Investigating the optimum timeline for final cure assessment of treated Visceral Leishmaniasis patients in Bangladesh

Bangladesh became the first country globally to receive validation for the public health elimination of Visceral Leishmaniasis (VL). However, while VL cases have declined, sequels such as treatment failure and relapse are increasing. The current practice of assessing VL cure at six months post-treatment may delay the identification of sequelae. This study aims to determine the time required for VL patients to achieve complete clinical recovery and parasitological clearance, contributing to sustainable elimination efforts. We enrolled 50 confirmed VL patients from VL-endemic subdistricts of Mymensingh between June 2016 and March 2018. All the enrolled patients were treated with a single dose of Liposomal Amphotericin B (LAmB) (10 mg/kg intravenous infusion). Blood samples were collected upon admission and monthly for six months post-treatment. Polymerase chain reaction (PCR) was performed on these samples. The Kaplan-Meier method was used to estimate the cumulative probability of cure time, with clinical and laboratory parameters measured monthly. The median cure time for the participants was one month. Within three months, 90% of the patients were cured, and all patients fully recovered by six months. A significant difference in cure time was noted between individuals with spleen sizes below and above 8 cm (p = 0.0002). Additionally, nutritional improvements were evident, with increased BMI and a decrease in underweight proportions. Hemoglobin levels showed significant improvement in the early months post-treatment, with complete resolution or significant reduction of splenomegaly observed in all patients by three months, prompting reconsideration of the final cure declaration to three months instead of six months after treatment. Adjusting this cure declaration (while retaining 6, 12, 24, 36, 48, and 60 months of follow-up) will facilitate early detection of non-responsive cases and optimize resource allocation crucial for sustaining VL elimination efforts.