Abstract
Simple SummaryAnthelmintic resistance (AR) is a serious threat to animal health and has a major economic impact worldwide due to production and financial losses. Currently, there are three classes of anthelmintics most commonly used in small ruminants: the benzimidazoles (BZs), macrocyclic lactones (MLs) and cholinergic agonists (especially levamisole; LEV). The widespread use of those products has led to the emergence of drug-resistant parasite strains. In the present study, we describe for the first time a case of resistance to anthelmintics in goats in Romania. Resistance was detected and confirmed for two chemical groups of anthelmintics (MLs and BZs) by in vivo faecal egg count reduction test (FECRT) and in vitro methods: the egg hatch test (EHT) and larval development test (LDT). Considering the increasing prevalence of AR in goat herds in Europe and around the globe, we believe that the findings of our study on AR in goats in Romania do not represent a singular event and could hence be just the noticeable part of a much wider issue.Currently, there are three classes of anthelmintics most commonly used in small ruminants: the benzimidazoles (BZs), macrocyclic lactones (MLs) and cholinergic agonists (especially levamisole; LEV). The widespread use of those products has led to the emergence of drug-resistant parasite strains which represents a serious threat to the livestock industry. In the present study, we describe for the first time a case of resistance to anthelmintics in goats in Romania. The study was carried out in 2021 in a dairy goat herd from the Transylvania region. Two types of diagnostic methods were used to confirm anthelmintic resistance (AR). First, the faecal egg count reduction test (FECRT), an in vivo AR diagnostic method, was used to evaluate the efficacy of eprinomectin (EPM). The results of this test were analysed applying two different calculative methods that are used only in treated animals (without the control group). Furthermore, two in vitro methods were used: the egg hatch test (EHT) for the detection of resistance to BZs, and the larval development test (LDT) for detection of resistance to all three classes of anthelmintics. The results of FECRT indicate the resistance of gastrointestinal nematodes (GINs) to EPM in both calculative methods (FECR1 = −88% and FECR2 = −202%). In addition, the results obtained for ivermectin aglycone (IVM-AG) in LDT also indicate resistance to drugs from MLs group, especially avermectins. Similarly, the results of in vitro methods (EHT and LDT) indicate resistance to BZs in this herd. LEV was the only drug that stopped the development of L3 larvae 100% (LDT). H. contortus was the only nematode species found in coproculture after EPM treatment. Furthermore, H. contotus L3 larvae was the only species found in the wells with the highest concentrations of thiabendazole (TBZ) and IVM-AG in LDT. This suggests that resistance to both BZs and MLs was present for that species.
Highlights
Parasitic infections, especially those caused by gastrointestinal nematodes (GINs), are one of the main causes of economic losses in goat production worldwide [1]
Considering the increasing prevalence of anthelmintic resistance (AR) in goat herds in Europe and around the globe, we believe that the findings of our study on AR in goats in Romania do not represent a singular event and could be just the noticeable part of a much wider issue
Results of the egg hatch test (EHT) were determined as the TBZ concentration required to inhibit 50% or 99% of the eggs from hatching and the number of hatched eggs at a concentration of 0.1 μg/mL of TBZ, since the results of Coles et al [5] suggest that this discrimination concentration (DC) prevents hatching of 99% of susceptible eggs
Summary
Especially those caused by gastrointestinal nematodes (GINs), are one of the main causes of economic losses in goat production worldwide [1]. The infection with GINs, such as Haemonchus contortus, Trichostrongylus spp. and Teladorsagia spp. threatens the profitability and sustainability of goat production [1,2]. Their control is mainly based on the use of anthelmintics [3]. The increase in MDR among GINs and the lack of sufficiently effective alternative methods of control and prophylaxis of parasitic infections are an increasing threat to small ruminant health and production around the globe [8,9]. The situation is similar in goat herds outside of Europe as described in USA [26], South Africa [27], Kenya [28], Cuba [29], Malaysia [30], India [31], Australia [32], and New Zealand [33]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
