Dictyocaulosis - Sheep

Pathogenesis

• Dictyocaulus filaria
  • Similar to D. viviparus in cattle
  • Lesions tend to be less widespread because worm numbers are generally low

Diagnosis

• Grazing history
• Clinical signs
• Faecal examination (larval identification possible by examining head, e.g. Dictyocaulus filaria (knob) or tail, e.g. Muellerius (single spine), Protostrongylus (wavy, no spine) → prognosis)

Control

• Dictyocaulus filaria:
  • Difficult because outbreaks are unpredictable
  • PGE control measures are normally sufficient to prevent outbreaks of disease
  • Where these occur, remove and treat affected stock, replace with older immune sheep if necessary
  • A commercial vaccine was available in the Middle East, though its use (were it still available) would be uneconomic in the UK