Secnidazole for the treatment of giardiasis in naturally infected cats.

Giardia duodenalis causes enteric infections in humans and animals worldwide. Inefficiency of metronidazole is commonly reported in the veterinary clinic routine in the treatment of giardiasis in dogs and cats. The aim of this study was to evaluate the efficacy of secnidazole in the control of infection caused by G. duodenalis in naturally infected cats. For this purpose two experiments were carried out. In the first experiment seven cats were infected with G. duodenalis and treated orally with a single dose of secnidazole (30 mg kg(-1)). In the second experiment a total of 16 cats were used, 11 naturally infected with G. duodenalis and five negative for the parasite. Animals were divided into three groups: group A (n=5) was composed by non-infected animals (negative control), group B (n=5) consisted of infected but untreated animals and group C (n=6) was composed by cats treated orally with a single dose of secnidazole (30 mg kg(-1)). Hematological and biochemical parameters were evaluated before and after treatment. The first experiment reached 100% of efficacy because no cysts were found in the feces after treatment. However, doubts about intoxication and interference with hematological and biochemical parameters came to light. No side effects were observed, and the biochemical and hematological parameters of treated animals remained within physiological range, except for one feline which had elevation of liver enzymes. Based on these results, the utilization of secnidazole could be suggested for the treatment of giardiasis in cats. The main advantage of this treatment is that only a single dose is required, which is interesting in animals hard to handle like cats.