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The economic impact of gastrointestinal (GI) nematode infections on livestock production is well documented worldwide. Increasing evidence supports the hypothesis that parasite colonization induces significant changes in the GI tract environment and, therefore, in the landscape where the microbiota and parasites occur. Understanding the interactions between bacterial and parasite populations in the digestive tract of livestock may be useful to design parasite control strategies based on microbiota modification. The aims of this work were to investigate the impact of the oxytetracycline-mediated manipulation of the gut microbial community on the composition of GI nematode populations in naturally infected sheep and to explore changes in the GI microbial communities after nematode population treatment with the anthelmintic compound monepantel. Extensive manipulation of the GI microbiota with a therapeutic dose of the long-acting oxytetracycline formulation did not induce significant changes in the GI nematode burden. The gut microbiota of treated animals returned to control levels 17 days after treatment, suggesting strong resilience of the sheep microbial community to antibiotic-mediated microbiota perturbation. A significant decrease of the bacterial Mycoplasmataceae family (Log2FC = -4, Padj = 0.001) and a marked increase of the Methanobacteriaceae family (Log2FC = 2.9, Padj = 0.018) were observed in the abomasum of sheep receiving the monepantel treatment. While a comprehensive evaluation of the interactions among GI mycoplasma, methanobacteria and nematode populations deserves further assessment, the bacteria-nematode population interactions should be included in future control programs in livestock production. Understanding how bacteria and parasites may influence each other in the GI tract environment may substantially contribute to the knowledge of the role of microbiota composition in nematode parasite establishment and the role of the parasites in the microbiota composition., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Mate et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Mammalian efflux transporters of the ATP-binding cassette (ABC) regulate cellular levels of endo- and xenobiotics by transporting molecules across cell membranes and are involved in diverse biological processes. Over-expression of these ABC transporters has been involved in macrocyclic lactone resistance. The main goal of this work was to compare the gene expression of the whole ABC-transporter superfamily in isolates of the sheep nematode Haemonchus contortus with different degrees of susceptibility to ivermectin (IVM). Additionally, the effects of in vivo IVM treatment were evaluated in the resistant isolates. Parasite-free Corriedale lambs were artificially infected with either IVM-susceptible or IVM-resistant H. contortus isolates. The differential expression of ABC transcripts in H. contortus female worms with differential susceptibility to IVM were assessed by RNA-seq. Additionally, the transcription levels of ABC-transporter genes in IVM-resistant adult worms recovered from treated sheep at 12 and 24 h after IVM administration were compared to those of IVM-R worms collected from untreated sheep. The comparative analysis of the ABC-transcripts revealed some minor differences in the expression levels of HCON_00042800 (pgp-3), HCON_00020200.mod (ced-7c), HCON_00085890 (abt-4), HCON_00063000 (pmp-5) and HCON_00116670 (wht-8), indicating that, at transcriptional level, these ABC-genes alone cannot explain resistance in H. contortus. HCON_00130060 (pgp-9.2) was highly differentially expressed in resistant isolates compared to susceptible ones, which agrees with previous reports suggesting that pgp-9 may be one of the most relevant candidates contributing to the multi-genic nature of the IVM resistance trait., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Bovine leukemia virus (BLV) is a δ-retrovirus responsible for Enzootic Bovine Leukosis (EBL), a lymphoproliferative disease that affects cattle. The virus causes immune system deregulation, favoring the development of secondary infections. In that context, mastitis incidence is believed to be increased in BLV infected cattle. The aim of this study was to analyze the transcriptome profile of a BLV infected mammary epithelial cell line (MAC-T). Our results show that BLV infected MAC-T cells have an altered expression of IFN I signal pathway and genes involved in defense response to virus, as well as a collagen catabolic process and some protooncogenes and tumor suppressor genes. Our results provide evidence to better understand the effect of BLV on bovine mammary epithelial cell's immune response., Competing Interests: The authors have declared that no competing interests exist.

The efflux transporter P-glycoprotein (P-gp) has been implicated in multidrug resistance of different nematode parasites affecting livestock species. Increased expression of P-gp in nematodes after their in vitro as well as in vivo exposure to anthelmintics suggests a role of P-gp in drug resistance. The current study evaluated the P-gp gene expression in a highly-resistant isolate of the sheep nematode Haemonchus contortus, selected after exposure to ivermectin (IVM) treatments at 10-fold the therapeutic dose. Four lambs were artificially infected with L 3 (7000 L 3 /animal) of a previously selected IVM highly resistant H. contortus isolate. Forty five (45) days after infection, adult worms were collected at 0 (untreated), 6, 12 and 24 h post-oral IVM (2 mg/kg) administration. The relative transcription levels of different H. contortus P-gp genes were studied by quantitative real-time PCR (qPCR) and confirmed by RNA-seq. P-gp1 and P-gp11 gene expressions did not change throughout the experimental sampling period. P-gp3 and P-gp9.1 transcripts decreased significantly at both 12 and 24 h post IVM exposure. P-gp2 expression was progressively increased in a time-dependent manner at 1.81 (6 h), 2.08 (12 h) and 2.49 (24 h)-fold compared to adult worms not exposed (control 0 h) to IVM, although without reaching statistically significant differences (P > 0.05). P-gp12 was neither detected by qPCR nor by RNA-seq analysis. These relatively modest changes in the P-gp gene expression could not be enough to explain the high level of IVM resistance displayed by the H. contortus isolate under assessment. Overexpression of membrane drug transporters including P-gp has been associated with IVM resistance in different nematode parasites. However, some evidences suggest that resistance to IVM and other macrocyclic lactones may develop by multiple mechanisms. Further studies are needed to improve the understanding of resistance mechanisms in adult stages of H. contortus., (Copyright © 2018 Elsevier B.V. All rights reserved.)