Several years ago, Rochalimaea henselae has emerged as an agent of bac
illary angiomatosis, bacillary peliosis and recurrent septicaemia that
generally occur in patients infected with human immunodeficiency viru
s. An aetiologic role in cat scratch disease is also suspected widely
on the basis of a serologic survey. Its slow growth and its culture re
quirement explain that this pathogen, a gram-negative bacterium, could
not be isolated until 1990. Moreover, blood and tissue samples reques
t lysis and crushing for recovering by culture. The clinical, histolog
ical, microbiological and pathogenic aspects of these infections are d
escribed and discussed.