From Cat scratch disease to Bartonella henselae infection.

Cat scratch disease (CSD) is a relatively common disease mainly caused by Bar-tonella henselae. In this issue of Clinical Infectious Diseases, Maman et al. [1] report on musculoskeletal manifestations of CSD, extending the spectrum of clinical manifestations of B. henselae infection by including chronic arthritis, as well as emphasizing the prevalence of arthralgias. As a matter of fact, CSD is a paradigm for the evolution of knowledge following the discovery of an etiologic agent for an infectious disease. In many cases, such as the example outlined here, a very specific clinical form of a disease is described first. The first formal description of CSD was made in Paris and was named " maladie des griffes du chat " in 1950 to acknowledge the link between the disease and cats [2]. Typical CSD develops after contact with a cat and comprises subacute regional lymphadenopathies that can be associated with a primary skin lesion and systemic manifestations [3]. The etiologic agent of this clinical entity remained elusive for years; however, some serum samples (from patients with CSD) reacted with chlamydial antigens. Cross-reactivity occurred between Chlamydia species and Bartonella species, which was later determined to be the cause of CSD [4]. Significant progress was made with electronic microscopic methods [5] and when an argentic histological staining method called Warthin Starry was used to detect bacteria-like black spots in lymph node specimens [3, 6]. In the AIDS era, a completely new clinical entity, bacillary angiomatosis, was described. It is antibiotic sensitive and involves cutaneous vas-cular tumors. Positive results by Warthin Starry staining of biopsy specimens suggested a possible link between bacillary an-giomatosis and CSD [7, 8]. In November 1990, a single issue of the New England Journal of Medicine highlighted 3 different approaches to pathogen discovery. Relman et al. [9] used 16 S rRNA–based universal amplification and sequencing to identify bacteria not yielded by culture in a patient with bacillary an-giomatosis for the first time. Slater et al. [10] grew a fastidious gram-negative bacterium in specimens from febrile patients with AIDS, and finally, Perkocha et al. [11] identified Warthin Starry–positive bacteria in a biopsy specimen from a patient with hepatic peliosis and AIDS [12]. It was later recognized that the 3 teams were describing the same bacterium [12]. B. henselae was linked to CSD by chance. In fact, when Regnery et al. [13] from the Centers for Disease Control and Prevention were testing a …