Further observations on Strongyloides westeri dermatitis: Recovery of larvae from soil and bedding, and survival in treated sites

Abstract Two horses repeatedly underwent episodes of frenzy characterised by extreme discomfort and hyperactivity. Within 2 days of an attack the lower extremities of both hind legs of one subject were uniformly swollen, while on the second subject skin lesions erupted 3–4 days after an attack and swelling persisted for 2–3 weeks. Filariform larvae of Strongyloides westeri were cultured from soil and sawdust where the subjects were kept. Larvae were cultured from soil of low pH (4.5–5.8) but were abselnt from neutral or alkaline soils. Larvae were found in sawdust with a wide pH range. It is thought lthat the attacks were caused by a percutaneous invasion of filariform larvae of S. westeri, which requiretd moist warm weather and low pH soils or sawdust to survive and resist desiccation.