Leprosy among schoolchildren in the Amazon region: A cross-sectional study of active search and possible source of infection by contact tracing

Integrated control of neglected tropical diseases in Brazil: document review of a national campaign in light of WHO recommendations

Objective

To describe the results of a national campaign aimed at the integrated control of neglected tropical diseases in Brazil in light of the World Health Organization (WHO) official documentation related to the integration of strategies for the prevention, control, and elimination or eradication of neglected tropical diseases.

Methods

A document review that included official WHO documents published between 2007 and 2020 and campaign results extracted from the official technical report produced by the Brazilian Ministry of Health.

Results

The integrated control of neglected tropical diseases was gradually incorporated in the WHO documentation over time. Preventive chemotherapy through mass drug administration, intensified case management, and integrated vector management were extensively recommended as strategies for integrated control. The Brazilian campaign was carried out in four iterations between 2013 and 2017. Children aged 5 to 14 years enrolled in municipal public schools nationwide were targeted. In summary, a total of 1 074 and 73 522 new cases of leprosy and trachoma, respectively, were detected. Nearly 18 million doses of preventive chemotherapy for soil-transmitted helminthiasis were administered. More than 700 cases of schistosomiasis were diagnosed and treated.

Conclusions

The integrated strategies implemented in Brazil throughout the campaign generated results aligned with the WHO recommendations for the control of neglected tropical diseases, especially those regarding mass drug administration, active case detection, and intensified case management. Therefore, the continuity of the campaign with adequate evaluation tools must be encouraged as a constant public health policy in the Brazilian government agenda.

Leprosy among children in an area without primary health care coverage in Caratateua Island, Brazilian Amazon

Introduction

The detection of leprosy in children is an important epidemiological marker of the disease, indicating the community's early exposure to Mycobacterium leprae and active transmission of the infection.

Methods

In order to detect new cases among children by combining clinical evaluation and laboratory tests, we conducted an active case finding among individuals under 15 years old on Caratateua Island, located in the city of Belém, in the Pará state, an endemic region in the Amazon. Dermato-neurological examination, collection of 5 mL of peripheral blood for IgM anti-PGL-I antibody titration, and intradermal scraping for bacilloscopy and amplification of the specific RLEP region by qPCR were performed.

Results

Out of the 56 examined children, 28/56 (50%) new cases were identified. At the time of evaluation, 38/56 (67.8%) children presented one or more clinical alterations. Seropositivity was detected in 7/27 (25.9%) new cases and 5/24 (20.8%) undiagnosed children. DNA amplification of Mycobacterium leprae was observed in 23/28 (82.1%) of new cases and in 5/26 (19.2%) of non-cases. Out of the total cases, 11/28 (39.2%) were exclusively diagnosed by clinical evaluation performed during the active case finding. Seventeen new cases (60.8%) were detected considering the clinical alterations found in addition to positive results for qPCR. In this group, 3/17 (17.6%) qPCR-positive children presented significant clinical changes 5.5 months after the first evaluation.

Discussion

Our research detected a number of cases 5.6 times higher compared to the total number of pediatric cases recorded throughout the year 2021 in the municipality of Belém, which shows a critical scenario of underdiagnosing of leprosy among children under 15 years old in the region. We propose the use of qPCR technique to identify new cases among children with oligosymptomatic or early disease in endemic areas, in addition to the training of Primary Health Care professionals and the implementation of the Family Health Strategy coverage in the visited area.

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.

Clusters of risk for the occurrence of leprosy and disabilities in children under 15 years of age in Cuiabá: a geospatial study

OBJECTIVE

This study aimed to analyze the spatial distribution of leprosy and disabilities in children under 15 years of age in Cuiabá.

METHODS

Ecological study carried out in the city of Cuiabá, Mato Grosso, Brazil. The study population consisted of leprosy cases in children under 15 years old notified in the Notifiable Diseases Information System, between 2008 and 2018. Based on residential addresses, cases were georeferenced. In the analysis of the spatial distribution of the cases, the estimation of the Kernel density was used and, later, the statistics of spatial, spatio-temporal and Spatial Variation in Temporal Trends were applied.

RESULTS

514 cases of leprosy were reported in children under 15 years of age in Cuiabá, with a percentage of 10.1% of cases with degree of physical disability 1 and 2.3% with degree of physical disability 2 at the time of diagnosis. With the techniques of spatial and spatio-temporal scanning, clusters of risk for leprosy were identified in the North, West, East and South regions of Cuiabá, and with the technique of Spatial Variation in Temporal Trends, a cluster was identified in the West region of Cuiabá.

CONCLUSION

In Cuiabá, cases of leprosy in children under 15 years of age with disabilities were distributed throughout the urban area of the city, with the highest density of cases in the North and West regions, followed by the East region. The clusters with the highest Relative Risk were identified in the East and West regions, characterized by having low and medium income levels.

Clusters of risk for the occurrence of leprosy and disabilities in children under 15 years of age in Cuiabá: a geospatial study

ABSTRACT Objective This study aimed to analyze the spatial distribution of leprosy and disabilities in children under 15 years of age in Cuiabá. Methods Ecological study carried out in the city of Cuiabá, Mato Grosso, Brazil. The study population consisted of leprosy cases in children under 15 years old notified in the Notifiable Diseases Information System, between 2008 and 2018. Based on residential addresses, cases were georeferenced. In the analysis of the spatial distribution of the cases, the estimation of the Kernel density was used and, later, the statistics of spatial, spatio-temporal and Spatial Variation in Temporal Trends were applied. Results 514 cases of leprosy were reported in children under 15 years of age in Cuiabá, with a percentage of 10.1% of cases with degree of physical disability 1 and 2.3% with degree of physical disability 2 at the time of diagnosis. With the techniques of spatial and spatio-temporal scanning, clusters of risk for leprosy were identified in the North, West, East and South regions of Cuiabá, and with the technique of Spatial Variation in Temporal Trends, a cluster was identified in the West region of Cuiabá. Conclusion In Cuiabá, cases of leprosy in children under 15 years of age with disabilities were distributed throughout the urban area of the city, with the highest density of cases in the North and West regions, followed by the East region. The clusters with the highest Relative Risk were identified in the East and West regions, characterized by having low and medium income levels

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.

Leprosy: A Review of Epidemiology, Clinical Diagnosis, and Management

Leprosy is a neglected infectious disease caused by acid-fast bacillus Mycobacterium leprae. It primarily affects the skin and then progresses to a secondary stage, causing peripheral neuropathy with potential long-term disability along with stigma. Leprosy patients account for a significant proportion of the global disease burden. Previous efforts to improve diagnostic and therapeutic techniques have focused on leprosy in adults, whereas childhood leprosy has been relatively neglected. This review aims to update the diagnostic and therapeutic recommendations for adult and childhood leprosy. This review summarizes the clinical, bacteriological, and immunological approaches used in the diagnosis of leprosy. As strategies for the diagnosis and management of leprosy continue to develop better and more advanced knowledge, control and prevention of leprosy are crucial.

[Epidemiological behavior of leprosy in several Latin American countries, 2011-2020Comportamento epidemiológico da hanseníase em vários países da América Latina, 2011-2020]

Objective

To describe the epidemiological behavior of leprosy in several Latin American countries during 2011-2020, based on World Health Organization (WHO) indicators.

Methods

Cross-sectional, descriptive and quantitative study with official data on incidence and prevalence in the general population, children, clinical form and cases with grade 2 disability from WHO records between 2011 and 2020. The eight countries in Latin America that reported most cases were selected and analyses were carried out using simple descriptive and comparative statistics between different variables.

Results

During the study period, 301 312 cases of leprosy were reported in the selected countries: Argentina, Brazil, Colombia, Cuba, Dominican Republic, Mexico, Paraguay, and Venezuela. Brazil is the only country in the region with a prevalence greater than 1 per 10 000, representing 93.77% of all cases. Brazil and the Dominican Republic showed an increase in prevalence during 2011-2019, while in other countries the trend was decreasing. The disease is more frequent in men, and multibacillary cases significantly exceed paucibacillary ones. Brazil showed the highest incidences of cases of childhood leprosy and grade 2 disability during the evaluated period.

Conclusion

In Latin America, leprosy is only considered a public health problem in Brazil; however, most countries in the region continue to report cases annually, revealing a lack of adequate medical care. This study confirmed the importance of active surveillance, early diagnosis and planning of actions against the disease in all the countries evaluated with the aim of reducing its transmission.

Pediatric Leprosy Profile in the Postelimination Era: A Study from Surabaya, Indonesia

Children who live in leprosy-endemic areas are susceptible to infection due to early and frequent exposure to Mycobacterium leprae. Indonesia is on the verge of eliminating this disease (prevalence rate < 1/10,000 population), but pediatric leprosy continues to occur in low-endemic areas. This study aimed to evaluate pediatric leprosy over a decade in a tertiary hospital in Surabaya, Indonesia. A retrospective study of leprosy in children under 15 years old between 2010 and 2019 was conducted in the Morbus Hansen Division, Outpatient Clinic at Dr. Soetomo Hospital in Surabaya, Indonesia. Seventy pediatric leprosy cases were identified between 2010 and 2019, consisting of 58 multibacillary (MB)-type cases and 12 paucibacillary (PB)-type cases. Slit skin smear (SSS) was positive in 26 cases. There were two cases of grade-2 disability and 15 cases of leprosy reaction (erythema nodosum leprosum) in children at the time of diagnosis. There was an insignificant decline in the number of pediatric leprosy cases in the last 10 years. Cases and disabilities in children were found in some leprosy pocket areas even though the national elimination rate has been achieved. MB infections, disability, and treatment defaults were common problems in pediatric leprosy.

Spatio-temporal analysis of leprosy risks in a municipality in the state of Mato Grosso-Brazilian Amazon: results from the leprosy post-exposure prophylaxis program in Brazil

BACKGROUND

Leprosy post-exposure prophylaxis (LPEP) with single dose rifampicin (SDR) can be integrated into different leprosy control program set-ups once contact tracing has been established. We analyzed the spatio-temporal changes in the distribution of index cases (IC) and co-prevalent cases among contacts of leprosy patients (CP) over the course of the LPEP program in one of the four study areas in Brazil, namely the municipality of Alta Floresta, state of Mato Grosso, in the Brazilian Amazon basin.

METHODS

Leprosy cases were mapped, and socioeconomic indicators were evaluated to explain the leprosy distribution of all leprosy cases diagnosed in the period 2016-2018. Data were obtained on new leprosy cases [Notifiable diseases information system (Sinan)], contacts traced by the LPEP program, and socioeconomic variables [Brazilian Institute of Geography and Statistics (IBGE)]. Kernel, SCAN, factor analysis and spatial regression were applied to analyze changes.

RESULTS

Overall, the new case detection rate (NCDR) was 20/10 000 inhabitants or 304 new cases, of which 55 were CP cases among the 2076 examined contacts. Changes over time were observed in the geographic distribution of cases. The highest concentration of cases was observed in the northeast of the study area, including one significant cluster (Relative risk = 2.24; population 27 427, P-value < 0.001) in an area characterized by different indicators associated with poverty as identified through spatial regression (Coefficient 3.34, P-value = 0.01).

CONCLUSIONS

The disease distribution was partly explained by poverty indicators. LPEP influences the spatial dynamic of the disease and results highlighted the relevance of systematic contact surveillance for leprosy elimination.

Effects on the daily lives of children and teenagers who lived with leprosy

ABSTRACT The study aims to understand the effects of the disease on the daily lives of children and teenagers affected by leprosy. This was a qualitative research based on the theoretical framework of ‘The Sociology of Erving Goffman’. We interviewed 14 participants individually, nine children and five teenagers, who underwent treatment for leprosy and were cured. A semi-structured interview was used, covering sociodemographic information and guiding questions about the participants’ experiences with the disease, family, social aspects, and perceptions derived from the experiences. The data were analyzed by the sociology of Erving Goffman. The narratives emphasized the effects on daily life related to leprosy discovery, interaction networks, such as family and health professionals, health care, overcoming strategies and expectations. It was verified that the predominant element of the research is anchored in the fear of being discovered and discredited, in the perspective of having their identity of health resignified, by the illness, and by the evidence in view of the participant’s experience due to prejudice, anonymity, and secret. This symbolically suggests that the participants experienced a certain construction of negative social life around leprosy. The illness directly interferes with their daily life and development, especially in the participant’s social relationships.

Repercussões no cotidiano de crianças e adolescentes que viveram com hanseníase

RESUMO O estudo apresenta como objetivo compreender as repercussões da doença na vida cotidiana de crianças e adolescentes acometidos pela hanseníase. Trata-se de uma pesquisa qualitativa com base no referencial teórico ‘A Sociologia de Erving Goffman’. Foram entrevistados, individualmente, 14 participantes, sendo 9 crianças e 5 adolescentes tratados e curados da hanseníase. Utilizou-se entrevista semiestruturada, abrangendo informações sociodemográficas e questões norteadoras sobre a vivência dos participantes com a doença, aspectos familiares, sociais e percepções advindas da experiência. Os dados foram analisados pela sociologia de Erving Goffman. As narrativas enfatizam as repercussões do cotidiano relacionados com a história da descoberta da hanseníase, as redes de interação como família e profissionais de saúde, dos cuidados com a própria saúde, de estratégias de superação e expectativas. Verificou-se que o elemento predominante da pesquisa se ancora no temor de ser descoberto e desacreditado, na perspectiva de ter sua identidade de sadio ressignificada, pelo adoecimento e perante a vivência dos participantes com o preconceito, sigilo e segredo. Conclui-se, de modo simbólico, que os participantes vivenciaram uma construção de vida social negativa em torno da hanseníase. O adoecimento interfere de modo direto no cotidiano e desenvolvimento dos participantes, repercutindo principalmente nas relações sociais.

Active case detection methods for crusted scabies and leprosy: A systematic review

BACKGROUND

Crusted scabies is endemic in some remote Aboriginal communities in the Northern Territory (NT) of Australia and carries a high mortality risk. Improvement in active case detection (ACD) for crusted scabies is hampered by a lack of evidence about best practice. We therefore conducted a systematic review of ACD methods for leprosy, a condition with similar ACD requirements, to consider how findings could be informative to crusted scabies detection.

METHODS AND PRINCIPLE FINDINGS

We conducted systematic searches in MEDLINE, CINAHL, Scopus and the Cochrane Database for Systematic Reviews for studies published since 1999 that reported at least one comparison rate (detection or prevalence rate) against which the yield of the ACD method could be assessed. The search yielded 15 eligible studies from 511. Study heterogeneity precluded meta-analysis. Contact tracing and community screening of marginalised ethnic groups yielded the highest new case detection rates. Rapid community screening campaigns, and those using less experienced screening personnel, were associated with lower suspect confirmation rates. There is insufficient data to assess whether ACD campaigns improve treatment outcomes or disease control.

CONCLUSION

This review demonstrates the importance of ACD campaigns in communities facing the highest barriers to healthcare access and within neighbourhoods of index cases. The potential benefit of ACD for crusted scabies is not quantified, however, lessons from leprosy suggest value in follow-up with previously identified cases and their close contacts to support for scabies control and to reduce the likelihood of reinfection in the crusted scabies case. Skilled screening personnel and appropriate community engagement strategies are needed to maximise screening uptake. More research is needed to assess ACD cost effectiveness, impact on disease control, and to explore ACD methods capable of capturing the homeless and highly mobile who may be missed in household centric models.

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 social network approach for the study of leprosy transmission beyond the household

BACKGROUND

Mycobacterium leprae was the first microorganism directly associated with a disease, however, there are still important gaps in our understanding of transmission. Although household contacts are prioritized, there is evidence of the importance of extrahousehold contacts. The goal of this article is to contribute to our understanding of the transmission of leprosy ex-household.

METHODS

We compare co-location data of 397 leprosy cases and 211 controls drawn from the Centro de Dermatologia Sanitária D. Libânia in Fortaleza, Brazil. We collected lifetime geolocation data related to residence, school attendance and workplace and developed novel methods to establish a critical distance (Rc) for exposure and evaluated the potential for transmission for residence, school and workplace.

RESULTS

Our methods provide different threshold values of distance for residence, school and workplace. Residence networks demonstrate an Rc of about 500 m. Cases cluster in workplaces as well. Schools do not cluster cases.

CONCLUSIONS

Our novel network approach offers a promising opportunity to explore leprosy transmission. Our networks confirm the importance of coresidence, provide a boundary and suggest a role for transmission in workplaces. Schools, on the other hand, do not demonstrate a clustering of cases. Our findings may have programmatic relevance.

COMPARING SOCIO-ECONOMIC CONDITIONS OF MOTHER AND CHILDREN WITH LEPROSY IN ENDEMIC AND NON-ENDEMIC AREAS IN EAST JAVA, INDONESIA

Background

Leprosy is a disease that causes social, psychological, and economic issues. Failure to treat the causes of the immune system dysregulation in endemic areas of leprosy conditions makes the transmission of the bacteria easier. This paper aims to analyze the comparison of family income, occupation types of mothers and fathers, number of children, access to health facilities, and education of mothers, fathers, and children in mothers and children with leprosy in endemic and non-endemic areas.

Materials and Methods

A cross sectional study by survey was done in both an endemic and a non-endemic area of leprosy in Tuban Regency, East Java, Indonesia. Retrieval of research data was done using interview techniques. Respondents who participated in this study were 106 pairs of mother and child respondents who met the research restriction criteria. Subjects were divided into 5groups based on diagnosis of leprosy and area of living. Bivariate analysis was performed by comparing the independent variables in each group A, B, C, and D with group E.

Results

It was found that the variables that differed significantly between the endemic and non-endemic areas were the variable number of children with a p-value=0.004, family income with a p-value=0.049 and the variable mother's education with a p-value=0.016. Meanwhile, other variables do not have significant difference.

Conclusions

We found significant difference on the number of children, father's education, mother's education, and family income. These variables can be a risk factor for leprosy. To make efforts to prevent the transmission of leprosy, stakeholders should consider these factors.

Incidence of and Factors Associated With Leprosy Among Household Contacts of Patients With Leprosy in Brazil

Importance

Despite progress toward reducing global incidence, leprosy control remains a challenge in low- and middle-income countries.

Objective

To estimate new case detection rates of leprosy among household contacts of patients with previously diagnosed leprosy and to investigate its associated risk factors.

Design, Setting, and Participants

This population-based cohort study included families registered in the 100 Million Brazilian Cohort linked with nationwide registries of leprosy; data were collected from January 1, 2007, through December 31, 2014. Household contacts of patients with a previous diagnosis of leprosy from each household unit were followed up from the time of detection of the primary case to the time of detection of a subsequent case or until December 31, 2014. Data analysis was performed from May to December 2018.

Exposures

Clinical characteristics of the primary case and sociodemographic factors of the household contact.

Main Outcomes and Measures

Incidence of leprosy, estimated as the new case detection rate of leprosy per 100 000 household contacts at risk (person-years at risk). The association between occurrence of a subsequent leprosy case and the exposure risk factors was assessed using multilevel mixed-effects logistic regressions allowing for state- and household-specific random effects.

Results

Among 42 725 household contacts (22 449 [52.5%] female; mean [SD] age, 22.4 [18.5] years) of 17 876 patients detected with leprosy, the new case detection rate of leprosy was 636.3 (95% CI, 594.4-681.1) per 100 000 person-years at risk overall and 521.9 (95% CI, 466.3-584.1) per 100 000 person-years at risk among children younger than 15 years. Household contacts of patients with multibacillary leprosy had higher odds of developing leprosy (adjusted odds ratio [OR], 1.48; 95% CI, 1.17-1.88), and the odds increased among contacts aged 50 years or older (adjusted OR, 3.11; 95% CI, 2.03-4.76). Leprosy detection was negatively associated with illiterate or preschool educational level (adjusted OR, 0.59; 95% CI, 0.38-0.92). For children, the odds were increased among boys (adjusted OR, 1.70; 95% CI, 1.20-2.42).

Conclusions and Relevance

The findings in this Brazilian population-based cohort study suggest that the household contacts of patients with leprosy may have increased risk of leprosy, especially in households with existing multibacillary cases and older contacts. Public health interventions, such as contact screening, that specifically target this population appear to be needed.

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

Reduction in incidence has been associated with the introduction of novel approaches, like chemo/immune-prophylaxis. Incidence determined through follow-up cohort studies can evaluate the implementation of these innovative policies towards control and prevention. We have assessed the incidence in our contacts cohort over past 33 years, considering the effect of demographic and clinical variables. Survival analysis was used to estimate the risk of leprosy. A total of 9024 contacts were evaluated, of which 192 developed leprosy, resulting in an overall incidence of 1.4/1000 person-years. The multivariate analysis showed that the major risk factors were (i) contact from MB index cases and (ii) consanguinity (iii) intra household contact. Lower risk was detected for contacts with BCG scar who were revaccinated. There was a significant decrease in accumulated risk between the 2011-2019 period compared with 1987, probably linked to the improvement in laboratory tools to monitor contacts, thereby providing early diagnosis of contacts at intake and reduction of transmission. Our findings suggest that a combination of contact surveillance and tracing, adequate neurodermatological examination, and availability of molecular tools is highly effective in supporting early diagnosis, while a second dose of the BCG vaccination can exert extra protection.

Prototype multi-biomarker test for point-of-care leprosy diagnostics

To end the decade-long, obstinately stagnant number of new leprosy cases, there is an urgent need for field-applicable diagnostic tools that detect infection with Mycobacterium leprae, leprosy's etiologic agent. Since immunity against M. leprae is characterized by humoral and cellular markers, we developed a lateral flow test measuring multiple host proteins based on six previously identified biomarkers for various leprosy phenotypes. This multi-biomarker test (MBT) demonstrated feasibility of quantitative detection of six host serum proteins simultaneously, jointly allowing discrimination of patients with multibacillary and paucibacillary leprosy from control individuals in high and low leprosy endemic areas. Pilot testing of fingerstick blood showed similar MBT performance in point-of-care (POC) settings as observed for plasma and serum. Thus, this newly developed prototype MBT measures six biomarkers covering immunity against M. leprae across the leprosy spectrum. The MBT thereby provides the basis for immunodiagnostic POC tests for leprosy with potential for other (infectious) diseases as well.

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Prototype MBT that quantitatively detects six host-derived biomarkers is developed

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The immunopathological spectrum of leprosy is ideally suited to evaluate the MBT

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MBT discriminated patients with leprosy from controls in a high and non-endemic area

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Application of the MBT using low invasive fingerstick blood is technically feasible

Leprosy in Nepal: a re-emerging threat

Nepal has long been known as a leprosy endemic country. However, in 2010, the application of World Health Organization guidelines in Nepal led to the misleading determination that leprosy had been 'eliminated' there. This misnomer has contributed to the current situation in which leprosy is on the increase. A national active case finding program is urgently required.

[Epidemiological characteristics of leprosy in elderly Brazilians and comparison with other age groups (2016-2018)]

The article aimed to describe epidemiological indicators and characteristics of new cases of leprosy in elderly Brazilians in 2016-2018, compared to other age groups. A descriptive cross-sectional cohort study was conducted with data from the Information System on Diseases of Notification (SINAN). New leprosy cases were categorized by age groups: 60 or more, 40-59, 15-39, and 15 years of age. Pearson's chi-square test was used to verify differences between groups. A total of 81,205 new leprosy cases were reported in Brazil. Of these, 24.1% were elderly, 37.7% from 40-59 years, 31.9% from 15-39 years, and 6.3% in individuals under 15 years of age. The elderly showed higher proportions (p < 0.001) of cases in males (60.1%), with multibacillary classification (81.3%), and with physical disability grade 2 (PDG2) (11.4%) when compared to the other groups. However, the proportion of new cases detected in the elderly based on contact testing (4.9%) was the lowest among all the age brackets (p < 0.001). The mean detection rate and rate of new cases with PDG2 at diagnosis were higher among the elderly (25.1/100,000 and 28.6/million inhabitants, respectively) compared to other age groups in Brazil as a whole and in the regions and states. Important differences were seen in the epidemiological and clinical profile of leprosy in the elderly compared to other age brackets, especially higher proportions of multibacillary cases, new cases with PDG2, and low detection by contact testing. The findings highlighted the need for leprosy control in this age group, aimed at contributing to interruption of transmission of the disease.

Leprosy Transmission in Amazonian Countries: Current Status and Future Trends

Purpose of Review

Leprosy is one of the first pathologies described in the history of mankind. However, the ecology, transmission, and pathogenicity of the incriminated bacilli remain poorly understood. Despite effective treatment freely distributed worldwide since 1995, around 200,000 new cases continue to be detected yearly, mostly in the tropics. This review aims to discuss the unique characteristics of leprosy in Amazonian countries, which exhibit a very heterogeneous prevalence among human and animal reservoirs.

Recent Findings

Groundbreaking discoveries made in the last 15 years have challenged the dogmas about leprosy reservoirs, transmission, and treatment. The discovery of a new leprosy causative agent in 2008 and the scientific proof of zoonosis transmission of leprosy by nine-banded armadillos in the southern USA in 2011 challenged the prospects of leprosy eradication. In the Amazonian biome, nine-banded and other armadillo species are present but the lack of large-scale studies does not yet allow accurate assessment of the zoonotic risk. Brazil is the second country in the world reporting the highest number of new leprosy cases annually. The disease is also present, albeit with different rates, in all neighboring countries. Throughout the Amazonian biome, leprosy is mainly found in hyperendemic foci, conducive to the emergence and transmission of drug-resistant strains.

Summary

The deepening of current knowledge on leprosy reservoirs, transmission, and therapeutic issues, with the One Health approach and the help of molecular biology, will allow a better understanding and management of the public health issues and challenges related to leprosy in Amazonia.

Quantitative PCR for leprosy diagnosis and monitoring in household contacts: A follow-up study, 2011-2018

Household contacts (HHC) of leprosy patients exhibit high-risk of developing leprosy and contact tracing is helpful for early diagnosis. From 2011 to 2018,2,437 HHC were examined in a clinic in Rio de Janeiro, Brazil and 16S qPCR was used for diagnosis and monitoring of contacts. Fifty-four HHCs were clinically diagnosed with leprosy at intake. Another 25 exhibited leprosy-like skin lesions at intake, 8 of which were confirmed as having leprosy (50% of which were qPCR positive) and 17 of which were diagnosed with other skin diseases (6% qPCR positive). In skin biopsies, qPCR presented a sensitivity of 0.50 and specificity of 0.94. Furthermore, 955 healthy HHCs were followed-up for at least 3 years and skin scrapings were collected from earlobes for qPCR detection. Positive qPCR indicated a non-significant relative risk of 2.52 of developing the disease. During follow-up, those who progressed towards leprosy exhibited 20% qPCR positivity, compared to 9% of those who remained healthy. Disease-free survival rates indicated that age had a significant impact on disease progression, where patients over 60 had a greater chance of developing leprosy [HR = 32.4 (3.6-290.3)]. Contact tracing combined with qPCR may assist in early diagnosis and age is a risk factor for leprosy progression.

Social and environmental conditions related to Mycobacterium leprae infection in children and adolescents from three leprosy endemic regions of Colombia

Background

Leprosy is is still considered a public health issue and in Colombia 7–10% of new cases are found in children, indicating both active transmission and social inequality. We hypothesized that circulating antibodies against Natural Octyl Disaccharide-Leprosy IDRI Diagnostic (NDO-LID) (a combination of Mycobacterium leprae antigens) could reveal the social and environmental aspects associated with higher frequencies of M. leprae infection among children and adolescents in Colombia.

Methods

An observational cross-sectional study was conducted involving sampling from 82 children and adolescents (younger than 18 years of age) who had household contact with index leprosy patients diagnosed in the last 5 years. Data were analyzed through bivariate analysis made by applying a Pearson x² test for qualitative variables, while quantitative variables, depending on their distribution, were analyzed using either a Student’s t-test or Mann-Whitney U test. Multivariate analysis was performed using a multiple regression and binomial logistic approach.

Results

A bivariate analysis demonstrated that antibody titers against NDO-LID were significantly greater in children and adolescents with a low socioeconomic status that had: lived in vulnerable areas of the UAChR shared region; eaten armadillo meat; exposure of over 10 years to an index case and; not received BCG immunization. Moreover, a multivariate analysis showed that residing in the UAChR region has a strong association with a greater possibility of M. leprae infection.

Conclusions

M. leprae transmission persists among young Colombians, and this is associated with social and environmental conditions. An intensification of efforts to identify new leprosy cases in vulnerable and forgotten populations where M. leprae transmission continues therefore appears necessary.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-4120-2) contains supplementary material, which is available to authorized users.

Evaluation of Immunodiagnostic Tests for Leprosy in Brazil, China and Ethiopia

Leprosy remains persistently endemic in several low- or middle income countries. Transmission is still ongoing as indicated by the unabated rate of leprosy new case detection, illustrating the insufficiency of current prevention methods. Therefore, low-complexity tools suitable for large scale screening efforts to specifically detect M. leprae infection and diagnose disease are required. Previously, we showed that combined detection of cellular and humoral markers, using field-friendly lateral flow assays (LFAs), increased diagnostic potential for detecting leprosy in Bangladesh compared to antibody serology alone. In the current study we assessed the diagnostic performance of similar LFAs in three other geographical settings in Asia, Africa and South-America with different leprosy endemicity. Levels of anti-PGL-I IgM antibody (humoral immunity), IP-10, CCL4 and CRP (cellular immunity) were measured in blood collected from leprosy patients, household contacts and healthy controls from each area. Combined detection of these biomarkers significantly improved the diagnostic potential, particularly for paucibacillary leprosy in all three regions, in line with data obtained in Bangladesh. These data hold promise for the use of low-complexity, multibiomarker LFAs as universal tools for more accurate detection of M. leprae infection and different phenotypes of clinical leprosy.