Status of Anthelmintic Resistance against Ancylostoma spp. in Naturally Infected Dogs

Background: Anthelmintic efficacy field surveys in dogs are extremely sparse as compared to ruminants. Therefore the present study was planned with the objective to know the status of anthelmintic resistance against Ancylostoma spp. in naturally infected dogs. Methods: A total of 754 faecal samples of dogs were collected to know the prevalence of gastrointestinal parasites. Saturated salt floatation technique was applied for the detection of nematode eggs. Out of which forty dogs, having egg per gram of faeces (epg) more than 300 for Ancylostoma spp., were selected and randomly divided into four study groups of 10 dogs per group. Group I served as untreated control. Dogs of Group II, III and IV were given fenbandazole @ 50 mg/kg BW, pyrantel @ 15 mg/kg BW and Ivermectin @ 0.6 mg/kg BW once orally respectively. Faecal samples were collected pre-treatment on day 0 and post-treatment on days 10 and 14 from naturally infected dogs in field-trial conditions and efficacy was calculated as per standard protocol of WAAVP. Result: The overall prevalence of gastrointestinal parasites was 22.41% which was comparatively higher in stray dogs, female dogs and in monsoon season. Among different parasites Ancylostoma spp. had highest prevalence (12.33%). Efficacy of fenbendazole at day 10 post infection was 96% with lower 95% confidence interval of 88%. Efficacy of pyrantel at day 10 post infection was 97% with lower 95% confidence interval of 88%. Efficacy of Ivermectin at day 10 post infection was 99% with lower 95% confidence interval of 93%. As per WAAVP guidelines, both fenbendazole and pyrantel showed suspected resistance while Ancylostoma worms were susceptible for Ivermection. All the three anthelmintic were 100% effective at day 14 post treatment.