Veterinary parasitology最新文献

{"title":"Development of deep learning-based mobile application for the identification of Coccidia species in pigs using microscopic images","authors":"Naseeb Singh ,&nbsp;Vijay Mahore ,&nbsp;Meena Das ,&nbsp;Simardeep Kaur ,&nbsp;Surabhi Basumatary ,&nbsp;Naphi Roi Shadap","doi":"10.1016/j.vetpar.2024.110376","DOIUrl":"10.1016/j.vetpar.2024.110376","url":null,"abstract":"<div><div>Coccidiosis is a gastrointestinal parasitic disease caused by different species of <em>Eimeria</em> and <em>Isospora</em>, poses a significant threat to pig farming, leading to substantial economic losses attributed to reduced growth rates, poor feed conversion, increased mortality rates, and the expense of treatment. Traditional methods for identifying Coccidia species in pigs rely on fecal examination and microscopic analysis, necessitating expert personnel for accurate species identification. To address this need, a deep learning-based mobile application capable of automatically identifying different species of <em>Eimeria</em> and <em>Isospora</em> was developed. The present study focused on six species, namely, <em>E</em>. <em>debliecki</em>, <em>E</em>. <em>perminuta</em>, <em>E</em>. <em>porci</em>, <em>E</em>. <em>spinosa</em>, <em>E</em>. <em>suis</em>, and <em>Isospora suis</em>, commonly found in pigs of the North Eastern Hill (NEH) region of India. Utilizing a two-stage approach, segmentation of coccidia oocysts in microscopic images using convolutional neural networks (CNNs), followed by species identification by same network was carried out in this work. Resource-efficient models, including EfficientNetB0, EfficientNetB1, MobileNet, and MobileNetV2, within an encoder-decoder architecture were utilized to extract features. Transfer learning was applied to enhance model accuracy during training. Additionally, a marker-controlled watershed algorithm was implemented to separate touching cells, thus reducing misclassification. The results demonstrate that all the developed models effectively segmented/classified Coccidia species, achieving mean Intersection-over-Union (m-IoU) values exceeding 0.92, with individual class IoU scores above 0.90. MobileNetV2 exhibited the highest m-IoU of 0.95, followed by EfficientNetB1 with an m-IoU of 0.94. For classification, MobileNetV2 demonstrated the highest performance, with accuracy, precision, and recall values of 0.93, 0.96, and 0.96, respectively. EfficientNetB1 yielded an accuracy of 0.91. The developed mobile application, tested on new data, achieved an identification accuracy of 91.0 %. These findings highlight the potential of deep learning-based mobile applications in effectively identifying Coccidia species in pigs, thus, providing a promising solution to mitigate reliance on expert personnel and laborious time-consuming experiments in this domain.</div></div>","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"334 ","pages":"Article 110376"},"PeriodicalIF":2.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142830083","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":"Evaluation of the transmission of Anaplasma marginale by Amblyomma tonelliae","authors":"Matilde Nahime Mazzucco Panizza ,&nbsp;Evelina Luisa Tarragona ,&nbsp;Patrick Stephan Sebastian ,&nbsp;Fernando Sebastian Flores ,&nbsp;Atilio José Mangold ,&nbsp;Santiago Nava","doi":"10.1016/j.vetpar.2024.110380","DOIUrl":"10.1016/j.vetpar.2024.110380","url":null,"abstract":"<div><div>This study aimed to evaluate <em>A. marginale</em> transstadial (TST) and transovarial transmission (TOT) by <em>Amblyomma tonelliae</em> through vector competence assays and analysis of natural infection in free-living ticks. This three-host tick species was chosen as model because it is a usual parasite of cattle in all their parasitic stages, making them potential vectors through TST or TOT. Experiment 1 was performed to evaluate TST of <em>A. marginale</em> field strains and M1 strain, and the experiment 2 to evaluate TST and TOT of <em>A. marginale</em> S1P strain from an experimentally acutely infected calf. Free-living larvae, nymphs and adults of <em>A. tonelliae</em> were analyzed to evaluate natural infection with <em>A. marginale</em>. One nymph pool of the experiment 2 resulted positive (minimum infection rate of 1.25 %). However, the negative results of both vector competence assays and the molecular analysis of free-living ticks indicate that the transmission of <em>A. marginale</em> by <em>A. tonelliae</em> would not occur. This finding aligns with three of the four existing studies on the TST and TOT of <em>A. marginale</em> by ticks of the <em>Amblyomma</em> genus.</div></div>","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"334 ","pages":"Article 110380"},"PeriodicalIF":2.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142872858","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":"Interleukin-13 partly induced by the NLRP3 inflammasome promotes Trichinella spiralis encapsulation in infected mice","authors":"Xuanrui Liu ,&nbsp;Bo Zhang ,&nbsp;Zhiyuan Zhang ,&nbsp;Xueting Wang ,&nbsp;Tongxuan Zhang ,&nbsp;Haibin Huang ,&nbsp;Chunwei Shi ,&nbsp;Wentao Yang ,&nbsp;Yanlong Jiang ,&nbsp;Xin Cao ,&nbsp;Jianzhong Wang ,&nbsp;Yan Zeng ,&nbsp;Chunfeng Wang ,&nbsp;Nan Wang ,&nbsp;Guilian Yang","doi":"10.1016/j.vetpar.2024.110386","DOIUrl":"10.1016/j.vetpar.2024.110386","url":null,"abstract":"<div><div><em>Trichinella spiralis</em> infection is a serious parasitic zoonosis in which a collagenous capsule surrounding the larva is developed in the striated muscle cells. However, the mechanism of <em>T. spiralis</em> encapsulation is currently poorly understood. It has been reported that <em>T. spiralis</em> infection can induce the production of IL-13 via the NLRP3 inflammasome, and it has also been suggested IL-13 thus produced may be involved in <em>T. spiralis</em> encapsulation. This research aimed to clarify the involvement of NLRP3 and IL-13 in the <em>T. spiralis</em> capsule formation process. IL-13 and NLRP3 inhibitors were used in a <em>T. spiralis</em> infected mouse model and in C₂C₁₂ cells to analyze the role of IL-13 and NLRP3 in encapsulation. The results showed that <em>T. spiralis</em> infection significantly increased the expression levels of IL-13 and collagen IV and VI. The production of collagen around the <em>T. spiralis</em> encapsulation zone was significantly inhibited when an IL-13 inhibitor was applied. Moreover, the expression levels of IL-13 and collagen IV and VI were significantly decreased by the NLRP3 inhibitor in vitro and in vivo. The above results indicated that NLRP3 can participate in the development of <em>T. spiralis</em> encapsulation by regulating IL-13 expression and stimulating collagen IV and VI synthesis during <em>T. spiralis</em> infection.</div></div>","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"334 ","pages":"Article 110386"},"PeriodicalIF":2.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142898429","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":"Comparison of in vitro and in vivo resurrection success of three ovine gastrointestinal nematode species following different cryopreservation strategies","authors":"A.A. Morrison ,&nbsp;L.M. Andrews ,&nbsp;M. O’Shea ,&nbsp;E. Geddes ,&nbsp;D.J. Bartley","doi":"10.1016/j.vetpar.2025.110422","DOIUrl":"10.1016/j.vetpar.2025.110422","url":null,"abstract":"<div><div>Nematode infective larvae (L₃) of veterinary importance have been cryopreserved in liquid nitrogen (LN₂) to minimize the need for continued passage through live animals. Health and safety concerns, combined with increasing pressures to reduce running and maintenance costs have driven the need to explore alternative preservation techniques. Super-cold (-150°C) freezers have been used for long term storage of cell lines, but no published data were available for livestock gastro-intestinal nematodes (GIN). <em>In vitro</em> and <em>in vivo</em> survivability of L₃ of three GIN species (<em>Teladorsagia circumcincta</em> (MTci2), <em>Trichostrongylus colubriformis</em> (MTco1) and <em>Haemonchus contortus</em> (MHco3 and MHco18)) were assessed following three cryopreservation storage methods. In brief, fifty thousand larvae were exsheathed, and cryopreserved using one of three methods; either snap frozen in LN₂ before storage at −150 °C (LN/-150°C); stored directly at −150°C or stored in LN₂ (LN). <em>In vitro</em> survivability of L₃ (dead versus alive) were assessed at approximately 1, 2, 4, 6, 11 and 23 months post −150°C and LN/-150°C storage. Larvae were defrosted and left in PBS overnight at 39.6°C and 10 % CO₂ prior to dead/alive assessment. An <em>in vivo</em> study was undertaken with L₃ following 4 months of storage. The tubes stored directly in −150°C have consistently shown ≥ 90 % <em>in vitro</em> survivability for all isolates, whereas LN/−150°C showed inter species variability (range: 7–63 % survivability). The <em>in vivo</em> assessment demonstrated a significant difference in establishment with overall group mean establishment ranging from 9 % in the LN/−150°C to 62 % of the fresh larvae, with the −150°C and LN groups establishing 25 % and 10 % respectively.</div></div>","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"334 ","pages":"Article 110422"},"PeriodicalIF":2.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143419798","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":"Nematophagous fungi to controlling gastrointestinal nematodes in small ruminants: A systematic review","authors":"Luis Eduardo Meira Faria ,&nbsp;Júlia dos Santos Fonseca ,&nbsp;Jackson Victor de Araújo ,&nbsp;Lorendane Millena de Carvalho ,&nbsp;George Rego Albuquerque ,&nbsp;Wendell Marcelo de Souza Perinotto","doi":"10.1016/j.vetpar.2025.110410","DOIUrl":"10.1016/j.vetpar.2025.110410","url":null,"abstract":"<div><div>Gastrointestinal nematode infections are responsible for production losses in small ruminant worldwide. Moreover, anthelmintic resistance has increased mortality. New sustainable control strategies have been developed to overcome this problem. Biological control has emerged as a new trend with the recent market introduction of bioproducts. This systematic review aimed to analyze publications on the production of formulations and bioproducts based on helminthophagous fungi used to control gastrointestinal nematodes in sheep and goats, and to survey patents filed with this recommendation. The guidelines PRISMA 2020 were used, searching from 2004 to 2024. The following scientific databases were used: Springer, Science Direct, SciELO, Web of Science, Google Scholar, CAPES Journals and PubMed. The search for patents was carried out using the PATENTSCOPE database. Duplicate articles; review/opinion articles; studies in other animal species; studies without approval by an ethics committee; and tests performed only under in vitro conditions were excluded. Nine studies were included, six of which tested formulations and three tested bioproducts. <em>Duddingtonia flagrans</em> was most frequently included (8), being found in the two available bioproducts. Brazil shows the largest number of studies in the area (5). Sheep were more frequent (7) than those with goats (2). Reduction percentages ranged from 6 % to 96.6 %. Regarding patent searches, only three were found, two of which were for <em>D. flagrans</em> formulations and one for a utility model with <em>Arthrobotrys drechslen</em>. <em>D. flagrans</em> is the nematophagous fungus with the greatest potential to produce bioproducts in the biological control of gastrointestinal nematodes in small ruminants.</div></div>","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"334 ","pages":"Article 110410"},"PeriodicalIF":2.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377903","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":"A national survey of the gastrointestinal nematode control practices used by goat producers in the United States","authors":"Ryan H. Avery ,&nbsp;Natalie J. Urie ,&nbsp;Matthew A. Branan ,&nbsp;Alyson M. Wiedenheft ,&nbsp;Elliott Dennis ,&nbsp;Katherine L. Marshall ,&nbsp;Joan M. Burke ,&nbsp;James E. Miller","doi":"10.1016/j.vetpar.2024.110375","DOIUrl":"10.1016/j.vetpar.2024.110375","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Gastrointestinal nematode (GIN) parasites are a major constraint to goat production. GIN parasite control has relied primarily on the use of anthelmintic drugs. A major issue in goat operations globally, including in the United States (U.S.), is that GIN populations have developed widespread resistance to current anthelmintic drugs. Widespread anthelmintic resistance is a major concern to U.S. goat producers, but there currently remains limited information on what goat production practices are used nationally to combat GIN infections and prevent anthelmintic resistance. The current practices used by goat producers to control GIN parasites and reduce anthelmintic resistance on their operations were evaluated as part of the 2019 National Animal Health Monitoring System (NAHMS) study, which was conducted by the U.S. Department of Agriculture (USDA). The study aims were to determine GIN parasite burden at both the individual animal- and operation-level, investigate geographic patterns of GIN parasitism, and identify risk factors associated with infection prevalence and intensity. The study covered 24 U.S. states, representing 80.4 % of U.S. goats on operations with ≥ 5 goats and 75.8 % of operations with ≥ 5 goats. Data from fecal samples submitted for fecal egg count (FEC) analysis and individual goat- and operation-level questionnaires were collected from 9879 goats across 623 operations. The estimated, weighted mean operation- and animal-level FEC for goats was 658 and 651 eggs per gram, respectively. Across all goats tested, parasite burden was found to be over-dispersed, with the top 24.1 % of animals contributing to 80 % of the total FEC. Geographically, lungworm prevalence was significantly lower in the Southwest region compared with the Northeast, Northwest, and Southeast regions. For GIN FEC values, the highest operation-level counts were found in the Northeast and Southeast region, and the highest animal-level counts were found in the Southeast region by univariate analysis and the Northeast and Southeast regions by multiple regression analysis. Univariate analysis revealed that primary operation production type, primary land/facility management type, primary grazing/browsing management, FAMACHA© card usage, body condition categorization, and month of sample collection were significant factors impacting mean FEC at both the operation- and animal-level. U.S. regionality, goat type, breed, FAMACHA© score, and browsing schedule were found to be significant at the animal-level. Multiple regression analysis at the operation-level revealed that deworming frequency in the previous 12 months, pasture housing practices, and the interaction between region and sample collection date were significant factors that impacted the mean FEC. Multiple regression analysis at the animal-level revealed that goat type, FAMACHA© score, body condition categorization, primary grazing/browsing management, primary operation production type, the interaction b","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"334 ","pages":"Article 110375"},"PeriodicalIF":2.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142932737","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":"Autoantibodies against phosphatidylserine and DNA during canine Dirofilaria immitis infection","authors":"Victor M. Montenegro ,&nbsp;Mónica Delgado Hernandez ,&nbsp;Alicia Rojas ,&nbsp;Juan Rivera-Correa","doi":"10.1016/j.vetpar.2025.110392","DOIUrl":"10.1016/j.vetpar.2025.110392","url":null,"abstract":"<div><div>Heartworm infection caused by <em>Dirofilaria immitis</em> induces a devastating disease that greatly affects the global canine population. The mechanism leading to heartworm pathology has been attributed to be mostly by mechanical damage of the worm to the dog´s vascular system and immune-mediated, but the latter processes are not completely understood. Autoantibodies targeting host molecules such as lipids and nucleic acids have been described with pathological roles during malaria and COVID-19 and mediating anemia and thrombocytopenia. We hypothesized that autoantibodies could be present and have a pathological role during canine heartworm disease caused by <em>D. immitis.</em> In this study, we analyzed the levels of autoantibodies (IgM and IgG) against membrane lipid phosphatidylserine (PS) and DNA in the serum of 169 canine samples based on <em>D. immitis</em> infection. First, our results found significant levels of anti-PS IgM and IgG autoantibodies that were associated with <em>D. immitis</em>-positive when compared to <em>D. immitis</em>-negative samples. Second, we found that autoantibodies, particularly anti-PS, are correlated with hematological parameters such as low platelet count suggesting an association with pathologies such as thrombocytopenia. Altogether, these findings elucidate the understudied presence and pathological role of autoantibodies during canine heartworm disease by <em>D. immitis</em> with implications as biomarkers of disease.</div></div>","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"334 ","pages":"Article 110392"},"PeriodicalIF":2.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142972373","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":"Effects of combinations of the essential oils trans-anethole, thymol and carvacrol against larvae of the screwworm fly Cochliomyia hominivorax in vitro","authors":"Monique Taveira Medeiros ,&nbsp;Diefrey Ribeiro Campos ,&nbsp;Jéssica Dávila de Assis ,&nbsp;Gabriela Ferreira de Oliveira ,&nbsp;Thais Paes Ferreira ,&nbsp;Anna Carolina Teixeira de Jesus ,&nbsp;Thais Ribeiro Correia ,&nbsp;Fabio Barbour Scott ,&nbsp;Yara Peluso Cid ,&nbsp;Katherina Coumendouros","doi":"10.1016/j.vetpar.2025.110398","DOIUrl":"10.1016/j.vetpar.2025.110398","url":null,"abstract":"<div><div>This study investigated the combined effect of trans-anethole, carvacrol and thymol on third-instar larvae of <em>C. hominivorax.</em> For this experiment, third-stage larvae of <em>C. hominivorax</em> were removed from a laboratory colony to perform an <em>in vitro</em> bioassay. The three volatile compounds used in this study, trans-anethole, carvacrol and thymol. Different dilutions of these volatile compounds were performed with the diluent acetone (99.5 %) to determine the associative effect (synergism, addition or antagonism). Three concentrations below the estimated LC₅₀ were prepared (10, 20 and 100 μg.cm⁻²). These compounds were impregnated in filter paper discs, which were dried and transferred to Petri dishes. Ten larvae were added to each dish and incubated in climate-controlled chambers at 28 ± 1 ºC and 75 ± 10 % relative humidity for 24 and 48 hours. Mortality was assessed based on the absence or change in larval movement, as observed under a stereomicroscope. After 24 hours, trans-anethole (A) caused mortality rates in the range of 23–33.5 %, carvacrol (C) of 9–59 % and thymol (T) of 27–81.5 %, in the three concentrations evaluated. The combination of trans-anethole with carvacrol resulted in mortality rates between 11 % and 50 %, demonstrating antagonistic action. The combination of trans-anethole with thymol caused mortality of 12.5–55.5 %, and the combination of carvacrol with thymol generated mortality of 75.5–99.5 %, indicating synergism. After 48 hours, (A) produced a mortality range of 29–49 %, (C) of 10.5–63 %, and (T) of 37.5–86 % in the three concentrations, maintaining the same relationship of antagonistic and synergistic activity. The combination of trans-anethole with carvacrol resulted in mortality rates between 16 % and 56.5 %, while the combination of trans-anethole with thymol caused mortality of 27.5–62.5 % and the combination of carvacrol with thymol presented mortality between 83 % and 99.5 %. Hence, there was an antagonistic effect when trans-anethole was associated with carvacrol and thymol and a dose-dependent synergistic effect when carvacrol was associated with thymol against third instar larvae of <em>C. hominivorax.</em></div></div>","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"334 ","pages":"Article 110398"},"PeriodicalIF":2.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143029461","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":"Antagonistic interactions between spinosad and macrocyclic lactones in combination against larvae of the sheep blowfly, Lucilia cuprina, in vitro","authors":"Andrew C. Kotze ,&nbsp;Aleta G. Knowles","doi":"10.1016/j.vetpar.2024.110389","DOIUrl":"10.1016/j.vetpar.2024.110389","url":null,"abstract":"<div><div>Control of the sheep blowfly relies on insecticides, however resistance is currently impacting on their efficacy. The use of insecticides in combination (mixtures) is considered to be a useful strategy to delay resistance under some circumstances. The present study aimed to examine the combination of spinosad with macrocyclic lactones in order to determine if the two drug classes showed any interactions that would impact on the usefulness of a combination product for flystrike control. We used isobologram analysis to examine drug interactions in <em>in vitro</em> bioassays with the larval stages of the sheep blowfly. In initial single drug assays, ivermectin and abamectin showed similar EC₅₀ against blowfly larvae, while moxidectin and spinosad were 20- and 30-fold less potent, respectively. Combinations of spinosad and each of the macrocyclic lactones showed a pattern of interactions dominated by antagonistic or additive relationships when combined at different ratios. Peaks in antagonism were associated with combinations at ratios equivalent to, or close to, the relative EC₅₀s when used alone. The antagonism was strongest for moxidectin, with combination index values up to 1.82 at the EC₅₀ and 3.2 at the EC₉₀ at a spinosad: moxidectin ratio of 0.78:1. Maximum combination index values for ivermectin and abamectin at the EC₉₀ were 1.61 and 1.42, at ratios of 27:1 and 31:1, respectively, indicating a significant degree of antagonism for both combinations. We suggest that the observed antagonism may be due to interactions at common ion channel receptors, although this requires confirmation. The study highlights the need to examine drug interactions as a component of determining the suitability of specific drug combinations for parasite control.</div></div>","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"334 ","pages":"Article 110389"},"PeriodicalIF":2.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143182789","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":"Antagonistic activity of Pochonia chlamydosporia against three helminth eggs and characterization of its serine protease","authors":"Luyao Hao ,&nbsp;Fengmiao Zhao ,&nbsp;Yuan Guo ,&nbsp;Yuan Ma ,&nbsp;Zhengyi Li ,&nbsp;Wen Wang ,&nbsp;Hongliang Luo ,&nbsp;Rui Wang","doi":"10.1016/j.vetpar.2024.110374","DOIUrl":"10.1016/j.vetpar.2024.110374","url":null,"abstract":"<div><div>To address the economic burden caused by livestock parasitic diseases, particularly gastrointestinal nematodes (GIN) and liver flukes, which are exacerbated by growing anthelmintic resistance, researchers are increasingly focusing on biological control strategies as a promising solution. Among these, the fungus <em>Pochonia chlamydosporia</em> has demonstrated promising helminth control properties. This study explored the potential of <em>P. chlamydosporia</em> in controlling helminth infections by examining its effects on helminth eggs. <em>P. chlamydosporia</em> was cultured on 2 % water agar (WA) plates, and the eggs of three parasite species (<em>Fasciola hepatica</em>, <em>Parascaris spp.</em>, and <em>Nematodirus oiratianus</em>) were placed on these plates. The impact of the fungus on the eggs was assessed using light microscopy and scanning electron microscopy (SEM). Eggs were introduced into a liquid medium to stimulate <em>P. chlamydosporia</em>’ s predatory activity. The culture filtrate was tested for protease activity and its efficacy against nematode eggs was evaluated. The extracellular alkaline serine protease was purified and characterized through ammonium sulfate precipitation and Sephadex G - 100 chromatography. <em>P. chlamydosporia</em> showed type 1, type 2, and type 3 effects on eggs. (Type 1 effect: physiological and biochemical impact without morphological damage to the eggshell, with visible hyphae adhering to the eggshell; Type 2 effect: lytic effect causing morphological changes in both the embryo and eggshell, without hyphal penetration; Type 3 effect: lytic effect with morphological changes in the embryo and eggshell, along with hyphal penetration and internal egg colonization). Light microscope and SEM observations revealed that <em>P. chlamydosporia</em> destroyed the eggs through mycelial growth, appressoria formation, penetration, and degradation stages. Moreover, the addition of nematode eggs stimulated the secretion of extracellular proteins, including proteases, with induction filtrate showing high ovicidal activity. The molecular mass of the protease was approximately 40 kDa estimated by SDS–PAGE. The optimum activity of the protease was at pH 10 and 60 ℃. The purified protease was highly sensitive to phenylmethyl sulfonyl fluoride (PMSF), indicating it belonged to the serine protease family. The findings suggest that <em>P. chlamydosporia</em> could be an effective biological control agent for helminth diseases in livestock.</div></div>","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"334 ","pages":"Article 110374"},"PeriodicalIF":2.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142819466","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}