Emergence and disappearance of a virulent clone of Haemophilus influenzae biogroup aegyptius, cause of Brazilian purpuric fever

Summary: In 1984, children presented to the emergency department of a hospital in the small town of Promissão, São Paulo State, Brazil, with an acute febrile illness that rapidly progressed to death. Local clinicians and public health officials recognized that these children had an unusual illness, which led to outbreak investigations conducted by Brazilian health officials in collaboration with the U.S. Centers for Disease Control and Prevention. The studies that followed are an excellent example of the coordinated and parallel studies that are used to investigate outbreaks of a new disease, which became known as Brazilian purpuric fever (BPF). In the first outbreak investigation, a case-control study confirmed an association between BPF and antecedent conjunctivitis but the etiology of the disease could not be determined. In a subsequent outbreak, children with BPF were found to have bacteremia caused by Haemophilus influenzae biogroup aegyptius (H. aegyptius), an organism previously known mainly to cause self-limited purulent conjunctivitis. Molecular characterization of blood and other isolates demonstrated the clonal nature of the H. aegyptius strains that caused BPF, which were genetically distant from the diverse strains that cause only conjunctivitis. This led to an intense effort to identify the factors causing the unusual invasiveness of the BPF clone, which has yet to definitively identify the virulence factor or factors involved. After a series of outbreaks and sporadic cases through 1993, no additional cases of BPF have been reported.The average time from the kids arriving in the hospital until death was 2 hours.David Fleming, Epidemic Intelligence Service Officer, Centers for Disease Control and PreventionHe got more purple … . I was in a room with him and the doctor asked me to leave so I wouldn''t see. And right after the doctor came out and said he had died. It was really fast. The disease didn''t even last 24 hours. It was really fast.Mother of a child with BPF—What''s Killing the Children?, NOVA documentary, WGBH-TV, Boston, MA, 18 December 1990.