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Garner G, Vosloo W, Tapsuwan S, Bradhurst R, Seitzinger AH, Breed AC, Capon T. Comparing surveillance approaches to support regaining free status after a foot-and-mouth disease outbreak. Prev Vet Med 2021; 194:105441. [PMID: 34352519 DOI: 10.1016/j.prevetmed.2021.105441] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Revised: 06/22/2021] [Accepted: 07/15/2021] [Indexed: 11/30/2022]
Abstract
Following an FMD eradication program, surveillance will be required to demonstrate that the program has been successful. The World Organization for Animal Health (OIE) provides guidelines including waiting periods and appropriate surveillance to support regaining FMD-free status. Serological surveillance is the recommended method for demonstrating freedom but is time consuming and expensive. New technologies such as real-time reverse transcription polymerase chain reaction (RT-qPCR) tests and sampling techniques such as bulk milk testing (BMT) of dairy cattle, oral swabs, and saliva collection with rope tethers in piggeries could enable surveillance to be done more efficiently. Epidemiological modelling was used to simulate FMD outbreaks, with and without emergency vaccination as part of the response, in Australia. Baseline post-outbreak surveillance approaches for unvaccinated and vaccinated animals based on the European FMD directive were compared with alternative approaches in which the sampling regime, sampling approaches and/or the diagnostic tests used were varied. The approaches were compared in terms of the resources required, time taken, cost, and effectiveness i.e., ability of the surveillance regime to correctly identify the infection status of herds. In the non-vaccination scenarios, the alternative approach took less time to complete and cost less, with the greatest benefits seen with larger outbreaks. In vaccinated populations, the alternative surveillance approaches significantly reduced the number of herds sampled, the total number of tests done and costs of the post-outbreak surveillance. There was no reduction in effectiveness using the alternative approaches, with one of the benefits being a reduction in the number of false positive herds. Alternative approaches to FMD surveillance based on non-invasive sampling methods and RT-qPCR tests have the potential to enable post outbreak surveillance substantiating FMD freedom to be done more quickly and less expensively than traditional approaches based on serological surveys.
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Affiliation(s)
- Graeme Garner
- CSIRO-Land and Water, North Road, Acton, 2601, ACT, Australia
| | - Wilna Vosloo
- CSIRO-Australian Centre for Disease Preparedness, 5 Portarlington Road, 3220, Geelong, Australia
| | - Sorada Tapsuwan
- CSIRO-Land and Water, North Road, Acton, 2601, ACT, Australia
| | - Richard Bradhurst
- Centre of Excellence for Biosecurity Risk Analysis, School of BioSciences, University of Melbourne, Parkville, 3010, VIC, Australia
| | | | - Andrew C Breed
- Epidemiology and One Health Section, Department of Agriculture, Water and the Environment, Canberra, 2601, ACT, Australia; School of Veterinary Science, University of Queensland, Brisbane, Australia
| | - Tim Capon
- CSIRO-Land and Water, North Road, Acton, 2601, ACT, Australia
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Lazarus DD, Peta F, Blight D, Van Heerden J, Mutowembwa PB, Heath L, Blignaut B, Opperman PA, Fosgate GT. Efficacy of a foot-and-mouth disease vaccine against a heterologous SAT1 virus challenge in goats. Vaccine 2020; 38:4006-4015. [PMID: 32312581 DOI: 10.1016/j.vaccine.2020.04.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 04/03/2020] [Accepted: 04/06/2020] [Indexed: 11/25/2022]
Abstract
Goats are susceptible to infection with foot-and-mouth disease virus (FMDV), but their role in the epidemiology of the disease and response to vaccination is poorly understood. In southern Africa, FMDV serotypes Southern African Territories (SAT) 1, 2 and 3 are known to be endemic. In this study, we evaluated the efficacy of a pentavalent FMD vaccine in goats against heterologous challenge with a pool of field SAT1 FMDV. Forty FMD sero-negative goats (6-12 months of age) of mixed sexes were randomly allocated to one of five treatment groups: full cattle dose (2 ml), 1/3rd (0.67 ml), 1/6th (0.33 ml), 1/12th (0.16 ml) or unvaccinated placebo control. Goats were vaccinated with an inactivated pentavalent FMD vaccine containing serotypes SAT1, SAT2 and SAT3 on day 0 and revaccinated at day 20 post vaccination. Thereafter, thirty-four goats were challenged by tongue inoculation at day 41 post-vaccination using 104.57 50% tissue culture infective dose (TCID50) FMDV SAT1 pool. Animals were examined daily and clinical signs were scored. Rectal temperatures were measured daily, with temperatures ≥40 °C defined as fever. Clinical specimens (nasal, oral and rectal swabs) were collected on days 0, 2, 4 and 6 post challenge. Viral shedding was determined using reverse-transcriptase real-time PCR. None of the goats vaccinated with the full cattle dose developed secondary lesions. All vaccinated groups had lower temperatures compared to the unvaccinated controls (P < 0.001). Based on RT-PCR results, goats in the unvaccinated control group shed more virus compared to all groups except for 1/12th (P < 0.05), while goats in the full dose group shed less virus than goats in the 1/12th and the unvaccinated control group (P < 0.05). The results suggest that the 1/3rd (0.67 ml) dose of the vaccine is sufficient to reduce viral shedding after heterologous challenge with a FMDV SAT1 pool.
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Affiliation(s)
- D D Lazarus
- University of Pretoria, Faculty of Veterinary Science, Department of Production Animal Studies, Onderstepoort, South Africa; National Veterinary Research Institute, Foot-and-Mouth Disease Virus Research Laboratory, Vom, Nigeria.
| | - F Peta
- Agricultural Research Council, Onderstepoort Veterinary Research, Transboundary Animal Diseases, Onderstepoort, South Africa
| | - D Blight
- University of Pretoria, Faculty of Veterinary Science, Department of Production Animal Studies, Onderstepoort, South Africa; Agricultural Research Council, Onderstepoort Veterinary Research, Transboundary Animal Diseases, Onderstepoort, South Africa
| | - J Van Heerden
- Agricultural Research Council, Onderstepoort Veterinary Research, Transboundary Animal Diseases, Onderstepoort, South Africa
| | - P B Mutowembwa
- Agricultural Research Council, Onderstepoort Veterinary Research, Transboundary Animal Diseases, Onderstepoort, South Africa
| | - L Heath
- Agricultural Research Council, Onderstepoort Veterinary Research, Transboundary Animal Diseases, Onderstepoort, South Africa
| | - B Blignaut
- University of Pretoria, Faculty of Veterinary Science, Department of Production Animal Studies, Onderstepoort, South Africa
| | - P A Opperman
- University of Pretoria, Faculty of Veterinary Science, Department of Production Animal Studies, Onderstepoort, South Africa; Agricultural Research Council, Onderstepoort Veterinary Research, Transboundary Animal Diseases, Onderstepoort, South Africa
| | - G T Fosgate
- University of Pretoria, Faculty of Veterinary Science, Department of Production Animal Studies, Onderstepoort, South Africa
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Stenfeldt C, Arzt J. The Carrier Conundrum; A Review of Recent Advances and Persistent Gaps Regarding the Carrier State of Foot-and-Mouth Disease Virus. Pathogens 2020; 9:E167. [PMID: 32121072 PMCID: PMC7157498 DOI: 10.3390/pathogens9030167] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 02/25/2020] [Accepted: 02/25/2020] [Indexed: 12/12/2022] Open
Abstract
The existence of a prolonged, subclinical phase of foot-and-mouth disease virus (FMDV) infection in cattle was first recognized in the 1950s. Since then, the FMDV carrier state has been a subject of controversy amongst scientists and policymakers. A fundamental conundrum remains in the discordance between the detection of infectious FMDV in carriers and the apparent lack of contagiousness to in-contact animals. Although substantial progress has been made in elucidating the causal mechanisms of persistent FMDV infection, there are still critical knowledge gaps that need to be addressed in order to elucidate, predict, prevent, and model the risks associated with the carrier state. This is further complicated by the occurrence of a distinct form of neoteric subclinical infection, which is indistinguishable from the carrier state in field scenarios, but may have substantially different epidemiological properties. This review summarizes the current state of knowledge of the FMDV carrier state and identifies specific areas of research in need of further attention. Findings from experimental investigations of FMDV pathogenesis are discussed in relation to experience gained from field studies of foot-and-mouth disease.
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Affiliation(s)
- Carolina Stenfeldt
- Foreign Animal Disease Research Unit, Agricultural Research Service, US Department of Agriculture, Plum Island animal Disease Center, Orient, NY 11957, USA
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS 66506, USA
| | - Jonathan Arzt
- Foreign Animal Disease Research Unit, Agricultural Research Service, US Department of Agriculture, Plum Island animal Disease Center, Orient, NY 11957, USA
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Stenfeldt C, Pacheco JM, Singanallur NB, Vosloo W, Rodriguez LL, Arzt J. Virulence beneath the fleece; a tale of foot-and-mouth disease virus pathogenesis in sheep. PLoS One 2019; 14:e0227061. [PMID: 31891626 PMCID: PMC6938329 DOI: 10.1371/journal.pone.0227061] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 12/10/2019] [Indexed: 11/18/2022] Open
Abstract
Foot-and-mouth disease virus (FMDV) is capable of infecting all cloven-hoofed domestic livestock species, including cattle, pigs, goats, and sheep. However, in contrast to cattle and pigs, the pathogenesis of FMDV in small ruminants has been incompletely elucidated. The objective of the current investigation was to characterize tissue- and cellular tropism of early and late stages of FMDV infection in sheep following three different routes of simulated natural virus exposure. Extensive post-mortem harvest of tissue samples at pre-determined time points during early infection (24 and 48 hours post infection) demonstrated that tissues specifically susceptible to primary FMDV infection included the paraepiglottic- and palatine tonsils, as well as the nasopharyngeal mucosa. Additionally, experimental aerosol inoculation of sheep led to substantial virus replication in the lungs at 24-48 hours post-inoculation. During persistent infection (35 days post infection), the paraepiglottic- and palatine tonsils were the only tissues from which infectious FMDV was recovered. This is strikingly different from cattle, in which persistent FMDV infection has consistently been located to the nasopharyngeal mucosa. Analysis of tissue sections by immunomicroscopy revealed a strict epithelial tropism during both early and late phases of infection as FMDV was consistently localized to cytokeratin-expressing epithelial cells. This study expands upon previous knowledge of FMDV pathogenesis in sheep by providing detailed information on the temporo-anatomic distribution of FMDV in ovine tissues. Findings are discussed in relation to similar investigations previously performed in cattle and pigs, highlighting similarities and differences in FMDV pathogenesis across natural host species.
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Affiliation(s)
- Carolina Stenfeldt
- Department of Agriculture, Foreign Animal Disease Research Unit, Agricultural Research Service, U.S., Plum Island Animal Disease Center, NY, Greenport, United States of America
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS, United States of America
| | - Juan M. Pacheco
- Department of Agriculture, Foreign Animal Disease Research Unit, Agricultural Research Service, U.S., Plum Island Animal Disease Center, NY, Greenport, United States of America
| | | | - Wilna Vosloo
- Australian Animal Health Laboratory, CSIRO-Health and Biosecurity, Geelong, Australia
| | - Luis L. Rodriguez
- Department of Agriculture, Foreign Animal Disease Research Unit, Agricultural Research Service, U.S., Plum Island Animal Disease Center, NY, Greenport, United States of America
| | - Jonathan Arzt
- Department of Agriculture, Foreign Animal Disease Research Unit, Agricultural Research Service, U.S., Plum Island Animal Disease Center, NY, Greenport, United States of America
- * E-mail:
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Lazarus DD, Mutowembwa PB, Sirdar MM, Rametse TM, Heath L, Opperman PA, Burroughs RE, Fosgate GT. Clinical presentation of FMD virus SAT1 infections in experimentally challenged indigenous South African goats. Small Rumin Res 2019. [DOI: 10.1016/j.smallrumres.2019.09.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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