Further observations on Strongyloides westeri dermatitis: recovery of larvae from soil and bedding, and survival in treated sites.
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 absent from neutral or alkaline soils. Larvae were found in sawdust with a wide pH range. It is thought that the attacks were caused by a percutaneous invasion of filariform larvae of S. westeri, which required moist warm weather and low pH soils or sawdust to survive and resist desiccation.
Dewes
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Ruakura Animal Health Laboratory, Hamilton, New Zealand.
Townsend
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