UPDATE ON CANINE AND FELINE BLOOD DONOR SCREENING FOR BLOOD BORNE PATHOGENS Wardrop et al, JVIM 2016 Consensus statement

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1 UPDATE ON CANINE AND FELINE BLOOD DONOR SCREENING FOR BLOOD BORNE PATHOGENS Wardrop et al, JVIM 2016 Consensus statement BACKGROUND: 3 types of pathogens: o Vector-borne (testing recommended) o Non-vector-borne (testing recommended) o Other pathogens (testing not recommended) Pathogens for which testing was recommended met at least ¾ of these criteria: o Causes clinical infection after blood transmission o Causes subclinical infection so carriers might be misinterpreted as healthy donors o Can be detected using culture/molecular methods from blood o Could cause life-threatening illness and is hard to eliminate with antimicrobials Consensus developed optimal and minimal standards for testing o Minimal could be used if expensive to test, or not an endemic area o Made the statement: apparently healthy donor may be acceptable in the situation with low risk of transmission and high risk of death without transfusion o Annual testing is recommended TESTING: **usually combination of serology and PCR are recommended** Light microscopy: staining artifacts = false positives, requires skilled personnel, time consuming o NOT recommended as only test Culture: transient bacteremia can occur in healthy animals and may not cause clinical illness in recipient, so regular blood cultures are not recommended; cultures used to check for contamination of blood bags Serum antigen tests: may be good POC testing depending on the agent Molecular assays: PCR usually indicates viable organisms because immune system typically clears nonviable organisms; false negatives could occur with low quantities of agents in the bloodstream Antibody tests: IFA, ELISA; false negatives with pathogens that don t result in immune response, subacute infections, immunocompromised patients DOG PATHOGENS VECTOR-BOURNE PATHOGENS Dirofilaria immitis Transfusion of microfilaria does not result in heartworm disease in the recipient so doesn t meet full criteria o BUT is associated with Wolbachia and can be infectious to mosquito vectors Recommendation: o Screened when in endemic areas and placed on prophylaxis 1) Anaplasma phagocytophilum & platys Phagocytophilum: granulocytic anaplasmosis o Transmitted by Ixodes or transfusions, causes subclinical infections o Many dogs are seropositive in endemic areas, but remain PCR negative o Rare to have seronegative dogs be PCR positive (but can happen) o Recommendation: Optimal: serology and PCR (exclude if either is positive) Minimal: PCR only (or even serology only) Platys: infectious canine cyclic thrombocytopenia o Transmitted by Rhipicephalus sanguineus, causes persistent subclinical infection and mild thrombocytopenia (transfusion transmission has NOT been reported) o Serological cross-reactions with A. phago are common, but not all tests able to detect Platys antibodies o Recommendation:

2 Optimal: use serology + PCR for detection Minimal: PCR only (serology only isn t recommended because not all assays are able to detect Platys antibodies) 2) Babesia vogeli & gibsoni Rhipicephalus ticks B. canis: greyhounds; B. gibsoni: fighting pit bulls (or dogs that have been bitten by a pit bull) o o Optimal: PCR (broad spectrum against all Babesia) + serology (against each species) Minimal: broad-range PCR only (unless in a high risk group and then recommend additional PCR testing to enhance sensitivity) 3) Bartonella henselae & vinsonii Vectored by fleas or ticks Transmission by transfusion has not been reported but it fits all the other criteria so theoretically it could happen? Serology isn t helpful because often are seronegative; PCR without culture is not sensitive; culture takes a long time and is expensive o Optimal: BAPGM culture + PCR o Minimal: PCR negative 4) Ehrlichia canis, ewingii, chaffeensis Canis is most important o Optimal: serology and PCR o Minimal: PCR or serology for E canis because so important; PCR only or no screening for the others 5) Hemoplasmas: Mycoplasma haemocanis, candidatus M. haematoparvum, candidatus M. haemominutum M. haemocanis: can cause anemia in splenectomized dogs (or with other co-morbidities) Currently unclear about the risk of other 2 species also Very difficult to eliminate with antibiotics (usually remain as a carrier) o Minimal: PCR (only for M. haemocanis, nothing for the others) 6) Hepatozoon canis & americanum Rhipicephalus and Amblyomma ticks Lethargy, fever, locomotion abnormalities, hyperesthesia, PLN; circulate in peripheral blood as gamonts in leukocytes No reports of transmission by transfusion (serology is not available) 7) Leishmania spp Transmission occurs in Mediterranean regions by bites from infected female sandflies; vector in North America might by Lutzomyia shannoni Dog to dog transmission has been hypothesized; visceral leishmania has been transmitted by blood transfusions to dogs Very rare except in the foxhound population (endemic) Serology cross-reacts with Trypanosoma cruzi o Optimal: Serology and PCR o Minimal: PCR and serology in high risk, nothing in low risk dogs 8) Neorickettsia risticii

3 No documented transmission by blood transfusion 9) Rickettsia felis Detected in dogs with heavy flea infestations, not associated with disease in dogs, screening optional 10) Trypanosoma cruzi Hemoflagellate protozoan (feces-contaminated bite OR ingestion of the bug) Transfusion-acquired infection has been documented in people (especially immunocompromised), but not yet reported in dogs o Optimal: serology (especially in high-risk areas) NON-VECTOR BOURNE PATHOGENS 11) Brucella Gram negative, zoonotic pathogen; venereal transmission, oronasal contact with vaginal discharge, aborted material or urine Blood transfusion transmission has NOT been reported (however, prolonged bacteremia occurs after transmission so potential for this to occur) Serological screening of potential donors for antibotics using rapid slide agglutination test is recommended o Optimal: 1 neg RSAT is enough to rule out in a castrated animal, but need multiple in an intact sexually active animal (testing serology) OTHER PATHOGENS 12) Borellia burgdorferi Ixodes ticks Testing not necessary negligible risk of transmission through transfusions in people 13) Neorickettsia helminthoeca Doesn t cause subclinical infections, not likely to be transfused from healthy dog 14) Rickettsia rickettsii RMSF, acute systemic infection of vascular endothelial cells Acute infection is quickly cleared, chronic infections have NOT been reported 15) West Nile virus Mosquito-borne zoonotic arbovirus (Flavivirus) Fever, headache, muscle ache, skin rash, meningoencephalitis, rare in our pets CAT PATHOGENS VECTOR BOURNE PATHOGENS 1) Anaplasma phagocytophilum & platys A phago can cause mild clinical illness that resolves quickly with administration of doxy A platys has been rarely documented so if cats live in areas with Rhipicephalus ticks, could consider testing

4 + serology o Minimal: Serology or PCR 2) Bartonella henselae Very common in cats 93% seroprevalance; cats are reservoirs with C felis being the vector (cat flea) o High levels of bacteremia can occur in healthy cats too! o Even if seropositive, many cats will limit their bacteremia over time (so may still be able to use those cats) Can cause either prolonged subclinical bacteremia, or clinical sequelae also Can be transmitted by blood transfusions, storing blood does NOT inactivate it o Optimal: serology + PCR or culture o Minimal: PCR (if seropositive and PCR negative, should still be ok because not bacteremic) 3) Cytauxzoon felis Tickbourne protozoal pathogen (Piroplasmida) Causes severe acute systemic illness: fever, cytopenias, MODS and feath Tick transmission schizogony in myeloid cells merogony in RBCs Carrier state (disease in the RBCs) may be associated with chronically infected animals (not a risk for transmission) May be disease positive PRIOR to developing illness, so have to be careful there o Optimal: use indoor only cats with ectoparasite control, PCR in endemic areas is recommended 4) Ehrlichia canis 5) Hemoplasmas: Mycoplasma haemofelis, candidatus M haemominutum and candidatus M turicensis M haemofelis causes infectious anemia, but the others are higher prevelance (10-25%) and less pathogenic frequently found in healthy animals and doesn t even cause disease in immunosuppressed cats M haemofelis is inactivated after 1 week storage, the others after 1 month storage Can be transmitted by aggressive interactions between cats and experimentally through blood for all o Minimal: PCR for M haemofelis, no testing for the others 6) Neorickettsia risticii NON-VECTOR BOURNE PATHOGENS 7) FELV Transmitted by saliva, but also by blood transfusion Tests for coral viral antigen p27 (ELISA) Regressive infection can occur: where antigen stays in tissues and results in transient or undetectable antigenemia with proviral DNA in the blood (can get re-activation with or without immunosuppression) o These can STILL transmit infection when regressor! o Optimal: FELV antigen, don t use free roaming cats, test for proviral DNA/PCR o Minimal: FELV antigen

5 8) FIV Transmitted through bite wounds and inoculation of infected blood Test for antibodies with ELISA, ELISA cannot tell between vaccinated and infected cats o Optimal: eliminate seropositive (whether infected or vaccinated) o Minimal: eliminate seropositive OTHER PATHOGENS 9) Corona virus Transmission of virus does NOT occur via blood transfusion (no documentation) Antibody titers and PCR can be positive and cats can be healthy No testing necessary 10) Rickettsia felis No testing needed 11) Toxoplasmosis No testing needed (transmission doesn t occur via blood) **see the end of the paper for management techniques/general recommendations