Veterinary parasitology最新文献

{"title":"Coxiella R1 symbiont regulates the Asian long-horned tick on its reproduction and development","authors":"Weiqing Zheng,&nbsp;Jintong Fu,&nbsp;Jingzhi Huang,&nbsp;Yongwei Wen,&nbsp;Siyu Fang,&nbsp;Xiaoyan Yang,&nbsp;Qianfeng Xia","doi":"10.1016/j.vetpar.2025.110456","DOIUrl":"10.1016/j.vetpar.2025.110456","url":null,"abstract":"<div><div>The Asian long-horned tick <em>Haemaphysalis longicornis</em>, is a hematophagous ectoparasite that causes important public and veterinary health concerns. Different species of ticks harbor a symbiont bacterium of the genus <em>Coxiella</em>. A <em>Coxiella</em> sp. bacterial endosymbiont was highly prevalent in laboratory-reared <em>H. longicornis</em>. The endosymbiont sequence was 100 % identical to those of <em>H. longicornis Coxiella</em>-like endosymbionts and thus named <em>Coxiella</em> R1 in the present study. <em>Coxiella</em> R1 was detected in all stages of tick and in greatest numbers in nymphs and unfed adult females. We manipulated the numbers of <em>Coxiella</em> R1 in ticks by injecting engorged females or capillary tube feeding of flat females with tetracycline. Both of the administration routes were efficient in reducing the symbiont densities. Microinjection of tetracycline solution reduced 25.53 % of <em>Coxiella</em> R1 in eggs harvested just before hatching, whereas, the reduction rate for capillary tube feeding climbed to 81.70 %. Ticks with <em>Coxiella</em> R1 suppression laid abnormal eggs which were wrinkled, flat, and black, and linked each other to form a line. Ticks that had been treated with tetracycline had lower hatching rates in comparison to controls. In addition, larvae with tetracycline treatment less infested hosts and thus had lower engorgement rates than ticks that received PBS alone. The findings indicate that <em>Coxiella</em> R1 is a primary and obligate endosymbiont, and capable of modulating the obligately hematophagous parasites in egg laying and hatching, and larva blood feeding. The results also suggest that tetracycline treatment could be added to an integrated pest management tool menu for control of the Asian long-horned ticks.</div></div>","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"336 ","pages":"Article 110456"},"PeriodicalIF":2.0,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143680355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Detection of Trichinella spp. in free-ranging carnivores and wild boars in Switzerland","authors":"Walter Basso ,&nbsp;Gastón Moré ,&nbsp;Diana Gliga ,&nbsp;Iris Marti ,&nbsp;Norbert Müller ,&nbsp;Britta Lundström-Stadelmann ,&nbsp;Caroline F. Frey","doi":"10.1016/j.vetpar.2025.110454","DOIUrl":"10.1016/j.vetpar.2025.110454","url":null,"abstract":"<div><div>Wolves (<em>Canis lupus lupus</em>) and lynx (<em>Lynx lynx</em>) are officially monitored species in Switzerland. Deceased individuals are subjected to post-mortem examination and collection of baseline health data. The procedure includes an assessment of different infectious agents, including <em>Trichinella</em> spp., the cause of a notifiable zoonotic infection. Between May 2009 and May 2023, a total of 100 wolves and 250 lynx were tested at the National Reference Laboratory for Trichinellosis by the artificial digestion method. Additionally, muscle samples from 8838 wild boars (<em>Sus scrofa</em>), 27 red foxes (<em>Vulpes vulpes</em>), and 23 European badgers (<em>Meles meles</em>), mainly submitted by Swiss hunters, were also analysed for <em>Trichinella</em> infection. <em>Trichinella</em> spp. larvae were detected in 16/100 (16 %) wolves, 41/250 (16.4 %) lynx, 2/27 (7.4 %) red foxes, 0/23 (0 %) badgers, and 1/8838 (0.01 %) wild boars. All positive samples were further tested by multiplex PCR to identify the parasite at the species/genotype level. Two species were detected: <em>T. britovi</em> (in 14 wolves, 33 lynx, 2 red foxes and 1 wild boar) and <em>T. spiralis</em> (in one lynx). In nine cases, the molecular identification was not possible. Although no cases of <em>Trichinella</em> spp. infection in domestic swine and horses were detected in the last decades in Switzerland, we revealed that these parasites, most frequently <em>T. britovi</em>, are still present in Swiss wildlife. Therefore, inspection of game meat remains very important, and the occurrence of sporadic infection in domestic animals cannot be excluded.</div></div>","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"336 ","pages":"Article 110454"},"PeriodicalIF":2.0,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143706465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Eucalyptus oil: A promising anticoccidial agent with multifaceted protective effects","authors":"Jun-jie Huang ,&nbsp;Jie-yu Shi ,&nbsp;Kai-yuan Li ,&nbsp;He Zheng ,&nbsp;Wen-hai Zhang ,&nbsp;Xiao-bin Yi ,&nbsp;Ming-jiang Liu ,&nbsp;Ruo-nan Bo ,&nbsp;Jin-gui Li","doi":"10.1016/j.vetpar.2025.110455","DOIUrl":"10.1016/j.vetpar.2025.110455","url":null,"abstract":"<div><div>In-feed preventive coccidiostat additives are regarded as the primary choice of coccidiosis control, whereas the lasting appearance of drug resistance seriously hampered its application. Eucalyptus oil (EUC) has been evidenced to possess anti-malaria and anti-helminth efficacy. Confronting the urgent requirements for novel anticoccidial remedies, EUC was picked to scrutinize its anticoccidial efficacy with the <em>in vivo</em> coccidiosis model. Birds were orally administrated with 8 × 10⁴ sporulated oocysts and treated with 20 mg/kg EUC in feed during the whole experimental period, diclazuril (DIC) was selected as a positive control. The results manifested that EUC supplementation lessened cecal damage, oocyst shedding and mortality, and recovering body weight gain, so the anticoccidial index (ACI) was up to 160, indicating moderate anticoccidial activity. Additionally, the safeguarding effects of EUC on <em>E. tenella-</em>evoked cecal damage were respectively evidenced on macroscopic, histopathological, and ultrastructural levels. Meanwhile, EUC also exerted an inhibitory effect on redox imbalance and inflammatory response caused by <em>E. tenella</em>. Moreover, EUC treatment remarkably suppressed the invasion-related gene transcriptional level and enhanced the apoptosis mRNA expression level of coccidia. Besides, EUC noticeably decreased the <em>Clostridium perfringens</em> (<em>C. perfringens</em>) proliferation <em>in vivo</em> and <em>in vitro</em>. In conclusion, the EUC additive presented a moderate anticoccidial effect which is associated with the remission activity on <em>E. tenella-</em>induced cecal injury, redox imbalance, and inflammatory response which may be associated with inhibitory effect on <em>Eimeria</em> invasion and <em>C. perfringens</em> proliferation, and activating influence on coccidial apoptosis.</div></div>","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"336 ","pages":"Article 110455"},"PeriodicalIF":2.0,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143674601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Caryophyllene oxide from bioassay-guided fractionation of Toona sinensis essential oil shows insecticidal activity against poultry red mite (Dermanyssus gallinae)","authors":"Wenchang Fan ,&nbsp;Kaiyang Cao ,&nbsp;Dongying Wang ,&nbsp;Liping Ma","doi":"10.1016/j.vetpar.2025.110442","DOIUrl":"10.1016/j.vetpar.2025.110442","url":null,"abstract":"<div><div>The widespread distribution and ecumenical abundance of the poultry red mite, <em>Dermanyssus gallinae</em> (De Geer), in chicken houses, has been bringing about one intractable challenge for the egg-laying hens. However, because of the appearance of drug resistance and the animal safety legislation, the search for some effective insecticidal agents is necessary. In the present investigation, the essential oil extracted from the tender shoots and young leaflets of <em>Toona sinensis</em> (Chinese toon, TSEO) were demonstrated to be not only display significant antioxidant effect, but also revealed prominent insecticidal activity against the poultry red mite. Briefly, in contact toxicity bioassay, the LC₅₀ value was 7.3 μg/mL. In fumigant toxicity bioassay, the highest mortality in the closed container method, and the mortality was 72.5 %. In repellent activity bioassay and residual toxicity bioassay, when TSEO was administrated at the concentration of 20.0 μg/cm³, 89.2 % of mites were repelled for up to six days. Moreover, caryophyllene oxide, was considered to be the compound in TSEO that displayed insecticidal effect against the mites. Therefore, together with the essential oil TESO, caryophyllene oxide can be developed and employed as potential insecticidal agents against the mites in future.</div></div>","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"336 ","pages":"Article 110442"},"PeriodicalIF":2.0,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143609984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Whole-genome sequences revealed genomic diversity and selection signatures of Dermacentor silvarum in Shaanxi, China","authors":"Yi-yao Mou ,&nbsp;Meng-ke Lin ,&nbsp;Yu-ying Yang ,&nbsp;Yu-kun Kang ,&nbsp;Ya-qing Li ,&nbsp;Tian-yuan Liu ,&nbsp;Chu-zhao Lei ,&nbsp;Qing Lin","doi":"10.1016/j.vetpar.2025.110444","DOIUrl":"10.1016/j.vetpar.2025.110444","url":null,"abstract":"<div><div><em>Dermacentor silvarum</em> (<em>D. silvarum</em>) is an arthropod that feeds on blood. It is a primary tick species found in northern China that poses a significant security risk to the health and life of the host, as it has the potential to transmit a variety of pathogens to humans and animals. Through ongoing research on tick genome sequences, researchers have successfully assembled and reported reference genomes for numerous tick species. These significant advances have greatly accelerated the study of tick biology and population genomics. <em>D. silvarum</em> samples were obtained from the body surface of free-range goats in Yulin, Shaanxi Province, China. The whole genomes of the samples were resequenced and merged with preexisting data from the National Genomics Data Center database (project ID: PRJCA002242) to analyze the genetic structure, genetic diversity, mitochondrial genetic structure, and selection signatures of <em>D. silvarum</em> in the Shaanxi Province. Based on the available data, the <em>D.silvarum</em> species in China could be classified into two main branches. These populations exhibited low nucleotide diversity. A slight discrepancy was noted between the mitochondrial phylogenetic tree and the autosomal whole-genome phylogenetic tree of <em>D. silvarum</em>, consistent with a previous study. In the selected analysis of <em>D. silvarum</em> in the Shaanxi Province, China, genes linked to immunity, iron storage, fatty acid biosynthesis, pesticide defense, and blood digestion were identified. Leutriene A4 hydrolase (LOC119466376) was also identified, although its function remains unknown. This information is crucial for understanding the biology of <em>D. silvarum</em> and developing management measures.</div></div>","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"336 ","pages":"Article 110444"},"PeriodicalIF":2.0,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143636390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Resistance of Rhipicephalus microplus to different acaricides in tropical climates: Are the laboratory and field results related?","authors":"Vanessa Ferreira Salvador ,&nbsp;Igor Maciel Lopes de Morais ,&nbsp;Luccas Lourenzzo Lima Lins Leal ,&nbsp;Gabriel Lopes Tamiozo ,&nbsp;Haile Dean Figueiredo Chagas ,&nbsp;Isabela Santos Silva ,&nbsp;Lorena Lopes Ferreira ,&nbsp;Fernando de Almeida Borges ,&nbsp;Marcia Cristina Azevedo Prata ,&nbsp;Livio Martins Costa-Junior ,&nbsp;Alvimar José da Costa ,&nbsp;Caio Márcio de Oliveira Monteiro ,&nbsp;Welber Daniel Zanetti Lopes","doi":"10.1016/j.vetpar.2025.110441","DOIUrl":"10.1016/j.vetpar.2025.110441","url":null,"abstract":"<div><div>The aim of this study was therefore to investigate the relationship between laboratory (Larval Packet Test -LPT; Larval Immersion Test – LIT; Adult Immersion Test – AIT) and field studies using active ingredients or commercial formulations to control <em>R. microplus</em> in a tropical region. This comparative study was carried out with four populations of <em>R. microplus</em> from four Brazilian farms. For laboratory assays, technical grade compounds of cypermethrin and chlorpyrifos were used in the LPT, while fipronil and ivermectin were used in the LIT. The AIT was conducted using commercial spray formulations containing pyrethroid and organophosphate: cypermethrin 187.5 ppm + chlorpyrifos 375 ppm + fenthion 187.5 ppm and chlorpyrifos 825 ppm + High-Cis cypermethrin 99 ppm. For the field assays, the same commercial products of the AIT used, a pour-on formulation of fipronil 1 mg/kg, injectable 200 µg/kg ivermectin, injectable 630 µg/kg ivermectin, injectable 200 µg/kg doramectin and injectable 200 µg/kg moxidectin. For field studies, populations of <em>R. microplus</em> with the mean therapeutic efficacy ≤89 %, on days 7 up to 21 post-treatment, were classified as resistant to such compounds. To standardize the comparative analysis between laboratory and field results, this same value of larval efficacy or mortality (≤89 %) was used to classify the population as resistant by laboratory tests (LPT, LIT, and AIT). Of the 16 laboratory tests conducted using <em>R. microplus</em> larvae (LPT and LIT), 66.6 % showed no relation with field study results. Inconsistencies were observed in 100 % of cases for spray formulations, 25 % for fipronil, and 75 % for macrocyclic lactones. Although the efficacy results of the AIT with commercial formulations were slightly higher than the therapeutic efficacy observed in the field, it is important to note that there was a 100 % positive relation in the classification of the status of the four populations, which were all considered susceptible in both laboratory and field analyses. These findings demonstrate that, in situations like this study, it is essential to calibrate laboratory tests using larvae, particularly against field results, for each formulation. This approach will allow for more accurate recommendations regarding the use of a chemical formulation for a specific tick population. Furthermore, it reduces the risk of incorrectly identifying <em>R. microplus</em> population as resistant or susceptible and helps clarify the practical implications of resistance.</div></div>","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"336 ","pages":"Article 110441"},"PeriodicalIF":2.0,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143619331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Differential detection of ovine Theileria species using loop-mediated isothermal amplification combined with nanoparticle-based lateral flow biosensor","authors":"Haohan Zhu ,&nbsp;Shuaiyang Zhao ,&nbsp;Jin Luo ,&nbsp;Muhammad Kashif Obaid ,&nbsp;Shaohua Zhang ,&nbsp;Peiqi Liu ,&nbsp;Jianxun Luo ,&nbsp;Hong Yin ,&nbsp;Junlong Liu ,&nbsp;Guiquan Guan","doi":"10.1016/j.vetpar.2025.110443","DOIUrl":"10.1016/j.vetpar.2025.110443","url":null,"abstract":"<div><div>Ovine theileriosis is an important tick-borne protozoan disease. It has been reported that three <em>Theileria</em> species are responsible for ovine theileriosis in China, which are <em>T. luwenshuni</em>, <em>T. uilenbergi</em>, and <em>T. ovis</em>. Here, we established three detection techniques based on loop-mediated isothermal amplification (LAMP) and nanoparticle-based lateral flow biosensor (LFB) for the infection of the three <em>Theileria</em> species. Three LAMP primer sets were designed targeting the nucleotide sequences of the 28S rRNA gene of <em>T. luwenshuni</em>, <em>T. uilenbergi</em>, and <em>T. ovis</em>. We used LAMP coupled with real-time fluorescence detection to optimize the concentrations of dNTP Mix, MgSO4, and Bst 2.0 DNA polymerase, as well as the reaction temperature of the LAMP assay, and then combined LAMP with LFB (LAMP-LFB). The entire detection assay process, including genomic DNA extraction (40 min), LAMP reaction (40 min), and LFB readout (&lt;5 min), can be completed within 85 min. The established assays can specifically detect species of <em>T. luwenshuni</em>, <em>T. uilenbergi</em>, and <em>T. ovis</em> infection without cross-reaction with other <em>Theileria</em>, <em>Babesia</em>, and <em>Anaplasma</em> species. The detection limits of the LAMP-LFB assays for <em>T. luwenshuni</em>, <em>T. uilenbergi</em>, and <em>T. ovis</em> plasmid templates were 2.72 × 10² copies/μL, 2.96 × 10³ copies/μL, and 3.05 × 10¹ copies/μL, respectively. Finally, we compared the established LAMP-LFB assay with the traditional PCR assay. The results showed that the total coincidence rates were 96.67 % (<em>T. luwenshuni</em>), 96.67 % (<em>T. uilenbergi</em>), and 93.33 % (<em>T. ovis</em>), respectively. In general, we developed a rapid, simple, sensitive, and specific technique for differential detection of <em>T. luwenshuni</em>, <em>T. uilenbergi</em>, and <em>T. ovis</em> infection in small ruminants.</div></div>","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"336 ","pages":"Article 110443"},"PeriodicalIF":2.0,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Smart application of silver nanoparticles in the treatment of chicken coccidiosis in combination with special supplement to alleviate its toxicity","authors":"Marwa M. Khalifa ,&nbsp;Hend I. Mohamed ,&nbsp;Reem M. Ramadan ,&nbsp;Fady Sayed Youssef ,&nbsp;Mohamed M. El-Bahy ,&nbsp;Shimaa Abdel-Radi","doi":"10.1016/j.vetpar.2025.110440","DOIUrl":"10.1016/j.vetpar.2025.110440","url":null,"abstract":"<div><div>This study investigated the efficacy of a locally formulated nano-silver particle (Ag-NPs) treatment for controlling <em>Eimeria</em> spp. in chickens. Various concentrations of Ag-NPs were evaluated for their ability to inhibit the sporulation of five <em>Eimeria</em> species oocysts in vitro, with LC₅₀ and LC₁₀₀ values determined. The most effective concentrations (20 μg/mL and 25 μg/mL) were administered to experimentally infected chickens for five consecutive days through their feed, either as a normal diet or supplemented with a Vitamin A, E, C, and selenium complex (VSeC). Results showed a significant reduction in the number of oocysts shed, lower lesion scores, and improved weight gain in chickens treated with Ag-NPs, with effects comparable to the reference drug Amprolium. Ag-NPs at 25 μg/mL exhibited the highest efficacy, though mild silver toxicity was observed. Supplementation with VSeC enhanced all parameters and mitigated the mild toxicity associated with the high-dose Ag-NP treatment. Further analysis of redox parameters (malondialdehyde, catalase, glutathione peroxidase, and superoxide dismutase) and liver (alanine aminotransferase, aspartate aminotransferase) and kidney function (serum urea, creatinine) revealed slight elevations in these markers, which were negligible in the VSeC-supplemented groups. In conclusion, Ag-NPs at doses of 20–25 μg/mL for five days were effective in controlling <em>Eimeria</em> infection in chickens. The inclusion of VSeC in the feed provided protective effects, alleviating potential toxicity and enhancing overall treatment outcomes.</div></div>","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"336 ","pages":"Article 110440"},"PeriodicalIF":2.0,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143562523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multiple-species resistance to avermectin anthelmintics on beef cattle farms in Georgia, USA","authors":"Leonor Sicalo Gianchini ,&nbsp;Kelsey L. Paras ,&nbsp;Melissa M. George ,&nbsp;Sue B. Howell ,&nbsp;Bob Storey ,&nbsp;Matthew J. Denwood ,&nbsp;Ray M. Kaplan","doi":"10.1016/j.vetpar.2025.110435","DOIUrl":"10.1016/j.vetpar.2025.110435","url":null,"abstract":"<div><div>Anthelmintic resistance (AR) in gastrointestinal nematodes (GIN) is a worldwide problem in all livestock production systems. Several prevalence studies performed internationally demonstrate that AR in cattle parasites is a growing problem; however, there are no published studies on prevalence in the United States (USA). In this study, we performed fecal egg count reduction tests (FECRT) on twelve cow-calf farms in Georgia, USA. On all farms the efficacy of eprinomectin pour-on (Eprinex®) and doramectin injectable (Dectomax®) was tested individually, as well as a combination treatment of doramectin injectable with oral fenbendazole (Safe-guard®). Fenbendazole was also tested individually on 7 farms, and long-acting eprinomectin (LongRange®) on one farm. FECRTs were performed, analyzed and interpreted following the 2023 WAAVP guidelines. Coprocultures were conducted to assess genus-specific efficacy. Overall, 100 % (12/12) and 75 % (9/12) of farms had resistance to at least one of the avermectin drugs tested in one or more GIN species, respectively. FECR ranged from 14.0 % to 96.8 % (mean=61.81 %) and 8.9–97.9 % (mean=66.87 %) for eprinomectin and doramectin, respectively; this difference was not significant (<em>P</em> = 0.924). In contrast, FECR for fenbendazole was high on all 7 farms tested, with just one farm demonstrating a low level of resistance. The combination treatment of doramectin plus fenbendazole was effective on all 12 farms (mean FECR=98.75 %), being significantly higher than for eprinomectin or doramectin (<em>P≤</em>0.001). Where coproculture data were sufficient to evaluate genus-specific reduction, resistance to <em>Cooperia spp., Haemonchus spp.</em> and <em>Ostertagia spp.</em> was present on 11/12 (92 %)<em>,</em> 6/8 (75 %), and 4/10 farms (40 %), respectively. These data demonstrate that resistance to avermectin drugs is highly prevalent in <em>Cooperia</em>, <em>Haemonchus</em>, and <em>Ostertagia</em> on beef farms in Georgia. Though these data represent just one southern state, given the high level of movement of cattle in the USA, AR in GIN of cattle is likely to be highly prevalent throughout not only the southern USA, but across much of the country.</div></div>","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"336 ","pages":"Article 110435"},"PeriodicalIF":2.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143550257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genetic diversity analysis of benzimidazole resistance-associated genes in Haemonchus contortus from four regions in southern Xinjiang","authors":"Reyilanmu Tuerhong ,&nbsp;Waresi Tuersong ,&nbsp;Ailixire Maimaiti ,&nbsp;Hailiqiemu Maimaitiyiming ,&nbsp;Ying Zhang ,&nbsp;Dilare Xuekelaiti ,&nbsp;Abudusaimaiti Tuoheti ,&nbsp;Lianxi Xin ,&nbsp;Saifuding Abula","doi":"10.1016/j.vetpar.2025.110426","DOIUrl":"10.1016/j.vetpar.2025.110426","url":null,"abstract":"<div><div>To assess the genetic diversity of the I β-tubulin haplotype gene associated with benzimidazoles (BZs) resistance in <em>Haemonchus contortus</em> populations across southern Xinjiang, the sampled populations from four distinct areas to detect the BZs resistance-related I-β tubulin gene and analyse its genetic sequences and structure. The results revealed substantial haplotype diversity and nucleotide polymorphisms across the four populations, with nucleotide diversity (Pi) ranging from 0.03471 to 0.10390 and haplotype diversity (Hd) from 0.945 to 1.000. A low genetic differentiation index (Fst) among populations in the four regions ranging from 0.03354 to 0.12056 suggests weak genetic structure differentiation and frequent gene flow between populations. AMOVA indicated that 91 % of genetic variation was due to within-population differences, suggesting minimal impact of geographical location on <em>H. contortus</em> population structure in southern Xinjiang. Phylogenetic and network analyses showed that 36 <em>H. contortus</em> haplotypes from diverse geographic sources clustered into a single branch with interwoven patterns. Notably, drug resistance mutations showed two origins at E198A, while multiple origins likely exist for the F200Y mutation. This study provides the first genetic diversity analysis of benzimidazole resistance-related genes in <em>H. contortus</em> populations in southern Xinjiang, offering preliminary insights into the spread of resistance and supporting disease control efforts.</div></div>","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"336 ","pages":"Article 110426"},"PeriodicalIF":2.0,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143562524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}