Location: Foreign Animal Disease Research
Project Number: 8064-32000-061-21-A
Project Type: Cooperative Agreement
Start Date: Sep 30, 2014
End Date: Sep 29, 2019
Foot-and-Mouth Disease (FMD) is the most important agriculture-associated disease in the world due to extreme contagiousness, broad species range and tremendous economic consequence associated with introduction into disease-free zones. The disease is endemic in Vietnam which has varying incidence of outbreaks of FMDV serotypes O, A and Asia 1. Currently, there is little information regarding disease persistence in Asian buffalo and cattle as reservoirs. This collaborative research project between ARS, PIADC and the Department of Animal Health (DAH), Vietnam, seeks to generate knowledge of genetic and antigenic trends of Foot-and-Mouth Disease Viruses (FMDVs) circulating and emerging in Vietnam and across Southeast Asia. Information generated will be used to enhance Vietnam’s ability to control FMD and facilitate preparedness of USA for accidental or intentional introduction of novel FMDV strains. 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. Field sample collection from asymptomatic cattle and Asian buffalo to determine applicability as routine manner of FMDV surveillance in Vietnam. 3. Survey and analyze FMDVs 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.
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. Areas of surveillance will be determined. FMD-non-structural protein (FMD-NSP) serosurveys will be conducted to identify high-probability herds for finding carriers. Serial probang sampling 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. Sera, vesicle epithelium and probang samples will be collected from affected animals in FMD outbreak zones throughout Vietnam. Those samples will then be screened for FMDV and vRNA. 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.