Pediatric pneumonia, pleural effusion, and pericarditis following cat scratch disease and serological cross-reactions among Bartonella henselae and Rickettsia japonica determined by indirect fluorescence antibodies

Cat scratch disease is associated with a variety of systemic manifestations. We report a pediatric case associated with pneumonia, pleural effusion, and pericarditis. A 3-year-old boy developed prolonged fever unresponsive to antibiotic treatment, including azithromycin and minocycline. Although the fever resolved with corticosteroid treatment, Bartonella henselae IgG titer was positive in indirect fluorescence antibodies, as was Rickettsia japonica IgG titer. Both titers were significantly reduced by serum absorption with B. henselae antigens, and we observed a serological cross-reaction between B. henselae and R. japonica.