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Title: Clinical and virological dynamics of a serotype O 2010 South East Asia lineage foot-and-mouth disease virus in sheep using natural and simulated natural inoculation and exposure systems

Author
item STENFELDT, CAROLINA - Oak Ridge Institute For Science And Education (ORISE)
item Pacheco Tobin, Juan
item SINGANALLUR, NAGENDRAKUMAR - Australian Animal Health
item DE CARVALHO FERREIRA, HELENA - Oak Ridge Institute For Science And Education (ORISE)
item HOWEY, ERIN - Oak Ridge Institute For Science And Education (ORISE)
item VOSLOO, WILNA - Australian Animal Health
item Rodriguez, Luis
item Arzt, Jonathan

Submitted to: Veterinary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/4/2015
Publication Date: 4/15/2015
Publication URL: https://handle.nal.usda.gov/10113/61578
Citation: Stenfeldt, C., Pacheco Tobin, J., Singanallur, N.B., De Carvalho Ferreira, H.C., Howey, E.B., Vosloo, W., Rodriguez, L.L., Arzt, J. 2015. Clinical and virological dynamics of a serotype O 2010 South East Asia lineage foot-and-mouth disease virus in sheep using natural and simulated natural inoculation and exposure systems. Veterinary Microbiology. DOI:10.1016/j.vetmic.2015.04.004.

Interpretive Summary: A naturally occurring strain of foot-and-mouth disease virus (FMDV), obtained from a sample collected during a recent outbreak of foot-and-mouth disease (FMD) in the Republic of Korea, was used to infect sheep. Four different systems for infecting sheep were evaluated in parallel experimental studies. Two of these systems, consisting either of virus exposure through an aerosol mask, or direct deposition of virus deep within the nasal cavity, have been developed in order to mimic the natural course of FMD infection. These two new systems were compared to two conventional systems consisting of virus delivery through injection in the foot, or direct contact exposure to other sheep that are already infected. All four exposure systems were efficient in generating consistent clinical disease with high similarity within exposure groups. The findings also indicate that the virus strain used for the investigations causes severe disease in sheep. The data presented supports the use of the newly developed simulated natural systems for virus exposure of sheep for experimental studies of FMDV and provides evidence of the importance of the upper respiratory tract as a starting point for FMDV infection in sheep.

Technical Abstract: Infection dynamics of a recent field isolate of foot-and-mouth disease virus (FMDV), serotype O, topotype South East Asia, lineage Myamar ’98 were evaluated in sheep using four different systems for virus exposure. Two novel, simulated natural, inoculation systems consisting of intra-nasopharyngeal (INP) deposition and aerosol inoculation were evaluated in comparison with two conventional systems: coronary band inoculation and direct contact exposure. All four exposure systems were efficient in generating consistently severe, generalized FMD with synchronous clinical characteristics within exposure groups, indicating that this Myamar '98 strain is highly virulent in sheep. Infection dynamics were similarly rapid following INP and coronary band injection, with both systems leading to significantly earlier detection of virus shedding when compared to aerosol inoculation and contact exposure. The data presented support application of the simulated natural inoculation systems presented herein as valid alternatives to conventionally used exposure systems for studies of FMDV pathogenesis and vaccinology in sheep. Furthermore, these data suggest that targeted exposure of the ovine pharynx is highly efficient for generating consistent FMDV infection in sheep, which supports critical involvement of this anatomic region as a site of primary virus replication in this host species.