Ruminant lungworm Flashcards Preview

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Flashcards in Ruminant lungworm Deck (27):
1

dictyocaulus viviparus

bovine
trichostrongyle
in trachea + larger bronchi
parasitic bronchitis
calves - poor thrift
dairy cow - decr milk yield

2

dictyocaulus viviparus - immunity

rapidly acquired after heavy exposure
minimal age resistance

3

dictyocaulus viviparus - pathogenesis - penetration

week 1
larvae migrate to lungs
no clinical signs

4

dictyocaulus viviparus - pathogenesis - prepatent

weeks 1-3
development + migration of larvae - bronchiolitis - eosinophilic exudate - blocks passage of air - alveolar collapse distal to blockage - clinical signs (tachypnoea, coughing)

5

dictyocaulus viviparus - pathogenesis - patent

weeks 4-8
worms mature + egg producing
Bronchitis (due to adult worms)
parasitic pneumonia

6

dictyocaulus viviparus - pathogenesis - post-patent

weeks 8-12
most of worms expelled
clinical signs flare up in 25% cases
alveolar epithelialisation, interstitial emphysema, pulmonary oedema, 2º bacterial infn.

7

dictyocaulus viviparus - pathogenesis - re-infection

Immune cattle only show clinical signs if exposed to v.large challenge
larvae killed in lungs
Parasite granulomata (5mm, grey-green)
Eosinophilic plugs in bronchioles

8

dictyocaulus viviparus - diagnosis in calves

Seasonal incidence, previous grazing history, clinical signs
Faecal examination (Baerman technique)
PME

9

larval identification - lungworm

Short (300u)
Blunt tail
Intestinal

10

larval identification - GIT

Longer (700 -1,000u)
Longer tail
Intestinal CELLS

11

dictyocaulus viviparus - PME - lesion distribution

Diaphragmatic lobes most affected
Plum-coloured areas of consolidation

12

dictyocaulus viviparus - PME - lung perfusion

Remove heart, lungs and trachea
tie off pulmonary veins + wash out lungs + collect water

13

dictyocaulus viviparus - diagnosis in adults

Seasonal incidence, previous grazing history, clinical signs
Faecal examination (Baerman technique)
Blood (and milk) examination (ELISA)
Grass examination (for larvae around dungpats)
Response to anthelmintic treatment

14

dictyocaulus viviparus - control

vaccine
Vaccinate 6 and 2 weeks pre-turnout
never mix vaccinated + non-vaccinated calves
prevents disease, not infection
can use anthelmintics with long residual activity

15

Dictyocaulus filaria

most important lungworm in sheep + goat
Chronic cough + unthriftiness
Temperate areas - sporadic
Warmer climates - disease outbreaks

16

Dictyocaulus filaria - life cycle

Direct (similar to Dictyocaulus viviparus in cattle)
Prepatent period longer (5 weeks)

17

Dictyocaulus filaria - pathogenesis

Similar to Dictyocaulus viviparus
Lesions less widespread (fewer worms)

18

Dictyocaulus filaria - identification

short larva
dense food granules
blunt tail
protoplasmic knob on head

19

Dictyocaulus filaria, Muellerius, Protostrongylus - diagnosis

Seasonal incidence, previous grazing history, clinical signs
Faecal exam (Baerman technique)
Post mortem examination

20

Dictyocaulus filaria - PME

Similar to Dictyocaulus viviparus

21

Dictyocaulus filaria - control

Difficult; outbreaks unpredictable
PGE control measures normally prevent disease
Outbreak - treat affected stock, house / move to
clean grazing
vaccine no longer ecconomical

22

Muellerius, Protostrongylus

Common
not major pathogens
Little economic importance

23

Muellerius, Protostrongylus - life cycles

Indirect )
Adult worms in alveoli / parenchyma (Muellerius)
or small bronchioles (Protostrongylus)
Prepatent period 6-10 weeks (Muellerius), 5-6 weeks (Protostrongylus)

24

Muellerius - pathogenesis

Nodular lesions in lung parenchyma

25

Protostrongylus - pathogenesis

Adult worms block small bronchioles - debris accumulates distal to blockage

26

PME - muellerius

palpable nodules on/just under lung surface

27

Muellerius, Protostrongylus - control

Unlikely to be necessary - non pathogenic
Difficult - wide range of intermediate hosts, prolonged survival of larvae in faeces