Protostrongylus rufescens

Protostrongylus species

Life-Cycles

• • Indirect life-cycle involving mollusc intermediate hosts
  • L1 passed in faeces, penetrate foot of mollusc, develop to L3 in 2-3 weeks
  • Infected mollusc ingested with grass
  • L3 released by digestion and travel to lungs by lymphatic route
  • Adults found in alveoli/parenchyma (Muellerius) or small bronchioles (Protostrongylus)
  • Prepatent period 6-10 weeks (Muellerius), 5-6 weeks (Protostrongylus)

Epidemiology

• • High prevalence because of wide range of intermediate hosts, prolonged survival of larvae in faeces, long periods of patency (>2 years) and poor host immunity