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.

Hemoplasmas. Dogs can be infected with several hemoplasma species, including Mycoplasma haemocanis, "Candidatus M. haematoparvum," and possibly also "Candidatus M. haemominutum" or a related organism. [29] [30] [31] Although ticks have been implicated in transmission of M. haemocanis, the mechanism of transmission has not been proven. Kenneled dogs and research animals appear to be at higher risk for infection by M. haemocanis. Diagnosis of infection is based on PCR assay of whole blood. 32 No serologic assay for hemoplasma infection is commercially available. In general, dogs are subclinically infected with these organisms, but M. haemocanis can cause anemia in splenectomized dogs, with a few case reports of infected dogs with other immunocompromising comorbidities. Only a single clinical infection with "Candidatus M. haematoparvum" has been reported in a splenectomized dog with hemic neoplasia being treated with chemotherapy, and it was unclear to what extent the hemoplasma played a role in development of anemia. 33 This dog received several units of blood products, some of which tested positive using PCR for "Candidatus M. haematoparvum," and tested negative before transfusion (Sykes et al, unpublished data). Therefore, optimally, donor dogs should be screened for all hemoplasma by PCR assay and excluded if positive (Table 1) . However, until more is learned about the risk of transfusing blood testing positive for "Candidatus M. haemominutum" and "Candidatus M. haematoparvum", testing for these pathogens could be considered optional. It also should be kept in mind that the prevalence of hemoplasma infection in the general client-owned pet dog population in North America appears to be low (<5%). 34 Whether the viability of canine hemoplasma species is lost during storage of blood products (see feline hemoplasmas) requires further study. Because antimicrobial therapy does not reliably eliminate hemoplasmas, the panel does not recommend treating potential donors with antimicrobials in an attempt to eliminate infection.