With global warming and socioeconomic developments, there is a tendency toward the emergence and spread of mountain-type zoonotic visceral leishmaniasis (MT-ZVL) in China. Timely identification of the transmission risk and spread of MT-ZVL is, therefore, of great significance for effectively interrupting the spread of MT-ZVL and eliminating the disease. In this study, 26 environmental variables—namely, climatic, geographical, and 2 socioeconomic indicators were collected from regions where MT-ZVL patients were detected during the period from 2019 to 2021, to create 10 ecological niche models. The performance of these ecological niche models was evaluated using the area under the receiver-operating characteristic curve (AUC) and true skill statistic (TSS), and ensemble models were created to predict the transmission risk of MT-ZVL in China. All ten ecological niche models were effective at predicting the transmission risk of MT-ZVL in China, and there were significant differences in the mean AUC (H = 33.311, p < 0.05) and TSS values among these ten models (H = 26.344, p < 0.05). The random forest, maximum entropy, generalized boosted, and multivariate adaptive regression splines showed high performance at predicting the transmission risk of MT-ZVL (AUC > 0.95, TSS > 0.85). Ensemble models predicted a transmission risk of MT-ZVL in the provinces of Shanxi, Shaanxi, Henan, Gansu, Sichuan, and Hebei, which was centered in Shanxi Province and presented high spatial clustering characteristics. Multiple ensemble ecological niche models created based on climatic and environmental variables are effective at predicting the transmission risk of MT-ZVL in China. This risk is centered in Shanxi Province and tends towards gradual radiation dispersion to surrounding regions. Our results provide insights into MT-ZVL surveillance in regions at high risk of MT-ZVL.

Background: Visceral leishmaniasis (VL) is one of the most important neglected tropical diseases transmitted by the biting of sandflies. Although VL has been eliminated in several regions of China during the last century, the mountain-type zoonotic visceral leishmaniasis (MT-ZVL) have reemerged in the hilly areas of China in recent decades. The purpose of this study is to set up an indicator framework for assessing the transmission risk of the MT-ZVL in China, to provide insights into the formulation of MT-ZVL control strategies.Methods: A 3-level indicator framework was established based on literature review and expert interviews. The indicator system was screened according to scientific information, necessity, operability, and the weighted importance scoring of the indicators, and the normalized weight of each indicator are calculated. The reliability of the Delphi method was evaluated by the positive coefficient of the experts, the degree of expert authority, and the coordination coefficient of experts' opinions. The comprehensive weight of the tertiary indicators was determined by the Delphi and the entropy weight method. Results: A total of 30 questionnaires were delivered, and 28 received valid responses (93.3%). The expert authority coefficients were greater than 0.80 after two rounds of expert consultation, and the coordination coefficient of the experts’ opinions was 0.250−0.277 and 0.187−0.272 in each round, respectively (all, P < 0.05). An indicator framework was finally established including four primary indicators, 11 secondary indicators, and 35 tertiary indicators. Among the primary indicators, the variable with the highest normalized weight was biological factors (0.268), followed by interventions (0.261), environmental factors (0.242), and social factors (0.229). Among the secondary indicators, the top 4 normalized weights included climatic features (0.122), geographical features (0.120), sandflies (0.097), and dogs (0.096). Among the tertiary indicators, the top 4 normalized comprehensive weights were the population density of sandflies (0.075), topography (0.057), the population density of dogs and dog tethering (0.056) and the use of bed nets or other protective measures (0.056). Conclusions: This study constructed an indicator framework for assessing the transmission risk and strengthening public health education of MT-ZVL based on the Delphi and entropy weight method, and provided insights into formulating strategies and measures for the prevention and control of MT-ZVL in China.

Background: Hand, foot, and mouth disease (HFMD) remains a major public-health concern in China. While the monovalent EV-A71 vaccine has effectively reduced EV-A71–associated cases, it offers no protection against CV-A16. The introduction of a bivalent EV-A71/CV-A16 vaccine may offer broader protection, but its economic viability under different immunization strategies remains uncertain. Methods: We developed a dynamic transmission model integrated with cost-effectiveness analysis to assess the epidemiological and economic impact of a hypothetical bivalent EV-A71/CV-A16 vaccine in China. Based on the immunization program policy, seven vaccination strategies, vaccine effectiveness (VE) levels ranging from 50–95% against EV-A71/CV-A16, and coverage levels from 0–95% were evaluated. The threshold vaccine price (TVP) was derived based on incremental cost-effectiveness ratio (ICER) calculations. Cost-effectiveness was assessed using willingness-to-pay (WTP) thresholds defined as 1–3 times the gross domestic product (GDP) per capita. Results: The mean cost of two doses of the monovalent EV-A71 vaccine was USD133.0 (95% CI: 126.9–139.1). Strategy 2, which targeted individuals unvaccinated with the monovalent EV-A71 vaccine, demonstrated the most favorable cost-effectiveness. At 45% coverage and 85% vaccine effectiveness, the estimated threshold price per dose was USD 107.7 (95% CI: 103.4–112.0), with threshold vaccine prices increasing as coverage declined. When vaccination coverage exceeded 80%, the threshold vaccine price decreased substantially, falling below USD 45.9 (95% CI: 43.5–48.3) per dose. Conclusions: Large-scale inclusion in the national immunization program may not be economically justified at current cost levels. Targeted voluntary vaccination of unvaccinated, susceptible populations represents a more cost-effective and practical strategy during the early stage of vaccine introduction.