Trichostrongyloidea 3 Ostertagia, T. axei Flashcards
What is common name for Ostertagia, species it infects, preferred site within host
brown stomach worm
sheep, goat, cattle
abomasum
Where do ostertagia principally occur (region)
southern australia- high rainfall areas
Where does L3 ostertagia occur in the host
L3 exsheaths in rumen, migrates to gastric gland to molt->L4
LUMEN OF THE ABOMASAL GLANDS
L3 is resistant and may survive over summer in fecal pellet
What is the PPP of ostertagia
18-21 days
Does hypobiosis occur with ostertagia
hypobiosis is common (6 months)
When does inhibition occur in ostertagia
inhibition occurs in the spring, emerge in autumn- summer weather too harsh for survival
Pathogenesis: what does migration of ostertagia larvae into the abomasal glands cause
hyperplasia and metaplasia (nodules) of gland cells, necrosis of gland cells occurs in areas of direct contact with larvae
Ostertagia cause hyperplasia and metaplasia of abomasal gland cells what does this lead to
reduction in number of acid (parietal) and pepsin secreting (cheif) cells in the abomasum->mucus secreting cells predominate and stomach pH rises
What will you grossly see in the abomasum with infection of Ostertagia
areas of cell hyperplasia (raised pin point white foci), around pylorus and maybe in folds of fundus (heavy infection)
Why is digestion of food impaired in ostertagia infection
pepsinogen is not converted to pepsin at high pH
Why do the pepsinogen concentrations in blood rise with ostertagia infection
increased secretion and greater mucosal permeability
What does ostertagia secrete that leads to increased gut motility->diarrhea
parasympathomimetic substances
What are the different species of Ostertagia and what host do they infect
O. circumcincta- sheep
O. trifurcata- sheep
Teladorsagia davtiana- sheep
O. ostertagi- cattle
what is the most important parasite of cattle in southern Australia (temperate areas)
Ostertagia ostertagi
What are 3 defining features of Ostertagia
• cervical papillae
• spicules terminate in 3 stubby hooked
processes
• small vulval flap
host immunity against ostertagia
develops in older animals and stunts worms->fewer eggs produced
What are 2 differences of ostertagia in sheep and O.ostertagi in cattle
- Faecal mass as a reservoir for larvae
2. Inhibited larvae can emerge synchronously
What larval stage of ostertagia can survive for long periods in a cattle dung patty
L3
Explain type 1 ostertagiasis in cattle infected with ostertagia ostertagi
• young animals • no immunity • occurs in spring • diagnose with egg counts, plasma pepsinogen - similar to what is seen in sheep
Explain type 2 ostertagiasis in cattle infected with ostertagia ostertagi
• larvae emerge synchronously • 2-4 year old animals • precipitated by “stress” (calving) • erratic in occurrence (some years, few cattle affected) • occurs in autumn • diagnose with plasma pepsinogen
What is the common name for Trichostrongylus axei, where does it occur in host and what species does it infect
stomach hairworm
abomasum
sheep, cattle, horse, pig, man
What does T axei do to the host
causes disruption of the epith, loss of plasma proteins into abomasum->pH risees and excess mucus produced
how many T axei can kill a lamb and why is this so
40,000 can kill because they are highly pathogenic
Because of T axei host range what
they are important to consider in mixed grazing situations
