Objective::Leprosy prevention and treatment is a significant global public health and social challenge. Southwest China remains a high-burden area for leprosy. Analyzing the epidemic characteristics of different regions is crucial for tailoring effective prevention and control measures. This study aimed to characterize the epidemiological profile of leprosy in China from 2022 to 2023, providing essential data to inform future prevention and control strategies.Methods::Data were extracted from the Leprosy Management Information System in China, encompassing 31 provinces, autonomous regions, and municipalities from 2022 to 2023, and data from the Hong Kong Special Administrative Region, the Macau Special Administrative Region, and the Taiwan region were not available in the system and thus were not included in this analysis. Descriptive statistical methods were used to analyze the demographic and clinical characteristics, including sex, age, geographic distribution, and disability grade.Results::In total, 617 new leprosy cases were identified nationwide in 2022 and 2023, corresponding to a detection rate of 0.22 per million population. Among these, 380 cases (61.6%) involved male individuals, 588 cases (95.3%) were classified as multibacillary, 136 cases (22.0%) affected individuals with grade 2 disability, 114 cases (18.5%) involved migrant individuals, and 5 cases (0.8%) occurred in children under 15 years of age. In both years, 57.7% of new detected cases (356/617) were concentrated in Southwest China. Across the 2-year period, 47 relapse cases were reported. The registered prevalence was 1.279 per million population at the end of 2022, based on 1,806 cases. By the end of 2023, this number declined to 1.201 per million, based on 1,693 cases.Conclusion::Although the overall prevalence of leprosy in China is low, the disease continues to be geographically widespread and unevenly distributed. Southwest China remains a key region for targeted control efforts.

Gansu in northwestern China has maintained leprosy elimination at the national and county level, yet localized transmission persists in certain endemic foci. This 70-year analysis (1950-2020) assessed the impact of key control strategies using an interrupted time-series analysis of new case detection rate (NCDR) with break points at the 1958 "survey-isolate-treat" strategy and the 1987 multidrug therapy (MDT) rollout. Among 4,872 registered cases, NCDR rose initially and then declined steadily to 0.027/100,000 by 2020. Significant geographic clustering was observed in southeastern counties (Moran's I = 0.403, P < 0.05). Most cases were male farmers (male-to-female ratio 2.37:1), and Han ethnicity accounted for 75.9% of all cases. The proportion of multibacillary cases increased significantly from 78.0% before 1987 to 84.9% after MDT implementation. Time-series analysis indicated that the 1958 strategy was associated with a sustained decline in detection rates during the high-endemic phase, whereas MDT introduction in 1987 led to an immediate level reduction during the low-endemic phase. These results underscore the complementary role of historical integrated control measures and modern chemotherapy in sustaining leprosy elimination. However, transmission persists, and the rising proportion of multibacillary cases highlights the ongoing need for targeted active surveillance, contact screening, and strengthened early detection to achieve WHO 2030 eradication targets.

BACKGROUND:With the prevalence of leprosy dramatically declining, the focus of leprosy control has gradually shifted from the implementation of multidrug therapy (MDT) to accelerating the reduction of the disease burden and preventing disability. Southwestern China currently bears the highest leprosy burden in China and more than half of the disability cases reported every year are from this region. However, the potential risk factors of leprosy disability in this area remain unknown. METHODS:In this study, we evaluated the physical disabilities of 4578 leprosy patients in southwest China from 2010 to 2020. Clinical and epidemiological factors associated with physical disability resulting from leprosy were identified using multinomial logistic regression. RESULTS:A total of 4578 leprosy cases with complete information were reported in southwestern China during the 11 years. Among them, 1126 (24.60%) patients were diagnosed with grade 2 disability (G2D), and 737 (16.10%) were confirmed with grade 1 disability (G1D) at diagnosis. The potential factors associated with G2D are as follows: nerve damage, male, leprosy reaction, older age of the patient, the longer delay in diagnosis, and more skin lesions. Furthermore, nerve damage, leprosy reaction, male, older age, and longer delayed diagnosis were the main risk factors of G1D. Among them, nerve damage, older age, longer delayed diagnosis, male, and leprosy reaction were the common risk factors for G1D and G2D. CONCLUSION:In our study, we found older age, longer delayed diagnosis, male, more skin lesions, more nerve lesions, and leprosy reactions were associated with leprosy disability. These findings provide a foundation for the development of targeted interventions aimed at the early identification of individuals at higher risk of physical disability, as well as for self-care and health education to promote timely medical consultation to prevent leprosy-related disabilities.

Background Despite many efforts to control leprosy worldwide, it is still a significant public health problem in low- and middle-income regions. It has been endemic in China for thousands of years, and southwest China has the highest leprosy burden in the country. Methods This observational study was conducted with all newly detected leprosy cases in southwest China from 2010 to 2020. Data were extracted from the Leprosy Management Information System (LEPMIS) database in China. The Joinpoint model was used to determine the time trends in the study area. Spatial autocorrelation statistics was performed to understand spatial distribution of leprosy cases. Spatial scan statistics was applied to identify significant clusters with high rate. Results A total of 4801 newly detected leprosy cases were reported in southwest China over 11 years. The temporal trends declined stably. The new case detection rate (NCDR) dropped from 4.38/1,000,000 population in 2010 to 1.25/1,000,000 population in 2020, with an average decrease of 12.24% (95% CI: −14.0 to − 10.5; P < 0.001). Results of global spatial autocorrelation showed that leprosy cases presented clustering distribution in the study area. Most likely clusters were identified during the study period and were frequently located at Yunnan or the border areas between Yunnan and Guizhou Provinces. Secondary clusters were always located in the western counties, the border areas between Yunnan and Sichuan Provinces. Conclusions Geographic regions characterized by clusters with high rates were considered as leprosy high-risk areas. The findings of this study could be used to design leprosy control measures and provide indications to strengthen the surveillance of high-risk areas. These areas should be prioritized in the allocation of resources.

Background The mechanism of livedoid vasculopathy (LV) remains unknown.Objectives To investigate the association between coagulation factors and LV and to assess the efficacy and safety of rivaroxaban in the treatment of patients with LV.Methods From May 2019 to July 2022, 89 patients with LV and 35 healthy controls were included in a cross-sectional cohort to measure the levels of coagulation factors. In addition, 55 patients with LV treated with rivaroxaban were included in a treatment cohort to assess the complete remission rate of ulcers (n = 44) and retiform purpura (n = 11) within 12 weeks.Results In the cross-sectional cohort, the activities of coagulation factor X in patients with LV were significantly higher than those in healthy controls: median 110.5% [interquartile range (IQR) 97.5-127.0%] vs. 101.3% (IQR 91.6-115.6); P = 0.05. In addition, coagulation factor X activities in the progressive stage were higher than at the stable stage: median 111.6% (IQR 102.3-132.5) vs. 105.4% (IQR 92.9-118.8); P = 0.04. Moreover, coagulation factor X activities were higher at the progressive stage than at the stable stage in a subgroup of 20 patients with LV (P = 0.04). In the treatment cohort taking rivaroxaban, 91% (40/44) of patients with ulcers achieved complete remission within 12 weeks, and 73% (8/11) of patients with retiform purpura achieved complete remission within 12 weeks. Mild side-effects occurred in 25% of patients (14/55), including menorrhagia (n = 10), gingival bleeding (n = 3) and haemorrhage (n = 1).Conclusions Coagulation factor X was associated with the incidence and severity of LV in this study. In addition, rivaroxaban was an effective and safe treatment for ulcers and retiform purpura in people with LV. This study found that coagulation factor X is associated with the incidence and severity of livedoid vasculopathy (LV). In addition, as an inhibitor of factor Xa, rivaroxaban was an effective and safe treatment for ulcers and retiform purpura in patients with LV. Importantly, the early administration of rivaroxaban for retiform purpura prevented its progression to ulcers.

BackgroundThe manifestations of bullous pemphigoid (BP) and herpes simplex virus (HSV) infection are similar in oral mucosa, and the laboratory detection of HSV has some limitations, making it difficult to identify the HSV infection in oral lesions of BP. In addition, the treatments for BP and HSV infection have contradictory aspects. Thus, it is important to identify the HSV infection in BP patients in time.ObjectiveTo identify the prevalence and clinical markers of HSV infection in oral lesions of BP.MethodsThis prospective cross-sectional descriptive analytical study was conducted on 42 BP patients with oral lesions. A total of 32 BP patients without oral lesions and 41 healthy individuals were enrolled as control groups. Polymerase chain reaction was used to detect HSV. Clinical and laboratory characteristics of patients with HSV infection were compared with those without infection.ResultsA total of 19 (45.2%) BP patients with oral lesions, none (0.0%) BP patients without oral lesions, and four (9.8%) healthy individuals were positive for HSV on oral mucosa. Among BP patients with oral lesions, the inconsistent activity between oral and skin lesions (p=0.001), absence of blister/blood blister in oral lesions (p=0.020), and pain for oral lesions (p=0.014) were more often seen in HSV-positive than HSV-negative BP patients; the dosage of glucocorticoid (p=0.023) and the accumulated glucocorticoid dosage in the last 2 weeks (2-week AGC dosage) (p=0.018) were higher in HSV-positive BP patients. Combining the above five variables as test variable, the AUC was 0.898 (p<0.001) with HSV infection as state variable in ROC analysis. The absence of blister/blood blister in oral lesions (p=0.030) and pain for oral lesions (p=0.038) were found to be independent predictors of HSV infection in multivariable analysis. A total of 14 (73.7%) HSV-positive BP patients were treated with 2-week famciclovir and the oral mucosa BPDAI scores significantly decreased (p<0.001).ConclusionHSV infection is common in BP oral lesions. The inconsistent activity between oral and skin lesions, absence of blister in oral lesions, pain for oral lesions, higher currently used glucocorticoid dosage, and higher 2-week AGC dosage in BP patients should alert physicians to HSV infection in oral lesions and treat them with 2-week famciclovir in time.

Objective: Leprosy is an infectious diseases that remains a concerning public health issue. The infection of Mycobacterium leprae still exists at the county level in hard-to-access areas in southwest China. An accurate analysis of the prevalence of leprosy in various regions is necessary for the formulation of prevention and control strategies, so we conducted this study to describe the epidemiological characteristics of leprosy in China in 2021 and provide essential information for future national leprosy control and prevention strategies. Methods: We collected epidemiological data of leprosy from 31 provinces, autonomous regions, and municipalities of China (except for Hong Kong, Macao, and Taiwan) provided by the Leprosy Management Information System. We performed a comparative analysis of the epidemiological features of patients with leprosy including age, sex, geographical distribution, and grade of disability. Results: In total, 374 newly detected leprosy cases were reported nationwide in China in 2021, giving an incidence rate of 0.27 per million population, which represented a decrease of 7.9% compared with 2020. Among the population with leprosy in 2021 that comprised 238 males (63.6%) and 136 females (36.4%), 1.9% (7/374) were children younger than 15 years, 92.8% (347/374) had multibacillary leprosy, and 18.2% (68/374) had grade 2 disability. More than half of the new leprosy cases (54.8%, 205/374) were distributed in southwest China. There were 33 relapsed leprosy cases reported in 2021. By the end of 2021, there were 1,897 registered leprosy cases reported nationwide, giving a prevalence rate of 1.35 per million population. Conclusion: The leprosy epidemic in China shows a downward trend in terms of the prevalence and incidence rates. However, the high prevalence of leprosy in southwest China is still a matter of concern.

BACKGROUNDPrevious studies have suggested that a single dose of rifampin has protective effects against leprosy in close contacts of patients with the disease. Rifapentine was shown to have greater bactericidal activity against Mycobacterium leprae than rifampin in murine models of leprosy, but data regarding its effectiveness in preventing leprosy are lacking.METHODSWe conducted a cluster-randomized, controlled trial to investigate whether single-dose rifapentine is effective in preventing leprosy in household contacts of patients with leprosy. The clusters (counties or districts in Southwest China) were assigned to one of three trial groups: single-dose rifapentine, single-dose rifampin, or control (no intervention). The primary outcome was the 4-year cumulative incidence of leprosy among household contacts.RESULTSA total of 207 clusters comprising 7450 household contacts underwent randomization; 68 clusters (2331 household contacts) were assigned to the rifapentine group, 71 (2760) to the rifampin group, and 68 (2359) to the control group. A total of 24 new cases of leprosy occurred over the 4-year follow-up, for a cumulative incidence of 0.09% (95% confidence interval [CI], 0.02 to 0.34) with rifapentine (2 cases), 0.33% (95% CI, 0.17 to 0.63) with rifampin (9 cases), and 0.55% (95% CI, 0.32 to 0.95) with no intervention (13 cases). In an intention-to-treat analysis, the cumulative incidence in the rifapentine group was 84% lower than that in the control group (cumulative incidence ratio, 0.16; multiplicity-adjusted 95% CI, 0.03 to 0.87; P = 0.02); the cumulative incidence did not differ significantly between the rifampin group and the control group (cumulative incidence ratio, 0.59; multiplicity-adjusted 95% CI, 0.22 to 1.57; P = 0.23). In a per-protocol analysis, the cumulative incidence was 0.05% with rifapentine, 0.19% with rifampin, and 0.63% with no intervention. No severe adverse events were observed.CONCLUSIONSThe incidence of leprosy among household contacts over 4 years was lower with single-dose rifapentine than with no intervention. (Funded by the Ministry of Health of China and the Chinese Academy of Medical Sciences; Chinese Clinical Trial Registry number, ChiCTR-IPR-15007075.).

Background Leprosy, caused by Mycobacterium leprae infection, mainly affects skin and peripheral nerves and may further lead to disability and deformity if not treated timely. The new case detection rate of leprosy in children reflects the active transmission of leprosy infection. This study aims to present the epidemiology and clinical characteristics of new leprosy cases in children in China from 2011 to 2020. Methodology/Principal findings All data from leprosy patients younger than 15 years old were extracted from the Leprosy Management Information System in China (LEPMIS). Statistical Package for the Social Sciences (SPSS) version 12.0 was used for descriptive and analytical statistics of the epidemiological and clinical indicators by the Mann-Whitney test, Kruskal-Wallis test, and Fisher’s exact test. And geographical distribution was analyzed by ArcGIS 10.5. A total of 152 pediatric new cases of leprosy were found over the last decade. The new case detection rate of pediatric leprosy cases decreased from 0.13 to 0.02 per 1,000,000 population over the last ten years. New pediatric cases had a higher new case detection rate in Guizhou, Sichuan, and Yunnan Provinces. All but 7 provinces in China achieved zero new child case for consecutive five years. The onset of leprosy peaked between 10 and 14 years of age, and the male to female ratio was 1.71:1. Pediatric patients were predominantly infected from symptomatic household adult contacts HHCs. Multibacillary leprosy (MB) was the most common. However, a low proportion of patients developed leprosy reaction and grade 2 disability. Conclusions/Significance The new case detection rate of pediatric leprosy cases has decreased over the past ten years in China. Spatial analysis indicated clusters in high-endemic areas. Leprosy transmission has stopped in the majority of provinces in China. However, sporadic cases may continue to exist for a long time. Active surveillance especially contact tracing should be focused on in future plan for management of leprosy, and interventions in leprosy clusters should be prioritized.

Objective:To analyze epidemiological characteristics of leprosy in China from 2016 to 2020, and to provide a scientific basis for further elimination of leprosy.Methods:Data collation and statistical analysis were conducted on annual reports on leprosy epidemic surveillance in China (excluding Hong Kong, Macao, and Taiwan regions) from 2016 to 2020.Results:From 2016 to 2020, a total of 2 697 new cases of leprosy were reported in China, including 46 (1.71%) children, 894 (33.15%) females, 374 (13.87%) floating people, 2 443 (90.58%) multibacillary cases, and 546 (20.24%) cases of grade 2 disabilities. A total of 203 relapsed cases were reported in the meantime. By the end of 2020, there had been 1 893 registered leprosy cases in China, and the number of cases was 68.62% fewer than that in 2010 (6 032 cases) ; there were 36 (1.2%) counties or cities with a prevalence rate above 1 per 100 000, and 72 (17.73%) new cases suffered from grade 2 disabilities.Conclusion:From 2016 to 2020, the reported incidence and prevalence of leprosy in China steadily decreased year by year, and overall, leprosy was still lowly prevalent.

To the Editor: Pemphigus vulgaris (PV) and herpes simplex virus (HSV) infections mainly manifest as erosions in the oral mucosa; so, it is difficult to identify HSV infection in oral lesions of PV. PV is mainly treated with immunosuppressants, which may reactivate and disseminate HSV. 1 Demitsu T. Kakurai M. Azuma R. Hiratsuka Y. Yamada T. Yoneda K. Recalcitrant pemphigus foliaceus with Kaposi's varicelliform eruption: report of a fatal case. Clin Exp Dermatol. 2008; 33: 681-682 Crossref PubMed Scopus (18) Google Scholar Therefore, it is necessary to explore the clinical features of HSV infection in patients with PV with oral lesions.

BACKGROUND:Leprosy is a chronic infectious disease that causes disabilities and deformities. Early detection is a major strategy for leprosy control. This study reported a new practice of suspicious symptom monitoring for early detection of leprosy.METHODS:A descriptive and comparative analysis between a non-strategy group of pre-implementation of suspicious symptom monitoring in 2005-2011 and a strategy group of strategy implementation in 2012-2018 was conducted through indicators of the number of times of misdiagnoses, delayed period, proportion of early detected cases, and proportion of disabilities.RESULT:Compared with the non-strategy group in 2005-2011, the median number of times of misdiagnoses was decreased from two times to zero times (z = 4.387, P < 0.001), and the median delayed period of newly detected cases were shortened from 24 months to 13 months (z = 2.381, P < 0.001), the proportion of early detected cases was increased from 43.7% to 75.2% (χ2  = 29.464, P < 0.001), the proportion of grade 2 disabilities was decreased from 28.6% in the highest year of 2005 to 4.0% in the lowest year of 2014, and the average proportion of disabilities was decreased from 33.5% to 17.6% (χ2  = 9.421, P = 0.002) in the strategy group in 2012-2018, respectively.CONCLUSION:Suspicious symptom monitoring promoted early detection of cases by reducing the number of times misdiagnosis of leprosy patients, shortening the delayed period, increasing the proportion of early detection, and decreasing the proportion of disabilities. It is an important and recommendable public health strategy for leprosy prevention and control in a low epidemic condition.

Objective:To optimize indirect immunofluorescence on salt-split skin (IIF-SSS), and to evaluate its performance in detection of bullous pemphigoid (BP) antibodies.Methods:Normal human foreskin and non-foreskin skin tissues were used to prepare salt-split substrates under 3 different experimental conditions: traditional group rotated at 4 ℃ for 48 - 72 hours, low-temperature immersion group soaked at 4 ℃ for 48 - 72 hours, room-temperature immersion group soaked at 25 ℃ (range: 23 - 27 ℃) for 24 hours. Serum samples were obtained from 20 patients with bullous pemphigoid (BP) in Hospital of Dermatology, Chinese Academy of Medical Sciences between August 2019 and August 2020, and subjected to IIF on the intact skin or salt-split substrates by using a multiple dilution method. Paired-sample t test was used for comparisons of means between two paired samples. Results:No dermal-epidermal separation was observed in the substrates prepared in the low-temperature immersion group at 48 - 72 hours, while dermal-epidermal separation occurred in the lower lamina lucida of the foreskin and non-foreskin substrates in the room-temperature immersion group and the traditional group. For the 20 patients with BP, the reciprocal end-point titers ( M[ Q1, Q3]) detected with the salt-split non-foreskin skin and salt-split foreskin in the room-temperature immersion group, and with the salt-split non-foreskin skin in the traditional group were 5 120 (2 560, 17 920), 1 280 (640, 2 560), 1 280 (640, 2 560), respectively. Moreover, 19 (95%) patients with BP showed that the reciprocal end-point titers detected with the substrates in the room-temperature immersion group were 1 - 5 times those in the traditional group ( t = 8.04, P<0.001), suggesting that the performance of salt-split skin in the room-temperature immersion group was superior to that in the traditional group in the detection of BP antibodies; however, there was no significant difference in the reciprocal end-point titers of BP antibodies between the salt-split foreskin in the room-temperature immersion group and salt-split non-foreskin skin in the traditional group ( t<0.001, P>0.05). The reciprocal end-point titers in 20 BP sera detected by conventional IIF on the intact non-foreskin skin and foreskin were 320 (160, 640) and 480 (160, 1 120), respectively; the reciprocal end-point titers detected by IIF on the salt-split foreskin and non-foreskin skin in the room-temperature immersion group, as well as on the salt-split non-foreskin skin in the traditional group, were all consistent with or 1 - 7 times higher than those detected by conventional IIF ( t = 6.47, 14.83, 5.26, respectively, all P<0.001) . Conclusion:The soaking method at room temperature 25 ℃ (23 - 27 ℃) for preparing salt-split substrates has advantages of short duration and simple procedure, and the sensitivity of IIF-SSS using the substrates prepared by this method is equal or superior to the traditional salt-split method for detecting BP antibodies.

Objective::To study the epidemiology of leprosy in China in 2019 and give suggestions to improve future leprosy control activities.Methods::We collected leprosy data from the Leprosy Management Information System in China, which includes data from 31 Chinese provinces, autonomous regions, and municipalities, except for Hong Kong, Macao, and Taiwan. We then performed a descriptive analysis of these data.Results::A total of 464 new leprosy cases were reported nationwide in 2019, with a case detection rate of 0.033/100,000. The proportions of children younger than 15 years, multibacillary cases, and cases with World Health Organization grade 2 disability were 1.3%, 90.3%, and 21.6%, respectively. A total of 2,219 leprosy cases were registered in China by the end of 2019, giving a prevalence rate of 0.158/100,000. Fifty-six counties had a prevalence rate of more than 1/100,000, and most of them were located in Southwest China. There were 31 reported relapse cases.Conclusion::The prevalence of leprosy has improved continuously throughout China, but the southwest region is still an area of concern.

麻风是麻风分枝杆菌感染所致的慢性传染性疾病,体液免疫及细胞免疫参与麻风的发病机制.目前血清抗体及辅助性T细胞2(Th2)相关细胞因子检测主要应用于诊断多菌型麻风(MB),辅助性T细胞1(Th1)相关细胞因子检测主要应用于诊断少菌型麻风(PB).microRNAs可用于区分瘤型及结核型麻风.但上述诊断试验的敏感性及特异性不一,何种标记物诊断效能更佳仍存在争议.本文主要从血清抗体、细胞因子及microRNA标记物检测及其临床应用等方面进行综述,以期为新型早期诊断麻风方法的优化提供依据.

Background: Previous studies suggest protection of a single dose of rifampicin(SDR) from developing leprosy among close contacts. This study aimed to evaluate the effectiveness of a single dose of rifapentine(SDL) to prevent leprosy in household contacts (HHCs) of leprosy cases in areas of low epidemic leprosy in China.Methods: In this cluster-randomised controlled trial, we randomised and allocated 207 clusters (counties) into three arms, the eligible HHCs of patients diagnosed with leprosy since 2010 received SDL, SDR or no post-exposure prophylaxis (PEP) interventions, respectively. The primary outcome was the incidence density of leprosy by the end of 4 th year of annual follow-up. The preventive effect of the interventions was estimated by generalized estimating equations with possion distribution for family function and reported as incidence density ratio (IDR). Safety and economic evaluation of the interventions were done in parallel with the trial. Findings: Enrolled counties were randomly allocated to the rifapentine group (n=68, 2004 participants), the rifampicin group (n=71, 2609 participants), and the control group (n=68, 2837 participants). A total of 22 new leprosy cases occurred during the 4-year follow-up, 1 in the rifapentine group (incidence rate 0.14 per 1000 person-years), 4 in the rifampicin group (0.43 per 1000 person-years), and 17 in the control group (1.71 per 1000 person-years), respectively. The reduction of incidence density in the rifapentine and rifampicin groups was 92.6% (IDR 0.100, 95% CI 0.013 to 0.755, P=0.026), and 78.1% (IDR 0.265, 95% CI 0.089 to 0.794, P=0.018), respectively. No severe adverse event was observed in the three groups. In total, 12 incremental leprosy cases were prevented, resulting in an incremental cost-effectiveness ratio (ICER) of $175·7 in the rifapentine group and $20·3 in the rifampicin group per one additional prevented leprosy case.Interpretation: SDL or SDR is effective, safe, cost-efficient in preventing the development of leprosy in HHCs of leprosy patients under low endemic situations in China. Rifapentine could effectively reduce the incidence density of leprosy in HHCs, especially in HHCs of MB index cases, HHCs of new diagnosed index cases, and spouse of index cases.Trial Registration Details: This study was registered with www.chictr.org.cn. ChiCTR-IPR-15007075.Funding Information: This study was funded by the Ministry of Health of China (201502008) and CAMS Innovation Fund for Medical Science (2016-I2M-1-005, 2017-I2M-B&R-14).Declaration of Interests: We declare no competing interests.Ethics Approval Statement: The protocol and informed consent forms (2014-KY-003) were approved by the Research Ethics Board of the Hospital of Dermatology, the Chinese Academy of Medical Science, and the four other participating units. The written informed consent was required before enrolment.

Objective:To describe the epidemiological characteristics of leprosy in China in 2020 and provide a basis for optimizing leprosy prevention and control strategies.Methods:We collected leprosy data from the Leprosy Management Information System in China,which includes data from 31 provinces,autonomous regions,and municipalities,except for Hong Kong,Macao,and Taiwan,and then performed a descriptive analysis of these data.Results:A total of 406 newly detected leprosy cases were reported nationwide in China in 2020,giving an incidence rate of 0.29 per 1,000,000 population.Among the population with leprosy,the proportions of children younger than 15 years,multibacillary cases,and cases with grade 2 disability were 1.2％,93.3％,and 17.7％,respectively.Southwest China was the region with the largest proportion of new leprosy cases(54.7％).There were 31 relapse leprosy cases reported in 2020.By the end of 2020,there were 1,893 registered leprosy cases reported nationwide,giving a prevalence rate of 1.35 per 1,000,000 population.Conclusion:Leprosy is at a low endemic level in China in terms of the prevalence and incidence rates.However,the geographical distribution of leprosy in China is unbalanced;leprosy is highly endemic in southwest China,including Yunnan,Guizhou,Sichuan,Guangdong,and Guangxi.

Background: Genome-wide association studies (GWASs) have identified some immune related single-nucleotide polymorphisms (SNPs) to be associated with leprosy. Methods: This study investigated the association of 17 SNPs based on previously published GWAS studies with susceptibility to leprosy, different polar forms and immune states of leprosy in a case-control study from southwestern China, including 1344 leprosy patients and 2732 household contacts (HHCs) (1908 relatives and 824 genetically unrelated contact individuals). The differences of allele distributions were analyzed using chi-squared analysis and logistic regression. Results: After adjusting covariate factors, rs780668 and rs3764147 polymorphisms influenced susceptibilities to genetically related or unrelated leprosy contact individuals. rs142179458 was associated with onset early cases, rs73058713 A allele and rs3764147 A allele increased the risk of reversal reaction, while rs3764147 G allele had higher risk to present lepromatous leprosy and erythema nodosum leprosum. Conclusion: Our results demonstrated that genetic variants in the LACC1, HIF1A, SLC29A3 and CDH18 genes were positively correlated with the occurrence of leprosy and leprosy clinical phenotypes, providing new insights into the immunogenetics of the disease.

BACKGROUND:There is a high incidence of leprosy among house-contacts compared with the general population. We aimed to establish a predictive model using these genetic factors along with epidemiological factors to predict leprosy risk of leprosy household contacts (HHCs). METHODS:Weighted genetic risk score (wGRS) encompassing genome wide association studies (GWAS) variants and five non-genetic factors were examined in a case-control design associated with leprosy risk including 589 cases and 647 controls from leprosy HHCs. We constructed a risk prediction nomogram and evaluated its performance by concordance index (C-index) and calibration curve. The results were validated using bootstrap resampling with 1000 resamples and a prospective design including 1100 HHCs of leprosy patients. FINDING:The C-index for the risk model was 0·792 (95% confidence interval [CI] 0·768-0·817), and was confirmed to be 0·780 through bootstrapping validation. The calibration curve for the probability of leprosy showed good agreement between the prediction of the nomogram and actual observation. HHCs were then divided into the low-risk group (nomogram score ≤ 81) and the high-risk group (nomogram score > 81). In prospective analysis, 12 of 1100 participants had leprosy during 63 months' follow-up. We generated the nomogram for leprosy in the validation cohort (C-index 0·773 [95%CI 0·658-0·888], sensitivity75·0%, specificity 66·8%). Interpretation The nomogram achieved an effective prediction of leprosy in HHCs. Using the model, the risk of an individual contact developing leprosy can be determined, which can lead to a rational preventive choice for tracing higher-risk leprosy contacts. FUNDING:The ministry of health of China, ministry of science and technology of China, Chinese academy of medical sciences, Jiangsu provincial department of science and technology, Nanjing municipal science and technology bureau.

Objective::To describe the epidemiological characteristics of leprosy in China in 2018 and provide the essential evidences for leprosy control.Methods::We collected data of leprosy cases nationwide from Leprosy Management Information System in China (LEPMIS) except Hong Kong, Macao, and Taiwan. And then we performed a descriptive and comparative analysis.Results::A total of 521 new leprosy cases were detected nationwide in 2018, with a case detection rate of 0.037/100,000. The proportion of children under 15 years of age, multi-bacillary (MB) cases, and cases with WHO grade 2 disability (G2D) were 1.3%, 89.4%, and 19.0%, respectively. There were 2,479 registered cases of leprosy in China by the end of 2018, accounting for a prevalence rate of 0.178/100,000, with 43 replase cases. Southwest China separately accounted for 312/521 (59.9%) newly detected cases and 1,180/2,479 (47.6%) registered cases of leprosy in China.Conclusion::China is a low endemic country for leprosy and the detection rate was much lower than the global average. Southwest China is still the key regions for leprosy control, including Yunnan, Guizhou, and Sichuan. In addition, leprosy in low endemic provinces also needs to be focused.