Asymptomatic human blood donors carriers of Leishmania infantum : potential reservoirs for visceral leishmaniasis in northwestern Iran

Abstract Background Little is known regarding transfusion-transmitted leishmaniasis (TTL) and the real global incidence of visceral leishmaniasis (VL) among blood donors as carriers of Leishmania spp in endemic VL foci including Iran. Recent epidemiological evidences indicate that blood donor may be harbor of Leishmania infantum ( L. infantum ) infection in Iran. Methods The aim of the present study was to determine the prevalence of Leishmania infection among blood donors in a main endemic focus of VL in Iran using DAT and polymerase chain reaction (PCR) based methods. Between July to September 2016, blood samples were collected from 600 apparently healthy blood donors from six blood donation centers and blood donation mobile unit in Ardabil Province, where VL cases had been recorded. Each of these samples was tested for anti- Leishmania antibodies, in direct agglutination test (DAT), and for L. infantum kDNA, the PCR-based assay. Results Of 600 blood donors, which were examined, 23 (3.8%) blood donors were seropositive by DAT and of 23 seropositive subjects, 82.6% (19/23) were positive by PCR. All the seropositive cases were males except one of them was female. Conclusions Our findings showed that many asymptomatic human carriers of L. infantum live in the endemic regions of northwestern Iran and potentially act as reservoirs of infection; those must be considered carefully by arrangement VL control strategies in the country.