Results of Bartonella henselae blood culture, polymerase chain reaction (PCR) assay on blood, or IgG antibody assays do not always correlate with the presence or absence of clinical disease in cats, and B. henselae IgG antibodies in serum do not always correlate with bacteremia. However, little is known concerning Bartonella spp. IgM antibodies in naturally exposed cats.
Bartonella spp. IgM antibodies in serum are associated with fever, stomatitis, and bacteremia based on PCR assay results in experimentally infected or client-owned cats.
Stored sera from cats experimentally infected with B. henselae by exposure to Ctenocephalides felis, client-owned cats with and without fever, and client-owned cats with and without stomatitis were studied.
A Bartonella spp. IgM ELISA was titrated with samples from experimentally infected cats and then test sera from client-owned cats were assayed. Associations among IgM ELISA results, clinical findings, and bacteremia as defined by Bartonella spp. PCR assay were assessed.
All experimentally infected cats developed Bartonella spp. IgM antibodies. Bartonella spp. IgM antibody assay results were not always in agreement with PCR assay results in client-owned cats (60%). Bartonella spp. DNA in blood, IgM antibodies, and IgG antibodies were not associated with the presence of fever or stomatitis.
Conclusions and Clinical Importance
Because Bartonella spp. IgM antibodies as measured by this assay were not associated with fever or stomatitis and were not always in agreement with PCR assay results, there appears to be little need for assessing individual client-owned cats for this antibody class alone.