Bacteria from the Bartonella genus are dynamic and zoonotic.These emerging infectious pathogens have been associated with a variety of mammalian reservoirs.This study evaluated the prevalence of Bartonella infection in exotic pet mammals imported into Japan. A total of 546 small mammals (including mice, chipmunks, jirds, gerbils, jerboas, rats, and squirrels) were studied. Blood was collected from each animal, and Bartonella was isolated from blood samples through previously defined protocols.
Genetic diversity was assessed by sequencing and analysis of the bacterial citrate synthase gene (gltA) from genomic DNA.Bartonella species were identified in 142 pets and were seen in both captive (37.3%) and bred (2.8%) animals. Phylogenetic analysis revealed 53 genotypes and 6 unique geno-groups; 17.6% of infected animals harbored more than one genotype—suggesting the potential for a wide,weakly specific host range.There was evidence for both host specificity and diversity in this group.These data suggest that exotic small mammals could serve as zoonotic Bartonella reservoirs.

COMMENTARY: Veterinarians must be aware of Bartonella zoonotic risks from exotic small mammals.This article suggests the potential for lower host specificity in some Bartonella strains among exotic pets. If such strains are highly pathogenic, they may pose great risk to human contacts. Strains identified in this group have been associated with human neuroretinitis and endocarditis.A recent article in the NewYork Times Magazine (April 12, 2009) described a Bartonella meningitis case in a patient who had sustained a cat bite.The presence of such popular culture references urges a critical awareness of the widespread public health risks and reservoirs of Bartonella species. The higher Bartonella prevalence in captive animals in this study suggests that exotic small mammal purchases should originate in breeder facilities.—Indu Mani, DVM, DSc (infectious disease)

Exotic small mammals as potential reservoirs of zoonotic Bartonella spp. Inoue K, Maruyama S, Kabeya H, et al. EMERG INFECT DIS 15:526-532, 2009.