Epidemiologic trends of leprosy for the 21st century

Trend of pediatric leprosy in an endemic area in Northeast of Brazil, 2008-2018

BACKGROUND

The incidence of leprosy in children is an important indicator of the disease's tendency in the general population and suggests intense circulation and transmission of Mycobacterium leprae.

OBJECTIVES

To describe the clinical, epidemiological characteristics and temporal dynamics of leprosy cases in children under 15 years of age from 2008 to 2018 in an endemic municipality.

METHODS

A descriptive study with an analytical approach was carried out with data from leprosy cases registered in the Brazilian Information System on Notifiable Diseases for the municipality of Cabo de Santo Agostinho, Pernambuco, Brazil.

RESULTS

Between 2008 and 2018, 112 new cases of leprosy were registered. Most cases were classified as paucibacillary leprosy and occurred in children living in urban areas. There was no significant difference in the incidence of leprosy during the study period. Only 4.5% of the sample presented reactional episodes, but a high number of cases were not evaluated for the occurrence of reactions.

CONCLUSIONS

The findings of this study show a high incidence of paucibacillary leprosy in children and adolescents, which reveals active transmission in the community and failures in the detection of new multibacillary cases among adults. Children between 10 and 14 years old are more vulnerable to M. leprae infection and mainly develop paucibacillary leprosy.

Self-healing in leprosy: A systematic review

BACKGROUND

Leprosy, caused by Mycobacterium leprae, affects multiple body systems and can lead to preventable disability if untreated. While multidrug therapy (MDT) has been available since 1982, historical evidence suggests that untreated leprosy can resolve spontaneously. Nevertheless, the prevalence of self-healing worldwide, as well as factors determining self-healing, remain unclear.

METHODS

A systematic review was conducted in 2023 with data from PubMed, Infolep, and Web of Sciences data bases, along with a google search. Data extraction and analysis followed PRISMA guidelines and were summarized in a separate Excel sheet. Included were English-language studies on self-healing in leprosy, regardless the year of publication.

RESULTS

We included six studies spanning from 1938 to 1978 exploring the incidence of self-healing in different countries and continents. Children, paucibacillary (PB) cases, and possibly males showed a higher probability of self-healing with an average healing time of two years.

DISCUSSION/CONCLUSION

Recent research on self-healing in leprosy is scarce and evidence limited. This is primarily due to ethical concerns regarding withholding effective treatment of diagnosed patients, and because of the absence of an agreed definition of self-healing. Nevertheless, self-healing appears to be a plausible phenomenon influenced by geographic and demographic factors, and the type of leprosy. We recommend further research on self-healing in leprosy, as it provides insight into the human immune system and the determinants of this phenomenon. More insight could help adapt clinical practices and public health strategies, thereby contributing to an effective management and control of this disease.

Focal slowing of nerve conduction velocity in leprosy patients unveiled through multisegmented nerve analysis

BACKGROUND AND AIMS

Leprosy is a chronic infectious disease caused by Mycobacterium leprae (M. leprae), an intracellular bacillus that systematically invades the peripheral nerves. Diagnosing leprosy neuropathy is still a defying skill, and late diagnosis and treatment are still a reality. Based on the biological characteristics of M. leprae, particularly its preference for invading the Schwann cells localized at the coldest areas of human body, we hypothesized that these areas have focal demyelination that may escape detection through standard nerve conduction studies (NCSs) protocols.

METHODS

Twenty-five patients with confirmed multibacillary leprosy and 14 controls were accessed. A multisegmented NCS protocol (MP) was performed, targeting short segments through the coldest areas, to identify focal areas of slowed conduction velocity. The effectiveness of this multisegmented protocol was compared to the standard protocol (SP) to detect abnormalities.

RESULTS

All leprosy patients presented an abnormal study with the MP, contrasting to 19 with the SP. The most frequent NCS pattern was an asymmetric neuropathy with focal slowing of conduction velocity, found in 23 out of 25 leprosy patients. Significant differences favoring the proposed method were observed when comparing the MP with the SP. Notably, the MP increased the sensitivity to detect abnormalities by 122%, 133%, and 257% for the median, peroneal, and tibial nerves, respectively. MP also increases sensitivity to detect focal abnormalities in the ulnar nerve.

INTERPRETATION

The MP protocol significantly increases the sensitivity of NCSs to detect neurophysiological abnormalities in leprosy neuropathy.

Effectiveness of Sensitization Campaigns in Reducing Leprosy-Related Stigma in Rural Togo: Protocol for a Mixed Methods Cluster Randomized Controlled Trial

BACKGROUND

In the global strategy to eliminate leprosy, there remains a need for early case detection to successfully interrupt transmissions. Poor knowledge about leprosy and leprosy-related stigma are key drivers of delayed diagnosis and treatment. Sensitization campaigns to inform and increase awareness among the general population are an integral part of many national neglected tropical disease programs. Despite their importance, the effectiveness of such campaigns has not been rigorously studied in the West African context. A multilingual rural setting with low health literacy in this region presents challenges to the potential impact of sensitization campaigns.

OBJECTIVE

The primary objective of this study is to assess the causal effect of common practice community sensitization campaigns on leprosy-related knowledge and stigma at the community level and among community health volunteers. Additionally, we will test the potential of novel educational audio tools in the 15 most prominent local languages to overcome literacy and language barriers and amplify sensitization campaigns.

METHODS

We will conduct a cluster randomized controlled trial using a sequential mixed methods approach in 60 rural communities across all regions of Togo, West Africa. The study features 2 intervention arms and 1 control arm, with intervention and control assignments made at the community level through randomization. Communities in intervention arm 1 will receive a sensitization campaign in line with the current Togolese national neglected tropical disease program. Communities in intervention arm 2 will receive the same sensitization campaign along with educational audio tools distributed to community households. The control arm will receive no intervention before data collection. Quantitative outcome measures on knowledge and stigma will be collected from a random sample of 1200 individuals. Knowledge will be assessed using the 9-item standardized Knowledge, Attitudes, and Practices Questionnaire. Stigma will be measured using the 7-item Social Distance Scale and the 15-item Explanatory Model Interview Catalogue Community Stigma Scale. We will estimate intention-to-treat effects at the individual level, comparing the outcomes of the intervention and control arms. In an accompanying qualitative component, we will conduct in-depth interviews with community members, community health volunteers, and health care workers in both treatment arms and the control arm to explore intervention and stigma-related experiences.

RESULTS

This paper describes and discusses the protocol for a mixed methods cluster randomized controlled trial. Data collection is planned to be completed in June 2024, with ongoing data analysis. The first results are expected to be submitted for publication by the end of 2024.

CONCLUSIONS

This trial will be among the first to test the causal effectiveness of community-based sensitization campaigns and audio tools to increase knowledge and reduce leprosy-related stigma. As such, the results will inform health policy makers, decision-makers, and public health practitioners designing sensitization campaigns in rural multilingual settings.

TRIAL REGISTRATION

German Clinical Trials Register DRKS00029355; https://drks.de/search/en/trial/DRKS00029355.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/52106.

Leprosy: treatment, prevention, immune response and gene function

Since the leprosy cases have fallen dramatically, the incidence of leprosy has remained stable over the past years, indicating that multidrug therapy seems unable to eradicate leprosy. More seriously, the emergence of rifampicin-resistant strains also affects the effectiveness of treatment. Immunoprophylaxis was mainly carried out through vaccination with the BCG but also included vaccines such as LepVax and MiP. Meanwhile, it is well known that the infection and pathogenesis largely depend on the host's genetic background and immunity, with the onset of the disease being genetically regulated. The immune process heavily influences the clinical course of the disease. However, the impact of immune processes and genetic regulation of leprosy on pathogenesis and immunological levels is largely unknown. Therefore, we summarize the latest research progress in leprosy treatment, prevention, immunity and gene function. The comprehensive research in these areas will help elucidate the pathogenesis of leprosy and provide a basis for developing leprosy elimination strategies.

Leprosy with type 1 reaction in a patient from Ontario, Canada without recent travel misdiagnosed as vasculitic neuropathy: a case report

BACKGROUND

Leprosy is rare within non-endemic countries such as Canada, where cases are almost exclusively imported from endemic regions, often presenting after an incubation period of as many as 20 years. Due to its rarity and prolonged incubation period, diagnosis is often delayed, which may result in neurologic impairment prior to the initiation of treatment. In this report we describe a case that is novel in its incubation period, which is the longest reported to-date and may have contributed to diagnostic delay. The case also uniquely demonstrates the challenges of distinguishing leprosy reactions from new rheumatologic manifestations in a patient with established autoimmune disease.

CASE PRESENTATION

We describe an 84-year-old male patient with rheumatoid arthritis on methotrexate and hydroxychloroquine, with no travel history outside Canada for 56 years, who presented in 2019 with new-onset paresthesias and rash. His paresthesias persisted despite a short course of prednisone, and his rash recurred after initial improvement. He underwent skin biopsy in May 2021, which eventually led to the diagnosis of leprosy. He was diagnosed with type 1 reaction and was started on rifampin, dapsone, clofazimine and prednisone, with which his rash resolved but his neurologic impairment remained.

CONCLUSION

This case report serves to highlight the potential for leprosy to present after markedly prolonged incubation periods. This is especially relevant in non-endemic countries that is home to an aging demographic of individuals who migrated decades ago from endemic countries. The importance of this concept is emphasized by the persistent neurologic impairment suffered by our case due to untreated type 1 reaction. We also demonstrate the necessity of skin biopsy in distinguishing this diagnosis from other autoimmune mimics in a patient with known autoimmune disease.

Gene Expression of Human Beta-Defensin-3 and Cathelicidin in the Skin of Leprosy Patients, Household Contacts, and Healthy Individuals from Indonesia

Background

Leprosy, a chronic infectious peripheral neuropathy, is caused by Mycobacterium leprae. This bacterium produces triacylated lipopeptides that can induce the immune system via the Toll-like receptor 2/1 (TLR 2/1) complex. Activation of TLR 2/1 produces proinflammatory cytokines and antimicrobial peptides (AMPs), including human beta-defensin-3 (HBD-3) and cathelicidin.

Purpose

To analyze differences in gene expression of HBD-3 and cathelicidin in the skin of leprosy patients, household contacts, and healthy individuals.

Patients and Methods

An analytic observational study was conducted at the Outpatient Clinic of Dermatology and Venereology of Dr Mohammad Hoesin General Hospital, Palembang, Indonesia, from January 2021 to June 2022. In each group of 18 subjects, 72 samples were collected, including skin lesion in leprosy patients, normal skin in leprosy patients, household contacts, and healthy individuals. A comparison of HBD-3 and cathelicidin gene expression between the four groups was analyzed using Pearson Chi Square, Kruskal-Wallis, and Mann-Whitney Test.

Results

The median value of HBD-3 gene expression on skin lesion in leprosy patients was 260.61 (0.19-3734.10); normal skin in leprosy patients was 1.91 (0.01-151.17); household contacts skin was 7.93 (0.27-121.10); and healthy individuals' skin was 1.00 (1.00-1.00) is highly significant difference (p < 0.0001). The median value of cathelicidin gene expression on skin lesion in leprosy patients was 38.72 (0.28-1852.17); normal skin in leprosy patients was 0.48 (0.01-15.83); household contacts skin was 9.8 (0.04-128.0); and healthy individual skin was 1.00 (1.00-1.00), also highly significant difference (p < 0.0001).

Conclusion

Gene expression of HBD-3 and cathelicidin increased in skin lesions of leprosy patients and household contacts.

Establishing a standard method for analysing case detection delay in leprosy using a Bayesian modelling approach

BACKGROUND

Leprosy is an infectious disease caused by Mycobacterium leprae and remains a source of preventable disability if left undetected. Case detection delay is an important epidemiological indicator for progress in interrupting transmission and preventing disability in a community. However, no standard method exists to effectively analyse and interpret this type of data. In this study, we aim to evaluate the characteristics of leprosy case detection delay data and select an appropriate model for the variability of detection delays based on the best fitting distribution type.

METHODS

Two sets of leprosy case detection delay data were evaluated: a cohort of 181 patients from the post exposure prophylaxis for leprosy (PEP4LEP) study in high endemic districts of Ethiopia, Mozambique, and Tanzania; and self-reported delays from 87 individuals in 8 low endemic countries collected as part of a systematic literature review. Bayesian models were fit to each dataset to assess which probability distribution (log-normal, gamma or Weibull) best describes variation in observed case detection delays using leave-one-out cross-validation, and to estimate the effects of individual factors.

RESULTS

For both datasets, detection delays were best described with a log-normal distribution combined with covariates age, sex and leprosy subtype [expected log predictive density (ELPD) for the joint model: -1123.9]. Patients with multibacillary (MB) leprosy experienced longer delays compared to paucibacillary (PB) leprosy, with a relative difference of 1.57 [95% Bayesian credible interval (BCI): 1.14-2.15]. Those in the PEP4LEP cohort had 1.51 (95% BCI: 1.08-2.13) times longer case detection delay compared to the self-reported patient delays in the systematic review.

CONCLUSIONS

The log-normal model presented here could be used to compare leprosy case detection delay datasets, including PEP4LEP where the primary outcome measure is reduction in case detection delay. We recommend the application of this modelling approach to test different probability distributions and covariate effects in studies with similar outcomes in the field of leprosy and other skin-NTDs.

Risk Factors for Disability Upgrading Among Leprosy Patients During Treatment: Multilevel Modeling Analysis

Background

Leprosy not only brings about bodily incapacity but also creates a nasty image of affected individuals, triggering discrimination and social stigma. The purpose of this study was to evaluate the status of leprosy disability in patients registered at the All African TB and Leprosy Rehabilitation and Training Center.

Methods

The study consists of 205 leprosy patients who were undergoing treatment at the All African TB and Leprosy Rehabilitation and Training Center from January 2015 to December 2019. Regional states of the patients were used as a clustering effect in the multilevel logistic regression model.

Results

In total, 205 (66.3%) completed records revealed patients with leprosy were disabled. Among these, 64.88% of them were males. In multilevel binary logistic regression analysis, the individual-level variables, such as median age (AOR = 1.1; 95% CI: 1.043, 1.13) of patients, patients with duration of symptom [7-12 months (AOR = 2.26; 95% CI: 1.50, 3.39), 13-24 months (AOR = 2.13; 95% CI: 1.44, 3.15), and more than 24 months (AOR = 2.67; 95% CI: 1.8, 4.02)], the absence of sensory loss (AOR = 0.84; 95% CI: 0.72, 0.96), and patients with asymmetry lesion distribution (AOR = 0.74; 95% CI: 0.65, 0.85), were the most significant determinant factors of disability. The default leprosy patient (AOR = 15.53; 95% CI: 1.82, 134.96) and new leprosy patient (AOR = 0.51; 95% CI: 0.33, 1.68) were the significant determinant factors of disability due to leprosy patients.

Conclusion

An individual-level factor on the risk of disability was higher as age increased and for patients with a longer duration of symptoms. The risk of disability was lower for patients who do not lose their sensation and for patients whose lesion distribution is asymmetrical. The community-level factor, patient categories, was also a significant factor in disability due to leprosy. Furthermore, programs should emphasize raising community awareness, focusing on key messages and early case detection campaigns, such as active surveys, as well as the availability of leprosy care in a public health facility.

Delayed detection of leprosy cases: A systematic review of healthcare-related factors

Background

In new leprosy cases, grade 2 disability (G2D) is still a public health burden worldwide. It is often associated with the delayed leprosy diagnoses that healthcare systems should play a crucial role in preventing. The aim of this systematic review was to identify healthcare factors related to delays in case detection in leprosy.

Methods

PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) was used as a guideline in this research. The study protocol was registered in the PROSPERO (International Prospective Register of Systematic Reviews) with reference code CRD42020189274. Data was collected from five electronic databases: Embase, Medline All Ovid, Web of Science, Cochrane CENTRAL, and the WHO Global Health Library.

Results

After applying the selection criteria for original empirical studies, and after removing duplicates, we included 20 papers from 4313 records. They had been conducted in ten countries and published between January 1, 2000, and January 31, 2021. We identified three categories of healthcare factors related to delayed case. 1) Structural factors, such as i) financial and logistic issues, and geographical circumstances (which we classified as barriers); ii) Health service organization and management including the level of decentralization (classified as facilitators). 2) Health service factors, such as problems or shortages involving referral centers, healthcare personnel, and case-detection methods. 3) Intermediate factors, such as misdiagnosis, higher numbers of consultations before diagnosis, and inappropriate healthcare services visited by people with leprosy.

Conclusions

Delays in leprosy case detection are due mainly to misdiagnosis. It is crucial to improve the training and capacity of healthcare staff. To avoid misdiagnosis and reduce detection delays, national leprosy control programs should ensure the sustainability of leprosy control within integrated health services.

New leprosy patients diagnosed with visible physical deformities represent a significant disease burden that also poses an important public health challenge. The physical deformities often result from long delays in case detection. Greater insight into the healthcare factors that contribute to such delays will support the development of effective prevention programs. We therefore reviewed all studies on the healthcare factors related to case-detection delay that had been published between January 1, 2000, and January 31, 2021. Twenty studies were included in our analysis. We found that misdiagnosis was a core healthcare factor related to delays. Other common factors included inappropriate health services, a high number of consultations before diagnosis; and a lack of referral centers, healthcare personnel, and case-detection methods. Detection delay was further influenced by geographical circumstances, financial and logistic issues, and health-service organization and management including the level of the decentralization of healthcare programs. Because delays in leprosy case detection are due mainly to misdiagnosis, we recommend to improve the training and capacity of healthcare staff. To avoid misdiagnosis and reduce detection delays, national leprosy control programs should ensure the sustainability of leprosy control within integrated health services.

Global epidemiology of leprosy from 2010 to 2020: A systematic review and meta-analysis of the proportion of sex, type, grade 2 deformity and age

The objectives of this study were to explore global epidemiological characteristics of leprosy, and to provide reference for the construction of prevention strategies for leprosy. Computer retrieval of the study on the epidemiology of leprosy from 2010 to 2020 in Web of Science, PubMed, and SCOPUS databases were summarized. The included studies were assessed for the quality of the AHRQ; the proportions of the study indices were meta-analyzed with Stata 16.0. A random effects model was adopted to merge categories, including sex, type, grade 2 deformity (G2D) and age group for meta-analysis. The subgroup analysis used region as a stratification factor to analyze whether there were differences in the indicators. The meta-analysis included 30 studies totaling 11,353 cases. The global pooled proportion of male to female subjects with leprosy was 63% (95% CI 59%, 66%) to 37% (95% CI 34%, 41%), respectively. The pooled multibacillary proportion and paucibacillary proportion were 69% (95% CI 62%, 76%) and 31% (95% CI 24%, 38%), respectively. The pooled grade 2 deformity (G2D) proportion was 22% (95% CI 15%, 30%). Among age groups, the pooled children proportion was 11% (95% CI 8%, 13%), and the pooled adult proportion was 89% (95% CI 87%, 92%). The subgroup analysis indicated that epidemiological indicators varied from country to country. This study suggested that disparities existed between sex, type, grade 2 deformity (G2D) and age group characteristics of leprosy from country to country.

Mycobacterium leprae induces Schwann cell proliferation and migration in a denervated milieu following intracutaneous excision axotomy in nine-banded armadillos

Nine-banded armadillos develop peripheral neuropathy after experimental Mycobacterium leprae infection that recapitulates human disease. We used an intracutaneous excision axotomy model to assess the effect of infection duration by M. leprae on axonal sprouting and Schwan cell density. 34 armadillos (17 naïve and 17 M. leprae-infected) underwent 3 mm skin biopsies to create an intracutaneous excision axotomy followed by a concentric 4-mm overlapping biopsy 3 and 12-months post M. leprae inoculation. A traditional distal leg biopsy was obtained at 15mo for intraepidermal nerve fiber (IENF) density. Serial skin sections were immunostained against a axons (PGP9.5, GAP43), and Schwann cells (p75, s100) to visualize regenerating nerves. Regenerative axons and proliferation of Schwann cells was measured and the rate of growth at each time point was assessed. Increasing anti-PGL antibody titers and intraneural M. leprae confirmed infection. 15mo following infection, there was evidence of axon loss with reduced distal leg IENF versus naïve armadillos, p < 0.05. This was associated with an increase in Schwann cell density (11,062 ± 2905 vs. 7561 ± 2715 cells/mm³, p < 0.01). Following excisional biopsy epidermal reinnervation increased monotonically at 30, 60 and 90 days; the regeneration rate was highest at 30 days, and decreased at 60 and 90 days. The reinnervation rate was highest among animals infected for 3mo vs those infected for 12mo or naïve animals (mean ± SD, 27.8 ± 7.2 vs.16.2 ± 5.8vs. 15.3 ± 6.5 mm/mm³, p < 0.05). The infected armadillos displayed a sustained Schwann cell proliferation across axotomy time points and duration of infection (3mo:182 ± 26, 12mo: 256 ± 126, naive: 139 ± 49 cells/day, p < 0.05). M. leprae infection is associated with sustained Schwann cell proliferation and distal limb nerve fiber loss. Rates of epidermal reinnervation were highest 3mo after infection and normalized by 12 mo of infection. We postulate that excess Schwann cell proliferation is the main pathogenic process and is deleterious to sensory axons. There is a compensatory initial increase in regeneration rates that may be an attempt to compensate for the injury, but it is not sustained and eventually followed by axon loss. Aberrant Schwann cell proliferation may be a novel therapeutic target to interrupt the pathogenic cascade of M. leprae.

Evaluation of Polymorphisms in Toll-Like Receptor Genes as Biomarkers of the Response to Treatment of Erythema Nodosum Leprosum

Erythema nodosum leprosum (ENL) is an inflammatory complication caused by a dysregulated immune response to Mycobacterium leprae. Some Toll-like receptors (TLRs) have been identified as capable of recognizing antigens from M. leprae, triggering a wide antimicrobial and inflammatory response. Genetic polymorphisms in these receptors could influence in the appearance of ENL as well as in its treatment. Thus, the objective of this work was to evaluate the association of genetic variants of TLRs genes with the response to treatment of ENL with thalidomide and prednisone. A total of 162 ENL patients were recruited from different regions of Brazil and clinical information was collected from their medical records. Genomic DNA was isolated from blood and saliva samples and genetic variants in TLR1 (rs4833095), TLR2 (rs3804099), TLR4 (rs1927914), and TLR6 (rs5743810) genes were genotyped by TaqMan real-time PCR system. In order to evaluate the variants' association with the dose of the medications used during the treatment, we applied the Generalized Estimating Equations (GEE) analysis. In the present sample, 123 (75.9%) patients were men and 86 (53.1%) were in treatment for leprosy during the ENL episode. We found an association between polymorphisms in TLR1/rs4833095, TLR2/rs3804099, TLR4/rs1927914, and TLR6/rs5783810 with the dose variation of thalidomide in a time-dependent manner, i.e., the association with the genetic variant and the dose of the drug was different depending on the moment of the treatment evaluated. In addition, we identified that the association of polymorphisms in TLR1/rs4833095, TLR2/rs3804099, and TLR6/rs5783810 with the dose variation of prednisone also were time-dependent. Despite these associations, in all the interactions found, the influence of genetic variants on dose variation was not clinically relevant for therapeutic changes. The results obtained in this study show that TLRs polymorphism might play a role in the response to ENL treatment, however, in this context, they could not be considered as useful biomarkers in the clinical setting due small differences in medication doses. A larger sample size with patients with a more genetic profile is fundamental in order to estimate the association of genetic variants with the treatment of ENL and their clinical significance.

Immunoassay standardization for the detection of immunoglobulin A (IgA) against Porphyromonas gingivalis antigens in saliva of individuals with and without leprosy

Leprosy reactions are immune processes that cause neural damage in individuals with leprosy. As periodontitis is an infectious disease related to its development, specific antibodies to periodontal pathogens must be evaluated to better understand the humoral mechanisms underlying this relationship. Therefore, the objective of this study was to standardize an immunoassay to measure IgA specific to P. gingivalis antigens in the saliva of individuals with leprosy. An ELISA checkerboard titration was performed. A validation test involving 53 individuals with leprosy, 24 with and 19 without periodontitis, was conducted and a ROC curve constructed to calculate sensitivity and specificity. The coefficient of the optical densities was 2.21 and 2.66 for P. gingivalis crude extract and the recombinant protein HmuY, respectively. Sensitivity and specificity for the P. gingivalis crude extract were 66.7% and 73.7%, respectively, and for HmuY, were 62.5% and 52.6%, respectively. Specific recognition of P. gingivalis occurred predominantly in individuals with periodontitis, which validates the use of this test for studying periodontitis in individuals with leprosy.

Trial registration CAEE 64476117.3.0000.0049, 21/07/2017, retrospectively registered

Geospatial epidemiology of leprosy in northwest Bangladesh: a 20-year retrospective observational study

Background

Leprosy is known to be unevenly distributed between and within countries. High risk areas or ‘hotspots’ are potential targets for preventive interventions, but the underlying epidemiologic mechanisms that enable hotspots to emerge, are not yet fully understood. In this study, we identified and characterized leprosy hotspots in Bangladesh, a country with one of the highest leprosy endemicity levels globally.

Methods

We used data from four high-endemic districts in northwest Bangladesh including 20 623 registered cases between January 2000 and April 2019 (among ~ 7 million population). Incidences per union (smallest administrative unit) were calculated using geospatial population density estimates. A geospatial Poisson model was used to detect incidence hotspots over three (overlapping) 10-year timeframes: 2000–2009, 2005–2014 and 2010–2019. Ordinal regression models were used to assess whether patient characteristics were significantly different for cases outside hotspots, as compared to cases within weak (i.e., relative risk (RR) of one to two), medium (i.e., RR of two to three), and strong (i.e., RR higher than three) hotspots.

Results

New case detection rates dropped from 44/100 000 in 2000 to 10/100 000 in 2019. Statistically significant hotspots were identified during all timeframes and were often located at areas with high population densities. The RR for leprosy was up to 12 times higher for inhabitants of hotspots than for people living outside hotspots. Within strong hotspots (1930 cases among less than 1% of the population), significantly more child cases (i.e., below 15 years of age) were detected, indicating recent transmission. Cases in hotspots were not significantly more likely to be detected actively.

Conclusions

Leprosy showed a heterogeneous distribution with clear hotspots in northwest Bangladesh throughout a 20-year period of decreasing incidence. Findings confirm that leprosy hotspots represent areas of higher transmission activity and are not solely the result of active case finding strategies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40249-021-00817-4.

Comparison of IL-17 and FOXP3+ Levels in Maternal and Children Leprosy Patients in Endemic and Nonendemic Areas

Leprosy, a chronic infection caused by M. leprae, has a complex transmission problem that makes eradication programs difficult. New cases and ongoing transmission of leprosy in endemic areas make individuals living in endemic environments vulnerable to leprosy. This can be caused by the dysregulation of immune system in individuals living in leprosy-endemic areas. Although the number of male leprosy patients is higher, female leprosy patients have more impact on the family health status due to close contact with family members, roles in the household, and parenting. This could cause the increased number of children leprosy patients. We investigated the dysregulation of immune system by comparing IL-17 and FOXP3+ levels occurring in maternal and child leprosy patients in endemic and nonendemic areas. The results of the study found a statistically significant difference in IL-17 levels between the MB leprosy patient group and the control group (p=0.048), where higher levels of IL-17 are observed in the control group. A significant difference also was found in FOXP3+ levels between the group of healthy children living in endemic and those living in nonendemic areas (p=0.047), where higher FOXP3+ is observed in the healthy children living in endemic areas group.

Post-translational knockdown and post-secretional modification of EsxA determine contribution of EsxA membrane permeabilizing activity for mycobacterial intracellular survival

Current genetic studies (e.g. gene knockout) have suggested that EsxA and EsxB function as secreted virulence factors that are essential for Mycobaterium tuberculosis (Mtb) intracellular survival, specifically in mediating phagosome rupture and translocation of Mtb to the cytosol of host cells, which further facilitates Mtb intracellular replicating and cell-to-cell spreading. The EsxA-mediated intracellular survival is presumably achieved by its pH-dependent membrane-permeabilizing activity (MPA). However, the data from other studies have generated a discrepancy regarding the role of EsxA MPA in mycobacterial intracellular survival, which has raised a concern that genetic manipulations, such as deletion of esxB-esxA operon or RD-1 locus, may affect other codependently secreted factors that could be also directly involved cytosolic translocation, or stimulate extended disturbance on other genes’ expression. To avoid the drawbacks of gene knockout, we first engineered a Mycobacterium marinum (Mm) strain, in which a DAS4+ tag was fused to the C-terminus of EsxB to allow inducible knockdown of EsxB (also EsxA) at the post-translational level. We also engineered an Mm strain by fusing a SpyTag (ST) to the C-terminus of EsxA, which allowed inhibition of EsxA-ST MPA at the post-secretional level through a covalent linkage to SpyCatcher-GFP. Both post-translational knockdown and functional inhibition of EsxA resulted in attenuation of Mm intracellular survival in lung epithelial cells or macrophages, which unambiguously confirms the direct role of EsxA MPA in mycobacterial intracellular survival.

Polymorphisms in mitochondrial ribosomal protein S5 (MRPS5) are associated with leprosy risk in Chinese

Leprosy is an infectious disease caused by Mycobacterium leprae (M. leprae), with about 210,000 new cases per year worldwide. Although numerous risk loci have been uncovered by genome-wide association studies, the effects of common genetic variants are relatively modest. To identify possible new genetic locus involved in susceptibility to leprosy, whole exome sequencing was performed for 28 subjects including 14 patients and 12 unaffected members from 8 leprosy-affected families as well as another case and an unrelated control, and then the follow-up SNP genotyping of the candidate variants was studied in case-control sample sets. A rare missense variant in mitochondrial ribosomal protein S5 (MRPS5), rs200730619 (c. 95108402T>C [p. Tyr137Cys]) was identified and validated in 369 cases and 270 controls of Chinese descent (Padjusted = 0.006, odds ratio [OR] = 2.74) as a contributing factor to leprosy risk. Moreover, the mRNA level of MRPS5 was downregulated in M. leprae sonicate-stimulated peripheral blood mononuclear cells. Our results indicated that MRPS5 may be involved in leprosy pathogenesis. Further studies are needed to determine if defective MRPS5 could lead to impairment of energy metabolism of host immune cells, which could further cause defect in clearing M. leprae and increase susceptibility to infection.

Understanding leprosy in a nonendemic area: a pilot study on knowledge, attitudes, beliefs of medical professionals from North-Western Italy

Background:

Describing knowledge, attitudes and beliefs about leprosy amongst Medical Professionals in a nonendemic area (Parma Province, North-Western Italy).

Methods:

A cross-sectional study was carried among a sample of Medical Professionals (MP; No. 242) during June and July 2019 as an on-line self-administered questionnaire including 21 true/false items about epidemiology, diagnosis, and clinical characteristics of leprosy. Effectors of better knowledge status (KS) and higher risk perception (RP) were assessed through calculation of respective multivariate odds ratios (OR) and 95% confidence intervals (95%CI) in two logistic regression analysis models.

Results:

A total of 102 questionnaires were retrieved (participation rate 42.1%; 67.6% of respondents <50 year-old). Of them, 10.8% had previously interacted with at least one leprosy case. Knowledge status (KS) was unsatisfying (59.7% correct answers), and also RP was relatively low, as 91.2% of them acknowledged leprosy as a severe disease, but only 42.2% identified leprosy as highly communicable. Knowledge gaps affected particularly understanding of epidemiology and non-dermatological issues. Moreover, 30.4% of respondents ignored that a treated leprosy case may remain in the community before disease eradication. The main effector of KS was having interacted with a leprosy case (OR 4.881 95%CI 1.245-36.905), while RP was negatively associated with a better KS (OR 0.094 95%CI 0.027-0.334), and working as general practitioner (OR 0.133 95%CI 0.031-0.562).

Conclusions:

While individual expertise of European MP on leprosy slowly disappears, significant knowledge gaps and the high share of misconceptions collectively stress that refresher training may improve early diagnosis and management of incident cases. (www.actabiomedica.it)

Patients with skin smear positive leprosy in Bangladesh are the main risk factor for leprosy development: 21-year follow-up in the household contact study (COCOA)

Background

Leprosy transmission is ongoing; globally and within Bangladesh. Household contacts of leprosy cases are at increased risk of leprosy development. Identification of household contacts at highest risk would optimize this process.

Methods

The temporal pattern of new case presentation amongst household contacts was documented in the COCOA (Contact Cohort Analysis) study. The COCOA study actively examined household contacts of confirmed leprosy index cases identified in 1995, and 2000–2014, to provide evidence for timings of contact examination policies. Data was available on 9527 index cases and 38303 household contacts. 666 household contacts were diagnosed with leprosy throughout the follow-up (maximum follow-up of 21 years). Risk factors for leprosy development within the data analysed, were identified using Cox proportional hazard regression.

Findings

The dominant risk factor for household contacts developing leprosy was having a highly skin smear positive index case in the household. As the grading of initial slit skin smear of the index case increased from negative to high positive (4–6), the hazard of their associated household contacts developing leprosy increases by 3.14 times (p<0.001). Being a blood relative was not a risk factor, no gender differences in susceptibility were found.

Interpretation

We found a dominance of a single variable predicting risk for leprosy transmission–skin smear positive index cases. A small number of cases are maintaining transmission in the household setting. Focus should be performing contact examinations on these households and detecting new skin smear positive index cases. Conducting slit-skin smears on new cases is needed for predicting risk; such services need supporting. If skin smear positive cases are sustaining leprosy infection within the household setting, the administration of single-dose rifampicin (SDR) to household contacts as the sole intervention in Bangladesh will not be effective.

The number of newly detected leprosy cases worldwide has remained stable over the last ten years. Household contacts of leprosy cases are at increased risk of leprosy development. Household contact examinations and case detection are critical aspects of control. Specific risk factors (recognizable by field staff) for leprosy development need to be identified to aid these control efforts. Targeted household examinations could increase early case detection: this is important because untreated leprosy cases are sustaining transmission.

This is the largest, most comprehensive study of development of leprosy in household contacts conducted recently with a maximum follow-up of 21 years. We found a single dominant risk factor for the development of leprosy in the household setting, namely slit skin smear positivity in the index case. This is important for leprosy control because household contact examinations can be focused on contacts at highest risk. Implementation would be simple as the risk factor is identified by leprosy staff in the field. Prioritising households known to be at highest risk of leprosy development would allow efficient allocation of resources. Our results cast doubt on the success of administering the recommended prophylactic intervention for contacts; the use of this intervention needs to be re-evaluated.

Trends and forecasts of leprosy for a hyperendemic city from Brazil's northeast: Evidence from an eleven-year time-series analysis

This study’s objective was to estimate the temporal trends of leprosy according to sex and age groups, as well as to estimate and predict the progression of the disease in a hyperendemic city located in the northeast of Brazil. This ecological time-series study was conducted in Imperatriz, Maranhão, Brazil. Leprosy cases diagnosed between 2006 and 2016 were included. Detection rates stratified by sex and age groups were estimated. The study of temporal trends was accomplished using the Seasonal-Trend Decomposition method and temporal modeling of detection rates using linear seasonal autoregressive integrated moving average model according to Box and Jenkins method. Trend forecasts were performed for the 2017–2020 period. A total of 3,212 cases of leprosy were identified, the average incidence among men aged between 30 and 59 years old was 201.55/100,000 inhabitants and among women in the same age group was 135.28/100,000 inhabitants. Detection rates in total and by sex presented a downward trend, though rates stratified according to sex and age presented a growing trend among men aged less than 15 years old and among women aged 60 years old or over. The final models selected in the time-series analysis show the forecasts of total detection rates and rates for men and women presented a downward trend for the 2017–2020 period. Even though the forecasts show a downward trend in Imperatriz, the city is unlikely to meet a significant decrease of the disease burden by 2020.

Hanseníase e carência social: definição de áreas prioritárias em estado endêmico do Nordeste brasileiro

RESUMO: Introdução: A hanseníase é uma doença que guarda estreita relação com as condições sociais e econômicas. O Brasil é o único país que ainda não alcançou a meta de eliminação da doença como problema de saúde pública. Objetivo: Este trabalho teve como objetivo analisar a associação entre a carência social dos municípios baianos e a detecção de casos novos de hanseníase na população, como instrumento para a definição de áreas prioritárias para intervenção. Metodologia: Trata-se de um estudo ecológico realizado no estado da Bahia, no período de 2001 a 2015. Variáveis analisadas: coeficiente de detecção casos novos, índice de carência social (ICS) e hanseníase em menores de 15 anos. O ICS foi construído com base em quatro variáveis: índice de performance socioeconômica, renda per capita, proporção de extremamente pobres e densidade domiciliar. Na análise espacial, foram utilizadas modelagem bayesiana empírica local e estatística de Moran global e local. Na análise estatística, foram empregados regressão multivariada, espacial e logística, cálculo do odds ratio e análise de variância. Resultados: A hanseníase apresentou distribuição heterogênea no estado, com concentração no eixo norte-oeste e sul. Dos municípios, 60,4% (n = 252) apresentaram muito baixa condição de vida. Observou-se associação entre as condições de vida e a detecção da hanseníase, com maiores coeficientes no grupo de município com melhor condição de vida (p < 0,001). Conclusão: As piores condições atuaram como um impeditivo ao diagnóstico, ao mesmo tempo que ampliaram o risco de adoecimento. As boas condições possuem efeito inverso.

Correlation of Plasma Level of Insulin-Like Growth Factor-1 (IGF-1) with Bacterial Index on Leprosy Patients in Bali

Background

Leprosy is an infection by Mycobacterium leprae, which influenced by cellular immunity. Leprosy tends to occur in low socio-economic and nutrition groups. Researchers try to prove the role of nutrition in the pathogenesis of leprosy. Insulin-like growth factor-1 (IGF-1) as a marker of nutritional status shown to play a role in cellular immunity.

Objective

To evaluate the correlation between IGF-1 with bacterial index (BI) on leprosy patients in Bali.

Methods

Cross-sectional study in Sanglah Public General Hospital, Denpasar of patients with paucibacillary (PB) and multibacillary (MB) leprosy were assessed for BI using slit-skin smear. All patients were tested for plasma IGF-1 using chemiluminescent immunometric assay Immulite. All data were analyzed using IBM SPSS ver. 24.0. The study has been approved by local Institutional Review Board with ethical clearance number 2017.02.1.0356.

Results

Our study involved 44 MB and 2 PB leprosy. The common age group affected was between 31~40 years old (23.9%), male (60.9%), and normal body mass index (BMI) (65.2%). Mean plasma IGF-1 level in PB leprosy was higher (91.07±0.74 ng/ml) than MB (82.74±6.44 ng/ml). The mean IGF-1 level decreases as BI increases in both groups (CI 95%=81.16~85.04; p<0.001). Pearson correlation test shows strong negative correlation (Pearson r=−0.976; p<0.001) with determinant coefficient (R₂) showing 95.2% (p<0.001).

Conclusion

In Balinese leprosy patients, severity of disease status measured by BI were found to be strongly correlated with the plasma IGF-1 level which may help preventing transmission in household contacts by improving nutritional status.

Epidemiology of leprosy in Italy (1920 - 2019): a comprehensive review on existing data

BACKGROUND AND AIMS

Incidence of leprosy in Italy has declined steadily over the last century, but available evidence remains fragmentary. Our review aims to summarize available data on the epidemiology of leprosy cases in Italy.

METHODS

The following keywords were used to explore PubMed and Embase: leprosy, Hansen's disease, (Mycobacterium) leprae, Italy, without any chronological restriction.

RESULTS

We identified a total of 39 reports, including 7 national reports, 11 international reports, 20 case reports. Notified leprosy cases were: 839 between 1925 and 1948; 434 between 1955 and 1979; 76 cases for the decade 1980-1989; 112 between 1990 and 1999; 62 between 2000 and 2009, and a total of 25 cases since 2009. Since 2003, 53% of all cases occurred in illegal residents. Focusing on individual cases, latency between early signs/symptoms and a proper diagnosis ranged between 2 and 20 years in 52.1% of individual cases.

CONCLUSION

Imported cases of leprosy are responsible for most leprosy incidence in Italy, and social stigma, the unfamiliarity of healthcare professionals with such disorders, and difficulties of some high-risk groups to be appropriately assessed hint to a possible under-diagnosis. Professionals should be made more aware of the potential for leprosy incidence among patients from countries where the disease is endemic.

Leprosy presenting as remitting seronegative symmetrical synovitis with pitting oedema syndrome - a case report

Background

Leprosy typically manifests with skin and peripheral nerve involvement. Musculoskeletal complaints are the third most common, and can be the sole presenting manifestation. They range from arthralgia/arthritis in reactional states to full mimics of systemic rheumatic diseases. Remitting Seronegative Symmetrical Synovitis with Pitting Oedema syndrome has only been described once in a patient with already diagnosed Leprosy.

Case report

A 68-year-old male, from an endemic region of familial amyloid polyneuropathy, presented with an inaugural Remitting Seronegative Symmetrical Synovitis with Pitting Oedema like syndrome, more that 20 years after travelling to Leprosy endemic areas. Arthritis would resurface whenever oral prednisone was tapered, so methotrexate was started, controlling the complaints. Only one year later, after the appearance of peripheral neuropathy and skin lesions, it was possible to diagnose Leprosy, through the identification of Mycobacterium leprae bacilli in a peripheral nerve biopsy.

Conclusion

This report is an example of the heterogeneity of manifestations of Leprosy, namely rheumatic, and the challenge of diagnosing it when typical complaints are absent. It is also a reminder that this disease should be considered whenever a patient with a combination of skin/neurologic/rheumatic complaints has travelled to endemic countries in the past.

Estratégias de controle e vigilância de contatos de hanseníase: revisão integrativa

RESUMO A pesquisa objetivou analisar as evidências científicas disponíveis sobre controle e vigilância epidemiológica de contatos de hanseníase. Trata-se de uma revisão integrativa norteada pela pergunta: qual a produção científica sobre controle e vigilância epidemiológica de contatos de hanseníase? Incluíram-se estudos primários, publicados em inglês, português ou espanhol nas bases de dados PubMed, Lilacs e Cinahl, entre 2008 e 2018, disponíveis na íntegra. A amostra foi composta por 19 estudos. Identificaram-se três categorias temáticas: fatores de risco para infecção e adoecimento entre os contatos de hanseníase, vigilância ativa de contatos de hanseníase e novas estratégias de controle e vigilância de contatos de hanseníase. Os resultados mostraram estudos voltados à prevenção e controle da hanseníase entre os contatos, entretanto, as evidências apontam novas estratégias que podem ser incorporadas à prática clínica visando à eliminação da hanseníase como problema de saúde pública no País.

Surveillance of intradomiciliary contacts of leprosy cases: perspective of the client in a hyperendemic municipality

OBJECTIVE

To characterize approach methods for intradomiciliary contacts (IdC) of leprosy cases resident in Northern Brazil, during 2001-2012.

METHOD

A cross-sectional and descriptive study in the state of Rondônia. Included IdC of leprosy cases diagnosed/reported in SINAN-Ministry of Health (MS), 2001-2012. A semi-structured instrument was applied to the IdCs, with six interventions: complete dermatological examination; complete neurological examination; BCG vaccination; instructions for return to the health unit; BCG guidance; and guidance to mobilize other contacts.Results: From a total of 459 IdCs included, failure to perform the dermatological examination was reported by 191 people (41.6%) and the neurological examination, by 252 (54.9%); 138 (30.1%) did not have BCG indicated and 122 (26.6%) did not receive guidelines; 257 (56.0%) were not advised to return for a new evaluation/follow-up and 186 (40.5%) were not asked to mobilize other contacts.

CONCLUSION

Despite the favorable indicators of IdC examination coverage in the state, the evaluation process presents patterns that indicate operational quality failures.

Towards leprosy elimination by 2020: forecasts of epidemiological indicators of leprosy in Corrientes, a province of northeastern Argentina that is a pioneer in leprosy elimination

BACKGROUND

Corrientes, a province of northeastern Argentina with endemic leprosy, has improved its epidemiological indicators, however, a study of the dynamics over time is lacking.

OBJECTIVES

We analysed data of 1308 leprosy patients between 1991 to 2014, and the forecast for 2020.

METHODS

Descriptive statistics and stepwise Bayesian model selection were performed. Forecasts were made using the median of 100,000 projections using the parameters calculated via Monte Carlo methods.

RESULTS

We found a decreasing number of new leprosy cases (-2.04 cases/year); this decrease is expected to continue by an estimated 20.28 +/- 10.00 cases by 2020, evidenced by a sustained decline in detection rate (from 11 to 2.9/100,000 inhabitants). Age groups that were most affected were 15-44 (40.13%) and 45-64 (38.83%) year olds. Multibacillary forms (MB) predominated (70.35%) and while gradually declining, between 10 and 30% developed disability grade 2 (DG2) (0.175 (0.110 - 0.337) DG2/MB cases), with a time delay between 0 to 15 years (median = 0). The proportion of MB clinic forms and DG2 increased and will continuously increase in the short term (0.036 +/- 0.018 logit (MB/total of cases).

MAIN CONCLUSIONS

Corrientes is on the way to eliminating leprosy by 2020, however the increased proportion of MB clinical forms and DG2 signals a warning for disease control efforts.

A tale of two neglected tropical infections: using GIS to assess the spatial and temporal overlap of schistosomiasis and leprosy in a region of Minas Gerais, Brazil

BACKGROUND

Despite public health efforts to reduce the global burden of leprosy, gaps remain in the knowledge surrounding transmission of infection. Helminth co-infections have been associated with a shift towards the lepromatous end of the disease spectrum, potentially increasing transmission in co-endemic areas.

OBJECTIVES

Using this biologically plausible association, we conducted a geographic information systems (GIS) study to investigate the spatial associations of schistosomiasis and leprosy in an endemic area of Minas Gerais (MG), Brazil.

METHODS

Data on new cases of Mycobacterium leprae and Schistosoma mansoni infections from 2007-2014 were retrieved from the Brazilian national notifiable diseases information system for seven municipalities in and surrounding Vespasiano, MG. A total of 139 cases of leprosy and 200 cases of schistosomiasis were mapped to a municipality level. For one municipality, cases were mapped to a neighborhood level and a stratified analysis was conducted to identify spatial associations.

FINDINGS

A relative risk of 6.80 [95% confidence interval (CI) 1.46 - 31.64] of leprosy was found in neighborhoods with schistosomiasis. Incidence rates of leprosy increased with corresponding incidence rates of schistosomiasis, and the temporal trends of both infections were similar.

CONCLUSIONS

The associations found in this project support the hypothesis that helminth infections may influence the transmission of leprosy in co-endemic areas.