In Vivo Study of the Therapeutic Efficacy of Benzimidazoles and Tetrahydropyrimidines in Strongylid Nematodes Infection in Dogs

Parasite infestations caused by Ancylostomidae and Strongyloididae nematodes affect both animals and humans, with increasing global resistance also reported in canine digestive nematodes. This study evaluated the efficacy of two anthelmintics – pyrantel (PIR) combined with febantel (FEB), and oxibendazole (OXI) – in 30 dogs from Cluj County. In vivo Fecal Egg Count Reduction Test was performed. Faecal samples for ante-therapeutic (AT) analysis were collected. PIR and FEB were administered to 20 dogs, while 10 received OXI. Post-treatment (PT) faecal samples were collected on days 7, 14, 21 and 28. At each time point, the intensity and prevalence were assessed by quantifying the number of eggs per gram of faeces (EPG) and the number of larvae per gram of faeces (LPG). All collected data was statistically analyzed. Initial prevalence averaged 50% across both groups, with mean intensities of 377.05 EPG and 1733.33 LPG, respectively. By day 28 PT, both the prevalence and intensity had dropped to zero in both groups. PIR+FEB combination showed high efficacy and no signs of resistance. In the group treated with OXI, statistical parameters fell below accepted thresholds by day 21 (EPG) and day 14 (LPG). Both anthelmintic products were effective against tested canine strongylid nematodes.