Parasitofauna and current status of anthelmintic resistance in Latvian sheep farms

• Published in: Veterinary World 2022-02, Vol.15 (2), p.414-418
• Main Authors: Keidāne, Dace, Kļaviņa, Alīna, Bergmane, Marta Barbara, Kovaļčuka, Līga
• Format: Article
• Language: English
• Subjects: anthelmintic resistance; gastrointestinal parasites; Ivermectin; Livestock; Livestock farms; Nematoda; sheep
• ISSN: 0972-8988; 2231-0916
• DOI: 10.14202/vetworld.2022.414-418

Parasitic invasions, especially gastrointestinal nematodes, are widespread and are one of the main problems in sheep farms. For this reason, sheep are dewormed more often than other livestock species, often several times a year. Concerns about antiparasitic resistance from the farmers and veterinarians have arisen because, on some farms, antiparasitic drugs are used routinely for very long periods. There are no data available on anthelmintic resistance in gastrointestinal nematodes in sheep in Latvia. Our work aimed to determine the most common endoparasites in sheep and the degree of anthelmintic resistance on sheep farms in Latvia. All sheep (577) underwent a coprological examination before the start of the study, and only sheep diagnosed with more than 200 McMaster eggs per gram of feces were included in the study. A fecal egg count reduction (FECR) test was performed on 20 sheep flocks in Latvia. In Latvia, sheep were most commonly infected with spp. 97% (confidence interval [CI] 95% 96-98). The second most commonly diagnosed species were 91% (CI 95% 89-93) and spp. 76% (CI 95%, 72-79). The ivermectin (IVM) FECR was 0.74% (0.73-0.74), showing resistance in all sheep farms included in this study. Albendazole (ABZ) FECR 0.89% (0.88-0.89) was effective. This study showed that the most popular deworming drugs (ivermectin, albendazole) in Latvia are ineffective in sheep. Additional studies on the use of IVM+ABZ combinations for deworming sheep should be performed.