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United States Department of Agriculture

Agricultural Research Service

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Research Project: Foot-and-Mouth Disease Virus Ecology and Surviellance in Vietnam; Exploiting Asymptomatic Carriers to Monitor Field Strains

Location: Foreign Animal Disease Research

Project Number: 8064-32000-057-68
Project Type: Interagency Reimbursable Agreement

Start Date: Jun 18, 2014
End Date: Jun 17, 2018

Objective:
This collaborative research project seeks to demonstrate the manner in which Foot-and-Mouth Disease Virus (FMDV) emerges to initiate outbreaks in Vietnam; specifically by focusing on the role of asymptomatic FMDV carrier buffalo and cattle. Specific objectives include: 1. Continuation of analysis of samples collected under research agreement 58-1940-0-070F “Molecular Epidemiology, Surveillance and Predictive Tools for FMD Control in Vietnam.” 2. Conduct field sampling from carrier cattle and buffalo to test applicability as routine manner of FMDV surveillance in Vietnam. 3. Survey and analyze FMDV associated with outbreaks in Vietnam. 4. Conduct capacity building for Department of Animal Health (DAH) staff in virus sequencing and antigen matching. 5. Sequence viruses collected through surveillance program for phylogenetic analysis. 6. Collect slaughterhouse samples to evaluate utility as routine manner of FMDV surveillance in Vietnam.

Approach:
1. Samples, inclusive of probang and tissue specimens from carrier buffalo and cattle, which have been collected and sent to ARS, PIADC, will be analyzed using rRT-PCR and virus isolation. Sequence analysis will be conducted to determine the phylogenetic relationships between outbreak FMDVs and those viruses that persist asymptomatically in cattle. Histological and immunohistochemical examination of tissues from FMDV-persistently infected buffalo will be conducted. Techniques will be developed for deep sequencing of FMDV for quasispecies analysis. 2. Geographic regions will be identified by Department of Animal Health (DAH) (Vietnam) collaborators. FMD-nonstructural protein (FMD-NSP) serosurveys will be conducted to identify high-probability herds for finding cariers. Serial probang samples will be conducted inclusive of screening probangs for FMDV and viral RNA (vRNA). Samples found positive will be sent to ARS, PIADC for further analysis. 3. Samples, inclusive of sera, vesicle epithelium and probang, will be collected from naturally occurring outbreak zones throughout Vietnam. These viruses will be isolated and undergo phylogenetic analysis. 4. DAH staff will be trained in antigen matching techniques and RNA sequencing. Cross-laboratory harmonization validation activities will also be conducted. ARS, PIADC staff will travel to Vietnam to provide follow-on necropsy training and laboratory skills. Monthly meetings and quarterly reports will strengthen capacity building efforts. 5. Probang samples found to contain FMDV RNA by DAH will be sequenced by ARS, PIADC and DAH. Data generated will provide geographic and temporal data, case history and animal demographics to determine quasispecies dynamics. 6. To determine FMDV persistence, probangs and tissue samples will be obtained from animals at Vietnamese slaughterhouses. These samples will be used as a surveillance tool for sequence analysis.

Last Modified: 7/4/2015
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