title: A Malaysia 97 monovalent foot-and-mouth disease vaccine (>6PD50/dose) protects pigs against challenge with a variant FMDV A SEA-97 lineage virus, 4 and 7 days post vaccination.
abstract: Pigs play a significant role during outbreaks of foot-and-mouth disease (FMD) due to their ability to amplify the virus. It is therefore essential to determine what role vaccination could play to prevent clinical disease and lower virus excretion into the environment. In this study we investigated the efficacy of the double oil emulsion A Malaysia 97 vaccine (>6PD50/dose) against heterologous challenge with an isolate belonging to the A SEA-97 lineage at 4 and 7 days post vaccination (dpv). In addition, we determined whether physical separation of pigs in the same room could prevent virus transmission. Statistically there was no difference in the level of protection offered by 4 and 7 dpv. However, no clinical disease or viral RNA was detected in the blood of pigs challenged 4 dpv, although three of the pigs had antibodies to the non-structural proteins (NSPs), indicating viral replication. Viral RNA was also detected in nasal and saliva swabs, but on very few occasions. Two of the pigs vaccinated seven days prior to challenge had vesicles distal from the injection site, but on the inoculated foot, and two pigs had viral RNA detected in the blood. One pig sero-converted to the NSPs. In contrast, all unvaccinated and inoculated pigs had evidence of infection. No infection occurred in any of the susceptible pigs in the same room, but separated from the infected pigs, indicating that strict biosecurity measures were sufficient under these experimental conditions to prevent virus transmission. However, viral RNA was detected in the nasal swabs of one group of pigs, but apparently not at sufficient levels to cause clinical disease. Vaccination led to a significant decrease in viral RNA in vaccinated pigs compared to unvaccinated and infected pigs, even with this heterologous challenge, and could therefore be considered as a control option during outbreaks.
authors.affiliation: Australian Animal Health Laboratory, CSIRO-Biosecurity Flagship, Geelong, Australia.
authors.forename: Singanallur Balasubramanian
authors.initials: SB
authors.lastname: Nagendrakumar
authors.affiliation: National Veterinary Company, Ho Chi Minh City, Vietnam.
authors.forename: Nguyen Thi Thu
authors.initials: NT
authors.lastname: Hong
authors.affiliation: Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
authors.forename: Fosgate T
authors.initials: FT
authors.lastname: Geoffrey
authors.affiliation: Australian Animal Health Laboratory, CSIRO-Biosecurity Flagship, Geelong, Australia.
authors.forename: Morris Michelle
authors.initials: MM
authors.lastname: Jacqueline
authors.affiliation: Australian Animal Health Laboratory, CSIRO-Biosecurity Flagship, Geelong, Australia.
authors.forename: Davis
authors.initials: D
authors.lastname: Andrew
authors.affiliation: Australian Animal Health Laboratory, CSIRO-Biosecurity Flagship, Geelong, Australia.
authors.forename: Giles
authors.initials: G
authors.lastname: Michelle
authors.affiliation: National Veterinary Company, Ho Chi Minh City, Vietnam.
authors.forename: Kim
authors.initials: K
authors.lastname: Van Phuc
authors.affiliation: National Veterinary Company, Ho Chi Minh City, Vietnam.
authors.forename: Quach Vo
authors.initials: QV
authors.lastname: Ngon
authors.affiliation: National Veterinary Company, Ho Chi Minh City, Vietnam.
authors.forename: Le Thi Thu
authors.initials: le TT
authors.lastname: Phuong
authors.affiliation: National Veterinary Company, Ho Chi Minh City, Vietnam.
authors.forename: Nguyen Ngoc Hong
authors.initials: NN
authors.lastname: Phuc
authors.affiliation: National Veterinary Company, Ho Chi Minh City, Vietnam.
authors.forename: Tran Xuan
authors.initials: TX
authors.lastname: Hanh
authors.affiliation: Center for Veterinary Diagnostics, Regional Animal Health Office 6, Ho Chi Minh City, Vietnam.
authors.forename: Vo
authors.initials: V
authors.lastname: Van Hung
authors.affiliation: Center for Veterinary Diagnostics, Regional Animal Health Office 6, Ho Chi Minh City, Vietnam.
authors.forename: Le Thi
authors.initials: le T
authors.lastname: Quynhanh
authors.affiliation: Center for Veterinary Diagnostics, Regional Animal Health Office 6, Ho Chi Minh City, Vietnam.
authors.forename: Tran Minh
authors.initials: TM
authors.lastname: Tan
authors.affiliation: Center for Veterinary Diagnostics, Regional Animal Health Office 6, Ho Chi Minh City, Vietnam.
authors.forename: Ngo Thanh
authors.initials: NT
authors.lastname: Long
authors.affiliation: Australian Animal Health Laboratory, CSIRO-Biosecurity Flagship, Geelong, Australia. Electronic address: wilna.vosloo@csiro.au.
authors.forename: Vosloo
authors.initials: V
authors.lastname: Wilna
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D005536:Foot-and-Mouth Disease / Q000517:prevention & control*; D029544:Foot-and-Mouth Disease Virus / Q000276:immunology* / Q000302:isolation & purification; D008296:Malaysia; D009297:Nasal Mucosa / Q000821:virology; D009821:Oils / Q000008:administration & dosage; D012367:RNA, Viral / Q000032:analysis; D012463:Saliva / Q000821:virology; D013552:Swine; D013553:Swine Diseases / Q000517:prevention & control*; D014765:Viral Vaccines / Q000008:administration & dosage* / Q000276:immunology* / Q000302:isolation & purification
chemical_list: D000276:Adjuvants, Immunologic; D000914:Antibodies, Viral; D009821:Oils; D012367:RNA, Viral; D014765:Viral Vaccines
keywords: Early protection; Foot-and-mouth disease; Heterologous challenge; Pigs; Serotype A; Vaccination