Effect of FMD vaccine antigen payload on protection, sub-clinical infection and persistence following needle challenge in sheep.
The relationship of Foot-and-Mouth Disease (FMD) virus antigen payload and single and double vaccinations in conferring protection against virus challenge in sheep was studied. Sheep vaccinated with half the cattle dose (1 ml) containing 15 and 3.75 μg of FMDV antigen with or without booster resisted virulent challenge on 21 days post vaccination or 7 days post booster. FMDV RNA could be detected in nasal secretions in 26% of vaccinated sheep (10(3.12) to 10(3.82) viral RNA copies) on day 35 post challenge. No live virus could be isolated after 5 days post challenge indicating that the risk of transmission of disease was probably very low. The finding showed that vaccines containing antigen payload of 1.88 μg may prevent or reduce the local virus replication at the oropharynx and shedding of virus from nasal secretions and thereby reduce the amount of virus released into the environment subsequent to exposure to live virus. Sheep with no vaccination or with poor sero conversion to vaccination can be infected without overt clinical signs and became carriers.
Madhanmohan
Muthukrishnan
M
FMDV Laboratory, Research and Development Centre, Indian Immunologicals Ltd., Gachibowli, Hyderabad 500032, India.
Nagendrakumar
Singanallur Balasubramanian
SB
Narasu
Mangamoori Lakshmi
ML
Srinivasan
Villuppanoor Alwar
VA
D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood; D000956:Antigens, Viral / Q000276:immunology; D058345:Asymptomatic Infections; D002353:Carrier State / Q000662:veterinary*; D005536:Foot-and-Mouth Disease / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D029544:Foot-and-Mouth Disease Virus / Q000276:immunology* / Q000302:isolation & purification / Q000502:physiology; D007115:Immunization Schedule; D007117:Immunization, Secondary / Q000379:methods*; D017817:Nasal Lavage Fluid / Q000821:virology; D016133:Polymerase Chain Reaction; D012367:RNA, Viral / Q000302:isolation & purification; D012756:Sheep / Q000276:immunology / Q000821:virology; D012757:Sheep Diseases / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D014611:Vaccination / Q000379:methods; D014765:Viral Vaccines / Q000008:administration & dosage / Q000276:immunology*; D014779:Virus Replication; D017201:Virus Shedding
D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D000956:Antigens, Viral; D012367:RNA, Viral; D014765:Viral Vaccines