It is important to distinguish between "H. influenzae" biogroup "aegyptius" and the clone referred to as the “BPF clone.” The non-clone, typical version of "H. aegyptius" manifests itself in non-invasive conjunctivitis. The epidemic nature of this bacteria has been seen in the high frequency of “control” subjects from the affected areas of Brazil that have or had recently had conjunctivitis. These control subjects did not develop Brazilian Purpuric Fever, and therefore were probably not carrying the more dangerous BPF clone of "H. influenzae" biogroup aegyptius. Affected patients who had recently had conjunctivitis developed a fever and other symptoms of BPF within 1 to 60 days.