Epidemiology and Infection

Bartonella infection in sylvatic small mammals of central Sweden

M. HOLMBERG a1c1, J. N. MILLS a2, S. MCGILL a1, G. BENJAMIN a1 and B. A. ELLIS a2
a1 Department of Medical Sciences, Section for Infectious Diseases, Uppsala University Hospital, S-751 85 Uppsala Sweden
a2 Centers for Disease Control and Prevention, Division of Viral and Rickettsial Diseases, 1600 Clifton Rd NE, Mailstop G14, Atlanta, GA 30333


Sylvatic small mammals were captured in rural habitats near Uppsala, Sweden, to measure the prevalence of bartonella infections, characterize bacterial isolates and identify their host range, and increase our understanding of host–pathogen ecology. During 7 nights of trapping at 3 localities, 236 small mammals were captured (trap success 30%). Bartonella were isolated from bloods of Apodemus flavicollis (19 of 110 tested), Apodemus sylvaticus (6/25), Clethrionomys glareolus (9/60), Microtus agrestis (1/3), Mus musculus (1/18), and Sorex araneus (3/20). Nucleotide sequencing (a 338 bp fragment of the gltA gene) of 40 isolates yielded 6 unique genotypes. Five of the 6 genotypes were most similar to other known bartonella isolated from Old World small-mammal hosts. The most frequent genotype (83%) was isolated from A. flavicollis and M. musculus and was identical to Bartonella grahamii, a recently demonstrated human pathogen. These two hosts were most frequently captured in and around human structures and work places, thus providing conditions that could potentially lead to frequent human infections.

(Accepted November 22 2001)

c1 Author for correspondence.