Successful use of secnidazole to manage a giardiosis outbreak in a shelter.

Giardia duodenalis is a common parasite in dogs in shelters where new introductions, including numerous juvenile individuals, are ongoing. A safe and effective single dose parasiticide is highly desirable for shelters experiencing disease caused by G. duodenalis (giardiosis). Secnidazole is an efficacious, low-cost medication used for the treatment of giardiosis in humans and has the advantage of requiring only a single oral dose. The aim of this study was to determine retrospectively the effectiveness of secnidazole on dogs of all ages during an outbreak of giardiosis in a shelter. Patients recruited into this retrospective study were divided into two groups. Group A consisted of adult dogs and weaned dogs (>10 weeks-of-age). Group B was comprised of puppies (<10 weeks-of-age). Giardiosis resolved in all 14 patients in Group A within 13 days following a single oral dose of secnidazole (30 mg/kg). There were no individuals with both gastrointestinal signs and a positive G. duodenalis antigen test at the time of the first and second follow-up examination. For the young puppies in Group B, giardiosis was reduced by 90% (9/10) within 22 days following two consecutive doses of secnidazole (30 mg/kg; 2 weeks apart). No adverse reactions were observed in any patients treated with secnidazole. Secnidazole is an effective and easily administered drug for the treatment of clinical canine giardiosis.