Is evaluation of a faecal smear a useful technique in the diagnosis of canine pulmonary angiostrongylosis?

OBJECTIVES: To describe a method of faecal smear production and to determine the sensitivity and specificity of faecal smear for detection of parasitic larvae using Baermann sedimentation as a gold standard.

METHODS: Faecal smears were produced from samples submitted to the Royal Veterinary College Diagnostic Laboratory Service for Baermann sedimentation. An inexperienced and an experienced assessor each examined the smear for larvae for a maximum of five minutes.

RESULTS: One hundred and eighty six samples were analysed of which 28 were positive for Angiostrongylus vasorum on Baermann sedimentation. The experienced assessor had a faecal smear sensitivity of 61% and a specificity of 100%. The inexperienced assessor had a faecal smear sensitivity of 54% and a specificity of 95%.

CLINICAL SIGNIFICANCE: Faecal smear is an effective and cheap aid to diagnosis of canine angiostrongylosis which can be readily performed in general practice. Its use leads to a rapid detection of infection compared to other available methods. This could lead to swifter treatment of the disease and a decrease in inappropriate diagnostics. A further diagnostic method, such as Baermann sedimentation, is recommended whether the faecal smear result is positive or negative.