Dictyocaulus (Lung worm)

Dictyocaulus (Lung worm)

·         This genus living in the bronchi of cattle, sheep, horses and donkeys

·         major cause of parasitic bronchitis   

Species	Host	Location
Dictyocaulus viviparus	Cattle and deer	Trachea and bronchi, particularly of the diaphragmatic lobes of lungs
D. filarial	Sheep and goat
D. arnfieldi	Donkeys and horses

Identification:

o   The adults are slender thread-like worms up to 8.0cm in length

o   Their location is also diagnostic

Dictyocaulus viviparus:

·   Is the cause of parasitic bronchitis in cattle

·   Mainly affects the young cattle during their first grazing season

·   The disease is also known as husk/hoose/verminous pneumonia/dictyocaulosis

·   The disease is characterized by bronchitis and pneumonia

·   It is prevalent in temperate areas with high rainfall

Life Cycle:

The female worms are ovo-viviparous (larva contained in egg/egg containing larva), eggs hatch immediately after laying at brochi (in Dictyocaulus arnfieldi, eggs hatched soon after being passed in faces

The L₁ migrates to the trachea, are swallowed and pass out in the faeces

      Within 5days

Under optimal condition, L₃ is developed; leave the fecal pat to reach the herbage either by their own motility or through other possible means

After ingestion, the L₃ penetrate the intestinal mucosa and pass to the mesenteric lymphnodes where they moult to become L_4.

After 1 week of infection, L₄ travel via the lymph and blood to lungs, and break out the capillaries into the alveoli

Final moult occurs in the bronchioles and the young adult move up the bronchi and become mature.

PPP: 1months (2-4 months in Dictyocaulus arnfieldi and 5 weeks in D. Filarial)