Veterinary parasitology最新文献

{"title":"Effects of a laminarin-rich algal extract on caecal microbiota composition, leukocyte counts, parasite specific immune responses and growth rate during Eimeria tenella infection of broiler chickens","authors":"Malin Boyner ,&nbsp;Emma Ivarsson ,&nbsp;Alma Hansen ,&nbsp;Anna Lundén ,&nbsp;Osama Ibrahim ,&nbsp;Robert Söderlund ,&nbsp;Gunnar Cervin ,&nbsp;Henrik Pavia ,&nbsp;Eva Wattrang","doi":"10.1016/j.vetpar.2024.110377","DOIUrl":"10.1016/j.vetpar.2024.110377","url":null,"abstract":"<div><div>Coccidiosis, infection with protozoan parasites of genus <em>Eimeria</em>, is a major problem in poultry husbandry world-wide. The disease is currently managed by coccidiostats and live vaccines, but these approaches are not sustainable. Hence, it is important to identify new means to control the infection and/or ameliorate its detrimental effects on gut health. Laminarin, a β-glucan found in marine brown algae, has prebiotic and bioactive properties that could be beneficial in coccidiosis control. The present study aimed to examine the potential of laminarin as an immunostimulatory and microbiota-regulatory compound in broiler chickens infected with <em>E. tenella</em>. Chickens were continuously fed a diet supplemented with a laminarin-rich algal extract (AE) from first feed and subsequently infected with <em>E. tenella</em> at 19 days old. The outcome of infection including caecal microbiota and some immune parameters were monitored during the experiment. Results showed that AE supplementation affected some lymphocyte subpopulations, with increased numbers of TCRγ/δ+CD8-, B-cells and CD4-CD8αβ+ cells and lower numbers of CD4+CD8αα+ cells in blood and increased proportions of CD4-CD8αβ+ spleen cells compared to those in control chickens. The AE diet did not affect parasite excretion, lesion scores or <em>E. tenella</em> specific T-cell responses. However, reductions of <em>E. tenella</em> induced contraction of <em>Bifidobacteriaceae</em> and expansion of <em>Clostridiaceae</em> in caecal microbiota were observed for AE fed chickens compared to chickens fed the control diet. Thus, AE feed supplementation induced some immunostimulatory activity in chickens and affected some of the alterations in caecal microbiota evoked by <em>E. tenella</em> infection.</div></div>","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"334 ","pages":"Article 110377"},"PeriodicalIF":2.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142878204","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":"Comparison of four commercial serological tests for the detection of Leishmania infantum antibodies in dogs","authors":"Andrea Murillo-Picco ,&nbsp;Sandra Gascón-Torrens ,&nbsp;Massimiliano Baratelli ,&nbsp;Lourdes Alarcón ,&nbsp;Marta Baxarias ,&nbsp;Tamara Rivero ,&nbsp;Laia Solano-Gallego","doi":"10.1016/j.vetpar.2025.110397","DOIUrl":"10.1016/j.vetpar.2025.110397","url":null,"abstract":"<div><div>Early detection and treatment of cases of <em>Leishmania infantum</em> infection are critical in controlling the spread of the disease in dogs. Several serological methods are available to support the diagnosis of canine leishmaniosis. The immunofluorescence antibody test (IFAT) and enzyme-linked immunosorbent assay (ELISA) are the main tests used by clinicians. High antibody levels are associated with severe parasitism and disease and are diagnostic of clinical leishmaniosis. Conversely, the presence of low antibody levels is not necessarily indicative of disease and may be more difficult to detect by serological tests. The aim of this study was to evaluate and compare the diagnostic performance of four commercially available serological tests, including ELISAs (CIVTEST® CANIS LEISHMANIA short and standard protocols), LEISHMANIA-ELISA DOG®, ELISA/S7® and MegaFLUO®LEISH IFAT, for the detection of specific antibodies against <em>L. infantum</em> antigens in dogs in different states of infection. Canine sera samples from seropositive sick infected dogs (<em>n</em> = 75), seropositive apparently healthy dogs (<em>n</em> = 48), and seronegative apparently healthy dogs from a high endemic area (Cadiz, <em>n</em> = 40) and seronegative apparently healthy dogs from very low endemic area of <em>L. infantum</em> infection (Asturias, <em>n</em> = 40) were classified based on the results of an <em>in-house</em> UAB ELISA as a reference test. The positive percent of agreement (PPA) and negative percent of agreement (NPA) observed for each test were as follows: CIVTEST® standard (93.4 %, 100 %) on 202 samples tested, CIVTEST® short (84.4 %, 100 %) on 202 samples tested, LEISHMANIA-ELISA DOG® (81.8 %, 72.2 %) on 138 samples tested, ELISA/S7® (34.8 %, 45 %) on 195 samples tested and MegaFLUO®LEISH IFAT (100 %, 100 %) on 203 samples tested, respectively. The accuracy was as follows: CIVTEST® standard (0.96), CIVTEST® short (0.91), LEISHMANIA-ELISA DOG® (0.77), ELISA/S7® (0.39), and MegaFLUO®LEISH IFAT (1). The Cohen´s Kappa index (<em>K</em>) from best to worst was: MegaFLUO®LEISH IFAT (<em>K</em> = 1), CIVTEST® standard (<em>K</em> = 0.92), CIVTEST® short (<em>K</em>=0.81), LEISHMANIA-ELISA DOG® (<em>K</em> =0.54), and ELISA/S7® (<em>K</em>=-0.19). Finally, the area under the receiver operating characteristic curve (AUC-ROC), in the ELISAs test, ordered from the maximum to the minimum value was: CIVTEST® short (1), CIVTEST® standard (0.99), LEISHMANIA-ELISA DOG® (0.87), and S7® (0.37). In conclusion, this study demonstrated that the diagnostic performance of the commercially available ELISA tests against <em>L. infantum</em> antigen can vary widely. Moreover, it highlights the fact that CIVTEST® CANIS LEISHMANIA is a reliable test to support the diagnosis of canine leishmaniosis in clinical settings.</div></div>","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"334 ","pages":"Article 110397"},"PeriodicalIF":2.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143181567","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":"Inhibition of Neospora caninum activity by niclosamide: Evidence from in vitro and in vivo studies","authors":"Feixue Liu ,&nbsp;Xin Li ,&nbsp;Liuzhenxiu Yan ,&nbsp;Xu Zhang ,&nbsp;Jin Sun ,&nbsp;Haitao Su ,&nbsp;Lu Li ,&nbsp;Sining Chen ,&nbsp;Lanbi Gao ,&nbsp;Pengtao Gong ,&nbsp;Nan Zhang ,&nbsp;Xichen Zhang ,&nbsp;Jianhua Li ,&nbsp;Xiaocen Wang","doi":"10.1016/j.vetpar.2024.110362","DOIUrl":"10.1016/j.vetpar.2024.110362","url":null,"abstract":"<div><div>Neosporosis caused by <em>Neospora caninum</em> (<em>N. caninum</em>) is one of the main causes of bovine miscarriage, but there are currently no effective drugs or vaccines for treatment and prevention. Our previous works have found that NLRP3 inflammasome activation participated in controlling <em>N. caninum</em> proliferation and niclosamide has been regarded as an NLRP3 inflammasome inducer. This study aimed to evaluate the resistance of niclosamide to <em>N. caninum</em> infection. Niclosamide-mediated NLRP3 inflammasome activation was determined by LDH and ELISA measurement of IL-1β release as a marker for inflammasome activation in a model of <em>N. caninum</em>-infected macrophages. The <em>in vitro</em> antiparasitic effect of niclosamide was further explored in Vero cells by plaque assays, qPCR, and Giemsa staining. The <em>in vivo</em> effects were investigated in <em>N. caninum</em>-infected mice by measuring parasite burden, histopathology, and survival. Results showed that niclosamide partially enhanced macrophage-mediated clearance of <em>N. caninum</em> via the NLRP3 inflammasome activation and displayed direct antiparasitic activity. Plaque assays confirmed significant inhibition of <em>N. caninum</em> growth, and niclosamide effectively reduced cell invasion and intracellular proliferation compared to toltrazuril. <em>In vivo</em>, after niclosamide treatment, the body weight was regained, survival rate was increased, tissue damage was reduced, and parasite burden in tissues was significantly decreased. The numerous vacuole formations were observed in niclosamide-treated <em>N. caninum</em> tachyzoites by electron microscopy. Mitochondrial membrane potential and ATP production of <em>N. caninum</em> tachyzoites were reduced considerably by niclosamide treatment. In conclusion, niclosamide showed strong potential as a therapeutic agent for <em>N. caninum</em> infection, offering a promising treatment option for neosporosis.</div></div>","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"334 ","pages":"Article 110362"},"PeriodicalIF":2.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142787228","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":"Nuclear morphology, chromatin compaction, and epigenetic changes in lymphocytes of dogs infected with Ehrlichia canis","authors":"Caio Rafael Siqueira Vasconcelos,&nbsp;Maysa Barbosa de Almeida,&nbsp;Caroline Pedroso de Oliveira,&nbsp;Jhuan Luiz Silva,&nbsp;Fernanda Gosuen Gonçalves Dias,&nbsp;Marcela Aldrovani Rodrigues","doi":"10.1016/j.vetpar.2024.110385","DOIUrl":"10.1016/j.vetpar.2024.110385","url":null,"abstract":"<div><div>Canine monocytic ehrlichiosis (CME), induced by <em>Ehrlichia canis</em>, is an important infectious disease in dogs, characterized by various clinical signs and consequent immune dysfunction. This study aimed to characterize nuclear morphology, chromatin compaction, histone H3 acetylation, and DNA methylation in lymphocytes from dogs naturally infected with <em>E. canis</em>, compared with healthy controls. A total of 30 dogs were included in this study, comprising 15 healthy dogs and 15 dogs with confirmed <em>E. canis</em> infection, verified through polymerase chain reaction. Blood samples were collected from these dogs to isolate peripheral blood mononuclear cells. The isolated cells were prepared into smears and stained using the Feulgen reaction for subsequent analysis. These stained smears underwent video imaging analysis to assess nuclear morphology and chromatin parameters. Additionally, lymphocytes isolated from the PBMCs were analyzed to quantify global levels of histone H3 acetylation and DNA methylation. The results indicated significant increases in nuclear size and alterations in chromatin architecture in the lymphocytes of dogs with <em>E. canis</em> infection. A significant reduction in histone H3 acetylation was observed in this group, suggesting a potential mechanism of transcriptional repression. In contrast, no significant differences in DNA methylation were detected between the infected dogs and the healthy controls. In conclusion, our findings reveal distinct morphological and epigenetic alterations in lymphocytes associated with <em>E. canis</em> infection, thereby enhancing the understanding of the immune dysfunction observed in dogs with CME.</div></div>","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"334 ","pages":"Article 110385"},"PeriodicalIF":2.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142898356","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":"Failure of doramectin and ivermectin in preventing Cochliomyia hominivorax myiasis in a subtropical region: A pharmacokinetic-pharmacodynamic study","authors":"Sebastián Muchiut ,&nbsp;María Victoria Miró ,&nbsp;Oscar Anziani ,&nbsp;Santiago Nava ,&nbsp;Adrián Lifschitz","doi":"10.1016/j.vetpar.2024.110384","DOIUrl":"10.1016/j.vetpar.2024.110384","url":null,"abstract":"<div><div>The aim of this work is to present a case study where the failure of IVM 3.15 % and DRM 1 % to prevent natural infestations of <em>C. hominivorax</em> larvae in Argentina is investigated based on field efficacy tests and a pharmacokinetic and pharmacodynamic analysis. Thirty male crossbred Braford calves were randomly assigned to three experimental groups (n = 10), the IVM 3.15 % group (subcutaneously at 630 µg/kg), the DRM 1 % group (subcutaneously at 200 µg/kg) and the control group (saline solution subcutaneously). All treatments were performed at the time of castration surgery through a scrotal incision, and the wounds were exposed to natural infestations of <em>C. hominivorax</em>. Wound inspections were carried out on days 3, 6, and 13 post-treatments. Jugular blood samples were taken from experimental animals at 3- and 6-days post-treatment. In presence of <em>C. hominivorax</em> larvae, samples of both the larvae and wound secretions were collected in plastic vials on days 3 and 6 to measure concentrations of both drugs by high-performance liquid chromatography. On day 3 post-treatment, active myiasis was observed in 9 animals from the control group, 5 from the IVM 3.15 % group, and 6 from the DRM 1 % group. On day 6 post-treatment, 5 and 3 new myiasis were detected in the IVM 3.15 % and DRM 1 % group, respectively. No larvae were observed in the wounds on day 13 post-treatment. Interestingly, DRM concentrations tended to be higher in larvae compared to IVM on day 3 post-treatment (p = 0.051), and IVM plasma concentrations tended to be higher than those measured for DRM on day 6 (p = 0.087). There was a very strong correlation between DRM and IVM concentrations in plasma and wound secretions and larvae. The uptake of DRM from wound secretions to larvae was 83 % greater than that of IVM (p = 0.03). The results of this trial suggest the presence of <em>C. hominivorax</em> resistance to DRM and highlight concern about the lack of effectiveness of IVM 3.15 % in preventing <em>C. hominivorax</em> infestations.</div></div>","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"334 ","pages":"Article 110384"},"PeriodicalIF":2.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142903564","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":"Antiparasitic effect of (+)-catechin derived from Pseudolarix amabilis against Dactylogyrus intermedius in goldfish","authors":"Jie Ji ,&nbsp;Xiang Gong ,&nbsp;Guanglu Liu ,&nbsp;Shaowu Yin ,&nbsp;Fei Ling ,&nbsp;Gaoxue Wang","doi":"10.1016/j.vetpar.2025.110399","DOIUrl":"10.1016/j.vetpar.2025.110399","url":null,"abstract":"<div><div>Medicinal plants are considered promising candidates for controlling parasitic pathogen in aquaculture. Our previous study demonstrated that the crude extracts of <em>Pseudolarix amabilis</em> exhibit promising anti<em>-Dactylogyrus intermedius</em> activity. However, the specific compounds responsible for the antiparasitic effects of these crude extracts remain elusive. In this study, the bioactive compounds from the ethyl acetate extract of <em>P. amabilis</em> were isolated by the multi-column chromatography and <em>in vivo</em> bioassay-guided methods. Two crystalline compounds were identified as (+)-catechin through the nuclear magnetic resonance spectroscopy and specific rotation analysis. (+)-Catechin showed 98.1 % antiparasitic activity at 20 mg/L with the median effective concentration (EC₅₀) of 4.3 mg/L. The 96 h median lethal concentration (LC₅₀) of (+)-catechin for zebrafish larvae and goldfish was determined to be 32.9 and 152.8 mg/L, respectively. The therapeutic index (TI) of (+)-catechin was 6.8 and 35.5, indicating a potential for safe application in aquaculture. These findings suggest that (+)-catechin could be further developed as a viable therapeutic agent against <em>D. intermedius</em>.</div></div>","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"334 ","pages":"Article 110399"},"PeriodicalIF":2.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143012657","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":"Establishment of the complete life cycle of Calicophoron daubneyi under experimental conditions","authors":"Christoph Wenzel ,&nbsp;Verena K. Elbert ,&nbsp;Sandra Haug ,&nbsp;Katja Voigt ,&nbsp;Frank Weber ,&nbsp;Viktoria Balasopoulou ,&nbsp;Eva Roden ,&nbsp;Yury Zablotski ,&nbsp;Markus Meissner ,&nbsp;Gabriela Knubben-Schweizer","doi":"10.1016/j.vetpar.2025.110391","DOIUrl":"10.1016/j.vetpar.2025.110391","url":null,"abstract":"<div><div>The complex life cycle of the rumen fluke <em>Calicophoron daubneyi</em> is similar to that of the liver fluke <em>Fasciola hepatica</em>. Interestingly, <em>C. daubneyi</em> and <em>F. hepatica</em> share the same intermediate host, <em>Galba truncatula</em>. However, in contrast to its relative, experimental production of metacercariae is a major challenge for <em>C. daubneyi</em>, hampering a detailed analysis of its life cycle, especially in the definitive host. <em>G. truncatula</em> snails collected from natural habitats were bred in glass Petri dishes and fed dried organic lettuce leaves. <em>C. daubneyi</em> eggs were obtained from feces of naturally infected cattle and incubated until miracidia were hatching. Subsequently, these miracidia were allowed to infect snails, which were kept under specific laboratory conditions to monitor the shedding of metacercariae. In total, 177 <em>G. truncatula</em> snails were exposed to <em>C. daubneyi</em> miracidia during eleven snail infection trials. Sixty-eight of these snails survived for longer than 30 days post-infection (p.i.). From day 35 p.i., seven snails from five trials started shedding an average number of 106 metacercariae (range: 38–186) per snail. Three ewe lambs (aged 7–10 months) were inoculated orally with 150 metacercariae each. A different batch of metacercariae (obtained from three different snail trials) was used for each lamb. Another two lambs served as controls. All animals were regularly examined clinically, hematologically and coproscopically, using sedimentation techniques for the detection of trematode eggs. Low numbers of <em>C. daubneyi</em> eggs were detected in fecal samples of two of the three inoculated lambs on day 86 post-inoculation (yielding ≤ 2 epg), but only one lamb continued to shed eggs (up to 6 epg) until the end of the experiment (day 104 post-inoculation). None of the animals showed any abnormal clinical findings or blood parameters throughout the course of the study. Production of <em>C. daubneyi</em> metacercariae under laboratory conditions is reported, followed by experimental infection of the definitive host, thus completing the full life cycle of this parasite under experimental conditions. However, neither the survival rate of the snails nor the amount of metacercariae produced were comparable to previously published experiments using <em>F. hepatica</em>, necessitating further optimization of the laboratory protocols. Nevertheless, the results can serve as a starting point for more in-depth studies of this increasingly important trematode.</div></div>","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"334 ","pages":"Article 110391"},"PeriodicalIF":2.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143012728","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":"First report of acute, visceral, fatal toxoplasmosis in a naturally infected calf (Bos taurus)","authors":"Jitender P. Dubey ,&nbsp;Alan F. Julian","doi":"10.1016/j.vetpar.2024.110373","DOIUrl":"10.1016/j.vetpar.2024.110373","url":null,"abstract":"<div><div>Cattle are considered resistant to clinical toxoplasmosis and viable <em>Toxoplasma gondii</em> is rarely isolated from bovine tissues. Currently, there is no histologically confirmed case of clinical toxoplasmosis in cattle. Here, the first confirmed case of acute toxoplasmosis in cattle is reported. A calf from New Zealand died of acute toxoplasmosis in 2012. Severe lesions were found in the intestinal mesentery and mesenteric lymph nodes. The mesenteric lymph nodes were edematous, and necrosis affected the entire parenchyma including blood vessels, associated with enormous numbers of tachyzoites. Lesions in liver were inflammatory, affecting periportal areas and central veins. Some hepatocytes were engorged with tachyzoites, and tissue cysts were present in the parenchyma. Focal pneumonitis and nephritis were associated with tachyzoites. Tachyzoites were seen in bronchioles, in renal glomeruli and in renal tubules. Diagnosis was confirmed immunohistochemically using <em>T. gondii</em> specific antibodies, but not <em>Neospora caninum -</em>specific antibodies. The presence of numerous tissue cysts was confirmed by immunohistochemical staining with bradyzoite-specific <em>T. gondii</em> antibodies (BAG1).</div></div>","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"334 ","pages":"Article 110373"},"PeriodicalIF":2.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142814469","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 fipronil efficacy and first molecular report of gamma-aminobutyric acid (GABA) gated chloride channel gene of Rhipicephalus microplus ticks in China and Pakistan","authors":"Muhammad Kashif Obaid ,&nbsp;Qiaoyun Ren ,&nbsp;Jin Luo ,&nbsp;Jinming Wang ,&nbsp;Muhammad Rashid ,&nbsp;Jehan Zeb ,&nbsp;Xiaoqing Zan ,&nbsp;Xinting Lan ,&nbsp;Guangyuan Liu ,&nbsp;Jianxun Luo ,&nbsp;Hong Yin ,&nbsp;Ze Chen ,&nbsp;Guiquan Guan","doi":"10.1016/j.vetpar.2025.110407","DOIUrl":"10.1016/j.vetpar.2025.110407","url":null,"abstract":"<div><div>Southern cattle tick, <em>Rhipicephalus</em> (<em>R</em>) <em>microplus</em>, is a major challenge in transmitting <em>Babesia</em> spp., <em>Theileria</em> spp., and <em>Anaplasma</em> spp., worldwide. Mitigation of this tick and associated pathogens is crucial for animal and human-health. In present study, laboratory-based larval packet tests (LPTs) were performed to assess fipronil efficacy against <em>R</em>. <em>microplus</em> ticks collected from four Chinese localities, Nanning, Guangshui, Macheng, and Tengchong. Additionally, we reported first molecular characterization of the full-length gamma-aminobutyric acid (GABA)-gated chloride channel gene of <em>R</em>. <em>microplus</em> ticks from China and Pakistan (Khyber Pakhtunkhwa and Punjab). For LPTs bioassay, fipronil’s concentrations (5-ppm, 25-ppm, 50-ppm, 75-ppm, 100-ppm) in acetone and DNase-free water were prepared. The highest average mortality rate of larvae was observed in Nanning (4.34–98.13 %) while lowest in Tengchong (5.70–82.29 %) via triplicate LPTs. The recorded LC₅₀ values were 33.2 ppm, 35.7 ppm, 49.7 ppm, and 55.4 ppm, respectively, for the four localities (Guangshui, Macheng, Nanning, and Tengchong) while the LC₉₉ values were 722 ppm, 827 ppm, 949 ppm, and 1342.3 ppm, respectively. The resistance factors (RR₅₀) were 13.83, 14.88, 20.71, and 23.08, indicating the development of level-II resistance in the tick populations from these regions respectively. Molecularly, consensus sequences of <em>R</em>. <em>microplus</em> GABA-gene from China and Pakistan resulted 99.24–99.52 % and 99.10–99.39 % identities with dieldrin-susceptible NRFS (GQ398111.1) and dieldrin-resistant (GQ398112.1) <em>R</em>. <em>microplus</em> ticks, respectively. Findings revealed 21 single nucleotide polymorphisms (SNPs) [8-non-synonymous (NS) and 13-synonymous (S)], including specifically 10-SNPs from Nanning, 9-SNPs from Macheng, 7-SNPs from Guangshui, 10-SNPs from Tengchong, and 9-SNPs from Pakistani <em>R. microplus</em> full-length GABA gene. Explicitly, we obtained one NS-SNP in TM3 (T-871-G; F-291-V) and two NS-SNPs in TM4 (A-1438-G; N-480-D and A-1439-G; N-480-G) regions of Chinese and Pakistani, while one NS-SNP in TM2 (A-763-G; T-255-A) region of Pakistani <em>R</em>. <em>microplus</em> ticks was documented. Coexistence among SNPs in TM3 (T-871-G; F-291-V), TM4 (A-1439-G; N-480-G) and one linker SNP (A-1378-G; S-460-G) were also recorded. Presence of SNPs and their coexistence suggest the possible tri-dimensional structural modification in GABA-Cl channels that might interfere with binding of fipronil, resulting in development of resistance. This comprehensive research will provide a basis for governmental and pharmaceutical industries for development of effective tick control-strategies as well as to manage the effectiveness and functionality of the available acaricides.</div></div>","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"334 ","pages":"Article 110407"},"PeriodicalIF":2.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143080323","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":"An RPA-CRISPR/Cas12a-assisted method for nucleic acid detection of Haemonchus contortus in sheep","authors":"Yutong Cao ,&nbsp;Qiankun Yang ,&nbsp;Yanbing Guo ,&nbsp;Xiaoceng Wang ,&nbsp;Xin Li ,&nbsp;Nan Zhang ,&nbsp;Wenxue Lu ,&nbsp;Jianhua Li ,&nbsp;Xichen Zhang ,&nbsp;Lili Cao ,&nbsp;Pengtao Gong","doi":"10.1016/j.vetpar.2025.110421","DOIUrl":"10.1016/j.vetpar.2025.110421","url":null,"abstract":"<div><div><em>Haemonchus contortus</em> (<em>H. contortus),</em> a highly pathogenic and blood-feeding nematode, could cause haemonchosis，resulting in tens of billions of dollars in production losses and significantly impacting the development of sheep husbandry. Rapid and accurate detection methods were particularly important for the prevention and control of haemonchosis. In this study, we developed a one-pot effective detection method that integrating recombinase polymerase amplification (RPA) with CRISPR/Cas12a technology based on the conserved region of <em>ITS2</em> of <em>H. contortus</em>, with readout through fluorescence signals visualized by lateral flow strips (LFS) and observable under UV or blue light. The detection procedure was successfully finished in within 1 h and demonstrated high specificity and sensitivity, with no cross-reactivity detected with nine other common ovine pathogens and a detection limit as low as 0.1 copies/μL for fluorescence and 100 copies/μL for LFS. Validation with 89 sheep fecal samples revealed a 46.07 % positivity rate, fully consistent with quantitative PCR results. In summary, the RPA-CRISPR/Cas12a method for <em>H. contortus</em> detection exhibited the advantages of high specificity, high sensitivity, and low device dependence, portable and visible results. The technique presented significant potential for large-scale clinical application and provided novel point-of-care testing for clinical use in remote rural and resource-constrained areas.</div></div>","PeriodicalId":23716,"journal":{"name":"Veterinary parasitology","volume":"334 ","pages":"Article 110421"},"PeriodicalIF":2.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143419856","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}