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.

Because the majority of states in the United States are endemic for C. felis, Bartonella spp. seroprevalence rates can be as high as 93%. 86 Thus, for many states, requiring that community-based blood donor cats be Bartonella spp. seronegative and PCR or culture negative could make it very difficult to find adequate numbers of donors. Although seropositive, many healthy cats infected by B. henselae-infected C. felis will limit bacteremia over time. Thus, the panel believes the minimal standard is to use a Bartonella spp. PCR negative cat ( Table 2) . Use of antibiotics does not consistently eliminate Bartonella spp. infections in cats, and thus PCR or culture positive cats should be excluded from the blood donor program. 87 Cytauxzoon felis. Cytauxzoon felis is a tickborne protozoal pathogen in the order Piroplasmida and family Theileriidae. In this section, cytauxzoonosis is used to denote the acute illness (ie, systemic inflammatory response syndrome, cytopenias, multi-organ failure) associated with C. felis infection. After tick transmission, the organism undergoes schizogony in myeloid cells (specific lineage is unknown) followed by merogony in erythrocytes. The schizogenous stage is associated with illness and disease can be transmitted experimentally by transmission of blood from a cat with cytauxzoonosis to a naive cat. 88 The majority of cats with cytauxzoonosis that are presented to veterinary hospitals develop severe febrile illness, cytopenias, and often die within 5 days of presentation if appropriate treatments are not given. A carrier state (erythrocyte infection only) has been identified that is not associated with clinical disease. 89 In fact, transfusion of blood from a chronically infected cat into a naive cat does not result in illness. A theoretical risk for transmission of cytauxzoonosis exists because parasitemia can precede illness. In experimental infection, parasite DNA can be detected as early as 7 days post-infection but clinical signs do not begin until 10-21 days post-infection. Serological assays are not available. Use of indoor only cats receiving appropriate ectoparasite prophylaxis is advised to avoid this disease in donor animals. Appropriate donor selection and pre-donation physical examinations should minimize transmission risk. The panel recommends as the optimal standard to use PCR negative cats in endemic areas (Table 2) .