2013 Annual Report
1a.Objectives (from AD-416):
This research project seeks to investigate the molecular epidemiology and pathogenesis of emerging strains of Foot-and-Mouth Disease Virus (FMDV) in Vietnam. Specific objectives include:
1. Increase the understanding of viral ecology of Foot-and-Mouth Disease (FMD) in Vietnam, specifically on the role of Asian buffalo on FMDV transmission in Vietnam.
2. Provide expertise on field epidemiology of FMD to help coordinate on-going collaborative research projects with the Department of Animal Health, Vietnam.
1b.Approach (from AD-416):
1. ARS, PIADC will provide MSU collaborators training in FMD epidemiology and diagnostics.
2. In collaboration with scientists from the National Center for Veterinary Diagnostics, Vietnam, MSU collaborators will travel to Vietnam to facilitate field sampling and characterize the molecular epidemiology (phylogenetics) of FMDV strains circulating in Vietnam. Studies will be conducted on the role of persistently infected ruminants, specifically buffalo, in FMDV ecology. Standard operating procedures will be established to quantitate the risk associated with animal movement in and out of FMD outbreak areas.
In FY 2013, the most significant accomplishment has been in facilitating the completion of the longitudinal study in south Vietnam with the Regional Animal Health Office number 6 (RAHO6). The ARS investigator travelled to Vietnam for 3 weeks in 2013. Time in country was divided between the Department of Animal Health (DAH) and National Center for Veterinary Diagnostics (NCVD) in Hanoi and the RAHO6 in Ho Chi Minh City to assist with data collection, data manipulation and participation in necropsies. This visit involved meeting with producers and local officials, the necropsy of two of the donor animals, and collection of any outstanding data. Continued communication and interaction with all study participants throughout the year has been an integral part of implementing the proper testing and monitoring procedures that have been used in this project.
In the south, two animals that were persistently infected with FMD were necropsied to study potential sites of viral infection and replication as well as evaluate test sensitivity. Discussions between investigators and producers have identified additional animals for possible necropsy. Serological and probang samples from the longitudinal study, along with necropsy samples, were identified and organized for shipment to PIADC. Introductory meetings were also held with potential collaborating investigators from the Australian Animal Health Laboratory (AAHL) and NAVETCO, a leading vaccine producer in Vietnam.
It was decided to discontinue longitudinal monitoring after initial screening of cattle and buffalo. Meetings were held with the virologists at NCVD to collect and verify any remaining test results from the initial FMD screening studies in the north. Previous outbreaks were discussed and potential target areas for future studies were identified.
In addition, we have developed educational materials for livestock producers and for veterinarians in Vietnam. Training was developed for laboratory and epidemiology staff at RAHO6 on interpreting and evaluating diagnostic testing procedures. Handouts in Vietnamese that were created on biosecurity for livestock farmers and veterinarians/para-veterinarians were created and distributed.
Major accomplishments to date include: the completion of longitudinal study demonstrating lack of transmission between persistently infected and sentinel animals, necropsy of persistently affected animals to examine potential sites of FMDV infection or replication and comparison of testing protocols to provide an estimate of the sensitivity of diagnostic tests used to identify persistently infected animals.
This is the first known attempt to document transmission of the virus by persistently infected buffalo and cattle to naïve animals. While our final transmission cells did not involve buffalo donor animals, the results of this study have been able to assist in the understanding the role of persistent carriers in disease transmission in the natural environment, providing an understanding of the interspecies transmission between infected Asian buffalo and naïve cattle, the development of standardized protocols for the detection of carrier animals, particularly in cattle and buffalo and providing additional support towards the development of sampling strategies for freedom from disease for quarantine/export certification.
No new technologies have been produced or transferred to date from this ongoing work. No peer-reviewed publications have been produced to date from this ongoing work.