The role of Branhamella catarrhalis in the "bloody-nose syndrome" of cynomolgus macaques.

During a 15-month period, 25 cynomolgus macaques (Macaca fascicularis) at the Johns Hopkins University were observed to have nasal discharge. Fifteen (60%) of these animals had positive nasal cultures for Branhamella catarrhalis. Clinical signs associated with infection by this bacterium were sneezing, epistaxis, and mucohemorrhagic nasal discharge. Treatment with antibiotics resulted in prompt resolution of clinical signs. Post-therapeutic nasal cultures were negative for B. catarrhalis. Two groups of clinically normal, culture-negative, cynomolgus macaques were inoculated with natural isolates of B. catarrhalis which had been passaged in culture for various amounts of time. Five of the eight animals inoculated became culture-positive and had mild nasal discharge. Presence of blood on nasal swabs was indicative of infection with B. catarrhalis. Three of the inoculated animals had post-swabbing epistaxis. This report documents the role of B. catarrhalis as an upper respiratory pathogen in the cynomolgus monkey which causes mild self-limiting disease reminiscent of the so-called "Bloody-Nose Syndrome." In addition to the obvious clinical significance of this finding to primate clinicians, development of an animal model for human disease caused by this organism may be possible.