed, passed out via faeces
- 1st stage larvae is ingested by slug or snail (intermediate host) and develops to 3rd stage larvae
- dog eats infected host
- larvae travel from stomach/intestine to mesenteric lymph nodes, develop from stage 3 - 5
- then travel via lymphatics HP vein/liver then to the vena cava, RV and then back to the pulmonary artery
Red fox
What parasite is found in all dogs and causes ocular larva migrans (migrate through eye) in humans?
Can also potentially cause
- visceral larva migrans (migrate through organs)
- neural larva migrans (migrate through brain)
- covert toxocariasis
What is its lifecycle?
Toxocara canis
Direct
- infected dog (definitive) passes toxocara eggs in faeces, milk, in utero
- in dog faeces the larva develop inside their eggs in the soil (L1 - 3)
- dogs injest larva-eggs
What is the only vaccine preventable parasitic disease?
Dictyocaulus viviparus (bovine lungworm)
- once exposed cattle develop immunity rapidly
Which species get which superfamily of lungworms?
Trichostrongyloidea
Metastronglyoidea
Cow, sheep, horse, goat, pig
Trichostrongyloidea - cow, sheep, horse
Metastronglyoidea - sheep, goat, pig
What are the Dictyocaulus spp. lugworms for the following species:
Cattle, camelids, deer
Sheep, goats
Donkeys, horses
Cattle, camelids, deer - Dictyocaulus viviparus
Sheep, goats - Dictyocaulus filaria
Donkeys, horses - Dictyocaulus arnfeldi
What are ways in which D. viviparus can be identified?
- Baermann apparatus for L1 larvae in faeces
- ELISA
- Post-mortem
Where does the adult Dictyocaulus spp. reside?
When can it cause parasitic pneumonia?
The adult lungworm resides in the trachea and bronchi (causes parasitic bronchitis)
Deposition of eggs/newly hatched larvae
What are clinical signs of D.viviparus?
Coughing
Increased respiratory rate (tachypnoea)
Lung auscultation (squeaks and crackles)
If infection severe animal may go into respiratory distress (gasping for air with head and neck outstretched, salivation, loss of appetite, fever)
What spreads Dictyocalaulus arnfieldi to horses?
Infection from donkeys so common when horse is sharing its pasture with a donkey
Can dictyocalaulus arnfeildi eggs/L1 be found in horse and donkey faeces?
What is a different and good way to identify if worms are present?
Horses: very few in faeces
Donkeys: lots in faeces
Branch-alveolar lavage/tracheal wash can reveal worms and high numbers of eosinophils if present
Where are adult Dictyocaulus arnfeildi found in donkeys?
In their small bronchi (cattle is large bronchi/trachea)
What immune cell can indicate parasitic infection?
If a high numbers of eosinophils are present
What treatment could be used for Dictocalaus arnfelildi?
Fenbendazole
What are the Metastrongyloidea lungworms for the following species:
Dog
Cat
Sheep + Goats
Swine
Dog - Angiostrongylus vasorum
Cat - Aelurostrongylus abstrusus
Sheep + Goats - Muellerius capillaris + Protostrongylus rufescens
Swine - mestastrongylus apri
Why are the clinical signs pf angiostrongylus vasorum so diverse?
It is so aggressive that it causes damage to the body activating the immune response causing a wide range of host specific responses
