1
|
Ellis J, Brown E, Colenutt C, Schley D, Gubbins S. Inferring transmission routes for foot-and-mouth disease virus within a cattle herd using approximate Bayesian computation. Epidemics 2024; 46:100740. [PMID: 38232411 DOI: 10.1016/j.epidem.2024.100740] [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] [Received: 03/31/2022] [Revised: 12/06/2023] [Accepted: 01/03/2024] [Indexed: 01/19/2024] Open
Abstract
To control an outbreak of an infectious disease it is essential to understand the different routes of transmission and how they contribute to the overall spread of the pathogen. With this information, policy makers can choose the most efficient methods of detection and control during an outbreak. Here we assess the contributions of direct contact and environmental contamination to the transmission of foot-and-mouth disease virus (FMDV) in a cattle herd using an individual-based model that includes both routes. Model parameters are inferred using approximate Bayesian computation with sequential Monte Carlo sampling (ABC-SMC) applied to data from transmission experiments and the 2007 epidemic in Great Britain. This demonstrates that the parameters derived from transmission experiments are applicable to outbreaks in the field, at least for closely related strains. Under the assumptions made in the model we show that environmental transmission likely contributes a majority of infections within a herd during an outbreak, although there is a lot of variation between simulated outbreaks. The accumulation of environmental contamination not only causes infections within a farm, but also has the potential to spread between farms via fomites. We also demonstrate the importance and effectiveness of rapid detection of infected farms in reducing transmission between farms, whether via direct contact or the environment.
Collapse
Affiliation(s)
- John Ellis
- The Pirbright Institute, Pirbright, Surrey, UK.
| | - Emma Brown
- The Pirbright Institute, Pirbright, Surrey, UK
| | | | | | | |
Collapse
|
2
|
Zewdie G, Akalu M, Tolossa W, Belay H, Deresse G, Zekarias M, Tesfaye Y. A review of foot-and-mouth disease in Ethiopia: epidemiological aspects, economic implications, and control strategies. Virol J 2023; 20:299. [PMID: 38102688 PMCID: PMC10724896 DOI: 10.1186/s12985-023-02263-0] [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] [Received: 07/29/2023] [Accepted: 12/07/2023] [Indexed: 12/17/2023] Open
Abstract
Foot-and-mouth disease (FMD) is a contagious viral disease that affects the livelihoods and productivity of livestock farmers in endemic regions. It can infect various domestic and wild animals with cloven hooves and is caused by a virus belonging to the genus Aphthovirus and family Picornaviridae, which has seven different serotypes: A, O, C, SAT1, SAT2, SAT3, and Asia-1. This paper aims to provide a comprehensive overview of the molecular epidemiology, economic impact, diagnosis, and control measures of FMD in Ethiopia in comparison with the global situation. The genetic and antigenic diversity of FMD viruses requires a thorough understanding for developing and applying effective control strategies in endemic areas. FMD has direct and indirect economic consequences on animal production. In Ethiopia, FMD outbreaks have led to millions of USD losses due to the restriction or rejection of livestock products in the international market. Therefore, in endemic areas, disease control depends on vaccinations to prevent animals from developing clinical disease. However, in Ethiopia, due to the presence of diverse antigenic serotypes of FMD viruses, regular and extensive molecular investigation of new field isolates is necessary to perform vaccine-matching studies to evaluate the protective potential of the vaccine strain in the country.
Collapse
Affiliation(s)
- Girma Zewdie
- National Veterinary Institute (NVI), P. O. Box: 19, Bishoftu, Ethiopia.
| | - Mirtneh Akalu
- National Veterinary Institute (NVI), P. O. Box: 19, Bishoftu, Ethiopia
- Koneru Lakshmaiah Education Foundation, Department of Biotechnology, Vaddeswaram, Guntur, Ap, 522502, India
| | | | - Hassen Belay
- Africa Union Pan African Veterinary Vaccine Center (AU-PANVAC), P. O. Box: 1746, Bishoftu, Ethiopia
| | - Getaw Deresse
- National Veterinary Institute (NVI), P. O. Box: 19, Bishoftu, Ethiopia
| | | | - Yeneneh Tesfaye
- National Veterinary Institute (NVI), P. O. Box: 19, Bishoftu, Ethiopia
| |
Collapse
|
3
|
Mielke SR, Lendzele S, Delgado AH, Abdoulmoumini M, Dickmu S, Garabed R. Patterns of foot-and-mouth disease virus detection in environmental samples in an endemic setting. Front Vet Sci 2023; 10:1157538. [PMID: 37396995 PMCID: PMC10312077 DOI: 10.3389/fvets.2023.1157538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 05/29/2023] [Indexed: 07/04/2023] Open
Abstract
Foot-and-Mouth Disease virus (FMDV) is endemic in several regions and is a virus that can persist in the environment dependent on pH, relative humidity (RH), temperature, and matrix (i.e., soil, water, or air). Our previously published analysis of available viral persistence data showed that persistence is likely affected by interactions between RH, temperature, and matrix. Understanding these relationships will aid efforts to eliminate FMD, which has significant impacts on economies and food security. In Cameroon, West Africa, the livestock system consists of mobile (transhumant), transboundary trade and sedentary herds. Studying this system can provide information about the patterns of environmental detection of FMDV RNA that may influence approaches to virus elimination on premises during an outbreak. To improve our understanding of these patterns, we collected samples from individuals, vehicles, and along cattle pathways at three sedentary herds beginning on day one of owner-reported outbreaks, ending by day 30, and tested for the presence of FMD viral RNA using rRT-PCR. Our analysis suggests that detection decreases in soil surface samples with increased distance from herd and time from the first report of disease. Whereas time but not distance decreases detection in air samples. Interaction of RH and temperature suggests increased detection at high temperatures (>24°C) and RH (>75%), providing us with new information about the patterns of FMD viral RNA detection in and around cattle herds that could help to inform targeted virus elimination strategies, such as location and application of disinfectants.
Collapse
Affiliation(s)
- Sarah R. Mielke
- Department of Veterinary Preventive Medicine, The Ohio State University College of Veterinary Medicine, Columbus, OH, United States
- United States Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS), Fort Collins, CO, United States
| | - Sevidzem Lendzele
- Transmissible Diseases Ecology Laboratory, Department of Environmental Health, Faculty of Technology and Health Management, Université Libreville Nord, Libreville, Gabon
| | - Amy H. Delgado
- United States Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS), Fort Collins, CO, United States
| | - Mamoudou Abdoulmoumini
- School of Veterinary Science and Medicine, University of Ngaoundéré, Ngaoundéré, Adamawa, Cameroon
| | - Simon Dickmu
- The National Veterinary Laboratory (LANAVET), Garoua North, Cameroon
- University of Bamenda, Bambili, Cameroon
| | - Rebecca Garabed
- Department of Veterinary Preventive Medicine, The Ohio State University College of Veterinary Medicine, Columbus, OH, United States
| |
Collapse
|
4
|
Ellis J, Brown E, Colenutt C, Gubbins S. Assessing the effectiveness of environmental sampling for surveillance of foot-and-mouth disease virus in a cattle herd. Front Vet Sci 2023; 10:1074264. [PMID: 36992974 PMCID: PMC10040685 DOI: 10.3389/fvets.2023.1074264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 02/22/2023] [Indexed: 03/15/2023] Open
Abstract
The survival of foot-and-mouth disease virus (FMDV) in the environment provides an opportunity for indirect transmission, both within and between farms. However it also presents the possibility of surveillance and detection via environmental sampling. This study assesses the effectiveness of environmental sampling strategies in the event of an outbreak, using a previous model for transmission of FMDV in a cattle herd that had been parameterized using data from transmission experiments and outbreaks. We show that environmental sampling can be an effective means of detecting FMDV in a herd, but it requires multiple samples to be taken on multiple occasions. In addition, environmental sampling can potentially detect FMDV in a herd more quickly than clinical inspection. For example, taking 10 samples every 3 days results in a mean time to detection of 6 days, which is lower than the mean time to detection estimated for the 2001 UK epidemic (8 days). We also show how environmental sampling could be used in a herd considered to be at risk as an alternative to pre-emptive culling. However, because of the time taken for virus to accumulate at the start of an outbreak, a reasonable level of confidence (> 99%) that an at-risk herd is indeed free from infection is unlikely to be achieved in less than 1 week.
Collapse
|
5
|
Airborne Transmission of Foot-and-Mouth Disease Virus: A Review of Past and Present Perspectives. Viruses 2022; 14:v14051009. [PMID: 35632750 PMCID: PMC9145556 DOI: 10.3390/v14051009] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 04/25/2022] [Accepted: 05/05/2022] [Indexed: 02/01/2023] Open
Abstract
The primary transmission route for foot-and-mouth disease (FMD), a contagious viral disease of cloven-hoofed animals, is by direct contact with infected animals. Yet indirect methods of transmission, such as via the airborne route, have been shown to play an important role in the spread of the disease. Airborne transmission of FMD is referred to as a low probability- high consequence event as a specific set of factors need to coincide to facilitate airborne spread. When conditions are favourable, airborne virus may spread rapidly and cause disease beyond the imposed quarantine zones, thus complicating control measures. Therefore, it is important to understand the nature of foot-and-mouth disease virus (FMDV) within aerosols; how aerosols are generated, viral load, how far aerosols could travel and survive under different conditions. Various studies have investigated emissions from infected animals under laboratory conditions, while others have incorporated experimental data in mathematical models to predict and trace outbreaks of FMD. However, much of the existing literature focussing on FMDV in aerosols describe work which was undertaken over 40 years ago. The aim of this review is to revisit existing knowledge and investigate how modern instrumentation and modelling approaches can improve our understanding of airborne transmission of FMD.
Collapse
|
6
|
Colenutt C, Brown E, Paton DJ, Mahapatra M, Parida S, Nelson N, Maud J, Motta P, Sumption K, Adhikari B, Kafle SC, Upadhyaya M, Pandey SK, Gubbins S. Environmental sampling for the detection of foot-and-mouth disease virus and peste des petits ruminants virus in a live goat market, Nepal. Transbound Emerg Dis 2021; 69:3041-3046. [PMID: 34331827 DOI: 10.1111/tbed.14257] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 07/20/2021] [Indexed: 01/15/2023]
Abstract
Livestock markets are considered vital parts of the agricultural economy, particularly in developing countries where livestock keeping contributes to both food security and economic stability. Animals from diverse sources are moved to markets, they mix while they are there and are subsequently redistributed over wide geographic areas. Consequently, markets provide an opportunity for targeted surveillance for circulating pathogens. This study investigated the use of environmental sampling at a live goat market in Nepal for the detection of foot-and-mouth disease virus (FMDV) and peste des petits ruminants virus (PPRV), both of which are endemic. Five visits to the market were carried out between November 2016 and April 2018, with FMDV RNA detected on four visits and PPRV RNA detected on all five visits. Overall, 4.1% of samples (nine out of 217) were positive for FMDV RNA and 60.8% (132 out of 217) were positive for PPRV RNA, though the proportion of positive samples varied amongst visits. These results demonstrate that non-invasive, environmental sampling methods have the potential to be used to detect circulation of high priority livestock diseases at a live animal market and, hence, to contribute to their surveillance and control.
Collapse
Affiliation(s)
| | - Emma Brown
- The Pirbright Institute, Pirbright, Surrey, UK
| | | | | | | | | | - Jenny Maud
- European Commission for the Control of Foot-and-Mouth Disease (EuFMD), Food and Agriculture Organization of the United Nations (FAO), Rome, Italy
| | - Paolo Motta
- European Commission for the Control of Foot-and-Mouth Disease (EuFMD), Food and Agriculture Organization of the United Nations (FAO), Rome, Italy
| | - Keith Sumption
- European Commission for the Control of Foot-and-Mouth Disease (EuFMD), Food and Agriculture Organization of the United Nations (FAO), Rome, Italy
| | - Bishnu Adhikari
- European Commission for the Control of Foot-and-Mouth Disease (EuFMD), Food and Agriculture Organization of the United Nations (FAO), Rome, Italy.,Food and Agriculture Organization of the United Nations, Nepal Country Office, Kathmandu, Nepal
| | - Sharmila Chapagain Kafle
- FMD and TADs Laboratory, Department of Livestock Services, Ministry of Livestock Development, Kathmandu, Nepal
| | - Mukul Upadhyaya
- Department of Livestock Services, Veterinary Epidemiology Centre, Ministry of Livestock Development, Kathmandu, Nepal
| | - Samjana Kafle Pandey
- Directorate of Animal Health, Department of Livestock Services, Ministry of Livestock Development, Kathmandu, Nepal
| | | |
Collapse
|
7
|
Paton DJ, Di Nardo A, Knowles NJ, Wadsworth J, Pituco EM, Cosivi O, Rivera AM, Kassimi LB, Brocchi E, de Clercq K, Carrillo C, Maree FF, Singh RK, Vosloo W, Park MK, Sumption KJ, Ludi AB, King DP. The history of foot-and-mouth disease virus serotype C: the first known extinct serotype? Virus Evol 2021; 7:veab009. [PMID: 35186323 PMCID: PMC8102019 DOI: 10.1093/ve/veab009] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/15/2023] Open
Abstract
Foot-and-mouth disease (FMD) is a highly contagious animal disease caused by an RNA virus subdivided into seven serotypes that are unevenly distributed in Asia, Africa, and South America. Despite the challenges of controlling FMD, since 1996 there have been only two outbreaks attributed to serotype C, in Brazil and in Kenya, in 2004. This article describes the historical distribution and origins of serotype C and its disappearance. The serotype was first described in Europe in the 1920s, where it mainly affected pigs and cattle but as a less common cause of outbreaks than serotypes O and A. No serotype C outbreaks have been reported in Europe since vaccination stopped in 1990. FMD virus is presumed to have been introduced into South America from Europe in the nineteenth century, although whether serotype C evolved there or in Europe is not known. As in Europe, this serotype was less widely distributed and caused fewer outbreaks than serotypes O and A. Since 1994, serotype C had not been reported from South America until four small outbreaks were detected in the Amazon region in 2004. Elsewhere, serotype C was introduced to Asia, in the 1950s to the 1970s, persisting and evolving for several decades in the Indian subcontinent and for eighteen years in the Philippines. Serotype C virus also circulated in East Africa between 1957 and 2004. Many serotype C viruses from European and Kenyan outbreaks were closely related to vaccine strains, including the most recently recovered Kenyan isolate from 2004. International surveillance has not confirmed any serotype C cases, worldwide, for over 15 years, despite more than 2,000 clinical submissions per year to reference laboratories. Serology provides limited evidence for absence of this serotype, as unequivocal interpretation is hampered by incomplete intra-serotype specificity of immunoassays and the continued use of this serotype in vaccines. It is recommended to continue strengthening surveillance in regions of FMD endemicity, to stop vaccination against serotype C and to reduce working with the virus in laboratories, since inadvertent escape of virus during such activities is now the biggest risk for its reappearance in the field.
Collapse
Affiliation(s)
- David J Paton
- The Pirbright Institute, Ash Road, Pirbright, Surrey GU24 0NF, UK
| | | | - Nick J Knowles
- The Pirbright Institute, Ash Road, Pirbright, Surrey GU24 0NF, UK
| | - Jemma Wadsworth
- The Pirbright Institute, Ash Road, Pirbright, Surrey GU24 0NF, UK
| | - Edviges M Pituco
- Pan American Foot-and-Mouth Disease and Veterinary Public Health Center, Pan American Health Organization/World Health Organization (PANAFTOSA/VPH-PAHO/WHO), Rio de Janeiro, Brazil
| | - Ottorino Cosivi
- Pan American Foot-and-Mouth Disease and Veterinary Public Health Center, Pan American Health Organization/World Health Organization (PANAFTOSA/VPH-PAHO/WHO), Rio de Janeiro, Brazil
| | - Alejandro M Rivera
- Pan American Foot-and-Mouth Disease and Veterinary Public Health Center, Pan American Health Organization/World Health Organization (PANAFTOSA/VPH-PAHO/WHO), Rio de Janeiro, Brazil
| | - Labib Bakkali Kassimi
- Animal Health Laboratory, UMR1161 Virology, INRAE, ANSES, ENVA, Paris-Est University, Maisons-Alfort 94700, France
| | - Emiliana Brocchi
- Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna (IZSLER), Via Bianchi, 9. 25124 Brescia, Italy
| | - Kris de Clercq
- Sciensano, Infectious Diseases in Animals, Ukkel 1180, Belgium
| | - Consuelo Carrillo
- Diagnostic Services of the Foreign Animal Disease Diagnostic Laboratories, NVSL-VS-APHIS (USDA), Greenport, NY 11944, USA
| | - Francois F Maree
- Transboundary Animal Diseases, Vaccine and Diagnostic Development Programme, Onderstepoort Veterinary Research Institute, Agricultural Research Council, Onderstepoort, Pretoria 0110, South Africa
| | - Raj K Singh
- ICAR-Directorate of Foot-and-Mouth Disease, Uttarakhand, Mukteswar 263138, India
| | - Wilna Vosloo
- Australian Animal Health Laboratory, CSIRO Health and Biosecurity, Geelong, Australia
| | - Min-Kyung Park
- Status Department, World Organisation for Animal Health (OIE), Paris 75017, France
| | - Keith J Sumption
- European Commission for the Control of Foot-and-Mouth Disease, Food and Agriculture Organization of the United Nations, Viale delle Terme di Caracalla, Rome 00153, Italy
| | - Anna B Ludi
- The Pirbright Institute, Ash Road, Pirbright, Surrey GU24 0NF, UK
| | - Donald P King
- The Pirbright Institute, Ash Road, Pirbright, Surrey GU24 0NF, UK
| |
Collapse
|
8
|
Brown E, Nelson N, Gubbins S, Colenutt C. Environmental and air sampling are efficient methods for the detection and quantification of foot-and-mouth disease virus. J Virol Methods 2020; 287:113988. [PMID: 33038353 PMCID: PMC7539831 DOI: 10.1016/j.jviromet.2020.113988] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 09/09/2020] [Accepted: 09/10/2020] [Indexed: 12/15/2022]
Abstract
Foot-and-mouth disease virus (FMDV) can be found in all secretions and excretions and the breath of acutely infected animals. FMDV can survive in the environment, providing an opportunity for surveillance. The objective of this study was to assess the efficiency of sampling methods for the recovery and quantification of FMDV from a range of environmental surfaces and in aerosols. Selected surfaces, based on those likely to be found on farms, were spiked with a range of concentrations of FMDV, left to dry and then the surface was swabbed with an electrostatic dust cloth. For aerosol sampling, FMDV was nebulised at different concentrations and distances from the sampler. Recovery of viral RNA and infectious virus was measured by RT-qPCR and virus isolation respectively. FMDV RNA was detected from all surfaces at all concentrations except from glass. Infectious virus was recovered from all surfaces but only at higher concentrations. The higher the starting concentration of virus the more efficient the recovery was from surfaces and recovery was more consistent from non-porous surfaces than porous surfaces. FMDV was detected in aerosol samples and the amount of virus recovered decreased as the distance between the nebuliser and sampler increased. The higher the starting concentration of virus the more efficient the recovery was from sampled aerosols. The information provided in this study could be used to direct environmental and aerosol sampling approaches in the field and improve the detection efficiency of FMDV from an environment, thus extending the toolbox available for diagnosis and surveillance of this pathogen.
Collapse
Affiliation(s)
- Emma Brown
- The Pirbright Institute, Ash Road, Pirbright, Surrey, GU24 0NF, United Kingdom.
| | - Noel Nelson
- The Pirbright Institute, Ash Road, Pirbright, Surrey, GU24 0NF, United Kingdom; The Met Office, FitzRoy Road, Exeter, Devon, EX1 3PB, United Kingdom
| | - Simon Gubbins
- The Pirbright Institute, Ash Road, Pirbright, Surrey, GU24 0NF, United Kingdom
| | - Claire Colenutt
- The Pirbright Institute, Ash Road, Pirbright, Surrey, GU24 0NF, United Kingdom
| |
Collapse
|
9
|
Miguel E, Grosbois V, Caron A, Pople D, Roche B, Donnelly CA. A systemic approach to assess the potential and risks of wildlife culling for infectious disease control. Commun Biol 2020; 3:353. [PMID: 32636525 PMCID: PMC7340795 DOI: 10.1038/s42003-020-1032-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 04/15/2020] [Indexed: 12/17/2022] Open
Abstract
The maintenance of infectious diseases requires a sufficient number of susceptible hosts. Host culling is a potential control strategy for animal diseases. However, the reduction in biodiversity and increasing public concerns regarding the involved ethical issues have progressively challenged the use of wildlife culling. Here, we assess the potential of wildlife culling as an epidemiologically sound management tool, by examining the host ecology, pathogen characteristics, eco-sociological contexts, and field work constraints. We also discuss alternative solutions and make recommendations for the appropriate implementation of culling for disease control.
Collapse
Affiliation(s)
- Eve Miguel
- Medical Research Council Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, UK.
- MIVEGEC (Infectious Diseases and Vectors: Ecology, Genetics, Evolution and Control), IRD (Research Institute for Sustainable Development), CNRS (National Center for Scientific Research), Univ. Montpellier, Montpellier, France.
- CREES Centre for Research on the Ecology and Evolution of Disease, Montpellier, France.
| | - Vladimir Grosbois
- ASTRE (Animal, Health, Territories, Risks, Ecosystems), CIRAD (Agricultural Research for Development), Univ. Montpellier, INRA (French National Institute for Agricultural Research), Montpellier, France
| | - Alexandre Caron
- ASTRE (Animal, Health, Territories, Risks, Ecosystems), CIRAD (Agricultural Research for Development), Univ. Montpellier, INRA (French National Institute for Agricultural Research), Montpellier, France
| | - Diane Pople
- Medical Research Council Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Benjamin Roche
- MIVEGEC (Infectious Diseases and Vectors: Ecology, Genetics, Evolution and Control), IRD (Research Institute for Sustainable Development), CNRS (National Center for Scientific Research), Univ. Montpellier, Montpellier, France
- UMMISCO (Unité Mixte Internationnale de Modélisation Mathématique et Informatiques des Systèmes Complèxes, IRD/Sorbonne Université, Bondy, France
- Departamento de Etología, Fauna Silvestre y Animales de Laboratorio, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México (UNAM), Ciudad de, México, México
| | - Christl A Donnelly
- Medical Research Council Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, UK
- Department of Statistics, University of Oxford, Oxford, UK
| |
Collapse
|