Exposure of Domestic Cats to Three Zoonotic Bartonella Species in the United States

Cat-associated Bartonella species, which include B. henselae, B. koehlerae, and B. clarridgeiae, can cause mild to severe illness in humans. In the present study, we evaluated 1362 serum samples obtained from domestic cats across the U.S. for seroreactivity against three species and two strain types of Bartonella associated with cats (B. henselae type 1, B. henselae type 2, B. koehlerae, and B. clarridgeiae) using an indirect immunofluorescent assay (IFA). Overall, the seroprevalence at the cutoff titer level of ≥1:64 was 23.1%. Seroreactivity was 11.1% and 3.7% at the titer level cutoff of ≥1:128 and at the cutoff of ≥1:256, respectively. The highest observation of seroreactivity occurred in the East South-Central, South Atlantic, West North-Central, and West South-Central regions. The lowest seroreactivity was detected in the East North-Central, Middle Atlantic, Mountain, New England, and Pacific regions. We observed reactivity against all four Bartonella spp. antigens in samples from eight out of the nine U.S. geographic regions.