Veterinary parasitology最新文献

The cattle tick Rhipicephalus microplus is the most economically important ectoparasite worldwide, affecting animal health, welfare, and cattle production in tropical and subtropical regions. Anti-tick vaccines have emerged as a promising alternative to chemical acaricides for cattle tick control. To date, studies with a peptide derived from the RmS-17 antigen have demonstrated protective efficacy against R. microplus tick infestation in cattle and shown the ability to elicit a strong, specific humoral immune response. Based on these findings, the present study evaluated the direct effects of anti-pRmS-17 antibodies on reproductive performance and tissue integrity using in vitro assays. A total of 45 semi-engorged R. microplus females were divided into three experimental groups and artificially fed for 48 h with anti-pRmS-17 IgG, anti-Bm86 IgG, or control serum to assess reproductive parameters. Additionally, 15 semi-engorged ticks were similarly fed and divided into three groups for histological analysis. The results showed that ticks fed with antigen-specific IgG antibodies showed significant reductions in oviposition (55% in the anti-Bm86 group) and egg hatching (47% in the anti-pRmS-17 group) compared with control ticks (P < 0.05). The histological analysis revealed marked morphological alterations in the midgut of IgG-fed ticks, including loss of germinative cells and reduced formation of new digestive cells, suggesting a delay in digestive metabolism. In conclusion, these findings provide functional and histological evidence supporting the relevance of pRmS-17 as a promising antigen for anti-tick vaccine development and its potential inclusion in integrated tick management programs to reduce the impact of R. microplus on cattle production.

Responsible for significant livestock losses, especially in tropical and subtropical regions, the tick Rhipicephalus microplus represents one of the main challenges for cattle farming and requires control in herds. However, the inappropriate use of synthetic acaricides has led to the development of chemical resistance in parasites, potential environmental contamination, and residues in animal products intended for human consumption. The objective of this research was to integrate in silico approaches and in vitro studies of eucalyptus wood vinegar (WV) on the reproduction of the tick R. microplus. For the experiment, cattle herds not receiving antiparasitic treatment were used, from which ingurgitated females were collected, identified, cleaned, weighed, and distributed into groups of ten for each WV concentration, with four replicates per treatment, totaling 280 specimens. In all tests, ticks were immersed in the WV at 6.25, 12.50, 25, 50, and 100% (mg mL^-1). Two control treatments were conducted, one negative (distilled water) and one positive with Amitraz (20 mg mL^-1). Regarding the reproductive parameters tested at the concentrations, they showed product efficiency values greater than 95%, indicating significant biological activity. Molecular docking revealed an interaction between the molecules 2-cyclopenten-1-one, furfural, and phenol-2-methoxy and the transmembrane protein GABA-gated chloride channel of the tick. This interaction was stable, as evidenced by the low binding energies and the molecular interactions formed, which most likely can explain the deadly effect of WV on the parasites. In conclusion, eucalyptus WV appears to be a viable natural alternative for controlling R. microplus.

Hyalomma scupense, the main vector of tropical theileriosis, presents taxonomic challenges that impede vector surveillance. This study combines targeted sampling of 20 morphologically-confirmed specimens from El Hessiene, Tunisia (36°50'N 10°12'E) with global GenBank analysis of mitochondrial markers 16S rRNA, 12S rRNA, and COI to assess genetic diversity, phylogeographic structure, and regional gene flow. All Tunisian sequences showed 99.88-100% identity to H. scupense references. Global analysis revealed moderate genetic diversity: 8 genotypes for 16S rRNA (Hd=0.551, π=0.0036), 13 for 12S rRNA (Hd=0.416, π=0.00907, highest variability), and 6 for COI (Hd=0.518, π=0.00142, most conserved). Phylogenetic analyses confirmed H. scupense monophyly, with COI resolving four well-supported geographic clusters (bootstrap 89-98%): North African (including all Tunisian isolates), European-Asian, Central Asian, and West Asian. Tunisian isolates formed a monophyletic North African cluster, indicating ongoing regional gene flow likely mediated by livestock movements. 12S rRNA/16S rRNA markers revealed finer regional structuring. These findings establish a polymorphism hierarchy (12S rRNA > 16S rRNA > COI) and validate multi-marker approaches for tick phylogeography. The North African cluster homogeneity underscores persistent gene flow, with implications for modeling Theileria annulata dispersion and One Health surveillance strategies across Maghreb. COI emerges as optimal for broad-scale phylogeography, while 12S rRNA suits population-level resolution. This baseline informs vector monitoring and control in tropical theileriosis-endemic regions.

Gastrointestinal nematodes (GIN) can impact on cattle health and welfare as well as cause economic losses associated with lower productivity but are often overlooked by farmers as a sub-clinical issue. Infections are routinely controlled with prophylactic use of anthelmintics but resistance to the available products has been reported. The prevalence of anthelmintic resistance (AR) in cattle GIN is advancing in certain species, making control more challenging. This study shows the current prevalence and diversity of GIN populations in British commercial cattle herds and the extent of infection in traded animals. Faecal samples were collected from 455 cattle herds; 395 from groups being sold through livestock auctions and a further 60 from samples submitted to the Animal and Plant Health Agency (APHA) for monitoring purposes. Faecal egg counts (FEC) were conducted on all samples and nematode eggs recovered for molecular species identification using Illumina MiSeq. Of the traded cattle, 67% had a positive faecal egg count, with a mean FEC of 20 eggs per gram (epg) (95% CI: 11 - 34). Samples from APHA had a mean FEC of 72 epg (95% CI: 56-93). Ostertagia ostertagi and Cooperia oncophora were the most common species identified, with co-infections of these two species found in 87% of samples. A diverse range of additional species were also identified, and these were found to vary with the pedigree status of cattle sampled and geographic location. Our results highlight that most cattle sold at auction were carrying GIN, which included a high prevalence of the pathogenic species O. ostertagi. These findings stress the need for effective biosecurity measures for new and returning cattle to minimise the movement of GIN between farms.

N. caninum is a parasite found worldwide that can be transmitted through contaminated food or from an infected mother to her offspring during pregnancy. This protozoan is a major threat to the healthy development of livestock, causing significant economic losses due to abortion, fetal death, and nervous system diseases in cattle. The effect of contact with cell debris from N. caninum on semen quality is not known, although infected animals shed DNA, protein, and even infective forms of the parasite. This study aimed to evaluate the effects of soluble N. caninum antigens on bovine semen quality in vitro. The spermatozoa were subjected to serial double dilutions of N. caninum antigens at high, medium, and low doses (8, 4, 2 µg/ml) using TALP-Sperm and TALP-Fert medium. Results indicated that soluble N. caninum antigens can affect the velocity and angle of sperm trajectory, both in the presence and absence of flow, within a simulated fallopian tube environment. In addition, several techniques, including Toulidine Blue, Propidium Iodide, transmission electron microscopy, Pisum sativum Lectins, and mitochondrial labeling with MitoTracker, have been used to demonstrate that treatment with soluble N. caninum antigens can affect the integrity of sperm chromatin and cause severe damage to the sperm membrane and acrosome. Finally, the spermatozoa were treated with antigens before in vitro embryo production, which impacted the cleavage and blastocyst rates. After being infected with N. caninum, bulls may experience changes in their sperm, which can compromise fertilization process and embryonic development, affecting their fertility.

This study aimed to investigate the in vitro and in silico anthelmintic activity of eugenol and derivatives against Haemonchus contortus and evaluated the cytotoxicity of these compounds. For this, acetyl eugenol (AE), benzoyl eugenol (BE), and methyl eugenol (ME) were synthesized. Eugenol, AE, BE, and, ME cytotoxicity was tested on HaCat cells and the anthelmintic effect was evaluated in the egg hatch test (EHT) and larval migration inhibition test (LMIT). Eugenol and the derivative with highest efficacy were evaluated in adult worm motility test (AWMT), followed by the assessment morphological and ultrastructural changes. In silico study was based on molecular docking with the phosphoethanolamine N-methyltransferase (PMT) enzyme. All compounds showed similar cytotoxicity profiles. Eugenol, AE, BE, and ME showed ovicidal and larvicidal effects on H. contortus. However, only the acetylation potentiated the anthelmintic effect of eugenol. In the EHT and LMIT, the EC₅₀ values of AE and eugenol were 0.19 and 0.21 mg/mL, and 0.56 and 1.35 mg/mL, respectively. In the AWMT, the EC₅₀ of eugenol and AE were both 0.11 mg/mL. The scanning and transmission electron microscopy revealed that eugenol and AE caused damage to the cuticle and internal tissues of H. contortus adults. Molecular docking suggested that eugenol and AE interact with the HcPMT. These findings indicate that acetylation may increase the anthelmintic effect of eugenol against H. contortus without significantly altering the cytotoxic potential. Therefore, in vivo assays must be realized to evaluate the toxicological safety and anthelmintic efficacy of eugenol and AE in small ruminants.