Bartonella henselae infection in British Columbia: Evidence for an endemicdisease among humans

Human bartonellosis in North America is mainly associated with Bartonella h enselae, and the availability of laboratory diagnostic tools has significan tly heightened awareness of the spectrum of human disease that is caused by this bacterium. We detail herein examples of illness in a pediatric popula tion which serve to confirm that B. henselae-associated disease exists in B ritish Columbia. Seroprevalence studies among asymptomatic adults and among children with symptomatic respiratory illness of other causation demonstra ted that 36.8% and 18.5% of sera, respectively, had IFA-IgG titres >= 1:256 . IFA-IgG titres did not vary significantly whether B. henselae ATCC 49793 or a local wild-type B. henselae isolate were used as substrate. An assessm ent of IgM response was consistent with the proposal that endemic seropreva lence is a function of past rather than recent exposure. Both clinical and serological studies are concordant in providing evidence that B. henselae i s endemic in British Columbia.