Survey of the incidence, diagnosis, clinical manifestations and treatment of Spirocerca lupi in South Africa

A questionnaire survey of 716 veterinary practices was undertaken to determine the incidence of Spirocerca lupi in dogs in South Africa. In total, 49% of the questionnaires were returned, indicating a possible incidence of 28%. Fewer than 4 cases per year were recorded by 82% of the respondents; 4-12 by 14%; 12-24 by 3%; and more than 48 by only 1%. No seasonal incidence was reported by 48% of the respondents. Large breeds were considered to be at greater risk by 43% of respondents. No specific age or sex was identified to be at higher risk. The most common complaints by owners and clinical findings were vomiting (46%), weight loss (27%), coughing (21%) or regurgitation (20%), although 14% of respondents reported no abnormal clinical findings. Diagnostic methods used were radiology (74%), endoscopy (27%), post mortem examination (34%) and faecal flotation (4%). Complications associated with S. lupi were reported by 76% of respondents, which included oesophageal neoplasia (41%), hypertrophic osteopathy (38%) and acute haemothorax (30%). Specific treatments were used by 58% of the respondents, whereas 42% of the respondents either used no treatment (72%) or recommended euthanasia (28%). Of the treatment group, 52% used ivermectin, 27% doramectin, 13% other deworming drugs (benzimidazoles, nitroscanate), and 8% used disophenol. Sixty-three percent of the respondents considered their treatment ineffective, whereas 31% considered it effective, and 6% were unsure. The overall mortality rate was high.