Goat Parasite Life Cycle Animations


Dictyocaulus filaria

Sheep and Goat Lungworm

The large, first-stage larvae can be easily identified in the feces.
The adult lungworm of sheep and goats lives in the bronchi of the lungs.
The adults are large and white in color.

Male has distinctive "fin" at the hind end

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Eggs are laid in the bronchi.
Rarely, they may hatch in the lungs, but usually are coughed up by the goat, then swallowed.

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The eggs hatch as they move through the digestive system.
The first stage larvae are passed with the feces.

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First stage larva survive on the food particles obtained from the goat's intestine.

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After 1 or 2 days, the larvae molt to the second stage.
The cuticle is retained which protects the larvae from the elements.

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In moist conditions and at a temperature of about 80 F (27 C),
the larvae molt to the third infective stage in about a week.

Third stage larvae are inactive, can withstand dry conditions for only a few days,
but live for months in moist conditions.
Resistant to low temperatures, they can survive on the pasture during the winter.

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The goat becomes infected with the larvae while feeding.

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The larvae travel to the intestine where they penetrate into the intestinal wall and migrate
to the lymph glands where they molt to the fourth stage.

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From the lymph vessels the larvae make their way to the blood which carries them to the
right side of the heart then to the lungs.

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The larvae break through from the capillaries into the air passages and mature
into egg-laying adults in about 4 weeks.

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Clinical signs

Causes bronchitis and inflammation to the air passages of the lungs.
Coughing is not always a symptom.

Can lead to secondary bacterial pneumonia.
Large infections can clog breathing passages resulting in shortness of breath.

Young goats and sheep are most affected.