The present invention is directed to novel nucleotide sequences of Senecavirus A (“SVA”), including novel genotypes thereof, which are useful as live attenuated and other vaccine compositions for treating and preventing diseases in swine and other animals. Vaccines provided according to the practice of the invention are effective against multiple swine SVA genotypes and isolates. Diagnostic and therapeutic sequences are also a feature of the present invention, as are infectious clones useful in the propagation of the virus and in the preparation of vaccines. Particularly important aspects of the invention include polynucleotide constructs that replicate in tissue culture and in host swine. The invention also provides for novel full length SVA genomes that can replicate efficiently in host animals and tissue culture.