Abstract
This month's Small Animal Review summarises three papers on a 'slow kill' protocol for treating heartworm in dogs; two cases of ocular onchocercosis in UK dogs imported from Europe and the use of urine and faecal samples in measuring exposure to aromatic amines.This prospective case series by Ames et al (2020) evaluated the adulticidal efficacy of topical 10% moxidectin/2.5% imidacloprid and doxycycline in dogs with naturally occurring heartworm (Dirofilaria immitis) infection. A sample of 22 infected dogs were treated with moxidectin/ imidacloprid at the licensed dosage for heartworm prevention twice monthly for 90 days and then monthly thereafter. Doxycycline (median dosage 12.6mg/kg/day) was also administered for the first 15 days. Although strict activity restriction was not imposed, owners were asked to prevent their dogs from exercising strenuously. Antigen testing was performed every 30-60 days until negative. Of the 22 dogs, 21 tested negative by 434 days (median 234). One dog remained positive 701 days after treatment initiation and was considered a treatment failure. Four dogs required treatment for coughs, thought to be a result of heartworm death, an average of 89 days after the start of treatment. One dog required hospitalisation for24 hours and recovered fully with corticosteroid therapy and supportive care, and two dogs were treated in an outpatient fashion with steroids. This treatment protocol was well tolerated and 96% (21 of 22) of dogs became antigen negative, although two dogs required over 1 year to achieve this result.
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