PROTECTIVE CAPACITY OF FOOT-AND-MOUTH DISEASE SOUTH AMERICAN VACCINE STRAINS O1CAMPOS, A24 AND A2001 AGAINST SOUTHEAST ASIAN VIRUSES OF CURRENTLY CIRCULATING TOPOTYPES

MARADEI E; PEDEMONTE, A.R.; BERGMANN I.E.; MALIRAT V; GALDO NOVO, S.

Bangkok

Encuentro; 2019 GFRA: Global Foot-and-Mouth Disease Research Alliance. SCIENTFIC MEETING; 2019

Global Foot-and-Mouth Disease Research Alliance

The selection and application of a highly immunogenic and broadly coss-reactive foot-and-mouth disease virus vaccine strain to control outbreaks is of utmost importance and is a constant concern of livestock control authorities worldwide. This is a rather complex and challenging task, mainly due to the lack of an ?in vitro? method to reliably infer the capacity of a vaccine strain to protect against circulating strains, and even possibly emerging ones in the field. In this work, a test algorithm is presented to estimate the protective capacity of vaccines, formulated with widely used South American vaccine strains, against field isolates currently circulating in Southeast Asia.Genetic and antigenic relationships were determined between vaccine strains O1 Campos, A24 Cruzeiro and A2001, and field isolates belonging to type O Mya98, Panasia2 and IND2001 lineages and CATHAY topotype, and to type A Sea 97 and GVII lineages through nucleotide sequencing and Mabs profiling.This allowed to select field strains representative of the presently circulating variants in Southeast Asia, to further perform virus neutralization tests using post-vaccination sera derived from cattle and pigs, to infer the effectiveness of high-quality vaccines applied in different formulations and vaccination schemes. Finally, and based on the results obtained, the gold standard in vivo challenge test was carried out against selected strains, which demonstrated the protective capacity of the South American strains against the type O and A strains currently circulating in Southeast Asia.