10/10/2026
in cattle (commonly known as verminous pneumonia, verminous bronchitis, or husk/hoose) is a severe respiratory disease caused by the nematode lungworm Dictyocaulus viviparus. It is characterized by tracheobronchitis, exudative pneumonia, and respiratory distress, most frequently seen in young grazing cattle during their first grazing season.Etiology and
Causative Agent: Dictyocaulus viviparus (slender, white, thread-like worms; males measure 3–5 cm, females up to 8 cm).
#Life_Cycle
Adult females in the bronchi lay larvated eggs that are coughed up, swallowed, and hatch into first-stage larvae (L1) in the intestinal tract.
L1 larvae are passed in f***s and develop on pasture through L2 to infective third-stage larvae (L3) in 5–7 days under favorable conditions.
#Dispersal: L3 larvae climb the sporangiophores of the dung fungus Pilobolus. When the fungus discharges spores, larvae can be propelled up to 3 meters, significantly expanding the grazing contamination radius.
Cattle ingest L3 while grazing. Larvae pe*****te the intestinal mucosa, enter mesenteric lymph nodes, molt to L4, travel via the lymphatic-vascular system to the heart and pulmonary capillaries, and break into the alveoli and airways.Diagnosis
Clinical Presentation: Rapid spread of deep, paroxysmal coughing across calves/heifers on late summer or autumn pasture.
Baermann Technique: Detection of live, active L1 larvae in fresh f***l samples (distinguished by brownish intestinal granules and absence of a caudal spine).
#Post_Mortem_Examination: Thread-like adult worms in the caudal lung lobes, frothy mucopurulent exudate obstructing bronchi, and wedge-shaped atelectasis.
Serology: ELISA can detect antibodies against lungworm antigen in serum or bulk milk (useful for herd surveillance).
#Treatment and Control
Anthelmintic Therapy:
Macrocyclic Lactones (Ivermectin, Doramectin, Moxidectin): Highly effective against adult and migrating larval stages, with persistent activity.
Benzimidazoles (Fenbendazole, Oxfendazole, Albendazole): High efficacy against both adults and developing stages.
Levamisole: Effective, particularly against adult worms.
Supportive Care: NSAIDs (e.g., flunixin meglumine, ketoprofen) to reduce bronchial inflammation; broad-spectrum antibiotics if secondary bacterial bronchopneumonia is suspected.
#Prevention & Management:
Vaccination: An oral irradiated-larval vaccine (Bovilis Huskvac) is used in endemic areas (administered in two doses before first turnout).
Pasture Management: Avoid turning susceptible calves onto pasture grazed by older, carrier cattle; coordinate strategic prophylactic anthelmintic treatments during high-risk seasons.
