1
|
Eltahir YM, Ishag HZA, Wadsworth J, Hicks HM, Knowles NJ, Mioulet V, King DP, Mohamed MS, Bensalah OK, Yusof MF, Gasim EFM, Hammadi ZMA, Shah AAM, Abdelmagid YA, Gahlan MAME, Kassim MF, Kayaf K, Zahran A, Nuaimat MMA. Molecular Epidemiology of Foot-and-Mouth Disease Viruses in the Emirate of Abu Dhabi, United Arab Emirates. Vet Sci 2024; 11:32. [PMID: 38250938 PMCID: PMC11154577 DOI: 10.3390/vetsci11010032] [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: 11/20/2023] [Revised: 01/04/2024] [Accepted: 01/06/2024] [Indexed: 01/23/2024] Open
Abstract
Foot-and-mouth disease (FMD) is an endemic disease in the United Arab Emirates (UAE) in both wild and domestic animals. Despite this, no systematic FMD outbreak investigation accompanied by molecular characterisation of FMD viruses (FMDVs) in small ruminants or cattle has been performed, and only a single report that describes sequences for FMDVs in wildlife from the Emirate has been published. In this study, FMD outbreaks that occurred in 2021 in five animal farms and one animal market in the Emirate of Abu Dhabi were investigated. Cases involved sheep, goats, and cattle, as well as Arabian oryx (Oryx leucoryx). Twelve samples were positive for FMDV via RT-qPCR, and four samples (Arabian oryx n = 1, goat n = 2, and sheep n = 1) were successfully genotyped using VP1 nucleotide sequencing. These sequences shared 88~98% identity and were classified within the serotype O, Middle East-South Asia topotype (O/ME-SA). Phylogenetic analysis revealed that the Arabian oryx isolate (UAE/2/2021) belonged to the PanAsia-2 lineage, the ANT-10 sublineage, and was closely related to the FMDVs recently detected in neighbouring countries. The FMDV isolates from goats (UAE/10/2021 and UAE/11/2021) and from sheep (UAE/14/2021) formed a monophyletic cluster within the SA-2018 lineage that contained viruses from Bangladesh, India, and Sri Lanka. This is the first study describing the circulation of the FMDV O/ME-SA/SA-2018 sublineage in the UAE. These data shed light on the epidemiology of FMD in the UAE and motivate further systematic epidemiological studies and genomic sequencing to enhance the ongoing national animal health FMD control plan.
Collapse
Affiliation(s)
- Yassir M. Eltahir
- Animals Extension and Health Services Division, Abu Dhabi Agriculture and Food Safety Authority (ADAFSA), Abu Dhabi P.O. Box 52150, United Arab Emirates
| | - Hassan Zackaria Ali Ishag
- Biosecurity Affairs Division, Development & Innovation Sector, Abu Dhabi Agriculture and Food Safety Authority (ADAFSA), Abu Dhabi P.O. Box 52150, United Arab Emirates
| | - Jemma Wadsworth
- FAO World Reference Laboratory for FMD (WRLFMD), The Pirbright Institute, Pirbright GU24, UK
| | - Hayley M. Hicks
- FAO World Reference Laboratory for FMD (WRLFMD), The Pirbright Institute, Pirbright GU24, UK
| | - Nick J. Knowles
- FAO World Reference Laboratory for FMD (WRLFMD), The Pirbright Institute, Pirbright GU24, UK
| | - Valérie Mioulet
- FAO World Reference Laboratory for FMD (WRLFMD), The Pirbright Institute, Pirbright GU24, UK
| | - Donald P. King
- FAO World Reference Laboratory for FMD (WRLFMD), The Pirbright Institute, Pirbright GU24, UK
| | - Meera Saeed Mohamed
- Animals Extension and Health Services Division, Abu Dhabi Agriculture and Food Safety Authority (ADAFSA), Abu Dhabi P.O. Box 52150, United Arab Emirates
| | - Oum Keltoum Bensalah
- Animals Extension and Health Services Division, Abu Dhabi Agriculture and Food Safety Authority (ADAFSA), Abu Dhabi P.O. Box 52150, United Arab Emirates
| | - Mohd Farouk Yusof
- Biosecurity Affairs Division, Development & Innovation Sector, Abu Dhabi Agriculture and Food Safety Authority (ADAFSA), Abu Dhabi P.O. Box 52150, United Arab Emirates
| | - Esmat Faisal Malik Gasim
- Biosecurity Affairs Division, Development & Innovation Sector, Abu Dhabi Agriculture and Food Safety Authority (ADAFSA), Abu Dhabi P.O. Box 52150, United Arab Emirates
| | - Zulaikha Mohamed Al Hammadi
- Biosecurity Affairs Division, Development & Innovation Sector, Abu Dhabi Agriculture and Food Safety Authority (ADAFSA), Abu Dhabi P.O. Box 52150, United Arab Emirates
| | - Asma Abdi Mohamed Shah
- Biosecurity Affairs Division, Development & Innovation Sector, Abu Dhabi Agriculture and Food Safety Authority (ADAFSA), Abu Dhabi P.O. Box 52150, United Arab Emirates
| | - Yasir Ali Abdelmagid
- Animals Extension and Health Services Division, Abu Dhabi Agriculture and Food Safety Authority (ADAFSA), Abu Dhabi P.O. Box 52150, United Arab Emirates
| | - Moustafa Abdel meguid El Gahlan
- Animals Extension and Health Services Division, Abu Dhabi Agriculture and Food Safety Authority (ADAFSA), Abu Dhabi P.O. Box 52150, United Arab Emirates
| | - Mohanned Fawzi Kassim
- Animals Extension and Health Services Division, Abu Dhabi Agriculture and Food Safety Authority (ADAFSA), Abu Dhabi P.O. Box 52150, United Arab Emirates
| | - Kaltham Kayaf
- Animal Development & Health Department, Ministry of Climate Change & Environment, Dubai P.O. Box 1509, United Arab Emirate
| | - Ahmed Zahran
- Animal Development & Health Department, Ministry of Climate Change & Environment, Dubai P.O. Box 1509, United Arab Emirate
| | - Mervat Mari Al Nuaimat
- Animal Development & Health Department, Ministry of Climate Change & Environment, Dubai P.O. Box 1509, United Arab Emirate
| |
Collapse
|
2
|
Guyver-Fletcher G, Gorsich EE, Tildesley MJ. A model exploration of carrier and movement transmission as potential explanatory causes for the persistence of foot-and-mouth disease in endemic regions. Transbound Emerg Dis 2021; 69:2712-2726. [PMID: 34936219 DOI: 10.1111/tbed.14423] [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: 06/11/2021] [Revised: 11/26/2021] [Accepted: 12/11/2021] [Indexed: 11/30/2022]
Abstract
Foot-and-mouth disease (FMD) is a virulent and economically important disease of livestock, still endemic in many areas of Asia and sub-Saharan Africa. Transmission from persistently infected livestock, also known as carriers, has been proposed as a mechanism to support the persistence of FMD in endemic regions. However, whether carrier livestock can infect susceptible animals is controversial; recovered virus is infectious and there are claims of field transmission, but it remains undemonstrated experimentally. Alternate hypotheses for persistence include the movement of livestock within and between regions, and fomite contamination of the environment. Using a stochastic compartmental ordinary differential equation (ODE) model, we investigate the minimum rates of carrier transmission necessary to contribute to the maintenance of FMD in a region, and compare this to the alternate mechanism of persistence through cattle shipments. We find that carrier transmission can theoretically support persistence even at transmission rates much lower than the highest realistic rates previously proposed, and that the parameters with the most effect on the feasibility of carrier-mediated persistence are the average duration of both the carrier phase and natural immunity. However, shipment-mediated persistence remains a viable alternate mechanism for persistence without carrier transmission.
Collapse
Affiliation(s)
- Glen Guyver-Fletcher
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, University of Warwick, Coventry, UK.,School of Life Sciences, University of Warwick, Coventry, UK
| | - Erin E Gorsich
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, University of Warwick, Coventry, UK.,School of Life Sciences, University of Warwick, Coventry, UK
| | - Michael J Tildesley
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, University of Warwick, Coventry, UK.,School of Life Sciences, University of Warwick, Coventry, UK.,Mathematics Institute, University of Warwick, Coventry, UK
| |
Collapse
|
3
|
Zaheer MU, Salman MD, Steneroden KK, Magzamen SL, Weber SE, Case S, Rao S. Challenges to the Application of Spatially Explicit Stochastic Simulation Models for Foot-and-Mouth Disease Control in Endemic Settings: A Systematic Review. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2020; 2020:7841941. [PMID: 33294003 PMCID: PMC7700052 DOI: 10.1155/2020/7841941] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 10/20/2020] [Accepted: 10/30/2020] [Indexed: 11/17/2022]
Abstract
Simulation modeling has become common for estimating the spread of highly contagious animal diseases. Several models have been developed to mimic the spread of foot-and-mouth disease (FMD) in specific regions or countries, conduct risk assessment, analyze outbreaks using historical data or hypothetical scenarios, assist in policy decisions during epidemics, formulate preparedness plans, and evaluate economic impacts. Majority of the available FMD simulation models were designed for and applied in disease-free countries, while there has been limited use of such models in FMD endemic countries. This paper's objective was to report the findings from a study conducted to review the existing published original research literature on spatially explicit stochastic simulation (SESS) models of FMD spread, focusing on assessing these models for their potential use in endemic settings. The goal was to identify the specific components of endemic FMD needed to adapt these SESS models for their potential application in FMD endemic settings. This systematic review followed the PRISMA guidelines, and three databases were searched, which resulted in 1176 citations. Eighty citations finally met the inclusion criteria and were included in the qualitative synthesis, identifying nine unique SESS models. These SESS models were assessed for their potential application in endemic settings. The assessed SESS models can be adapted for use in FMD endemic countries by modifying the underlying code to include multiple cocirculating serotypes, routine prophylactic vaccination (RPV), and livestock population dynamics to more realistically mimic the endemic characteristics of FMD. The application of SESS models in endemic settings will help evaluate strategies for FMD control, which will improve livestock health, provide economic gains for producers, help alleviate poverty and hunger, and will complement efforts to achieve the Sustainable Development Goals.
Collapse
Affiliation(s)
- Muhammad Usman Zaheer
- Animal Population Health Institute, Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins CO 80523, USA
- FMD Project Office, Food and Agriculture Organization of the United Nations, ASI Premises, NARC Gate # 2, Park Road, Islamabad 44000, Pakistan
| | - Mo D. Salman
- Animal Population Health Institute, Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins CO 80523, USA
| | - Kay K. Steneroden
- Animal Population Health Institute, Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins CO 80523, USA
| | - Sheryl L. Magzamen
- Department of Environmental and Radiological Health Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins CO 80523, USA
| | - Stephen E. Weber
- Animal Population Health Institute, Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins CO 80523, USA
| | - Shaun Case
- Department of Civil and Environmental Engineering, Walter Scott, Jr. College of Engineering, Colorado State University, Fort Collins CO 80521, USA
| | - Sangeeta Rao
- Animal Population Health Institute, Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins CO 80523, USA
| |
Collapse
|
4
|
McLachlan I, Marion G, McKendrick IJ, Porphyre T, Handel IG, Bronsvoort BMD. Endemic foot and mouth disease: pastoral in-herd disease dynamics in sub-Saharan Africa. Sci Rep 2019; 9:17349. [PMID: 31757992 PMCID: PMC6874544 DOI: 10.1038/s41598-019-53658-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 10/31/2019] [Indexed: 11/25/2022] Open
Abstract
Foot and mouth disease (FMD) burden disproportionally affects Africa where it is considered endemic. Smallholder livestock keepers experience significant losses due to disease, but the dynamics and mechanisms underlying persistence at the herd-level and beyond remain poorly understood. We address this knowledge gap using stochastic, compartmental modelling to explore FMD virus (FMDV) persistence, outbreak dynamics and disease burden in individual cattle herds within an endemic setting. Our analysis suggests repeated introduction of virus from outside the herd is required for long-term viral persistence, irrespective of carrier presence. Risk of new disease exposures resulting in significant secondary outbreaks is reduced by the presence of immune individuals giving rise to a period of reduced risk, the predicted duration of which suggests that multiple strains of FMDV are responsible for observed yearly herd-level outbreaks. Our analysis suggests management of population turnover could potentially reduce disease burden and deliberate infection of cattle, practiced by local livestock keepers in parts of Africa, has little effect on the duration of the reduced risk period but increases disease burden. This work suggests that FMD control should be implemented beyond individual herds but, in the interim, herd management may be used to reduced FMD impact to livestock keepers.
Collapse
Affiliation(s)
- I McLachlan
- The Epidemiology Economics and Risk Assessment (EERA) Group, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Edinburgh, Midlothian, Scotland, United Kingdom.
- Biomathematics and Statistics Scotland, Edinburgh, United Kingdom.
| | - G Marion
- Biomathematics and Statistics Scotland, Edinburgh, United Kingdom
| | - I J McKendrick
- Biomathematics and Statistics Scotland, Edinburgh, United Kingdom
| | - T Porphyre
- The Epidemiology Economics and Risk Assessment (EERA) Group, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Edinburgh, Midlothian, Scotland, United Kingdom
| | - I G Handel
- The Epidemiology Economics and Risk Assessment (EERA) Group, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Edinburgh, Midlothian, Scotland, United Kingdom
- Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Edinburgh, Midlothian, Scotland, United Kingdom
| | - B M deC Bronsvoort
- The Epidemiology Economics and Risk Assessment (EERA) Group, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Edinburgh, Midlothian, Scotland, United Kingdom
| |
Collapse
|
5
|
Tessema KM, Chirove F, Sibanda P. Modeling control of foot and mouth disease with two time delays. INT J BIOMATH 2019. [DOI: 10.1142/s179352451930001x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We develop a delay ordinary differential equation model that captures the effects of prophylactic vaccination, reactive vaccination, prophylactic treatment and reactive culling on the spread of foot and mouth disease (FMD) with time delays. Simulation results from the study suggest that increasing time delay while increasing the control strategies decreases the burden of FMD. Further, the results reveal, that decreasing time delay while decreasing the control strategies increases the burden of FMD. The intermediate scenarios of either (i) increasing time delay while decreasing control or (ii) decreasing time delay while increasing control have intermediate effects on burden reduction. Thus, the implementation of effective control strategies combination can play an important role in mitigating against the FMD burden.
Collapse
Affiliation(s)
- Kassahun M. Tessema
- School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, Private Bag X01 Scottsville 3209, Pietermaritzburg, South Africa
| | - Faraimunashe Chirove
- School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, Private Bag X01 Scottsville 3209, Pietermaritzburg, South Africa
| | - Precious Sibanda
- School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, Private Bag X01 Scottsville 3209, Pietermaritzburg, South Africa
| |
Collapse
|
6
|
Souley Kouato B, De Clercq K, Abatih E, Dal Pozzo F, King DP, Thys E, Marichatou H, Saegerman C. Review of epidemiological risk models for foot-and-mouth disease: Implications for prevention strategies with a focus on Africa. PLoS One 2018; 13:e0208296. [PMID: 30543641 PMCID: PMC6292601 DOI: 10.1371/journal.pone.0208296] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 11/15/2018] [Indexed: 11/18/2022] Open
Abstract
Foot-and-mouth disease (FMD) is a highly infectious transboundary disease that affects domestic and wild cloven-hoofed animal species. The aim of this review was to identify and critically assess some modelling techniques for FMD that are well supported by scientific evidence from the literature with a focus on their use in African countries where the disease remains enzootic. In particular, this study attempted to provide a synopsis of the relative strengths and weaknesses of these models and their relevance to FMD prevention policies. A literature search was conducted to identify quantitative and qualitative risk assessments for FMD, including studies that describe FMD risk factor modelling and spatiotemporal analysis. A description of retrieved papers and a critical assessment of the modelling methods, main findings and their limitations were performed. Different types of models have been used depending on the purpose of the study and the nature of available data. The most frequently identified factors associated with the risk of FMD occurrence were the movement (especially uncontrolled animal movement) and the mixing of animals around water and grazing points. Based on the qualitative and quantitative risk assessment studies, the critical pathway analysis showed that the overall risk of FMDV entering a given country is low. However, in some cases, this risk can be elevated, especially when illegal importation of meat and the movement of terrestrial livestock are involved. Depending on the approach used, these studies highlight shortcomings associated with the application of models and the lack of reliable data from endemic settings. Therefore, the development and application of specific models for use in FMD endemic countries including Africa is encouraged.
Collapse
Affiliation(s)
- Bachir Souley Kouato
- Research Unit in Epidemiology and Risk Analysis Applied to Veterinary Sciences (UREAR-ULiège), Fundamental and Applied Research for Animals & Health (FARAH) Centre, Faculty of Veterinary Medicine, University of Liege, Liege, Belgium
- Institut National de la Recherche Agronomique du Niger (INRAN), Niamey, Niger
| | - Kris De Clercq
- Operational Directorate Viral Diseases, Unit Vesicular and Exotic Diseases, Veterinary and Agrochemical Research Centre (CODA-CERVA), Brussels, Belgium
| | - Emmanuel Abatih
- Department of Mathematics, Computer Sciences and Statistics, University of Gent, Krijgslaan Gent, Belgium
| | - Fabiana Dal Pozzo
- Research Unit in Epidemiology and Risk Analysis Applied to Veterinary Sciences (UREAR-ULiège), Fundamental and Applied Research for Animals & Health (FARAH) Centre, Faculty of Veterinary Medicine, University of Liege, Liege, Belgium
| | - Donald P. King
- The Pirbright Institute, Ash Road, Pirbright, Surrey, United Kingdom
| | - Eric Thys
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Hamani Marichatou
- Université Abdou Moumouni de Niamey, Faculté d'Agronomie, Niamey, Niger
| | - Claude Saegerman
- Research Unit in Epidemiology and Risk Analysis Applied to Veterinary Sciences (UREAR-ULiège), Fundamental and Applied Research for Animals & Health (FARAH) Centre, Faculty of Veterinary Medicine, University of Liege, Liege, Belgium
- * E-mail:
| |
Collapse
|
7
|
Dynamics analysis of SIR epidemic model with correlation coefficients and clustering coefficient in networks. J Theor Biol 2018; 449:1-13. [PMID: 29649430 DOI: 10.1016/j.jtbi.2018.04.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 04/02/2018] [Accepted: 04/04/2018] [Indexed: 11/22/2022]
Abstract
In this paper, the correlation coefficients between nodes in states are used as dynamic variables, and we construct SIR epidemic dynamic models with correlation coefficients by using the pair approximation method in static networks and dynamic networks, respectively. Considering the clustering coefficient of the network, we analytically investigate the existence and the local asymptotic stability of each equilibrium of these models and derive threshold values for the prevalence of diseases. Additionally, we obtain two equivalent epidemic thresholds in dynamic networks, which are compared with the results of the mean field equations.
Collapse
|
8
|
Ringa N, Bauch CT. Spatially-implicit modelling of disease-behaviour interactions in the context of non-pharmaceutical interventions. MATHEMATICAL BIOSCIENCES AND ENGINEERING : MBE 2018; 15:461-483. [PMID: 29161845 DOI: 10.3934/mbe.2018021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Pair approximation models have been used to study the spread of infectious diseases in spatially distributed host populations, and to explore disease control strategies such as vaccination and case isolation. Here we introduce a pair approximation model of individual uptake of non-pharmaceutical interventions (NPIs) for an acute self-limiting infection, where susceptible individuals can learn the NPIs either from other susceptible individuals who are already practicing NPIs ("social learning"), or their uptake of NPIs can be stimulated by being neighbours of an infectious person ("exposure learning"). NPIs include individual measures such as hand-washing and respiratory etiquette. Individuals can also drop the habit of using NPIs at a certain rate. We derive a spatially defined expression of the basic reproduction number R0 and we also numerically simulate the model equations. We find that exposure learning is generally more efficient than social learning, since exposure learning generates NPI uptake in the individuals at immediate risk of infection. However, if social learning is pre-emptive, beginning a sufficient amount of time before the epidemic, then it can be more effective than exposure learning. Interestingly, varying the initial number of individuals practicing NPIs does not significantly impact the epidemic final size. Also, if initial source infections are surrounded by protective individuals, there are parameter regimes where increasing the initial number of source infections actually decreases the infection peak (instead of increasing it) and makes it occur sooner. The peak prevalence increases with the rate at which individuals drop the habit of using NPIs, but the response of peak prevalence to changes in the forgetting rate are qualitatively different for the two forms of learning. The pair approximation methodology developed here illustrates how analytical approaches for studying interactions between social processes and disease dynamics in a spatially structured population should be further pursued.
Collapse
Affiliation(s)
- Notice Ringa
- Botswana International University of Science and Technology, Department of Mathematics and Statistical Sciences, Private Bag 16, Palapye, Botswana
| | - Chris T Bauch
- University of Waterloo, Department of Applied Mathematics, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada
| |
Collapse
|
9
|
Knight-Jones TJD, Robinson L, Charleston B, Rodriguez LL, Gay CG, Sumption KJ, Vosloo W. Global Foot-and-Mouth Disease Research Update and Gap Analysis: 2 - Epidemiology, Wildlife and Economics. Transbound Emerg Dis 2016; 63 Suppl 1:14-29. [DOI: 10.1111/tbed.12522] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Indexed: 11/29/2022]
Affiliation(s)
| | | | | | - L. L. Rodriguez
- Plum Island Animal Disease Center; ARS; USDA; Greenport New York USA
| | - C. G. Gay
- Agricultural Research Service; USDA; National Program 103-Animal Health; Beltsville MD USA
| | - K. J. Sumption
- European Commission for the Control of FMD (EuFMD); FAO; Rome Italy
| | - W. Vosloo
- Australian Animal Health Laboratory; CSIRO-Biosecurity Flagship; Geelong Vic Australia
| |
Collapse
|
10
|
Ringa N, Bauch CT. Impacts of constrained culling and vaccination on control of foot and mouth disease in near-endemic settings: a pair approximation model. Epidemics 2014; 9:18-30. [PMID: 25480131 DOI: 10.1016/j.epidem.2014.09.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 09/19/2014] [Accepted: 09/21/2014] [Indexed: 11/18/2022] Open
Abstract
Many countries have eliminated foot and mouth disease (FMD), but outbreaks remain common in other countries. Rapid development of international trade in animals and animal products has increased the risk of disease introduction to FMD-free countries. Most mathematical models of FMD are tailored to settings that are normally disease-free, and few models have explored the impact of constrained control measures in a 'near-endemic' spatially distributed host population subject to frequent FMD re-introductions from nearby endemic wild populations, as characterizes many low-income, resource-limited countries. Here we construct a pair approximation model of FMD and investigate the impact of constraints on total vaccine supply for prophylactic and ring vaccination, and constraints on culling rates and cumulative culls. We incorporate natural immunity waning and vaccine waning, which are important factors for near-endemic populations. We find that, when vaccine supply is sufficiently limited, the optimal approach for minimizing cumulative infections combines rapid deployment of ring vaccination during outbreaks with a contrasting approach of careful rationing of prophylactic vaccination over the year, such that supplies last as long as possible (and with the bulk of vaccines dedicated toward prophylactic vaccination). Thus, for optimal long-term control of the disease by vaccination in near-endemic settings when vaccine supply is limited, it is best to spread out prophylactic vaccination as much as possible. Regardless of culling constraints, the optimal culling strategy is rapid identification of infected premises and their immediate contacts at the initial stages of an outbreak, and rapid culling of infected premises and farms deemed to be at high risk of infection (as opposed to culling only the infected farms). Optimal culling strategies are similar when social impact is the outcome of interest. We conclude that more FMD transmission models should be developed that are specific to the challenges of FMD control in near-endemic, low-income countries.
Collapse
Affiliation(s)
- N Ringa
- Department of Mathematics and Statistics, University of Guelph, 50 Stone Rd E, Guelph, ON N1G 2W1, Canada.
| | - C T Bauch
- Department of Mathematics and Statistics, University of Guelph, 50 Stone Rd E, Guelph, ON N1G 2W1, Canada; Department of Applied Mathematics, University of Waterloo, 200 University Avenue, West Waterloo, ON N2L 3G1, Canada
| |
Collapse
|