The ability of pathogens to obtain iron is a key feature during
the infection process.35 The frequency of hgbB in avian
strains was higher than the occurrence of 85% observed for
Ewers et al.,4 the only study that investigated its presence in
this host. On the other hand,the gene was detected in only 58%
of the strains from swine. Bethe et al.5 detected hgbB in less
frequency in diseased than in healthy animals, a result also
found by Shayegh et al.,29 who analyzed strains from ovine. In
both studies, there is not thought to be a relationship between
the presence of hgbB and pasteurellosis.