Background and Aim: Anthelmintics are used to control equine nematodes. However, helminth resistance to regularly used drugs is a well-known challenge. Among tests to assess effective control and monitor resistance, the most common is the fecal egg count reduction test (FECRT). In the absence of reliable FECRT results, the nematode egg reappearance period (ERP) is taken into account. This study aimed to examine horses from farms around the Moscow Region to assess nematode resistance through ERP after therapy. Materials and Methods: In the first stage, fecal samples from 280 horses were examined by the flotation method with a sodium nitrate solution. The eggs per gram (EPG) in feces were counted using the modified McMaster technique. One hundred and forty out of 280 horses were selected for further work. Five groups were formed: Two groups of horses infected with strongyles (n = 50) and three groups with Parascaris equorum (n = 90). Therapy against strongyles was performed with albendazole and ivermectin. Therapy for parascaridosis was performed with fenbendazole, ivermectin, and aversectin C. Samples from the horses in each group were taken on the 14th day (2 weeks), 28th day (4 weeks), 42nd day (6 weeks), 56th day (8 weeks), and 84th day (12 weeks) after treatment, and the amount of EPG in each sample was determined. Results: Overall, nematodes were found in 65% of the horses examined. P. equorum was most frequently recorded (42.1%) followed by Strongylidae gen. spp. (27.9%). The strongyles ERP after therapy with albendazole and ivermectin was estimated on 42 days (6 weeks). The growth of P. equorum eggs in the feces was observed from the 56th day (8 weeks) after therapy with fenbendazole, from the 42nd day (6 weeks) after therapy with ivermectin, and was observed from the 84th day (12 weeks) after the use of aversectin. Conclusion: Our study shows widespread reductions in nematode ERPs across the Moscow Region after ivermectin therapy in horses, suggesting that additional monitoring of these farms is needed for effective control of anthelmintic resistance.

The purpose of the research is to test different dehelminthization schemes of laboratory rats infected with cestodes Rodentolepis nana and nematodes Syphacia muris and evaluate the significance of combined environment disinfection measures. The practical experience of eradication (helminth eradication) in animals in a conventional vivarium was described.Materials and methods. Experiments were conducted to study the efficacy of anthelmintics and administration schemes against cestode and nematode infections in laboratory rats. In the first experiment, praziquantel was used at a dose of 10 mg/kg to treat rats infected with R. nana. In the second experiment, the comparative efficacy of fenbendazole, albendazole, and pyrantel was evaluated against syphaciosis at the recommended dosages of 20, 10, and 12.5 mg/kg, respectively. Each drug was given orally, individually, twice with an interval of 7 days. The third experiment tested different schemes for treating syphaciosis with fenbendazole. One group of rats was given the drug orally individually using an esophageal tube at a dose of 20 mg/kg once a day for 7 consecutive days. Other groups were given fenbendazole daily with food for 7 days (150 mg fenbendazole per 1 kg of food). In all three experiments, all animals were divided into groups, and their cells underwent a complex of additional disinfection measures, and those kept in cages without disinfection.Results and discussion. Praziquantel showed 100% efficacy at a single dose of 10 mg/kg in R. nana therapy. In animals without additional disinfection procedures, cestode eggs were again recorded starting from day 14 after the drug administration. In the group of animals with disinfection measures, pathogens were not detected during the experiment. Double administration of fenbendazole, albendazole and pyrantel in the recommended dosages against syphaciosis did not result in eradicated nematodes in the animals. The disinfection did not affect the obtained results. Fenbendazole administered daily for 7 days ensured helminth eradication in animals. However, on day 7 after the therapy, Syphacia sp. eggs were again found in the groups that received the drug individually intragastrically through a tube, regardless of whether their cells were disinfected. The animals that received fenbendazole with food and were regularly disinfested remained free from nematodes throughout the experiment until the additional disinfection measures were cancelled. In the absence of disinfection, released helminth eggs were recorded on day 14 after therapy.

No abstract

Mice are widely used as laboratory animals. Diagnosis of endoparasites is a necessary condition: this is a culling indicator of animals for SPF (specific pathogen free) vivariums, and for conventional vivariums, it is the necessary information for planning and the possibility of using these animals in various tests. This article describes live-time diagnostics of endoparasites in laboratory mice in SPF vivariums and in open-type vivariums. For the study, individual samples of faeces and bedding were taken from laboratory mice. Direct fecal smears were examined and the flotation method was used. The work was carried out in 2021–2022 in the Laboratory of Biology and Biological Basis of Preventive Measures of the VNIIP – FSC VIEV. During this study, the following 180 samples were taken: 138 individual faecal samples, 34 samples combined with the bedding, and 18 bedding samples. The studied samples were found to contain Giardia muris and Tritrichomonas sp., nematodes Aspiculuris tetraptera and Syphacia obvelata, and cestode Rodentolepis nana. Mixed invasions were also recorded. The results showed the need for planning work with laboratory mice in vivariums.