Incidence and persistence of asymptomatic Leishmania infection among HIV-infected patients in Trang province, Southern Thailand: A cohort study

Leishmaniasis poses a significant health burden, particularly among immunocompromised patients. In Thailand, Leishmania infection caused by Leishmania martiniquensis and Leishmania orientalis lacks information about the incidence and risk factors among HIV-infected populations. This longitudinal cohort study aimed to investigate the incidence and persistence of Leishmania infection among HIV-infected individuals in an affected area, Trang Province, Southern Thailand. The study also identified risk factors associated with the incidence of Leishmania infection. The study enrolled 373 participants in the HIV clinic, Trang Hospital, who initially tested negative for Leishmania infection during 2015-2016, and 133 individuals initially tested positive for Leishmania infection. Thus, follow-up visits of 506 participants occurred during 2018-2019. Direct Agglutination Test (DAT) and nested PCR (nPCR) identified incidents and persistent cases of Leishmania infection. Cox proportional-hazards regression analyses were performed to assess risk factors for the incidence of Leishmania infection. Among the initially negative group, 12 incident cases comprised one L. orientalis infection and 11 seropositive cases using DAT, resulting in a cumulative incidence of 3.2% and an incidence density of 10.38 per 1000 person-years. Increasing age was a significant predictor of the incidence of Leishmania infection. Five persistent cases comprised one Leishmania donovani complex and four seropositive cases using DAT in the initially positive group, with a cumulative persistence rate of 3.7% and a persistence density of 12.85 per 1000 person-years. All patients were asymptomatic. This study sheds light on the incidence and persistence of Leishmania infection among HIV-infected individuals in Trang Province, Southern Thailand, underscoring the importance of continued monitoring and tailored interventions to mitigate the impact of this co-infection.