Page Banner

United States Department of Agriculture

Agricultural Research Service

Related Topics

Research Project: APPLYING EPIDEMIOLOGICAL MODELS TO UNDERSTANDING THE EMERGENCE OF NEW FMD VIRUS ANTIGENIC AND GENETIC VARIANTS

Location: Foreign Animal Disease Research

2012 Annual Report


1a.Objectives (from AD-416):
The Foot-and-Mouth Disease (FMD) lab within the CADMS (Center for Animal Disease Modelling Systems) is located at the University of California, Davis and along with ARS, is a member of the Global Foot-and-Mouth Disease Research Alliance (GFRA). CADMS is currently compiling extensive global disease surveillance data and is developing a global web-based disease surveillance system, which has resulted in the FMD BioPortal, a publically-available site. ARS is interested in leveraging CADMS capabilities with our offshore research efforts in countries like India, Pakistan as well as future research projects in South East Asia. The objectives of this collaboration are: 1. To expand the UC Davis FMD BioPortal and to provide epidemiological information to ARS, PIADC to aid in current offshore FMD research projects in India, Pakistan and other future related projects. 2. Incorporate FMD virus sequences and epidemiological data provided from ARS collaborators in India, Pakistan and other future collaborators in South East Asia, into the BioPortal system. 3. Identify relationships between the variation in number of different nucleotides within the P1 gene of FMD virus provided by ARS collaborators in India, Pakistan and other future collaborators in South East Asia or ARS, PIADC and features of the host population that were associated with changes in the virus sequences. Amendment 1: 4. Elucidate epidemiological aspects of FMD transmission and spread in Pakistan. 5. Provide epidemiological support and contribute to the coordination of the FMD control program conducted by the FAO and other instititutions in Pakistan. 6. Contribute to build technical capacity for the National Veterinary Laboratory (NVL) and other institutions in Pakistan related to strengthen the FMD control program in the country.


1b.Approach (from AD-416):
1. ARS, PIADC will provide sequencing data and analysis of field isolates of viruses made available through UC Davis. This data will be incorporated into the BioPortal. 2. UC Davis will provide epidemiological expertise to ARS, PIADC to further basic and applied research. 3. Epidemiological information and sequences provided by ARS, PIADC and ICAR will be incorporated to the FMD BioPortal and will be made available to research partners and the general public in near real time. 4. Data will be used to quantify the relation between nucleotide variation in the P1 sequences of the viruses provided by ICAR and ARS, PIADC and the epidemiological factors hypothesized to be associated with such variation. Amendment 1: 5. Data will be analyzed to: a. Quantify the geographical variation of FMD risk in Pakistan and its association with epidemiological factors. b. Identify areas to gather field samples of FMD in endemic regions of Pakistan for analysis and surveillance. c. Estimate the impact and effectiveness of alternative control strategies, including vaccination, in Pakistan. d. Elaborate and estimating indicators to measure the impact of FMD control strategies in the field, including the implementation of a surveillance program. 6. Results of analyses will be used to elaborate technical recommendations and help to coordinate the design and implementation of an FMD vaccination pilot program in Pakistan. 7. Scientists from the National Veterinary Laboratory in Islamabad, Pakistan, and other individuals in the field will be trained in epidemiological aspects of FMD control.


3.Progress Report:

This collaboration expands the UC Davis Disease BioPortal (DBP) to provide epidemiological information to ARS/FADRU, to aid in current international FMD research projects, and to incorporate and analyze virus sequences made available to UC Davis by USDA-ARS using the DBP. During FY 2012 we have provided support to the Global Foot-and-mouth disease Research Alliance (GFRA)’s mission through presentations at international settings and by contributing with epidemiological expertise in the design of field studies, including those for USDA-ARS-led studies in Pakistan and Vietnam. Support was also provided to the analysis of data for the assessment of parenteral influence on the development of antibodies against FMD using data collected in Argentina under a USDA-ARS – Argentina collaboration. A training workshop on basic epidemiology was conducted in Pakistan. Veterinarians from the federal and provincial governments were training on basic aspects of epidemiological analysis, with particular reference to FMD epidemiology. The workshop participants identified risk factors associated with different production units and discussed the main components for a successful control program. Future research activities were also discussed. One of the most challenging aspects of FMD control is the high genetic variability of the FMD virus (FMDV). In endemic settings such as the Indian-sub continent, this variability has resulted in the emergence of pandemic strains that have spread widely and caused devastating outbreaks in disease-free areas. The constantly evolving and wide diversity of field FMDV strains is an obstacle for identifying vaccine strains that are successful in conferring protection against infection with field viruses. Quantitative knowledge of the factors that are associated with variability of the FMDV is prerequisite for preventing and controlling FMD in the Indian subcontinent. A hierarchical linear model was used to assess the association between the genetic variability of serotype O FMDV using viruses collected in Pakistan from 2005 to 2011 and time and spatial distance between isolates and differences in host species from which viruses were isolated. Significant amino acid and nucleotide variations was associated with spatial distance, but not with differences in host species, which is consistent with the frequent multi-species infection of this FMDV serotype O. Results from this study will contribute to the understanding of FMDV variability and to the design of FMD control strategies in the Indian subcontinent. Genetic characteristics of the host are known to be an important factor in the immune response for a number of diseases and conditions, and have been investigated mainly in specific immune responses elicited by discrete FMDV-derived peptide sequences. However little is known about the host-specific variation in the response. We measured neutralizing antibodies against three FMDV strains (O1/Campos, A24/Cruzeiro and A/Arg/01) 45 days post vaccination and quantified the breed- and individual-specific variation in the response. A multivalent commercial vaccine was used to immunize 377 naïve calves from four dairy farms in Argentina. Liquid phase blocking-ELISA was used to determine antibody titer. The Pearson correlation of antibody responses was computed to estimate the relationship between each two serotype responses in each calf. Immune response were significantly (P<0.05) correlated between virus strains. Hierarchical mixed regression models were formulated separately for each strain to estimate the association of the immune response with sire and sire breed. Herd was included as a random factor to control for lack of independence of within-herd observations. Sire’s breed was significantly associated with the immune response for the three FMDV strains. Calves from Jersey sires’ antibody titer were lower than calves from Holstein sires. Results suggest that neutralizing antibody response to FMDV vaccination was associated with breed effect, whereas no intra-breed significant variation was detected. In addition, work has been initiated to collaborate with researchers at USDA-ARS in the organization and analysis of data from different experiments conducted at PIADC in which concentration of the FMDV was measured in the air of rooms in which infected and in-contact animals were placed. A manuscript reviewing the global situation of FMDV over the last five years (2007-2012) is currently under preparation. FMDVs circulate in certain regions of Asia, Africa, and South America. Within these areas, the disease has been classified in seven geographic pools or clusters, in which similar virus strains have been historically found. The endemic features of genetic lineages within pools are usually given by ecological similarities, common livestock species demographics, management practiced, and cultural traditions. The geographic locations of FMDV pools describe a general approximation of the virus distribution, but there are transition areas where viruses endemic to different pools may co-exist under particular conditions. The current situation and most important epidemiological features reported over the last 5 years for FMD have been reviewed. Information was obtained from the OIE/FAO FMD Reference Laboratories Network, country reports to the OIE, scientific published literature, and international meetings. Among the features described in this review are the detection of new lineages of serotype A and O FMDV in northern Africa and southern Africa and the detection of at least 3 different lineages of serotype SAT 2 FMDV in Egypt, Libya and Palestinian Autonomous Territories. During FY 2012 training of one researcher/PhD student who is also as part of the ORISE program continued. Research conducted under this agreement also helped a graduate student in Nigeria to fulfill the requirements for his MsSc degree and acceptance to start a PhD program.

The technology that have been transferred in FY2012 is the population of epidemiological data in the UC Davis DPB. The DBP is a web-based system that provides real time or near real-time access to local, regional and global disease information and data. This system provides access to publicly available databases, as well as to private data through secure routing and sharing mechanisms. Publications for FY 2012 include: 1. Perez A, AlKhamis M, Carlsson U, Brito B, Carrasco-Medanic R, Whedbee Z, Willeberg P, 2011. Global surveillance of animal disease. Spatial and Spatio-temporal Epidemiology 2, 135–145 2. Mullner P, Zadoks R, Perez A, Spencer S, Schukken Y, French N, 2011. The integration of molecular tools into veterinary and spatial epidemiology. Spatial and Spatio-temporal Epidemiology 2, 159-171 3. Brito B, Perez AM, Cosentino B, Rodriguez LL, König GA, 2011. Factors associated with within-herd transmission of serotype A foot-and-mouth disease virus in cattle, during the 2001 outbreak in Argentina: A protective effect of vaccination. Journal of Transboundary and Emerging Diseases 58(5):387-393 4. Ehizibolo DO, Perez AM, Carrillo C, Pauszek S, AlKhamis M, Umoh JU, Ajogi I, Kazeem, HM, Ehizibolo PO, Fabian A, Berninger M, Moran K, Rodriguez LL, Metwally SA, 2011. Epidemiological Analysis, Serological prevalence and Genotypic Analysis of Foot-and-Mouth Disease Outbreak in Nigeria 2008-2009. Journal of Transboundary and Emerging Diseases. In review. 5. Brito B, Perez AM, Jamal SM, Belsham GJ, Pauszek SJ, Ahmed Z, Rodriguez L. Foot-and-mouth disease virus serotype O phylodynamics: genetic variability associated to epidemiological factors in Pakistan. Transboundary and Emerging Diseases. Submitted.


Last Modified: 12/27/2014
Footer Content Back to Top of Page