Leprosy among new child cases in China: Epidemiological and clinical analysis from 2011 to 2020.

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.

Suspicious symptom monitoring for leprosy: an optimal practice for early detection under a low endemic situation in Zhejiang Province, China.

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.

Single-Nucleotide Polymorphisms Related to Leprosy Risk and Clinical Phenotypes Among Chinese Population.

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.

Predictive nomogram for leprosy using genetic and epidemiological risk factors in Southwestern China: Case-control and prospective analyses.

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.

A study on gender differences in newly detected leprosy cases in Sichuan, China, 2000-2015.

BACKGROUND: Many researches on gender differences in leprosy found that female patients were detected with the disease later and had more serious disabilities than male patients. We analyzed the gender differences related to epidemiological characteristics of new leprosy cases detected from 2000 to 2015 in Sichuan Province, China. METHODS: A retrospective study was undertaken to analyze the gender differences with respect to age, delay in disease detection, the main modes of detection, and disability grade. The chi-squared test and t test were applied for the comparison using Epi Info 7.2 with a significance level of a = 0.05. The data were collected from the Leprosy Management Information System in China. RESULTS: A total of 2900 new leprosy cases were detected from 2000 to 2015, of whom 2075 (71.6%) were male and 825 (28.4%) were female with a gender ratio of 2.5. The gender ratio of patients aged 15-30 was significantly lower than that of patients aged 31-45 and 46-60. Male cases were older than female cases when they were detected. The proportion of Grade 2 Disability (G2D) among men (20.6%) was significantly higher than that among women (17.3%). The average period of delay in detection among male cases was similar with that among females cases. CONCLUSIONS: Gender-related differences existed among the leprosy cases detected from 2000 to 2015. Female patients were younger than male patients. The detection of leprosy in women was not later than in the case of men. The disability situation in men was more serious than in women.

[Epidemiological analysis on leprosy in China, 2009].

OBJECTIVE: To study the epidemiological characteristics of leprosy and to provide evidence for specific strategies development on leprosy control. METHODS: Descriptive analysis of data from the national leprosy surveillance system was carried out in 2009. RESULTS: A total number of 1597 new cases were detected in 2009 with a case detection rate of 0.120 per 100 000 population. The proportions of children under 15, multibacillary and disability grade 2 were 2.4%, 84.3% and 22.8% respectively. A total number of 148 relapse cases were reported in 2009, among which 69 cases were those relapsed after multi-drug therapy. The existing cases were 6603 by the end of 2009 with a prevalence rate of 0.049 per 10 000 populations, among which 3332 cases were on multi-drug therapy. CONCLUSION: The overall leprosy situation is considered to be at low endemic in China but the distribution is unequal, with pocket areas in Yunnan, Sichuan and Guizhou. In order to reach the target on leprosy elimination, which was considered as a public health and social problem, the input and efforts are needed for many years to come.

Insoluble beta-glucan from the cell wall of Candida albicans induces immune responses of human THP-1 monocytes through Dectin-1.

BACKGROUND: beta-glucan is the major structure component of Candida albicans (C. albicans) cell wall. It has been demonstrated that Dectin-1 as the principal C-type lectin pattern-recognition receptor (PRR) can recognize fungal beta-glucan and induce immune responses. In this study, we sought to clarify whether insoluble beta-glucan from the cell wall of C. albicans (CaIG) could induce immune responses in human THP-1 monocytes (a human acute monocytic leukemia cell line) and to determine the underlying mechanisms. METHODS: Human THP-1 monocytes were challenged with CaIG in vitro. The mRNA expression of Dectin-1, Toll-like receptors (TLR2), proinflammatory cytokine (TNF-alpha) and chemokine (IL-8) was assayed by real-time reverse transcription polymerase chain reaction (RT-PCR). The secretion of TNF-a and IL-8 were measured by enzyme-linked immunosorbent assay (ELISA). H(2)O(2) release was determined by microplate fluorescent assay. Western blotting was used to analyze IkappaB-a phosphorylation and degradation. RESULTS: Exposure of THP-1 monocytes to CaIG led to increased gene expression and secretion of TNF-alpha and IL-8. CaIG induced H(2)O(2) release in a time-dependent manner. CaIG hydrolyzed with zymolyase failed to induce gene expression and secretion of TNF-alpha, IL-8 and H(2)O(2) release. CaIG up-regulated the mRNA of Dectin-1, whereas the mRNA level of TLR2 was not altered. THP-1 monocytes challenged with CaIG resulted in the activation of NF-kappaB in a time-dependent manner. Dectin-1 inhibitor laminarin blocked the CaIG-induced production of TNF-alpha and H(2)O(2) in THP-1 monocytes, but no such effect was observed in pretreatment with anti-TLR2 neutralizing antibody and the LPS inhibitor (polymyxin B). CONCLUSION: CaIG may play a role in activation of immune responses in human THP-1 cells through Dectin-1, not TLR2.

[A long-term evolution on the epidemiological characteristics of leprosy, towards the goal of its elimination in 1949 - 2007 in China].

OBJECTIVE: To understand the epidemiological characteristics of leprosy during the evolution of the disease, towards the goal of elimination for the past 50 years and longer, so as to provide experiences for accelerating eradication of leprosy in China. METHODS: Data were collected from National Surveillance System of Leprosy which was composed annually of all the data from county-based leprosy unit reporting system. All the data were reviewed retrospectively. RESULTS: A total number of 487 900 leprosy patients were reported from 1949 to 2007 in China. The case detection rate reduced from the highest of 5.56/100 000 in 1958 to the lowest of 0.12/100 000 in 2007. Leprosy patients mainly distributed in mountain areas in Yunnan, Guizhou, Sichuan, Guangdong Guangxi, Hunan and Jiangxi provinces with warm and damp climate and underdeveloped economy. After more than 50 years of leprosy control efforts, the case detection rate declined quickly in provinces in the eastern and the southern parts but very slowly in provinces in the western and the southwestern part of China. The ratio of relapsed patients to newly detected ones increased from 1:139 in 1960s' to 1:10 after 1980s', annually. The proportion of child cases among newly detected patients had been 3% - 4% since 1968. In the recent 20 years, the proportion of new patients with positive skin smear gradually increased and the rate of disability grade two reached 20% and more. The average age of new patients upon diagnosis was 45 years old in the east coastal provinces but only 38 years old in the southwest provinces. A new finding was that some new patients detected in the east coastal provinces were immigrants from the southwestern provinces. CONCLUSION: With continuous socio-economic development and active efforts on leprosy control, the prevalence of leprosy gradually declined despite the long evolution period. Some negative events seemed to have influenced the trend of case detection.

Trends of case detection and other indicators of leprosy in China during 1985-2002.

OBJECTIVE: To analyze the trends of case detection and other indicators of leprosy in China during 1985-2002. METHODS: Data reported by each province were collected by China National Leprosy Database in Nanjing P.R. China. All data about registered cases were put into computer for analysis. RESULTS: From 1985 to 2002, a total of 49,477 new leprosy cases had been detected. Among them, 69.5% were multibacillary cases and 25.4% had grade 2 disability. The child cases aged below 15 years accounted for 3.74% of total cases. Totally, 5824 cases and 303 cases relapsed after dapsone (DDS) mono-therapy and multidrug therapy (MDT), respectively. Case detection showed a marked reduction from 0.47/100,000 in 1985 to 0.18/100,000 in 1993 although there were several spurts due to operational factors. From 1994, case detection showed no significant decline. The grade 2 disability among new patients decreased from 31.4% in 1985 to 23.4% in 2002. The child case detection rate among new cases fluctuated between 2.70%-3.56% from 1999 to 2002. The incidence of relapse declined after the introduction of DDS mono-therapy. However, it increased after the introduction of MDT. CONCLUSION: China experiences in leprosy control show that it will take a long time with continuing present leprosy control activities to bring down the case detection and other indicators to a very low level even after reaching the elimination goal of leprosy.