A RAPID DOT IMMUNOASSAY FOR DETECTING THE BRAZILIAN PURPURIC FEVER CLONE OF HAEMOPHILUS-INFLUENZAE BIOGROUP AEGYPTIUS WITH A FLOW-THROUGH DEVICE

Brazilian purpuric fever (BPF) is a highly fatal pediatric disease tha t may follow an episode of purulent conjunctivitis caused by a virulen t clone of Haemophilus influenzae biogroup aegyptius (Hae). Oral rifam pin prophylaxis, by eliminating carriage of the BPF clone in children with conjunctivitis, may prevent onset of the systemic disease. A test to detect the BPF clone directly from eye swabs could identify those in need of prophylaxis. This is a preliminary report of a rapid dot im munoassay performed on a ''flow-through'' cartridge that was developed for use under field conditions. The test is based upon recognition of a unique epitope of the 25-kDa pilin protein on the surface of BPF cl one cells by a monoclonal antibody. With 36 laboratory-maintained cult ures of Hae (15 clone isolates and 21 others), sensitivity of the assa y was 67% and specificity was 95%. When fimbrial-enriched (25-kDa+) ph enotypes of five false-negative clone strains were prepared for use as test antigens, sensitivity rose to 100%. Evaluation of the immunoassa y under field conditions is necessary to prove its efficacy.