[Synergy between infections by Escherichia coli with different virulence and Gumboro's disease virus [in chicken]]

avian infectious bursitis bacteriose bacterioses bacteriosis batteriosi bursite infettiva aviare chicks elisa enfermedad de gumboro escherichia in vivo experimentation maladie de gumboro pathogenicity pollito poussin pulcini servicios veterinarios servizi veterinari sperimentazione in vivo test elisa veterinary services