Efficacy of nitazoxanide to treat natural Giardia infections in dogs

Abstract

Background Giardia parasites cause gastrointestinal disease in humans, dogs, and many other animals worldwide. The treatment of dogs for giardiasis requires further investigation to ascertain levels of drug efficacy and the possibility of adverse side effects. Nitazoxanide (NTZ) has shown good clinical anti-Giardia activity in humans, yet it has not been evaluated for the treatment of giardiasis in dogs.MethodsThirty-five dogs, naturally infected with Giardia were divided into five groups (n = 7): dogs in group NTZ1, NTZ2, and NTZ3 were treated with a single oral dose of 37.5 mg/kg, 75 mg/kg, and 150 mg/kg, respectively, of NTZ on days 0 and 14. The fourth group was treated with a commercially available regimen that includes a combination of pyrantel, praziquantel, and febantel (FEB) administered orally for three consecutive days. Additionally, an untreated control group was established. Giardia cysts from the stool of each dog were quantified on days -3, 0, 5, 7, 9, 11, 14, 18, 25, and 28. Biochemical parameters were evaluated in all dogs, before the first treatment and after concluding the experiment.ResultsShedding of Giardia cysts was reduced in all treated groups when compared to untreated controls (P < 0.01). However, NTZ2, NTZ3, and FEB had a lower risk during the study. Furthermore, NTZ was also effective against another protozoan, Cryptosporidium spp. at doses of 75 mg/kg and 150 mg/kg, in contrast to the combination of febantel + pyrantel + praziquantel. Biochemical parameters of treated animals, namely, aspartate transaminase and alanine transaminase enzymes, remained within physiological ranges.ConclusionsBased on these results, the implementation of NTZ as a treatment for giardiasis in dogs is proposed. The administration of a single dose is an important advantage of NTZ because it reduces workload, particularly in animals placed in shelters and kennels, where handling of large numbers of animals is required, and personnel is frequently scarce.

Pharmacological Treatment of Giardiasis

“…This finding differs from those found by other authors such as Moron-Soto et al and other authors consulted [42,46,47], and totally contradictory with respect to human pediatric patients, where the effectiveness is 80% [48,49].…”

“…In recent years, it has been explored in the canine species for the treatment of G. intestinalis [42].…”

Occurrence and genotypes of Cryptosporidium spp., Giardia duodenalis, and Blastocystis sp. in household, shelter, breeding, and pet market dogs in Guangzhou, southern China

“…This could be related to the fact that the anthelminthic ingredients used for dogs in China mainly include ivermectin, pyrantel, praziquantel, pyrantel pamoate, febantel, nitazoxanide, metronidazole, and fenbendazole, most of which are also effective against protozoan infections, such as Giardia spp., Cryptosporidium spp., and Blastocystis sp. [46][47][48] . Thus, pet hygiene management is suggested to be a major risk factor for contracting these pathogens in dogs.…”

Prevalence of intestinal parasites in companion dogs with diarrhea in Beijing, China, and genetic characteristics of Giardia and Cryptosporidium species

“…On the other hand, most of the ingredients in these formulas were also experimentally shown to have efficacy against some protozoan parasites, such as Giardia spp. [e.g., (Barr et al 1994;Bowman et al 2009;Foletto et al 2015;Giangaspero et al 2002;Montoya et al 2008;Moron-Soto et al 2017;Zajac et al 1998)], which might explain partially the benefits of these deworming formulas against protozoan infections. Additionally, many companion dogs might have received specific anti-protozoan treatments, but their owners simply considered all treatments as deworming.…”