Phylograms revealed that the bcr gene in HPS-1 was most closely related to homologs identified in other members of the Pasteurellaceae, particularly G. parasuis, Actinobacillus indolicus, Bibersteinia trehalosi, Actinobacillus (A. pleuropneumoniae, A. suis, A. equuli, A. lignieresii, A. indolicus, and A. porcitonsillarum), and Mannheimia (M. haemolytica and M. varigena), all of which are known causative agents of upper respiratory tract infections (Fig. 6). Here, HPS1 is linked to Recurrent upper respiratory tract infections.