double-blind randomized efficacy field trial of alum precipi¬tated autoclaved leishmania major (alum-alm) vaccine mixed with bcg plus imiquimod vs. placebo control group

background: canine visceral leishmaniasis (cvl) is not only an emerging veterinary concern but also a public health threat in endemic areas. the aim of this study was to assess the efficacy, immunogenicity and safety of two doses of aluminum hydroxide (alum) precipitated leishmania major (alum-alm) mixed with bcg plus imiquimod against cvl. methods: a total of 560 ownership dogs were serologically tested and 234 healthy dogs with no clinical signs of cvl, no anti- leishmania antibodies and negative leish­manin skin test were selected and double-blind randomly injected intradermally either with 0.1 ml alum-alm (200µg protein) mixed with bcg (2 × 10 6 cfus) plus imiquimod (121 dogs) or with 0.1 ml of normal saline (113 dogs). results: the follow-up examinations showed that there was no side effect associated with the vaccination except one case. strong skin test conversion were seen in vac­cinated group (30.3%) compared to the control group (6.6%) at 22-24 weeks after the booster injection ( p <0.001). the seroconversion was 16.3% (18/110) in vaccinated group and 26.4% (28/106) in control group after two transmission cycles but the differ­ence was not significant ( p =0.095). the efficacy rate based on seroconversion was 40.4 %. conclusion: two injections of alum-alm mixed with bcg and imiquimod is safe, although decreases the seroconversion rate of cvl, but the overall efficacy was low.