Leprosy incidence and risk estimates in a 33-year contact cohort of leprosy patients

Temporal trends and space-time distribution of leprosy relapse in Brazil from 2001 to 2021

BACKGROUND

To analyse the temporal trends and spatiotemporal distribution of leprosy relapse in Brazil from 2001 to 2021.

METHODS

An ecological study with a temporal trend approach and space-time analysis of leprosy relapse in Brazil was carried out with data from the Notifiable Diseases Information System.

RESULTS

A total of 31 334 patients who experienced leprosy relapse were identified. The number of recurrent cases tended to increase throughout the study period, and this increase was significant among females and in almost all age groups, except for those <15, 50-59 and ≥70 y. Several clusters of high- and low-risk patients were identified across all regions with a heterogeneous distribution.

CONCLUSIONS

The burden of relapse showed an increasing trend in some groups and was distributed in all regions.

Spatiotemporal pattern of leprosy in southwest China from 2010 to 2020: an ecological study

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.

Serum lipocalin-2 levels are decreased in patients with leprosy

Background Leprosy is an infectious disease caused by Mycobacterium leprae affecting the skin, peripheral nerves and mucosae. Lipocalin-2 is a key component of the immune system's antimicrobial defence - it prevents iron uptake by binding and sequestering iron-scavenging siderophores and thus inhibits bacterial growth. Aim We evaluated serum lipocalin-2 levels in leprosy patients and its relationship to the pathogenesis and prognosis of the disease. Materials and methods In this case-control study, serum lipocalin-2 levels were measured by ELISA in 20 patients with leprosy and 20 healthy controls. Results Serum levels of lipocalin-2 were significantly reduced (P < 0.001) in leprosy patients as compared to controls. The levels were significantly higher (P < 0.014) in patients with multibacillary leprosy than in those with paucibacillary leprosy. Although the levels of lipocalin-2 were higher in patients with multiple nerve involvement as compared to those with involvement of 1 or 2 nerves, the results were not statistically significant. Limitation of the study The small sample size and the lack of different ethnic groups in the study were the major limitations of this study. Conclusion The lower lipocalin-2 concentrations in leprosy patients point to the importance of the protective functions of lipocalin-2. The elevated levels of lipocalin-2 observed in leprosy patients with neural involvement may be related to the reported neurodegenerative role of lipocalin-2.

High seropositivity against NDO-LID in a group of household contacts of leprosy patients. Are we close to leprosy elimination in Colombia?

INTRODUCTION

Leprosy is a chronic infectious disease caused by two mycobacteria (Mycobacterium leprae and Mycobacterium lepromatosis). The household contacts (HHC) of leprosy index cases are at higher risk of being infected with these mycobacteria. Therefore, serological testing in HHC would be an effective strategy to eliminate leprosy in Colombia.

OBJECTIVE

To determine the seroprevalence and factors associated with the infection by M. leprae in HHC.

METHODS

An observational study was conducted in 428 HHC located in the Colombian Caribbean, Andean, Pacific, and Amazonian regions. We evaluated the seropositivity and titrations of IgM, IgG, and protein A against NDO-LID.

RESULTS

The evaluated HHC showed high seropositivity, precisely 36.9% anti-NDO-LID IgM, 28.3% anti-NDO-LID IgG, and 47.7% protein A. Furthermore, Protein A showed a greater capacity to detect infected individuals than other anti-NDO-LID conjugates (p < 0.0001). This study did not show differences in the seropositivity according to sex or age of the HHC (p > 0.05). Higher seropositivity for IgM was evidenced mainly in HHC located in the Colombian Pacific region (p 0.001). This research did not show differences in the seropositivity for these serological tests between HHC of PB or MB leprosy patients (p > 0.05).

CONCLUSION

Leprosy transmission is still active between Colombian HHC. Consequently, controlling leprosy transmission in this population is fundamental to eradicating this disease.

Differences in responses to the intracellular macrophage environment between Mycobacterium bovis BCG vaccine strains Moreau and Pasteur

BACKGROUND

The Bacille Calmette-Guérin (BCG) vaccine comprises a family of strains with variable protective efficacy against pulmonary tuberculosis (TB) and leprosy, partly due to genetic differences between strains.

OBJECTIVES

Previous data highlighting differences between the genomes and proteomic profiles of BCG strains Moreau and Pasteur led us to evaluate their behaviour in the macrophage microenvironment, capable of stimulating molecular responses that can impact the protective effect of the vaccine.

METHODS

Strain infectivity, viability, co-localisation with acidified vesicles, macrophage secretion of IL-1 and MCP-1 and lipid droplet biogenesis were evaluated after infection.

FINDINGS

We found that BCG Moreau is internalised more efficiently, with significantly better intracellular survival up to 96 h p.i., whereas more BCG Pasteur bacilli were found co-localised in acidified vesicles up to 6 h p.i. IL-1β and MCP-1 secretion and lipid droplet biogenesis by infected macrophages were more prominent in response to BCG Pasteur.

MAIN CONCLUSION

Overall, our results show that, compared to Pasteur, BCG Moreau has increased fitness and better endurance in the harsh intracellular environment, also regulating anti-microbial responses (lower IL-1b and MCP-1). These findings contribute to the understanding of the physiology of BCG Moreau and Pasteur in response to the intraphagosomal environment in a THP-1 macrophage model.

Temporal trend, distribution and spatial autocorrelation of leprosy in Brazil: ecological study, 2011 to 2021

OBJECTIVE

To characterize the temporal trend and spatial behavior of leprosy in Brazil, from 2011 to 2021.

METHODS

This is an ecological study, with data from the Notifiable Diseases Information System, obtained in June 2022. The annual detection rate of new leprosy cases per 100 thousand inhabitants was calculated. To estimate the trend of the 2011-2019 and 2011-2021 series, the polynomial regression model was used, testing first-, second-, and third-order polynomials. For spatiality, natural breaks were used and, later, the univariate global and local Moran's indexes. A significance level of 5% was adopted and the analyses were performed using SPSS®, GeoDa®, and QGIS® software.

RESULTS

The findings indicated an upward trend in the incidence of leprosy in Brazilian regions and in 20 federative units between 2011 and 2019. However, there was a decrease in most of the country when considering the COVID-19 pandemic years. Spatiality showed that the highest detection rates throughout the period were observed in the North, Midwest, and Northeast regions, with high-risk clusters, and the lowest detection rates in the South and Southeast regions, with low-risk clusters.

CONCLUSION

The leprosy detection rate showed an upward trend in Brazil between 2011 and 2019, with greater spatial concentration in the North, Northeast, and Midwest regions. Nevertheless, the study raises an alert for the programmatic sustainability of leprosy control in Brazil, considering the drop in the COVID-19 pandemic, presumably due to the influence of the reorganization of the development of initiatives and provision of services in face of COVID-19.

Systematic Review of Survival Analysis in Leprosy Studies-Including the Following Outcomes: Relapse, Impairment of Nerve Function, Reactions and Physical Disability

Leprosy is a public health problem in South American, African and Oceanian countries. National programs need to be evaluated, and the survival analysis model can aid in the construction of new indicators. The aim of this study was to assess the period of time until the outcomes of interest for patients with or exposed to leprosy by means of survival analysis surveys. This review researched articles using the databases of PubMed, Science Direct, Scopus, Scielo and BVS published in English and Portuguese. Twenty-eight articles from Brazil, India, Bangladesh, the Philippines and Indonesia were included. The Kaplan-Meier method, which derives the log-rank test, and Cox's proportional hazards regression, which obtains the hazard ratio, were applied. The mean follow-up until the following outcomes were: (I) leprosy (2.3 years) in the population who were exposed to it, (II) relapse (5.9 years), (III) clinical manifestations before, during and after treatment-nerve function impairment (5.2 years), leprosy reactions (4.9 years) and physical disability (8.3 years) in the population of patients with leprosy. Therefore, the use of survival analysis will enable the evaluation of national leprosy programs and assist in the decision-making process to face public health problems.

Tendência temporal, distribuição e autocorrelação espacial da hanseníase no Brasil: estudo ecológico, 2011 a 2021

RESUMO Objetivo: Caracterizar a tendência temporal e o comportamento espacial da hanseníase no Brasil, de 2011 a 2021. Métodos: Estudo ecológico, com dados do Sistema de Informação de Agravos de Notificação, obtidos em junho de 2022. Calculou-se a taxa de detecção anual de casos novos de hanseníase por 100 mil habitantes. Para estimar a tendência das séries 2011–2019 e 2011–2021, empregou-se o modelo de regressão polinomial, testando polinômios de primeira, segunda e terceira ordem. Para a espacialidade, utilizaram-se as quebras naturais e, posteriormente, as estatísticas univariadas de Moran global e local. Adotou-se o nível de significância de 5% e as análises foram realizadas no Statistical Package for the Social Sciences — SPSS®, GeoDa® e QGIS®. Resultados: Os achados apontaram para a tendência crescente da incidência de hanseníase no Brasil, nas regiões e em 20 unidades da federação entre 2011 e 2019; contudo, houve decréscimo em grande parte do país ao se considerarem os anos pandêmicos. A espacialidade revelou que as maiores taxas de detecção, em todo o período, foram observadas nas Regiões Norte, Centro-Oeste e Nordeste, com clusters de alto risco, e as menores nas Regiões Sul e Sudeste, com aglomerados de baixo risco. Conclusão: A taxa de detecção da hanseníase apresentou tendência crescente no Brasil entre 2011 e 2019, com maior concentração espacial nas Regiões Norte, Nordeste e Centro-Oeste. Entretanto, o estudo traz um alerta para a sustentabilidade programática do controle da hanseníase no Brasil, dada a queda evidenciada na pandemia, presumivelmente por influência da reorganização da oferta de ações e serviços anteposta àCOVID-19.

BCG-induced immunity profiles in household contacts of leprosy patients differentiate between protection and disease

Leprosy is an infectious disease caused by Mycobacterium leprae leading to irreversible disabilities along with social exclusion. Leprosy is a spectral disease for which the clinical outcome after M. leprae infection is determined by host factors. The spectrum spans from anti-inflammatory T helper-2 (Th2) immunity concomitant with large numbers of bacteria as well as antibodies against M. leprae antigens in multibacillary (MB) leprosy, to paucibacillary (PB) leprosy characterised by strong pro-inflammatory, Th1 as well as Th17 immunity. Despite decades of availability of adequate antibiotic treatment, transmission of M. leprae is unabated. Since individuals with close and frequent contact with untreated leprosy patients are particularly at risk to develop the disease themselves, prophylactic strategies currently focus on household contacts of newly diagnosed patients. It has been shown that BCG (re)vaccination can reduce the risk of leprosy. However, BCG immunoprophylaxis in contacts of leprosy patients has also been reported to induce PB leprosy, indicating that BCG (re)vaccination may tip the balance between protective immunity and overactivation immunity causing skin/nerve tissue damage. In order to identify who is at risk of developing PB leprosy after BCG vaccination, amongst individuals who are chronically exposed to M. leprae, we analyzed innate and adaptive immune markers in whole blood of household contacts of newly diagnosed leprosy patients in Bangladesh, some of which received BCG vaccination. As controls, individuals from the same area without known contact with leprosy patients were similarly assessed. Our data show the added effect of BCG vaccination on immune markers on top of the effect already induced by M. leprae exposure. Moreover, we identified BCG-induced markers that differentiate between protective and disease prone immunity in those contacts.

Changes in B Cell Pool of Patients With Multibacillary Leprosy: Diminished Memory B Cell and Enhanced Mature B in Peripheral Blood

Despite being treatable, leprosy still represents a major public health problem, and many mechanisms that drive leprosy immunopathogenesis still need to be elucidated. B cells play important roles in immune defense, being classified in different subgroups that present distinct roles in the immune response. Here, the profile of B cell subpopulations in peripheral blood of patients with paucibacillary (TT/BT), multibacillary (LL/BL) and erythema nodosum leprosum was analyzed. B cell subpopulations (memory, transition, plasmablasts, and mature B cells) and levels of IgG were analyzed by flow cytometry and ELISA, respectively. It was observed that Mycobacterium leprae infection can alter the proportions of B cell subpopulations (increase of mature and decrease of memory B cells) in patients affected by leprosy. This modulation is associated with an increase in total IgG and the patient's clinical condition. Circulating B cells may be acting in the modulation of the immune response in patients with various forms of leprosy, which may reflect the patient's ability to respond to M. leprae.