Location: Foreign Animal Disease Research
Project Number: 8064-32000-057-43-N
Project Type: Non-Funded Cooperative Agreement
Start Date: Sep 1, 2012
End Date: Aug 31, 2014
This collaborative research project seeks to characterize the epidemiology of Foot-and-Mouth Disease Virus (FMDV) and the strains circulating in Pakistan in support of control strategies. The specific objectives of this research project include: 1. Identify current FMDV strains circulating in Pakistan. 2. Investigate the spatial and termporal distribution of FMDV and model the pattern of FMDV occurrence and transmission in Pakistan. 3. Carry out vaccine matching studies of the current circulating FMDV strains with vaccines to be used in control program. 4. Study the role of persistently infected cattle and Asian buffalo on the transmission of FMDV. 5. Characterize the anatomical pathology of persistence of FMDV in Asian buffalo and cattle. 6. If funding permits, carry out in vivo challenge studies to confirm in vitro vaccine matching.
To achieve our objective the following steps will be taken: 1. In close collaboration with the ongoing Foreign Agriculture Organization control project, the National Veterinary Laboratory (NVL) and the National Agriculture Research Center (NARC), sampling of FMDV will continue in Pakistan. The viruses will be isolated at either NVL or NARC and then shipped to ARS-PIADC for further molecular analysis. This will include sequencing and phylogenetic analysis. 2. At ARS-PIADC vaccine matching will be carried out using previously available vaccine sera and recent isolates. The assay carried out at ARS-PIADC will be harmonized with the World Reference Laboratory (WRL), Insitute for Animal Health (IAH) Pirbright, UK, to insure that the vaccine matching data is in agreement. If funding is available, a member from ARS-PIADC will travel to Pakistan to implement the vaccine matching protocol at NARC. If no funding is available alternative teaching methods, such as video conference calls, will be utilized. 3. In collaboration with the University of California-Davis, the Disease BioPortal will be used to display the spatial, temporal and phylogenetics of FMDV strains. The understanding of the patterns and dynamics of the disease will help to design appropriate control measures that might include other measures besides vaccine matching. 4. If funding is available, NARC will carry out in vivo challenge studies to verify the vaccine matching in vitro. 5. A number (20-40) of farms, with past history of FMDV and with at least 20 animals, will be selected for a prospective study. Blood, probang and nasal swabs will be collected from these animals. Blood will be tested for non-structural proteins (NSP) against FMDV using an ELISA. Probang and nasal swabs from all NSP positive animals will be processed by rRTPCR and virus isolation. Probang and nasal swab sampling from NSP positive animals will continue and will be collected after every 3-4 weeks day up to 90 days for determination of persistency and carrier animals. A comparison between probang data and nasal swabs will also be made. 6. Peri-urban farms which have Asian buffalo and cattle, age >6 months, for the market will be selected and registered. Both probang and blood samples will be collected for FMDV detection. All FMDV positive (NSP seropositive & probang rRT-PCR+) cases will be necropsied and various tissues will be collected, including roof of nasopharynx, dorsal soft palate, regional lymph nodes and tonsils. These samples will be screened by rRT-PCR, histopathology and immunomicrsoscopy at ARS PIADC.