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.

Leishmania spp. Leishmaniosis is caused by protozoal organisms of the genus Leishmania and is transmitted in Mediterranean regions by the bite of an infected female sandfly. The vector in North America is not known; Lutzomyia shannoni is the most highly suspected vector in the United States, but dog-to-dog transmission also has been hypothesized. 37 Visceral leishmaniosis, caused by Leishmania donovani, is considered an exotic disease in dogs in North America, with the exception of the foxhound population in which it is endemic. 38 Dogs in North America also have acquired the infection during travel to foreign countries months to years before diagnosis. Visceral leishmaniosis has been transmitted by blood transfusion to dogs, with clinically healthy foxhounds as blood donors. 39 A retrospective study (2000) (2001) (2002) (2003) performed on 12,000 serum samples from foxhounds and other canids in the United States reported an 8.9% seroprevalence in foxhounds, but no other randomly selected domestic dogs or wild canids were seropositive. 40 Because the infection appears to be only endemic within foxhounds in North America, screening of every potential blood donor is not necessary. However, all foxhounds and dogs with travel history to or from endemic countries should be screened for Leishmania spp infection using IFA serology performed by a reputable laboratory. Because IFA serology may lack sensitivity in subclinically infected dogs, 41 foxhounds or dogs living in or traveling to endemic areas, and found to be seronegative should then be screened additionally by Leishmania PCR. 38, 42, 43 The IFA assay for Leishmania spp. can cross-react with Trypanosoma cruzi. 44 Although dogs with either infection should be excluded as blood donors, Leishmania spp. seropositive dogs can be evaluated for the presence of specific antibodies to T. cruzi if further clinical information is desired. 44 Neorickettsia risticii. Dogs can be experimentally infected with N. risticii, and antibodies to N. risticii have been detected in pet dogs. [45] [46] [47] Polymerase chain reaction was used in 1 study to identify N. risticii obtained from blood cultures of 2 clinically ill dogs. 48 There is no documentation of transmission of N. risticii to dogs by blood transfusion. 45 Although the committee believes that optimally dogs should test PCR-negative for Neorickettsia risticii infections, no screening is also acceptable.