Dynamics of Leishmania-HIV Co-infection in Nigeria: Epidemiology, Clinical Spectrum, and Implications for Integrated Disease Management

Leishmania-HIV co-infection is an emerging syndemic that dramatically accelerates visceral leishmaniasis progression, reduces treatment efficacy, and increases relapse rates, yet its epidemiology and clinical spectrum in Nigeria remain largely unexplored despite expanding HIV prevalence in regions of emerging leishmaniasis transmission. This doctoral research characterises the epidemiology, clinical spectrum, and management implications of Leishmania-HIV co-infection in Nigeria, employing a multi-site prospective cohort design. Sites were established in Jigawa, Sokoto, and Katsina States, representing areas of documented or probable Leishmania transmission along the arid northwest corridor. HIV-positive patients attending ART clinics were screened for visceral leishmaniasis using the rK39 rapid immunochromatographic test, followed by confirmatory splenic or bone marrow aspiration microscopy and PCR in positives. Clinical staging, immune profiling using CD4 counts and plasma viral load, and cytokine profiling via multiplex ELISA characterised the immunological landscape of co-infection. Treatment outcomes following liposomal amphotericin B or miltefosine were tracked for 12 months. Evidence from 2020 to 2024 from East Africa confirms that Leishmania-HIV co-infected patients have five times higher treatment failure rates than HIV-negative VL patients. This study establishes baseline co-infection epidemiology for Nigeria, develops a predictive scoring tool for co-infection diagnosis, and proposes an integrated treatment protocol. Findings will be presented to the Nigeria Centre for Disease Control and the WHO NTD and HIV departments. Keywords: Leishmania-HIV co-infection, visceral leishmaniasis, epidemiology, integrated management, Northwest Nigeria.