2. Lung worms of sheep and goat
• Species are mainly…
Dictyocaulus filaria
Muellerius capillaris
Protostronglyus rufescens
These are all species encountered in these
small ruminants
5. Age group affected
• Lambs 4-6 months of age are most severely
affected but sheep of all ages are suceptible
6. • Infestations with cystocaulus ocreatus and
Neostrongylus linearis , the latter similar in
most of its characters to M.capillaris , have
also been observed in sheep in Great Britain
and Iran but their economic significance has
not been identified.
7. • D.filaria infestations in sheep appear to follow
the same pattern as those of D. viviparous in
calves but the number of lungworms is usually
low and widespread lesions are not common
8. Life Cycle
• The life cycle is direct and the third stage
larvae are long lived in damp, cools
surroundings .
• The lambs of one season are the main source
of infection for the next season’s lambs, but
overwintering larvae passed by the ewes and
yearlings also contribute to pasture
contamination .
9.
10. Epidemiology
• The prevalence of infection is low in spring
and summer but rises rapidly in the autumn
and winter when most clinical cases are seen
• Warm , wet summers give rise to heavier
burdens in the following autumn and winter.
11. • Acute cases , caused by massive infestations
with larvae ,do not appear to occur
• Adult worms live in the bronchi and causes
alveolar and bronchiolar damage.
• the resulting blockage of bronchioles by
exudates leads to the collapse of proportions
of lung
• The area of damage is usually not sufficiently
extensive to cause severe dyspnea.
12. Pathogenesis
• Adult worms live in bronchi , causes alveolar
and bronchial damage, resulting blockage by
exudates leading to collapse of part of lung.
• Cause dypsnea.
• Cough formation
• Minor irritation in intestinal minor irritation
• Alveolar epithelisation is also there
• Hypersensitivity is also seen
13. Clinical findings
• Bronchial irritation and its resulting cough ,
on moderate dyspnea and loss of condition
• there may be added fever and evidence of
toxemia if secondary bacterial infection occurs
14. Lab findings
• Depends on the detection of first stage larvae
in the faces of infested animals.
• Eosinophillia is seen
• Eggs are also seen in faecal examples.
15.
16. Necropsy findings
• lesions are similar to those of the sub acute
disease diseases in calves with exudates in
the bronchioles and scattered patches of
consolidation.
• Enlargement of the lungs due to edema and
emphysema , widespread areas of collapsed
tissue of dark pink , hemorrhagic bronchitis
with much fluid filling all the air passages and
enlargement of the regional lymph nodes .
17.
18. • Histologically the characteristic lesions are
edema , eosinophillic infiltration , dilation of
lymphatic's , filling of the alveoli and bronchi
with inflammatory debris and larvae in the
bronchioles and alveoli
• In sub acute cases interstitial emphysema is
usually gross, areas of dark pink consolidation
are present in all lobes but particularly in
diaphragmatic lobe and occupy about two
thirds of the lung volume and tend to be
gathered around the bronchi
19. Histology
• Eggs and larvae can be seen air the air p, the
passages, the alveoli show epithelisation.
• Giant cell reaction is also there
