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Benito AA, Anía S, Ramo MDLÁ, Baselga C, Quílez J, Tejedor MT, Monteagudo LV. Molecular Diagnosis of Footrot and Contagious Ovine Digital Dermatitis in Small Ruminants in the Iberian Peninsula. Animals (Basel) 2024; 14:481. [PMID: 38338124 PMCID: PMC10854840 DOI: 10.3390/ani14030481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 01/16/2024] [Accepted: 01/30/2024] [Indexed: 02/12/2024] Open
Abstract
Contagious ovine digital dermatitis (CODD) and footrot (FR), a sub-acute or acute necrotic (decaying) infectious disease involving the hoof and underlying tissues, pose economic challenges to herds in Spain and worldwide. The aetiological agent for FR is Dichelobacter nodosus, while CODD is caused by pathogenic Treponema phylogroups. We detail the findings derived from the analysis by qPCR of 105 pooled samples from 100 ovine and five caprine herds in Spain and Portugal, alongside 15 samples from healthy flocks in order to identify Dichelobacter nodosus, Fusobacterium necrophorum, Treponema spp., and three pathogenic Treponema phylogroups (T. phagedenis, T. medium, and T. pedis). Treponema spp. were detected in all 120 pools, including samples from the 15 healthy flocks where only one positive result for F. necrophorum was recorded. Mixed infections by agents different from Treponema spp. were identified in 68.57% of samples. Positive results for F. necrophorum and/or D. nodosus, were obtained for 91.4% of the pools, whereas the presence of the three pathogenic Treponema phylogroups was rare: each of them appeared in isolation in a single pool, while they were found in 18 pools in combination with other agents. While F. necrophorum was the sole finding in 16.2% of samples from affected herds, D. nodosus (the footrot causative agent) was only detected in 61% of affected farms. An improved qPCR protocol was implemented to determine the serogroups of D. nodosus in the samples and found all of them (except the G serogroup), often in combined infections (35.1%). This report concludes with comprehensive proposals for diagnosing, preventing, and treating hoof ailments, remarking the interest of the information about D. nodosus serogroups in order to improve the efficiency of immunization by choosing appropriate vaccine protocols.
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Affiliation(s)
- Alfredo A. Benito
- Exopol S.L., Pol Río Gállego D/14, San Mateo de Gállego, 50840 Zaragoza, Spain; (A.A.B.); (S.A.); (C.B.)
| | - Silvia Anía
- Exopol S.L., Pol Río Gállego D/14, San Mateo de Gállego, 50840 Zaragoza, Spain; (A.A.B.); (S.A.); (C.B.)
| | - María de los Ángeles Ramo
- Department of Animal Pathology, Faculty of Veterinary Sciences, University of Zaragoza, 50013 Zaragoza, Spain;
| | - Cristina Baselga
- Exopol S.L., Pol Río Gállego D/14, San Mateo de Gállego, 50840 Zaragoza, Spain; (A.A.B.); (S.A.); (C.B.)
| | - Joaquín Quílez
- Agrifood Institute of Aragón (IA2), University of Zaragoza-Centro de Investigación y Tecnología Alimentaria de Aragón (CITA), 50013 Zaragoza, Spain;
- Department of Anatomy, Embriology and Genetics, Faculty of Veterinary Sciences, University of Zaragoza, 50013 Zaragoza, Spain;
| | - María Teresa Tejedor
- Department of Anatomy, Embriology and Genetics, Faculty of Veterinary Sciences, University of Zaragoza, 50013 Zaragoza, Spain;
- Aragon Institute of Health Sciences (IACS), Centro de Investigación Biomédica en Red-Enfermedades Cardiovasculares (CIBERCV), 50009 Zaragoza, Spain
| | - Luis Vicente Monteagudo
- Agrifood Institute of Aragón (IA2), University of Zaragoza-Centro de Investigación y Tecnología Alimentaria de Aragón (CITA), 50013 Zaragoza, Spain;
- Department of Anatomy, Embriology and Genetics, Faculty of Veterinary Sciences, University of Zaragoza, 50013 Zaragoza, Spain;
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Gaspar D, Ginja C, Carolino N, Leão C, Monteiro H, Tábuas L, Branco S, Padre L, Caetano P, Romão R, Matos C, Ramos AM, Bettencourt E, Usié A. Genome-wide association study identifies genetic variants underlying footrot in Portuguese Merino sheep. BMC Genomics 2024; 25:100. [PMID: 38262937 PMCID: PMC10804546 DOI: 10.1186/s12864-023-09844-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 11/26/2023] [Indexed: 01/25/2024] Open
Abstract
BACKGROUND Ovine footrot caused by Dichelobacter nodosus (D. nodosus) is a contagious disease with serious economic and welfare impacts in sheep production systems worldwide. A better understanding of the host genetic architecture regarding footrot resistance/susceptibility is crucial to develop disease control strategies that efficiently reduce infection and its severity. A genome-wide association study was performed using a customized SNP array (47,779 SNPs in total) to identify genetic variants associated to footrot resistance/susceptibility in two Portuguese native breeds, i.e. Merino Branco and Merino Preto, and a population of crossbred animals. A cohort of 1375 sheep sampled across 17 flocks, located in the Alentejo region (southern Portugal), was included in the analyses. RESULTS Phenotypes were scored from 0 (healthy) to 5 (severe footrot) based on visual inspection of feet lesions, following the Modified Egerton System. Using a linear mixed model approach, three SNPs located on chromosome 24 reached genome-wide significance after a Bonferroni correction (p < 0.05). Additionally, six genome-wide suggestive SNPs were identified each on chromosomes 2, 4, 7, 8, 9 and 15. The annotation and KEGG pathway analyses showed that these SNPs are located within regions of candidate genes such as the nonsense mediated mRNA decay associated PI3K related kinase (SMG1) (chromosome 24) and the RALY RNA binding protein like (RALYL) (chromosome 9), both involved in immunity, and the heparan sulfate proteoglycan 2 (HSPG2) (chromosome 2) and the Thrombospodin 1 (THBS1) (chromosome 7) implicated in tissue repair and wound healing processes. CONCLUSION This is the first attempt to identify molecular markers associated with footrot in Portuguese Merino sheep. These findings provide relevant information on a likely genetic association underlying footrot resistance/susceptibility and the potential candidate genes affecting this trait. Genetic selection strategies assisted on the information obtained from this study could enhance Merino sheep-breeding programs, in combination with farm management strategies, for a more effective and sustainable long-term solution for footrot control.
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Affiliation(s)
- Daniel Gaspar
- Centro de Biotecnologia Agrícola E Agro-Alimentar Do Alentejo (CEBAL)/ Instituto Politécnico de Beja (IPBeja), 7801-908, Beja, Portugal
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Universidade do Porto, Campus de Vairão, R. Padre Armando Quintas 7, 4485-661, Vairão, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, Campus do Varão, Campus de Vairão, R. Padre Armando Quintas 7, 4485-661, Vairão, Portugal
| | - Catarina Ginja
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Universidade do Porto, Campus de Vairão, R. Padre Armando Quintas 7, 4485-661, Vairão, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, Campus do Varão, Campus de Vairão, R. Padre Armando Quintas 7, 4485-661, Vairão, Portugal
- CIISA, Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, Av. Universidade Técnica, 1300-477, Lisboa, Portugal
| | - Nuno Carolino
- CIISA, Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, Av. Universidade Técnica, 1300-477, Lisboa, Portugal
- Instituto Nacional de Investigação Agrária E Veterinária, I.P. (INIAV, I.P.), Avenida da República, Quinta Do Marquês, 2780-157, Oeiras, Portugal
- Escola Universitária Vasco da Gama, Av. José R. Sousa Fernandes 197, 3020-210, Lordemão, Coimbra, Portugal
| | - Célia Leão
- Centro de Biotecnologia Agrícola E Agro-Alimentar Do Alentejo (CEBAL)/ Instituto Politécnico de Beja (IPBeja), 7801-908, Beja, Portugal
- Instituto Nacional de Investigação Agrária E Veterinária, I.P. (INIAV, I.P.), Avenida da República, Quinta Do Marquês, 2780-157, Oeiras, Portugal
- MED - Mediterranean Institute for Agriculture, Environment and Development and CHANGE - Global Change and Sustainability Institute, CEBAL - Centro de Biotecnologia Agrícola e Agro-Alimentar do Alentejo, 7801-908, Beja, Portugal
| | | | | | - Sandra Branco
- MED-Mediterranean Institute for Agriculture, Environment and Development and CHANGE - Global Change and Sustainability Institute, University of Évora, Polo da Mitra, Ap. 94, 7006-554, Évora, Portugal
- Departamento de Medicina Veterinária, Escola de Ciências E Tecnologia, Évora University, Pólo da Mitra Ap. 94, 7002-554, Évora, Portugal
| | - Ludovina Padre
- MED-Mediterranean Institute for Agriculture, Environment and Development and CHANGE - Global Change and Sustainability Institute, University of Évora, Polo da Mitra, Ap. 94, 7006-554, Évora, Portugal
| | - Pedro Caetano
- MED-Mediterranean Institute for Agriculture, Environment and Development and CHANGE - Global Change and Sustainability Institute, University of Évora, Polo da Mitra, Ap. 94, 7006-554, Évora, Portugal
| | - Ricardo Romão
- MED-Mediterranean Institute for Agriculture, Environment and Development and CHANGE - Global Change and Sustainability Institute, University of Évora, Polo da Mitra, Ap. 94, 7006-554, Évora, Portugal
| | | | - António Marcos Ramos
- Centro de Biotecnologia Agrícola E Agro-Alimentar Do Alentejo (CEBAL)/ Instituto Politécnico de Beja (IPBeja), 7801-908, Beja, Portugal
- MED - Mediterranean Institute for Agriculture, Environment and Development and CHANGE - Global Change and Sustainability Institute, CEBAL - Centro de Biotecnologia Agrícola e Agro-Alimentar do Alentejo, 7801-908, Beja, Portugal
| | - Elisa Bettencourt
- MED-Mediterranean Institute for Agriculture, Environment and Development and CHANGE - Global Change and Sustainability Institute, University of Évora, Polo da Mitra, Ap. 94, 7006-554, Évora, Portugal
| | - Ana Usié
- Centro de Biotecnologia Agrícola E Agro-Alimentar Do Alentejo (CEBAL)/ Instituto Politécnico de Beja (IPBeja), 7801-908, Beja, Portugal.
- MED - Mediterranean Institute for Agriculture, Environment and Development and CHANGE - Global Change and Sustainability Institute, CEBAL - Centro de Biotecnologia Agrícola e Agro-Alimentar do Alentejo, 7801-908, Beja, Portugal.
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Serological Diversity of Dichelobacter nodosus in German Sheep Flocks. Animals (Basel) 2022; 12:ani12060753. [PMID: 35327150 PMCID: PMC8944645 DOI: 10.3390/ani12060753] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 03/13/2022] [Accepted: 03/14/2022] [Indexed: 12/04/2022] Open
Abstract
Simple Summary Footrot is an infectious hoof disease in sheep, caused by the bacterium Dichelobacter nodosus. The antigentic variation of the fimbrial proteins resulted in the description of up to ten serogroups (A–I and M). Vaccines against footrot target these fimbrial variants. Commercial vaccines are covering nine serogroups but have low efficacy compared to vaccines based on two serogroups. Therefore, our study investigated the prevalence and distribution of the nine serogroups A–I in German sheep flocks with the aim to detect the predominant serogroups guiding optimized vaccines based on two serogroups. Serogroup A was most common in our study, followed by serogroups B, H and C. More than one-third of the animals showed more than one serogroup. In flocks, we found, on average, 3.10 serogroups in a range of one to six. The nine serogroups were widely distributed across the flocks, with 50 different combinations across the 83 flocks investigated. The lack of two predominant serogroups in Germany impairs the nationwide protection against footrot by the usage of more efficient vaccines based on two serogroups and requires tailor-made flock-specific vaccines. Abstract Footrot is one of the major causes of lameness in sheep and leads to decreased animal welfare and high economic losses. The causative agent is the Gram-negative anaerobic bacterium Dichelobacter nodosus. The prevalence of D. nodosus in 207 sheep flocks across Germany was 42.9%. Based on the sequence variation in the type IV fimbrial gene fimA, D. nodosus can be subdivided into ten serogroups (A–I and M). There are commercially available vaccines covering nine serogroups, but the efficacy is low compared to bivalent vaccines. The aim of this study was to investigate the diversity of serogroups in Germany at the flock and animal levels. In total, we detected at least one serogroup in 819 samples out of 969 D. nodosus-positive samples from 83 flocks using serogroup-specific singleplex PCR for the serogroups A–I. Serogroup A was most prevalent at the animal level, followed by serogroups B, H and C. At the flock level, serogroups A and B had the highest prevalence, each with 64%, but only 40% of flocks had both. The average number of serogroups per animal was 1.42 (range one to five) and, per flock, 3.10 (range one to six). The serogrouping showed within-flock specific clusters but were widely distributed, with 50 different combinations across the flocks. The factors associated with the number of serogroups per animal and single serogroups were the load of D. nodosus, footrot score, sheep breed and flock. Our results indicate that efficient vaccination programs would benefit from tailor-made flock-specific vaccines and regular monitoring of circulating serotypes in the flock to be able to adjust vaccine formulations for nationwide progressive control of footrot in Germany.
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Smith KJ, Whittington RJ, Corrigan MA, Edmonstone BI, Cronin NA, Dhand NK, Dhungyel OP. Efficacy of bivalent fimbrial vaccines to control and eliminate intermediate forms of footrot in sheep. Aust Vet J 2021; 100:121-129. [PMID: 34897647 DOI: 10.1111/avj.13138] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 11/16/2021] [Accepted: 11/19/2021] [Indexed: 11/29/2022]
Abstract
OBJECTIVE The aim of this study was to determine the efficacy of serogroup-specific bivalent fimbrial vaccines in the control and elimination of relatively mild (intermediate) forms of footrot in sheep flocks in NSW, there being some evidence that such forms are difficult to control. METHODS Four flocks of sheep with history of footrot of intermediate virulence were selected based on clinical and bacteriological diagnoses. Dichelobacter nodosus serogroups included in bivalent vaccines at each farm were based on on-farm serogroup-prevalence data. Two doses of bivalent vaccine were administered with a 4-week interval between doses. Repeated post-vaccination inspections of all feet of between 100 and 119 animals per mob were conducted and foot swabs were collected for bacteriological testing. Blood samples were collected from 10 to 24 individually identified animals per flock at each inspection to check for agglutinating antibody responses. RESULTS In the majority of animals, antibody levels for serogroups included in each vaccine were above the level believed to be required for protective immunity. Footrot disappeared on farm 1 prior to vaccination, but did not reappear postvaccination. Footrot was controlled but not eliminated on farms 2, 3, and 4, where the prevalence and severity of the disease and number of serogroups present were reduced. CONCLUSION Serogroup-specific bivalent vaccines can be effective at controlling footrot caused by intermediate strains of D. nodosus.
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Affiliation(s)
- K J Smith
- Farm Animal Health, Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camden, New South Wales, 2570, Australia
| | - R J Whittington
- Farm Animal Health, Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camden, New South Wales, 2570, Australia
| | - M A Corrigan
- Murray LLS, Albury, New South Wales, 2640, Australia
| | - B I Edmonstone
- Central West LLS, Forbes, New South Wales, 2871, Australia
| | - N A Cronin
- Central West LLS, Forbes, New South Wales, 2871, Australia
| | - N K Dhand
- Farm Animal Health, Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camden, New South Wales, 2570, Australia
| | - O P Dhungyel
- Farm Animal Health, Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camden, New South Wales, 2570, Australia
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Qureshi S, Wani SA, Farooq S, Kashoo Z, Bhat B, Isfaqul Hussain M, Habib A, Altaf Bhat M, Khan SM, Pandit AA, Malla JA, Dar BA. Genome sequence of Dichelobacter nodosus JKS-07B isolate from J&K, India associated with virulent footrot of sheep. Sci Prog 2021; 104:368504211057678. [PMID: 34904916 PMCID: PMC10358635 DOI: 10.1177/00368504211057678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
INTRODUCTION Virulent footrot of sheep caused by Dichelobacter nodosus is associated with tremendous economic losses due to recurrent treatment costs and increased culling rates. This organism being a fastidious anaerobe is difficult to isolate on ordinary media that does not support its growth. The D. nodosus serogroup B isolate described in the present study has been used in the preparation of the whole-cell killed vaccine against footrot in India. D. nodosus serogroup B is the predominant serogroup involved in virulent footrot (lesion score 4) in India as well as in many sheep-rearing countries of the globe. METHODS Genomic DNA was extracted using wizard Genomic DNA purification kit. The whole genome of the D. nodosus strain B was sequenced using an Illumina HiSeq 2500 platform and annotated according to functional gene categories. Annotations were performed using in-house developed Perl scripts using Nr/Nt database, uniprot, Pfam, KEGG, Panther DB, and GO database. RESULT The assembled genome size is 1.311,533 Mb and GC content is 44.38. A total of 1215 protein-coding genes, 44tRNA and 7 rRNA were identified. The genome shows 98.63% sequence homology with the reference genome. However, 21 new genes have been identified in this genome. The information will provide insights into the various genes and regulators necessary for D. nodosus growth and survival. DISCUSSION The genome information of this serogroup B of D. nodosus isolate involved in 85-90% cases of virulent footrot of sheep in India provides further insights for improvement of the killed vaccine (B serogroup) developed recently in India. For the development of an efficacious vaccine against virulent footrot, it is essential to know the serological diversity as well as the virulent status of the strains of the D. nodosus. This serogroup isolate is a potential vaccine candidate to mitigate ovine footrot in India as the majority of virulent footrot cases belong to serogroup B of D. nodosus.
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Affiliation(s)
- Sabia Qureshi
- Anaerobic Laboratory, Division of Veterinary Microbiology & Immunology, FVSc & A.H, Shuhama (Aulesteng) SKUAST-K, India
| | - Shakil A Wani
- Anaerobic Laboratory, Division of Veterinary Microbiology & Immunology, FVSc & A.H, Shuhama (Aulesteng) SKUAST-K, India
| | - Shaheen Farooq
- Anaerobic Laboratory, Division of Veterinary Microbiology & Immunology, FVSc & A.H, Shuhama (Aulesteng) SKUAST-K, India
| | - Zahid Kashoo
- Anaerobic Laboratory, Division of Veterinary Microbiology & Immunology, FVSc & A.H, Shuhama (Aulesteng) SKUAST-K, India
| | - Basharat Bhat
- Division of Animal Genetics and Breeding, FVSc & A.H, Shuhama (Aulesteng) SKUAST-K, India
| | - Mohammad Isfaqul Hussain
- Anaerobic Laboratory, Division of Veterinary Microbiology & Immunology, FVSc & A.H, Shuhama (Aulesteng) SKUAST-K, India
| | - Aasim Habib
- Anaerobic Laboratory, Division of Veterinary Microbiology & Immunology, FVSc & A.H, Shuhama (Aulesteng) SKUAST-K, India
| | - Mohd Altaf Bhat
- Anaerobic Laboratory, Division of Veterinary Microbiology & Immunology, FVSc & A.H, Shuhama (Aulesteng) SKUAST-K, India
| | - Shafkat Majeed Khan
- Anaerobic Laboratory, Division of Veterinary Microbiology & Immunology, FVSc & A.H, Shuhama (Aulesteng) SKUAST-K, India
| | - Arif Ahmad Pandit
- Anaerobic Laboratory, Division of Veterinary Microbiology & Immunology, FVSc & A.H, Shuhama (Aulesteng) SKUAST-K, India
| | - Javeed A Malla
- Anaerobic Laboratory, Division of Veterinary Microbiology & Immunology, FVSc & A.H, Shuhama (Aulesteng) SKUAST-K, India
| | - Bilal Ahmad Dar
- Anaerobic Laboratory, Division of Veterinary Microbiology & Immunology, FVSc & A.H, Shuhama (Aulesteng) SKUAST-K, India
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Maier G, O'Connor AM, Sheedy D. The Evidence Base for Prevention of Infectious Bovine Keratoconjunctivitis Through Vaccination. Vet Clin North Am Food Anim Pract 2021; 37:341-353. [PMID: 34049664 DOI: 10.1016/j.cvfa.2021.03.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Pili and cytotoxins are important virulence factors and antigens for Moraxella spp. Local and systemic immunity may play a role in the body's response to infectious bovine keratoconjunctivitis (IBK). No evidence exists that eliminating the carrier state for IBK is possible or beneficial. Evidence for efficacious transfer of passive immunity from dams to calves is conflicting. Autogenous vaccines and commercial vaccines for putative pathogens for IBK have not yet shown efficacy in blinded randomized field trials. Study design features, such as randomization, blinding, diagnostic criteria, and use of a placebo, reduce the risk of bias in vaccine studies for IBK.
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Affiliation(s)
- Gabriele Maier
- Department of Population Health & Reproduction, School of Veterinary Medicine, University of California Davis, Davis, 1 Shieds Avenue, VM3B, Davis, CA 95616, USA
| | - Annette M O'Connor
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, 784 Wilson Road Room D-204, East Lansing, MI 48824-1314, USA.
| | - David Sheedy
- Veterinary Medicine Teaching and Research Center, School of Veterinary Medicine, University of California Davis, 18830 Road 112, Tulare, CA 93274, USA
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Vaccination against pathogenic clostridia in animals: a review. Trop Anim Health Prod 2021; 53:284. [PMID: 33891221 PMCID: PMC8062623 DOI: 10.1007/s11250-021-02728-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 04/12/2021] [Indexed: 12/02/2022]
Abstract
Clostridium is a Gram-positive, rod-shaped, anaerobic, and spore-forming bacterium, which is found in the surrounding environments throughout the world. Clostridium species cause botulism, tetanus, enterotoxaemia, gas gangrene, necrotic enteritis, pseudomembranous colitis, blackleg, and black disease. Clostridium infection causes severe economic losses in livestock and poultry industries. Vaccination seems to be an effective way to control Clostridial diseases. This review discusses the toxins and vaccine development of the most common pathogenic Clostridium species in animals, including Clostridium perfringens, Clostridium novyi, Clostridium chauvoei, and Clostridium septicum. In this comprehensive study, we will review different kinds of clostridial toxins and the vaccines that are experimentally or practically available and will give a short description on each vaccine focusing on its applications, advantages, and disadvantages.
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Zanolari P, Dürr S, Jores J, Steiner A, Kuhnert P. Ovine footrot: A review of current knowledge. Vet J 2021; 271:105647. [PMID: 33840488 DOI: 10.1016/j.tvjl.2021.105647] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 02/17/2021] [Accepted: 02/18/2021] [Indexed: 12/14/2022]
Abstract
Footrot is a contagious foot disease mainly affecting sheep. It is caused by the Gram-negative anaerobic bacterium Dichelobacter nodosus. Warm, wet environmental conditions favour development of footrot, and under perfect conditions, it takes just 2-3 weeks from infection to manifestation of clinical signs. Affected sheep show lameness of various degrees and often graze while resting on their carpi. Local clinical signs vary in severity and extent from interdigital inflammation (benign footrot) to underrunning of the complete horn shoe in advanced stages of virulent footrot. Laboratory diagnosis ideally involves collection of four-foot interdigital swab samples followed by competitive real time PCR, allowing for detection of the presence of D. nodosus and differentiation between benign and virulent strains. Laboratory-based diagnostics at the flock level based on risk-based sampling and pooling of interdigital swab samples are recommended. The list of treatment options of individual sheep includes careful removal of the loose undermined horn, local or systemic administration of antimicrobials, systemic administration of non-steroidal anti-inflammatories (NSAIDs) and disinfectant footbathing. Strategies for control at the flock level are manifold and depend on the environmental conditions and the procedures traditionally implemented by the respective country. Generally, measures consist of treatment/culling of infected sheep, vaccination and prevention of reinfection of disease-free flocks. Gaining deeper insight into the beneficial effects of NSAIDs, screening for eco-friendly footbath solutions, developing better vaccines, including the development of a robust, reproducible infection model and elucidation of protective immune responses, as well as the elaboration of effective awareness training programs for sheep farmers, are relevant research gaps.
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Affiliation(s)
- Patrik Zanolari
- Clinic for Ruminants, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Salome Dürr
- Veterinary Public Health Institute, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Jörg Jores
- Institute of Veterinary Bacteriology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Adrian Steiner
- Clinic for Ruminants, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
| | - Peter Kuhnert
- Institute of Veterinary Bacteriology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
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Abstract
The relatively low economic value of small ruminants places constraints upon vaccination in these species. In general, vaccination against clostridial diseases such as enterotoxemia and tetanus are most important. Enzootic pneumonia is a major cause of losses in intensively housed sheep. Footrot is a difficult disease to control because of the extreme antigenic diversity of its causal agent. In some areas soremouth vaccination is important. Bluetongue vaccination, even though complex, is also essential in some areas. Peste de petits ruminants is a growing cause for concern over much of Africa. Goats and llamas generally require the same vaccines as sheep.
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Gelasakis AI, Kalogianni AI, Bossis I. Aetiology, Risk Factors, Diagnosis and Control of Foot-Related Lameness in Dairy Sheep. Animals (Basel) 2019; 9:E509. [PMID: 31370310 PMCID: PMC6720304 DOI: 10.3390/ani9080509] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 07/24/2019] [Accepted: 07/25/2019] [Indexed: 12/20/2022] Open
Abstract
During the last twenty years, considerable research efforts have recognized the consequences of foot-related lameness primarily in cattle, and meat and wool sheep. Despite the lack of extensive epidemiological studies, field observations and isolated research reports in dairy sheep have suggested that the problem might be more severe in semi-intensive and intensive farming systems. Footrot, contagious ovine digital dermatitis, ovine interdigital dermatitis, white line disease, and pedal joint abscess are the most common causes of foot-related lameness. Dichelobacter nodosus, Fusobacterium necrophorum, Treponema spp., and Actinomyces pyogenes are the most significant foot-related lameness-associated pathogens. Despite a documented hereditary predisposition, environmental factors are the most important in determining the occurrence of foot-related lameness. Moist and warm environment, increased parity and milk yield, inappropriate housing conditions and infrastructures, inadequate hygiene status, imbalanced nutrition, and insufficient foot care are the most critical risk factors. Furthermore, a foot-lameness control plan should include targeted implementation of claw trimming and footbathing, evidence-based planning of hygiene measures in preventive veterinary practices (i.e., antibiotic administration, vaccinations against footrot), selective breeding to footrot resistance, and, most importantly, the continuous training of farming personnel. Controlling foot-lameness in dairy sheep is critical in determining the well-being of animals, and strongly affects the farm's profitability and sustainability.
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Affiliation(s)
- Athanasios I Gelasakis
- Laboratory of Anatomy and Physiology of Farm Animals, Department of Animal Science and Aquaculture, Agricultural University of Athens (AUA), Iera Odos 75 str., GR 11855, Athens, Greece.
| | - Aphrodite I Kalogianni
- Laboratory of Anatomy and Physiology of Farm Animals, Department of Animal Science and Aquaculture, Agricultural University of Athens (AUA), Iera Odos 75 str., GR 11855, Athens, Greece
| | - Ioannis Bossis
- Laboratory of Anatomy and Physiology of Farm Animals, Department of Animal Science and Aquaculture, Agricultural University of Athens (AUA), Iera Odos 75 str., GR 11855, Athens, Greece
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Humbert MV, Jackson A, Orr CM, Tews I, Christodoulides M. Characterization of two putative Dichelobacter nodosus footrot vaccine antigens identifies the first lysozyme inhibitor in the genus. Sci Rep 2019; 9:10055. [PMID: 31296905 PMCID: PMC6624275 DOI: 10.1038/s41598-019-46506-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 06/24/2019] [Indexed: 12/17/2022] Open
Abstract
The Gram-negative anaerobic bacterium Dichelobacter nodosus (Dn) causes footrot in ruminants, a debilitating and highly contagious disease that results in necrotic hooves and significant economic losses in agriculture. Vaccination with crude whole-cell vaccine mixed with multiple recombinant fimbrial proteins can provide protection during species-specific outbreaks, but subunit vaccines containing broadly cross-protective antigens are desirable. We have investigated two D. nodosus candidate vaccine antigens. Macrophage Infectivity Potentiator Dn-MIP (DNO_0012, DNO_RS00050) and Adhesin Complex Protein Dn-ACP (DNO_0725, DNO_RS06795) are highly conserved amongst ~170 D. nodosus isolates in the https://pubmlst.org/dnodosus/ database. We describe the presence of two homologous ACP domains in Dn-ACP with potent C-type lysozyme inhibitor function, and homology of Dn-MIP to other putative cell-surface and membrane-anchored MIP virulence factors. Immunization of mice with recombinant proteins with a variety of adjuvants induced antibodies that recognised both proteins in D. nodosus. Notably, immunization with fimbrial-whole-cell Footvax vaccine induced anti-Dn-ACP and anti-Dn-MIP antibodies. Although all adjuvants induced high titre antibody responses, only antisera to rDn-ACP-QuilA and rDn-ACP-Al(OH)3 significantly prevented rDn-ACP protein from inhibiting lysozyme activity in vitro. Therefore, a vaccine incorporating rDn-ACP in particular could contribute to protection by enabling normal innate immune lysozyme function to aid bacterial clearance.
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Affiliation(s)
- Maria Victoria Humbert
- Neisseria Research Group, Molecular Microbiology, Academic Unit of Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton Faculty of Medicine, Southampton, United Kingdom
| | - Alexandra Jackson
- Neisseria Research Group, Molecular Microbiology, Academic Unit of Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton Faculty of Medicine, Southampton, United Kingdom
| | - Christian M Orr
- Beamline I23, Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, United Kingdom
| | - Ivo Tews
- Biological Sciences, Institute for Life Sciences, B85 Highfield Campus, University of Southampton, Southampton, United Kingdom
| | - Myron Christodoulides
- Neisseria Research Group, Molecular Microbiology, Academic Unit of Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton Faculty of Medicine, Southampton, United Kingdom.
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Allworth MB, Egerton JR. Comparison of footbathing and vaccination to control ovine footrot in an experimentally infected flock. Aust Vet J 2018; 96:395-399. [PMID: 30255574 DOI: 10.1111/avj.12715] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2017] [Revised: 12/12/2017] [Accepted: 12/26/2017] [Indexed: 11/27/2022]
Abstract
OBJECTIVE Compare footbathing and vaccination for control of footrot during a transmission period in a sheep flock deliberately infected with multiple strains of Dichelobacter nodosus. METHODS The strains included a known virulent strain, a benign strain and several intermediate strains. The resulting footrot was clinically intermediate. A total of 1450 Polwarth sheep aged 1-3 years were allocated to one of five treatment groups: untreated, weekly walkthrough zinc sulfate footbathing, 1-hour stand-in Footrite® footbathing every 3 weeks, vaccination with a commercial multivalent whole-cell vaccine and vaccination with a novel recombinant DNA fimbrial vaccine. There were four replicates, in four paddocks. RESULTS Of the untreated animals, 76% had footrot. Footbathing, either weekly or every 3 weeks, restricted the prevalence to 6/283 (2%; 97% effective) and 18/275 (6.5%; 91% effective), respectively. This was significantly lower than the prevalence in either the untreated or vaccinated group (P < 0.001). Weekly footbathing resulted in significantly fewer affected sheep than footbathing for 1 h every 3 weeks (P < 0.05). Vaccination with either whole-cell or recombinant vaccines significantly (P < 0.001) reduced the prevalence ((142/280 (51%; 33% effective), 114/278 (41%; 46% effective) respectively), with the recombinant vaccine superior (P < 0.05) to whole-cell vaccination. Significantly (P < 0.05) fewer 1-year-old sheep had footrot than older sheep. A single Footrite treatment reduced the prevalence to 12% (53/445) compared with a prevalence of 57% (27/47) for untreated sheep (79% effective). CONCLUSION In this study footbathing was more effective than vaccination at controlling and treating multistrain footrot.
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Affiliation(s)
- M B Allworth
- Fred Morley Centre and Graham Centre, School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia
| | - J R Egerton
- Veterinary Clinical Sciences, University of Sydney, Camden, NSW, Australia
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Rossi A, Mónaco A, Guarnaschelli J, Silveira F, Iriarte A, Benecke AG, Chabalgoity JA. Temporal evolution of anti- Clostridium antibody responses in sheep after vaccination with polyvalent clostridial vaccines. Vet Immunol Immunopathol 2018; 202:46-51. [DOI: 10.1016/j.vetimm.2018.06.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 05/31/2018] [Accepted: 06/10/2018] [Indexed: 01/08/2023]
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Best N, Gwozdz J, Suter R, Rawlin G, Beddoe T. Direct serogrouping of Dichelobacter nodosus from Victorian farms using conventional multiplex polymerase chain reaction. BMC Res Notes 2018; 11:108. [PMID: 29415761 PMCID: PMC5804069 DOI: 10.1186/s13104-018-3229-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 02/02/2018] [Indexed: 11/13/2022] Open
Abstract
Objective Dichelobacter nodosus is the causative agent of footrot in sheep. Ovine footrot is a major problem in Australia that results in large economic losses and a represents a very significant animal welfare issue. D. nodosus is divided into 10 serogroups (A–I, M), based on sequence variation in the type IV fimbriae gene, fimA. Control of the bacteria is possible through use of serogroup-specific vaccination, however traditional identification of the serogroups of D. nodosus on infected sheep is time-consuming and costly. With the aim of reducing time and cost, a PCR assay was used to identify serogroups of D. nodosus directly from foot swabs of infected sheep in Victoria. Results It was shown that serogroup B was most common (10 locations), followed by A, G and H (4 locations), I and C (2 locations), D, E and F (1 location). Infections with multiple serotypes were observed in 50% of farms, with the remaining 50% having only a single serogroup detected. The ability to identify serogroups quickly and cheaply direct from foot swabs will aid the understanding of the epidemiology of D. nodosus and support control programs. Electronic supplementary material The online version of this article (10.1186/s13104-018-3229-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Nickala Best
- Department of Animal, Plant and Soil Science and Centre for AgriBioscience (AgriBio), La Trobe University, Bundoora, Melbourne, VIC, Australia
| | - Jacek Gwozdz
- Department of Economic Development, Jobs, Transport and Resources Centre for AgriBioscience (AgriBio), Victorian Government, Bundoora, Melbourne, VIC, Australia
| | - Robert Suter
- Department of Economic Development, Jobs, Transport and Resources, Victorian Government, Attwood, Melbourne, VIC, Australia
| | - Grant Rawlin
- Department of Economic Development, Jobs, Transport and Resources Centre for AgriBioscience (AgriBio), Victorian Government, Bundoora, Melbourne, VIC, Australia
| | - Travis Beddoe
- Department of Animal, Plant and Soil Science and Centre for AgriBioscience (AgriBio), La Trobe University, Bundoora, Melbourne, VIC, Australia.
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Zheng J, Sun L, Shu S, Zhu K, Xu C, Wang J, Wang H. Nuclear magnetic resonance-based serum metabolic profiling of dairy cows with footrot. J Vet Med Sci 2016; 78:1421-1428. [PMID: 27320815 PMCID: PMC5059369 DOI: 10.1292/jvms.15-0720] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Footrot is a debilitating and contagious disease in dairy cows, caused by the
Gram-negative anaerobe Dichelobacter nodosus. 1H-NMR (nuclear
magnetic resonance)-based metabolomics has been previously used to understand the
pathology and etiology of several diseases. The objective of this study was to
characterize serum from dairy cows with footrot (n=10) using 1H-NMR-based
metabolomics and chemometric analyses. 1H-NMR spectroscopy with multivariate
pattern recognition (principal component analysis and orthogonal partial least-squares
discriminant analysis) was performed to identify biomarkers in cows with footrot (F) and
healthy controls (C). 1H-NMR analysis facilitated the identification of 21
metabolites. Among these metabolites, 4 metabolites were higher and 17 metabolites were
lower in the F group than in the C group. The serum levels of 5 metabolites were
significantly different (P<0.05) between the two groups. The results
revealed that cows with footrot have altered carbohydrate, amino acid, lipid and energy
metabolic pathways. Metabolomic approaches are a clinically useful diagnostic tool for
understanding the biochemical alterations and mechanisms of several diseases.
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Affiliation(s)
- Jiasan Zheng
- College of Veterinary Medicine, Northeast Agricultural University, 59 Mucai Street, Harbin 150030, P.R. China
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Lacasta D, Ferrer L, Ramos J, González J, Ortín A, Fthenakis G. Vaccination schedules in small ruminant farms. Vet Microbiol 2015. [DOI: 10.1016/j.vetmic.2015.07.018] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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17
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Leitner DR, Lichtenegger S, Temel P, Zingl FG, Ratzberger D, Roier S, Schild-Prüfert K, Feichter S, Reidl J, Schild S. A combined vaccine approach against Vibrio cholerae and ETEC based on outer membrane vesicles. Front Microbiol 2015; 6:823. [PMID: 26322032 PMCID: PMC4531250 DOI: 10.3389/fmicb.2015.00823] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 07/27/2015] [Indexed: 11/28/2022] Open
Abstract
Enteric infections induced by pathogens like Vibrio cholerae and enterotoxigenic Escherichia coli (ETEC) remain a massive burden in developing countries with increasing morbidity and mortality rates. Previously, we showed that the immunization with genetically detoxified outer membrane vesicles (OMVs) derived from V. cholerae elicits a protective immune response based on the generation of O antigen antibodies, which effectively block the motility by binding to the sheathed flagellum. In this study, we investigated the potential of lipopolysaccharide (LPS)-modified and toxin negative OMVs isolated from V. cholerae and ETEC as a combined OMV vaccine candidate. Our results indicate that the immunization with V. cholerae or ETEC OMVs induced a species-specific immune response, whereas the combination of both OMV species resulted in a high-titer, protective immune response against both pathogens. Interestingly, the immunization with V. cholerae OMVs alone resulted in a so far uncharacterized and cholera toxin B-subunit (CTB) independent protection mechanism against an ETEC colonization. Furthermore, we investigated the potential use of V. cholerae OMVs as delivery vehicles for the heterologously expression of the ETEC surface antigens, CFA/I, and FliC. Although we induced a detectable immune response against both heterologously expressed antigens, none of these approaches resulted in an improved protection compared to a simple combination of V. cholerae and ETEC OMVs. Finally, we expanded the current protection model from V. cholerae to ETEC by demonstrating that the inhibition of motility via anti-FliC antibodies represents a relevant protection mechanism of an OMV-based ETEC vaccine candidate in vivo.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Stefan Schild
- Institute of Molecular Biosciences, University of GrazGraz, Austria
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Frosth S, König U, Nyman AK, Pringle M, Aspán A. Characterisation of Dichelobacter nodosus and detection of Fusobacterium necrophorum and Treponema spp. in sheep with different clinical manifestations of footrot. Vet Microbiol 2015; 179:82-90. [PMID: 25796133 DOI: 10.1016/j.vetmic.2015.02.034] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 02/26/2015] [Accepted: 02/27/2015] [Indexed: 10/23/2022]
Abstract
The aim of this study was to determine the proportion of Dichelobacter nodosus, Fusobacterium necrophorum and Treponema spp. in sheep with different clinical manifestations of footrot compared to healthy sheep both at flock and individual level. The second aim was to characterise D. nodosus with respect to virulence, presence of intA gene and the serogroups. Swab samples (n=1000) from footrot-affected (n=10) and healthy flocks (n=10) were analysed for the presence of D. nodosus, F. necrophorum and Treponema spp. by real-time PCR and culturing (D. nodosus only). Dichelobacter nodosus isolates (n=78) and positive swabs (n=474) were analysed by real-time PCR for the aprV2/B2 and the intA genes and by PCR for the fimA gene (isolates only). D. nodosus was more commonly found in flocks affected with footrot than in clinically healthy flocks. A significant association was found between feet with severe footrot lesions and the aprV2 gene and between feet with moderate or no lesions and the aprB2 gene, respectively. F. necrophorum was more commonly found in flocks with footrot lesions than in flocks without lesions. No significant association was found between sheep flocks affected with footrot and findings of Treponema spp. or the intA gene. Benign D. nodosus of six different serogroups was detected in twelve flocks and virulent D. nodosus of serogroup G in one. In conclusion, D. nodosus and F. necrophorum were more commonly found in feet with footrot than in healthy feet. The majority of D. nodosus detected was benign, while virulent D. nodosus was only detected in a single flock.
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Affiliation(s)
- Sara Frosth
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, P.O. Box 7028, SE-750 07 Uppsala, Sweden; Department of Bacteriology, National Veterinary Institute (SVA), SE-751 89 Uppsala, Sweden.
| | - Ulrika König
- Swedish Animal Health Service, Kungsängens gård, SE-753 23 Uppsala, Sweden.
| | - Ann-Kristin Nyman
- Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute (SVA), SE-751 89 Uppsala, Sweden.
| | - Märit Pringle
- Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute (SVA), SE-751 89 Uppsala, Sweden.
| | - Anna Aspán
- Department of Bacteriology, National Veterinary Institute (SVA), SE-751 89 Uppsala, Sweden.
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Bhardwaj V, Dhungyel O, de Silva K, Whittington RJ. Investigation of immunity in sheep following footrot infection and vaccination. Vaccine 2014; 32:6979-6985. [PMID: 25454866 DOI: 10.1016/j.vaccine.2014.10.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2014] [Revised: 10/07/2014] [Accepted: 10/16/2014] [Indexed: 11/17/2022]
Abstract
Ovine footrot is a major disease affecting sheep welfare and production. The anaerobic Gram-negative bacterium Dichelobacter nodosus is the essential transmitting agent. Monovalent or bivalent vaccines induce high levels of D. nodosus antibodies and are the basis of several successful footrot treatment, control and eradication programs. Due to the rapid rate of disease transmission within a flock, the presence of therapeutic vaccination non-responders has major implications for a control program. The aim of this study was to assess the immunological basis of a therapeutic vaccination non-response. Sheep (n=120) were infected with D. nodosus in an artificial pen challenge. Once disease had established, animals were vaccinated with a serogroup specific D. nodosus fimbrial vaccine. Based on the response to therapeutic vaccination, animals were allocated into one of three groups: (i) TVNR where disease persisted despite vaccination (ii) non-diseased, where disease never established and (iii) TVR, where disease was established but resolved with vaccination. Factors related to both the innate and adaptive immune pathways were assessed. These included antigen-specific serum antibodies, interferon-γ, interleukin-10, proliferation of lymphocyte subsets and phagocytic activity of leukocytes. There was no significant difference between the three groups of sheep for any of these parameters. All three groups of sheep produced antibody in excess of a previously published minimum antibody titre required for protection. Opsonising activity in sera from the three groups of sheep was also not significantly different and phagocytic cells from sheep from all three groups were able to destroy D. nodosus intracellularly. These findings show that the measured systemic adaptive and innate immune responses were unlikely to be the cause of a therapeutic vaccination non-response. They also show that the accepted minimum protective titre may be incorrect and may need further examination.
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Affiliation(s)
- Vidya Bhardwaj
- Farm Animal and Veterinary Public Health, Faculty of Veterinary Science, University of Sydney, 425 Werombi Road, Camden 2570, NSW, Australia
| | - Om Dhungyel
- Farm Animal and Veterinary Public Health, Faculty of Veterinary Science, University of Sydney, 425 Werombi Road, Camden 2570, NSW, Australia
| | - Kumudika de Silva
- Farm Animal and Veterinary Public Health, Faculty of Veterinary Science, University of Sydney, 425 Werombi Road, Camden 2570, NSW, Australia.
| | - Richard J Whittington
- Farm Animal and Veterinary Public Health, Faculty of Veterinary Science, University of Sydney, 425 Werombi Road, Camden 2570, NSW, Australia
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