Dictyocaulus

A genus of parasitic nematodes affecting the respiratory system of ruminants

Dictyocaulus viviparus, a lungworm affecting cattle.

Dictyocaulus is a genus of parasitic nematodes, commonly known as lungworms, that infect the respiratory system of ruminants such as cattle, sheep, and deer. These parasites are of significant veterinary importance due to their impact on livestock health and productivity.

Taxonomy

The genus Dictyocaulus belongs to the family Dictyocaulidae within the order Strongylida. The most notable species within this genus include:

• Dictyocaulus viviparus - primarily affects cattle.
• Dictyocaulus filaria - primarily affects sheep and goats.
• Dictyocaulus arnfieldi - primarily affects donkeys and horses.

Life Cycle

The life cycle of Dictyocaulus species is direct, meaning there are no intermediate hosts. The adult worms reside in the bronchi and bronchioles of the host's lungs, where they lay eggs. These eggs are coughed up, swallowed, and passed out in the feces as larvae. The larvae then develop in the environment and are ingested by grazing animals, completing the cycle.

Pathogenesis

Infection with Dictyocaulus species can lead to a condition known as parasitic bronchitis, or "husk" in cattle. The presence of the worms in the lungs causes irritation, leading to coughing, difficulty breathing, and reduced weight gain. Severe infections can result in pneumonia and even death if untreated.

Diagnosis

Diagnosis of Dictyocaulus infection is typically based on clinical signs, history of exposure, and detection of larvae in fecal samples using the Baermann technique.

Treatment and Control

Treatment involves the use of anthelmintic drugs, such as ivermectin and fenbendazole, which are effective against the adult and larval stages of the parasite. Control measures include pasture management and strategic deworming to reduce the risk of infection.

Related pages

• Nematode
• Parasitic disease
• Veterinary medicine