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Parasitology > Ruminant Trichostrongyles > Flashcards

Ruminant Trichostrongyles Flashcards

1
Q

Economic losses

A 
Pamb kid calve death
Adult ill thrift and death
Lower carcass value
Poor growth rate
Treatment and management costs
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2
Q

Teladorsagia circumcincta (brown stomach worm)

A

Sheep
Abomasal
Long and hair like
Dis seen in summer and autumn
Watery diarrhoea lost appetite and weight
Cause hyperplastic inflam of abomasal mucosa, repp gastric secr cells with non fxing cells
Hyperproteinaemia due to leakage across dam mucosa
Impaired abomasal fx assoc with pH alteration
Dev IC epi cells and mature emerge onto muc surf

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3
Q

Ostertagia ostertagi symptoms and pathogenesis

A

Larvae dev in and disrupt abomasal gastric glands adults emerge after 18d of infection
Sev path assoc with adult emergence
PH of abomasum rises as HCl secr cells replaced by indiff cells
Pepsin digestion of pro is inhib
Substantial albumin leakage through abomasal mucosa
Bact overgrowth in abomasum
Cause scour illthroft and suboptimal weight gains red milk yield

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4
Q

Haemonchus contortus

A 
Sheep
Abomasal
Blood feeder
Cause anaemia and hyperprotonaemia
Usually seen in lambs in late summer
Can occur in naive adults at any time of yr
Can cause sub mand oedems
Ascites
Ill thrift
Death
Scour seldom present
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5
Q

Trichostrongylus vitrinus (black scour worm)

A 
Prox small intest 
Just beliw muc layer
White and hair like
Burrow under mucosa causing villis atrophy so affect food digestion and adsorption
Muc hypertrophy
Pro leakage and electrolyte and mineral imbalance
Dis during autumn and early winter
Anotexia
Dark scour
Poor skel growth
Poor woll quality
Chronic ill thrift
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6
Q

Cooperia oncophora

A

Cattle
Mildly patjogenic
Assoc with inappetance and poor weight gain
Similar lifecycle to ostertagia
ML
Spec laxk of efficacy can be problem as just elim oo c have advantage and cause disease

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7
Q

Nematodirus battus

A 
Sm intest 
Long white worm coiled around villi
Catarrhal inflam of intestine
Dis of young lambs 6-12wk old may-jun
Cause acute onset diarrhoea lethargy abdom pain rapid weight loss dehydration sudden death
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8
Q

Nematode prod loss

A

Effect feed intake and usage so red growth rate
Hist parasite balance eg if previously unknown parasite encountered
Direct parasite effects
Indirect effects

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9
Q

Parasitic gastroenteritis most important in

A

Lambs in first grazing season
Naive ewes moved to contam pasture
Sheep with compr imm
Rams

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10
Q

Haemonchus lifecycle

A

Eggs shed in faeces
L1 and 3 dev in faeces
L3 onto herbage and exsheath in forestonach
L4 on muc surf of gut and feed on blood
Adult in lumen of gut feed on blood and mate and females lay eggs that are voided again

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11
Q

GIT nematode conditions

A

Hatching and dev of larvae in moist warm conditions min 7d in optimum
In optimal cond time between egg shedding and max L3 no on field is 3-6wk
Early larval stages easily killed by dessication
L3 can survive 6-12wk or longer on pasture and survive frosts
when cool damp conditions persist can survive for 12mnth (except haemonchus

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12
Q

T circumcincta pop dynamics in absence of control determined by

A

Pasture larval contam
Availability of L3
Build up of infection in sheep

There is an incr in FEC around parturition and early lactation
Comp between preg/lactation and inm resp
Ewes play ley role in teladorsagiosis epidemiology

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13
Q

Haemonchus teladorsag trichostrongylus dis risk for lambs assoc with

A

Overwintered L3 pop
Ewe faecal egg output
Autoinfection

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14
Q

Ostertagiosis patjigenesis

A

L3/4 in glands
Red parietal cells and incr undiff cells
Red HCl secr and cause leaky cell jctns
Pepsinogen gets into curc and plasma pros into GIT and red acidity cause pepsin not act from pepsinogen so pro not denatured and red bacteriostasis

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15
Q

Ostertagiosis epidemiology

A

L3 overwinter - die by mid summer cycled by calves early spring summer
Egg to L3 get faster as temp incr
L3 peak towards mid summer
Egg to L3 slows and stops kid autumn

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16
Q

Type 1 ostertagiosis dis

A

Dairy cattle
Overwintered L3 ingested early in grazing season dev into adults which are major source of subseq pasture larval contam
Rate of pasture larval contam highest mid summer as temp incre so most eggs deposited april-june all reach L3 stage
Ingestion of large L3 numbers causes clin type1 dis

17
Q

Spring calving beef cattlenostertagiosis

A

Most overwintered L3 ingested and killed in imm cows, thise remain on pasture mainly die before calf old enough to ingest much herbage
Level of pasture contam in late summer and autumn is low
Calves succeptible to parasitic gastroent in 2nd grazing season

18
Q

Autumn calving beef cattle

A

During first season similar to dairy calves

19
Q

Type 2 ostertagiosis

A

Low autumn temp cause a ltd no of ingested L3 to become arreasted at early L4 in abomasal glands
Presence of eL4 usually asympt
Dis occur in late winter when arrested all simultaneously complete dev and emerge as adults
Risk incr with dry summer follwied by autumn rains or any pasture management that delays exposure of calves o high level L3 contam

20
Q

Ostertagia imm

A

Acquired: unexposed suscept
Slow: not acquire until end of first season, maybe effect of suppresive anthelmithics?

21
Q

Nematodiris battus

A

L3 dev in egg and can survive freezing for up to 2 yrs
Hatch and release only after period of cold follwoed by daily max tamp above 10 degrees
So eggs passed one yr hatch the following en masse may-jun
Acute dis when hatch coincides with presence of susceptible lambs not seen when hatch occurs befor lambs able to graze or after they are 3mnth old
Accum of infected pasture over several yrs

22
Q

Nematodirus cycle

A 
Eggs shed in faeces
L1 and 2 dev in egg
L3 onto herbage and exsheath in forestomach
L4 on muc surf of gut
Adults in lumen
23
Q

Cattle lungworm

D viviparus

A

Adults in trachea and brinchi lay eggs cont L1 that hatch quickly are coughed up and swallowed amd passed in faeces
Dev to L3 can take min 5d in faeces, fastest with warm weather
L3 escape onto herbage is moisture dep
L3 ingested with grass and penetrate intestinal muc
Moult to L4 in mesenteric lymph nodes
Migrate to ventral parts of caudal
Ling lobes via blood and lymph
L4 enter albeoli moult to L5
Prepatent period 21-28d

24
Q

Cattle lungworm overwintering

A

Some L3 overwinter on pasture and some adults or inhib L4 survive in carriers
In wet conditions fungi facilitate airborne L3 spread to other pastures and may be spread by earthworms with manure or wildlife
No of L3 on pasture incr in wet warm conditions
V small infevtious dose

25
Q

Lungworm infection

A 
1o infect: most dis between aug and oct
Severely affected (mouth breathing) die
Less affected self curr in several mnths
Res milk yields
Reinfect of exposed cattle following mass challenhe
Following suppressive anthelmintic treatment for gastroent parasite control
Lungworm common in 1.5-2.5yr old cattle
Primary infection sometimes in older naive cattlr
Post patent dis:
alveolar epitheliasation
Prolif of type 2 pneumoncytes
Could be resp ti dead parasites
26
Q

Sheep lungworm

A

D filaria
May be assoc with outbreaks of coughing and pneumonia in late autumn
Usually incidiental pm finding
Life cycle of M capillaris involve mollusc intermed, sheep infect when eat mollusc with herbage, adult worms in albeoli cause many subpleural nodules
P rufescens involve mollisc int. slender red worms in small bronchioles

27
Q

D arnfueldi

A 
Lifecycle similar to d viviparus
Eggs infaecs
Ppp 2-4mnth
Reacg patency in donkeys and young horses no clin signs
No patency in adult horses clin signs
28
Q

What causes drop in live weight gain

A

Not parasite burden

It is the constant exposure to larvae

29
Q

Management strategies

A

Avoidance
Treatment
Limit egg output

Sk finish lambs quickly before pasture burden becomes prod limiting
Only graze succep on safe pasture
Suppres pasture contam with anthelmitics

30
Q

Clin paras gastroenteritis control

A

As long as no res to anthelmitics any can br used but lambs will fail to hit optimum weight gain when returned to contam pasture
So move to safe pastuee after dosage
If moxidectin used there is a meat wothdrawal period

31
Q

Cattle gastroent control and problems

A

Aim to limit L3 exposure
Dairy calves and autumn borne beef: anthelmintic during 1st grazing season
Spring born beef: anthelmintic at first housing and during 2nd season

Calves may not acquire imm so may still be succeptible
Need to permit sufficient L3 exposure fo stim imm without loss of prod
May not control lungworm

32
Q

Lungworm treatment

A

Anthelmintics
Anti inflam
Antibio

33
Q

Lung worm control

A

Evasive can be ineffective as safe grazing often fails to prevent
Suppressive anthelmintics used for gastrointest can be effective but cattle seuscep in following grazing season
If rely on anthelm during 1st half of season may be suscept in 2nd half
Prob with spring borne calves
Additional strategic treatments often req

Vacc with huskvac when infection present vacc animals still contrib to pasture contam so entire herd must be vacc

Parasitology (16 decks)

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