Evaluation of drug resistance to albendazole and levamisole against lung worms in goat flocks based on fecal larvae count reduction test.

Abstract

The over-use of anti-parasitic compounds as a method of control has led to insufficient effectiveness and widespread drug resistance worldwide. The aim of this study was to investigate the efficacy of albendazole and levamisole as anti-parasitic agents in a lung worm control program in goat flocks. During 2021 and 2022, a total of 110 goats (age of four months and above) were randomly selected from 11 herds in the north-western region of Iran including Saanen breed (both sexes of the same age). The results indicated that 3.60, 50.80 and 41.90% were respectively infected with <i>Dictyocaulus filaria</i>, <i>Muellerius capillaris</i> and <i>Proto-strongylus rufescens</i>, and generally all the lung parasites in goats of this region were resistant to albendazole and levamisole. Due to clinical importance of <i>D. filaria</i> in goats, the molecular analysis of two samples was also done. Sequencing results showed that the identified parasites were 100% similar to the reference sequences registered in the GenBank^®. The results of this research showed low level of these anthelmintics efficacy against <i>Dictyocaulus</i> and <i>Muellerius</i>. Generally, the lung parasites in goats of this region are resistant to albendazole and levamisole. The <i>P. rufescens</i> showed high resistance to these drugs. Totally, it can be concluded that the level of drug resistance varies in different parts of the world; but, the frequencies of drug resistance in different parts of the world are not the same, requiring more studies.