Update on Canine and Feline Blood Donor Screening for Blood-Borne Pathogens

Wardrop, K.J.; Birkenheuer, A.; Blais, M.C.; Callan, M.B.; Kohn, B.; Lappin, M.R.; Sykes, J.

Bartonella spp. A number of Bartonella spp. have been grown or amplified from the blood of cats, most commonly B. henselae, B. clarridgeiae, B. koehlerae, and B. quintana. 21 Cats are the reservoirs and Ctenocephalides felis is the vector for B. henselae, B. clarridgeiae, and B. koehlerae; these agents are extremely common in the blood of cats and their fleas. 82 Bartonella henselae appears to be the most likely to be pathogenic, but more studies are needed to determine disease associations with other species. Bartonella henselae infection was only documented by PCR assay in 2 of 117 (1.7%) community source cats used as blood donors in the United States, which likely reflects the use of flea control products. 83 Infected cats typically have a prolonged, subclinical bacteremia, but a number of clinical sequelae also occur. 21,84 Bartonella spp. can be transmitted by blood transfusion and storing blood does not inactivate the organism. f The most sensitive way to document Bartonella spp. in the blood of cats is by the concurrent use of specialized culture media and PCR assay using several blood samples. 25 Although this approach frequently is needed to prove the presence of Bartonella spp. in the blood of clinically ill dogs, whether the increased sensitivity is needed for screening cats to be used as blood donors remains to be proven. Because cats are the definitive host for B. henselae, high levels of bacteremia often are detected even when the cats are healthy. Thus, broad range PCR assays or PCR assays using specific primers that are used widely in commercial laboratories in the United States are likely to detect most infected cats (Table 3) . Bacteremia in cats infected with B. henselae by exposure to infected C. felis precedes seroconversion by 7-42 days and thus serology alone is inadequate as a screening test. 84 However, after immune responses develop, bacteremia can be intermittent in cats and a false negative result could occur only if a single sample is assayed. 85 Thus, the panel recommends as the optimal standard to use cats that are seronegative and PCR assay or culture negative (Table 2) .