F200Y polymorphism of the β-tubulin isotype 1 gene in Haemonchus contortus and sheep flock management practices related to anthelmintic resistance in eastern Amazon

Abstract

The objective of the present study was to determine the frequency of the F200Y polymorphism in the β-tubulin isotype 1 gene of Haemonchus contortus from various sheep flocks in eastern Amazon, and to identify management practices that may favor the emergence of resistance to anthelmintic drugs in the same area. In total, 305 specimens of H. contortus were collected from sheep at 12 farms located in the state of Pará. An allele-specific PCR was performed to detect the F200Y polymorphism, and questionnaires were used to obtain information about the farms and flocks. All genotypes were detected as follows: 31% of the parasites were RR, 37% of the parasites were SR, and 32% were SS. The completed questionnaires revealed that all farms employed semi-intensive farming systems, performed suppressive anthelmintic treatment, and based their choice of drug on cost and availability rather than on any knowledge regarding drugs that remained effective on their property. It can thus be concluded that the SNP in codon 200 of the β-tubulin isotype 1 gene is present in the H. contortus populations from eastern Amazon, and that a series of management practices that favor the emergence of anthelmintic resistance are employed on these farms.

The first molecular identification of benzimidazole resistance in Haemonchus contortus from goats in Thailand

“…Moreover, this technique is easy and rapid to determine the BZ resistance in H. contortus. We detected a high frequency of resistant homozygous RR in the southern region (65%) similar to the previous studies in China (31%), Egypt (69.44%), Northwest India (74%), North India (53-85%), Hungary (87.2%), Brazil (66.7-93.97%), India (98%), and East Amazon (100%) [14,[29][30][31][32][33][34][35]. The low frequencies of resistance allele (0-15%) in H. contortus in three others (the northern, western, and the central regions) are similar to a study in Brazil (5%) [36].…”

Assessing anthelmintic resistance risk in the post-genomic era: a proof-of-concept study assessing the potential for widespread benzimidazole-resistant gastrointestinal nematodes in North American cattle and bison

“…The F167Y (TTC > T A C) SNP was also present at moderate to low frequencies in each of these cases (2.22–40.58%). Haemonchus contortus is primarily a sheep parasite, which can also infect cattle, and surveys of sheep have shown high levels of benzimidazole resistance throughout Brazil, including Sao Paulo State (Niciura et al , 2012 ; Chagas et al , 2016 ). Since co-grazing of sheep and cattle is relatively common in Brazil, much more so than in the USA or Canada, it is possible that many of the cases of phenotypic benzimidazole resistance reported in Brazilian cattle could be due to H. contortus infections.…”

An Overview of Anthelmintic Resistance in Domestic Ruminants in Brazil

“…The molecular mechanism of resistance is better understood for benzimidazoles; therefore, it offers a potential opportunity to expand molecular diagnostic tests for drugs of this class [141]. For example, in Brazil, some studies were conducted using the β-tubulin isotype gene, a marker to monitor resistance [141][142][143]. In addition, molecular characterization is an essential tool for the validation and phylogenetic analysis of nematodes, such as allele-specific polymerase chain reaction, endpoint polymerase chain reaction (PCR), semi-quantitative PCR, quantitative PCR (qPCR), high-resolution melt curve analysis (HRMC) and "Nemabiome" internal transcribed spacer 2 (ITS-2) amplicon sequencing [144,145].…”