Unexpectedly high leprosy seroprevalence detected using a random surveillance strategy in midwestern Brazil: A comparison of ELISA and a rapid diagnostic test

Slit skin smear versus anti-phenolic glycolipid-I serology in diagnosis of leprosy: a cross sectional study

Leprosy is a chronic infectious disease which mainly affects the skin, nasal mucosa, and peripheral nerves. The aim of this study was to compare between the efficacies of serum anti-phenolic glycolipid 1 (APGL-I) level versus slit skin smear (SSS) in diagnosis of leprosy. This study involved 58 leprosy cases who were clinically examined, slit-skin smears were taken from all at diagnosis from four sites and APGL-I levels were seroassayed using ELISA. The mean age of studied group was 39.42 ± 15.2, 44.8% of patients were males and 55.2% were females. The majority of patients (72.4%) had multibacillary leprosy (MBL) followed by (27.6%) of patients had paucibacillary leprosy (PBL). SSS had sensitivity of 71.5% and specificity of 84% (area under curve; AUC = 0.763, 95% CI 0.427-0.823) while APGL-I had a sensitivity of 80% and specificity of 85% (area under curve; AUC = 0.830, 95% CI 0.424-0.852). Both serum Anti-PGL-1 levels and slit skin smear are useful in diagnosing leprosy, but their effectiveness depends on disease stage and patient's immune response. Being inexpensive, easy and noninvasive technique, APGL1 can be an adjunct method for the detection of leprosy in the population while slit skin smear having higher specificity. Combining both methods or using sequential diagnostic approaches could enhance accuracy and reduce missed diagnoses.

Innovative technologies to address neglected tropical diseases in African settings with persistent sociopolitical instability

The health, economic, and social burden of neglected tropical diseases (NTDs) in Africa remains substantial, with elimination efforts hindered by persistent sociopolitical instability, including ongoing conflicts among political and ethnic groups that lead to internal displacement and migration. Here, we explore how innovative technologies can support Africa in addressing NTDs amidst such instability, through analysis of WHO and UNHCR data and a systematic literature review. Countries in Africa facing sociopolitical instability also bear a high burden of NTDs, with the continent ranking second globally in NTD burden (33%, 578 million people) and first in internal displacement (50%, 31.6 million people) in 2023. Studies have investigated technologies for their potential in NTD prevention, surveillance, diagnosis, treatment and management. Integrating the evidence, we discuss nine promising technologies-artificial intelligence, drones, mobile clinics, nanotechnology, telemedicine, augmented reality, advanced point-of-care diagnostics, mobile health Apps, and wearable sensors-that could enhance Africa's response to NTDs in the face of persistent sociopolitical instability. As stability returns, these technologies will evolve to support more comprehensive and sustainable health development. The global health community should facilitate deployment of health technologies to those in greatest need to help achieve the NTD 2030 Roadmap and other global health targets.

ELISA-R: an R-based method for robust ELISA data analysis

Enzyme-linked immunosorbent assay (ELISA) is a technique to detect the presence of an antigen or antibody in a sample. ELISA is a simple and cost-effective method that has been used for evaluating vaccine efficacy by detecting the presence of antibodies against viral/bacterial antigens and diagnosis of disease stages. Traditional ELISA data analysis utilizes a standard curve of known analyte, and the concentration of the unknown sample is determined by comparing its observed optical density against the standard curve. However, in the case of vaccine research for complicated bacteria such as Mycobacterium tuberculosis (Mtb), there is no prior information regarding the antigen against which high-affinity antibodies are generated and therefore plotting a standard curve is not feasible. Consequently, the analysis of ELISA data in this instance is based on a comparison between vaccinated and unvaccinated groups. However, to the best of our knowledge, no robust data analysis method exists for "non-standard curve" ELISA. In this paper, we provide a straightforward R-based ELISA data analysis method with open access that incorporates end-point titer determination and curve-fitting models. Our modified method allows for direct measurement data input from the instrument, cleaning and arranging the dataset in the required format, and preparing the final report with calculations while leaving the raw data file unchanged. As an illustration of our method, we provide an example from our published data in which we successfully used our method to compare anti-Mtb antibodies in vaccinated vs non-vaccinated mice.

An update of the diagnosis, treatment, and prevention of leprosy: A narrative review

Leprosy is an infectious disease that remains a public health concern. It is caused by acid-fast Bacillus leprae, which primarily affects the skin and peripheral nerves, potentially leading to long-term disability and stigma. However, current and previous efforts have focused on developing better diagnostic and therapeutic interventions for leprosy, and its prevention needs to be addressed. In this review, we organize the currently published papers and provide updates on the global epidemiology, diagnosis, treatment, and prevention of leprosy. Several online databases, including MEDLINE (National Library of Medicine, Bethesda, MD), PubMed, EMBASE, Web of Science, and Google Scholar, were searched to collect relevant published papers. As a public health issue, the World Health Organization set the goal of leprosy elimination with a prevalence of <1 case per 10,000 people, which was achieved in 2000 and in most countries by 2010, mainly owing to the treatment of leprosy using drugs starting in 1980 and no-cost access for patients since 1995. Although diagnostic and therapeutic techniques have improved, the new occurrence of leprosy remains a critical global disease burden. With continuous technological improvements in diagnosing and treating leprosy, obtaining more relevant healthcare knowledge and preventing leprosy disability are crucial.

Exploring Active Case Detection Approaches for Leprosy Diagnosis in Varied Endemic Settings: A Comprehensive Scoping Review

(1) Background: The global burden of leprosy is not shared equally; with the majority of cases being diagnosed in Brazil, India, and Indonesia. Understanding the methods of active case detection (ACD) used in high and low endemic regions is vital for the development of future screening programs. (2) Methods: A systematic search of three databases, PubMed, Embase and Web of Science, was conducted for English language papers, published since the year 2000, which discussed the use of active case detection methods for leprosy screening. The paper utilised the Integrated Screening Action Model (I-SAM) as a tool for the analysis of these methods. (3) Results: 23 papers were identified from 11 different countries. The papers identified 6 different methods of active case detection: Household contact/social contact identification; door-to-door case detection; screening questionnaire distribution; rapid village surveys; school-based screening; and prison-based screening. 15 were located in high endemic regions and 8 of these were located in low endemic regions. (4) Conclusions: For selecting the appropriate methods of active case finding, the leprosy endemicity must be taken into consideration. The findings contribute to policy decision making allowing for more successful future leprosy case detection programs to be designed, ultimately reducing the global burden of the disease, and achieving the WHO's aim of zero leprosy.

Challenges and advances in serological and molecular tests to aid leprosy diagnosis

Leprosy is a neglected chronic infectious disease caused by obligate intracellular bacilli, Mycobacterium leprae and Mycobacterium lepromatosis. Despite multidrug therapy (MDT) success, leprosy accounts for more than 200,000 new cases yearly. Leprosy diagnosis remains based on the dermato-neurologic examination, but histopathology of skin biopsy and bacilloscopy of intradermal scraping are subsidiary diagnostic tests that require expertise and laboratory infrastructure. This minireview summarizes the state of the art of serologic tests to aid leprosy diagnosis, highlighting enzyme-linked immunosorbent assay (ELISA) and point-of-care tests (POCT) biotechnologies. Also, the impact of the postgenomic era on the description of new recombinantly expressed M. leprae-specific protein antigens, such as leprosy Infectious Disease Research Institute (IDRI) diagnostic (LID)-1 is summarized. Highly specific and sensitive molecular techniques to detect M. leprae DNA as the quantitative polymerase chain reaction (qPCR) and the loop-mediated isothermal amplification (LAMP) are briefly reviewed. Serology studies using phenolic glycolipid-I (PGL-I) semi-synthetic antigens, LID-1 fusion antigen, and the single fusion complex natural disaccharide-octyl (NDO)-LID show high sensitivity in multibacillary (MB) patients. However, serology is not applicable to paucibacillary patients, as they have weak humoral response and robust cell-mediated response, requiring tests for cellular biomarkers. Unlike ELISA-based tests, leprosy-specific POCT based on semi-synthetic PGL-I antigens and NDO-LID 1 antigen is easy to perform, cheaper, equipment-free, and can contribute to early diagnosis avoiding permanent incapacities and helping to interrupt M. leprae transmission. Besides its use to help diagnosis of household contacts or at-risk populations in endemic areas, potential applications of leprosy serology include monitoring MDT efficacy, identification of recent infection, especially in young children, as surrogate markers of disease progression to orient adult chemoprophylaxis and as a predictor of type 2 leprosy reactions. Advances in molecular biology techniques have reduced the complexity and execution time of qPCR confirming its utility to help diagnosis while leprosy-specific LAMP holds promise as an adjunct test to detect M. leprae DNA.

Effectiveness of population-wide screening and mass drug administration for leprosy control in Kiribati: the COMBINE protocol

INTRODUCTION

Progress towards leprosy elimination is threatened by increasing incidence in 'hot-spot' areas where more effective control strategies are urgently required. In these areas, active case finding and leprosy prevention limited to known contacts is insufficient for control. Population-wide active case-finding together with universal prevention through mass drug administration (MDA) has been shown to be effective in 'hot-spot' areas, but is logistically challenging and expensive. Combining leprosy screening and MDA with other population-wide screening activities such as for tuberculosis may increase programme efficiency. There has been limited evaluation of the feasibility and effectiveness of combined screening and MDA interventions. The COMBINE study aims to bridge this knowledge gap.

METHODS AND ANALYSIS

This implementation study will assess the feasibility and effectiveness of active leprosy case-finding and treatment, combined with MDA using either single-dose rifampicin or rifamycin-containing tuberculosis preventive or curative treatment, for reducing leprosy incidence in Kiribati. The leprosy programme will run over 2022-2025 in concert with population-wide tuberculosis screening-and-treatment in South Tarawa. The primary research question is to what extent the intervention reduces the annual leprosy new case detection rate (NCDR) in adults and children compared with routine screening and postexposure prophylaxis (PEP) among close contacts (baseline leprosy control activities). Comparisons will be made with (1) the preintervention NCDR separably among adults and children in South Tarawa (before-after study) and (2) the corresponding NCDRs in the rest of the country. Additionally, the postintervention prevalence of leprosy obtained from a survey of a 'hot-spot' sub-population will be compared with prevalence documented during the intervention. The intervention will be implemented in collaboration with the Kiribati National Leprosy Programme.

ETHICS AND DISSEMINATION

Approval has been obtained from the Kiribati Ministry of Health and Medical Services (MHMS), the University of Otago (H22/111) and the University of Sydney (2021/127) Human Research Ethics Committees. Findings will be shared with the MHMS, local communities and internationally through publication.

Effectiveness and safety of multidrug therapy containing clofazimine for paucibacillary leprosy and clarithromycin for rifampicin-resistant leprosy: a systematic review and meta-analysis

Introduction

The present study aimed to evaluate leprosy cure and relapse rates as primary outcomes related to two additional strategies for leprosy treatment: clofazimine for paucibacillary (PB) leprosy patients and clarithromycin for patients with rifampicin-resistant leprosy.

Methods

We conducted two systematic reviews (protocols CRD42022308272 and CRD42022308260). We searched the PubMed, EMBASE, Web of Science, Scopus, LILACS, Virtual Health Library and Cochrane Library databases, registers of clinical trial databases and gray literature. We included clinical trials evaluating the addition of clofazimine to PB leprosy treatment and the use of clarithromycin for treating patients with rifampicin-resistant leprosy. Risk of bias (RoB) in randomized clinical trials was assessed by the RoB 2 tool and that in non-randomized clinical trials was assessed by the ROBINS-I tool; and the certainty of the evidence was assessed by the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. A meta-analysis of dichotomous outcomes was performed.

Results

For clofazimine, four studies were included. Cure and relapse rates were not different with the addition of clofazimine to PB leprosy treatment and demonstrated very low certainty of evidence. For clarithromycin, six studies were included. Considerable heterogeneity resulted from the difference between comparators, and studies showed no difference in the assessed outcomes with the addition of clarithromycin to rifampicin-resistant leprosy treatment. Mild adverse events were reported for both drugs but did not significantly impact treatment.

Discussion

The effectiveness of both drugs still needs to be determined. Adding clofazimine to PB leprosy treatment may reduce the repercussions of an incorrect operational classification with no apparent relevant side effects.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022308272; https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022308260, identifier: CRD42022308272; CRD42022308260.

Serological testing for Hansen’s disease diagnosis: Clinical significance and performance of IgA, IgM, and IgG antibodies against Mce1A protein

Hansen’s disease (HD) is an infectious, treatable, and chronic disease. It is the main cause of infectious peripheral neuropathy. Due to the current limitations of laboratory tests for the diagnosis of HD, early identification of infected contacts is an important factor that would allow us to control the magnitude of this disease in terms of world public health. Thus, a cross-sectional study was conducted in the Brazilian southeast with the objective of evaluating humoral immunity and describing the accuracy of the immunoassay based on IgA, IgM, and IgG antibodies against surface protein Mce1A of Mycobacterium, the predictive potential of these molecules, the clinical significance of positivity, and the ability to segregate new HD cases (NC; n = 200), contacts (HHC; n = 105), and healthy endemic controls (HEC; n = 100) as compared to α-PGL-I serology. α-Mce1A levels for all tested antibodies were significantly higher in NC and HHC than in HEC (p &lt; 0.0001). The performance of the assay using IgA and IgM antibodies was rated as highly accurate (AUC &gt; 0.85) for screening HD patients. Among HD patients (NC), positivity was 77.5% for IgA α-Mce1A ELISA, 76.5% for IgM, and 61.5% for IgG, while α-PGL-I serology showed only 28.0% positivity. Multivariate PLS-DA showed two defined clusters for the HEC and NC groups [accuracy = 0.95 (SD = 0.008)] and the HEC and HHC groups [accuracy = 0.93 (SD = 0.011)]. IgA was the antibody most responsible for clustering HHC as compared to NC and HEC, evidencing its usefulness for host mucosal immunity and as an immunological marker in laboratory tests. IgM is the key antibody for the clustering of NC patients. Positive results with high antibody levels indicate priority for screening, new clinical and laboratory evaluations, and monitoring of contacts, mainly with antibody indexes ≥2.0. In light of recent developments, the incorporation of new diagnostic technologies permits to eliminate the main gaps in the laboratory diagnosis of HD, with the implementation of tools of greater sensitivity and accuracy while maintaining satisfactory specificity.

Silent peripheral neuropathy determined by high-resolution ultrasound among contacts of patients with Hansen's disease

Introduction

Hansen's disease (HD) primarily infects peripheral nerves, with patients without HD being free of peripheral nerve damage. Household contacts (HHCs) of patients with HD are at a 5-10 times higher risk of HD than the general population. Neural thickening is one of the three cardinal signs that define a case of HD according to WHO guidelines, exclusively considering palpation examination that is subjective and may not detect the condition in the earliest cases even when performed by well-trained professionals. High-resolution ultrasound (HRUS) can evaluate most peripheral nerves, a validated technique with good reproducibility allowing detailed and accurate examination.

Objective

This study aimed to use the peripheral nerve HRUS test according to the HD protocol as a diagnostic method for neuropathy comparing HHCs with healthy volunteers (HVs) and patients with HD.

Methods

In municipalities from 14 different areas of Brazil we selected at random 83 HHC of MB-patients to be submitted to peripheral nerve ultrasound and compared to 49 HVs and 176 HD-patients.

Results

Household contacts assessed by HRUS showed higher median and mean absolute peripheral nerve cross-sectional area (CSA) values and greater asymmetries (ΔCSA) compared to HVs at the same points. Median and mean absolute peripheral nerve CSA values were higher in patients with HD compared to HCCs at almost all points, while ΔCSA values were equal at all points. Mean ± SD focality (ΔTpT) values for HHCs and patients with HD, respectively, were 2.7 ± 2.2/2.6 ± 2.2 for the median nerve, 2.9 ± 2.7/3.3 ± 2.9 for the common fibular nerve (p > 0.05), and 1.3 ± 1.3/2.2 ± 3.9 for the ulnar nerve (p < 0.0001).

Discussion

Considering HRUS findings for HHCs, asymmetric multiple mononeuropathy signs (thickening or asymmetry) in at least 20% of the nerves evaluated could already indicates evidence of HD neuropathy. Thus, if more nerve points are assessed in HHCs (14 instead of 10), the contacts become more like patients with HD according to nerve thickening determined by HRUS, which should be a cutting-edge tool for an early diagnosis of leprosy cases.

Bacilloscopy and polymerase chain reaction of slit-skin smears and anti-phenolic glycolipid-I serology for Hansen's disease diagnosis

The bacilloscopy of the slit-skin smear (SSS) is the exclusive laboratory test associated with dermato-neurological evaluation for Hansen's disease (HD) diagnosis; however, it is negative in the majority of PB or primary neural forms. Thus, a PCR technique involving different sequences and target genes has been performed with an aim to increase the sensitivity and specificity of M. leprae identification, especially in patients with low bacillary loads. Additionally, serological assays based on antibody response reflect infection levels and indicate that this could be a simpler, less invasive technique for estimating M. leprae exposure. Serological tests and PCR have been shown to be more sensitive and accurate than the SSS. Our study aimed to measure accuracy and performance among the SSS and PCR of dermal scrapings stored on filter paper and APGL-I serology for diagnosis in HD. A cross-sectional study analyzing the medical records (n = 345) of an HD outpatient-dermatology clinic from 2014 to 2021 was conducted. Accuracy performance parameters, correlation, and concordance were used to assess the value among the SSS, PCR, and APGL-I exams in HD. The SSS presented 24.5% sensitivity, 100% specificity, 37.4% accuracy, and the lowest negative predictive value (21.5%). The PCR assay had 41, 100, and 51% sensitivity, specificity, and accuracy, respectively. PCR and APGL-I serology increased the detection of HD cases by 16 and 20.6%, respectively. PCR was positive in 51.3% of patients when the SSS was negative. The SSS obtained moderate concordance with PCR [k-value: 0.43 (CI: 0.33-0.55)] and APGL-I [k-value: 0.41 (CI: 0.31-0.53)]. A moderate positive correlation was found between the APGL-I index and the bacillary index (r = 0.53; P < 0.0001). Thus, the use of the SSS is a low sensitivity and accuracy method due to its low performance in HD detection. The use of PCR and serological tests allows for a more sensitive and accurate diagnosis of patients.

ELISA Test Based on the Phenolic Glycolipid-I (PGL-I) of Mycobacterium leprae: A Reality of a Laboratory from a Non-Endemic Country

Background: Leprosy is a neglected tropical disease caused by Mycobacterium leprae, leading to disabilities if untreated. The ELISA based on phenolic glycolipid I (PGL-I), or its synthetic version ND-O-BSA, is almost universally positive in multibacillary leprosy and thus extensively used in endemic countries. Household contacts with a positive antibody titer have ~6-fold higher probability to develop the disease than those with a negative titer. Thus, the aim of the study was to evaluate the performance of this ELISA in the setting of a non-endemic country. Methods: We calculate the cut-off using optimized O.D. thresholds, generated by receiver operating characteristics (ROC) curve analysis, testing 39 well-characterized sera obtained from lepromatous leprosy patients with strongly positive ND-O-BSAELISA titer and 39 sera from healthy non-endemic patients never exposed to M. leprae or M. tuberculosis. Indeed, we tested a second set of sera from suspected or confirmed leprosy or household contacts (SLALT group, n=50), and patients with tuberculosis (control group, n=40). Results: We detected 56.4% of SLALT and 22.5% of tuberculosis as positive, consistent with the literature. Conclusion: The ELISA based on ND-O-BSA may thus be considered a good option to be used in a non-endemic area as a screening tool in at risk population usually coming to our center.

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.

Serological Immunoassay for Hansen's Disease Diagnosis and Monitoring Treatment: Anti-Mce1A Antibody Response Among Hansen's Disease Patients and Their Household Contacts in Northeastern Brazil

Hansen's disease (HD) is an ancient disease, but more than 200,000 new cases were reported worldwide in 2019. Currently, there are not many satisfactory immunoassay methods for its diagnosis. We evaluated antibodies against Mce1A as a promising new serological biomarker. We collected plasma from new cases, contacts, and endemic controls in the city of Parnaíba and treated patients at Carpina, a former HD colony in Piauí state, northeastern Brazil. Receiver operating characteristic (ROC) curves were used to assess the assay thresholds, specificity and sensitivity of the IgA, IgM, and IgG antibodies against α-Mce1A by indirect ELISA and compared it with IgM anti-PGL-I and molecular diagnosis by quantitative polymerase chain reaction (qPCR). Venn diagrams were generated to represent the overlap in the antibody positivity pattern. Multivariate analysis was performed to assess the potential predictor of antibodies for the outcome of having an HD diagnosis. IgA and IgG were positive in 92.3 and 84% of patients, respectively. IgM was negative for all treated patients. IgG had a sensitivity and specificity of 94.7 and 100%, respectively. IgM-positive individuals had a 3.6 chance of being diagnosed with HD [OR = 3.6 (95% CI = 1.1-11.6); p = 0.028], while IgA-positive individuals had a 2.3 chance [OR = 2.3 (95% CI = 1.2-4.3); p = 0.005] compared to endemic controls. We found that the Mce1A antibody profile can be an excellent diagnostic method of HD. IgA is an ideal biomarker for confirming contact with the bacillus. IgM has potential in the detection of active disease. IgG antibodies confirm the performance of these serological markers in diagnosis and therapeutic follow-up.

Can Leprosy Reaction States Mimic Symptoms of Fibromyalgia? A Cross-Sectional Analytical Study

Leprosy causes significant pain in affected patients, especially those experiencing reactional states. Fibromyalgia is characterized by widespread pain and is often accompanied by fatigue. Confusion between the clinical manifestations of fibromyalgia and those of leprosy reactions is possible at the primary care level, the first contact with the health system in most cases. We aimed to determine whether the presence of leprosy reactional states is related to the development of signs and symptoms included in the case definition of fibromyalgia and establish recommendations for obtaining the correct diagnosis. We performed a cross-sectional study in which the main independent variable was the presence of any leprosy reactional state and the primary dependent variable was the diagnosis of fibromyalgia according to the 2016 Revisions of the 2010/2011Fibromyalgia Provisional Criteria of the American College of Rheumatology. Forty-three patients were included in the study. Twenty-eight (65.12%) patients had a type I reactional state, only 1 (2.33%) had an isolated type II reactional state, and 5 (11.63%) had both type I and type II reactional states. Only 2 patients who suffered from cooccurring type I and II reactional states obtained sufficient scores for the diagnosis of fibromyalgia. Although diffuse pain was common in leprosy patients, none of the types of reactional states were associated with a higher frequency of criteria for fibromyalgia. We can conclude that a leprosy reactional state is probably not a risk factor for fibromyalgia but can act as a confounder, as tender points may be similar in both diagnoses. In patients diagnosed with fibromyalgia, leprosy must be considered in the differential diagnosis in endemic regions.

Algorithm design for a cytokine release assay of antigen-specific in vitro stimuli of circulating leukocytes to classify leprosy patients and household contacts

Background

Immunological biomarkers have often been used as a complementary approach to support clinical diagnosis in several infectious diseases. The lack of commercially available laboratory tests for conclusive early diagnosis of leprosy has motivated the search for novel methods for accurate diagnosis. In the present study, we describe an integrated analysis of a cytokine release assay using a machine learning approach to create a decision tree algorithm. This algorithm was used to classify leprosy clinical forms and monitor household contacts.

Methods

A model of Mycobacterium leprae antigen-specific in vitro assay with subsequent cytokine measurements by enzyme-linked immunosorbent assay was employed to measure the levels of tumor necrosis factor (TNF), interferon-γ, interleukin 4, and interleukin 10 (IL-10) in culture supernatants of peripheral blood mononuclear cells from patients with leprosy, healthy controls, and household contacts. Receiver operating characteristic curve analysis was carried out to define each cytokine’s global accuracy and performance indices to identify clinical subgroups.

Results

Data demonstrated that TNF (control culture [CC]: AUC = 0.72; antigen-stimulated culture [Ml]: AUC = 0.80) and IL-10 (CC: AUC = 0.77; Ml: AUC = 0.71) were the most accurate biomarkers to classify subgroups of household contacts and patients with leprosy, respectively. Decision tree classifier algorithms for TNF analysis categorized subgroups of household contacts according to the operational classification with moderate accuracy (CC: 79% [48/61]; Ml: 84% [51/61]). Additionally, IL-10 analysis categorized leprosy patients’ subgroups with moderate accuracy (CC: 73% [22/30] and Ml: 70% [21/30]).

Conclusions

Together, our findings demonstrated that a cytokine release assay is a promising method to complement clinical diagnosis, ultimately contributing to effective control of the disease.

Standardization of SYBR Green-Based Real-Time PCR Through the Evaluation of Different Thresholds for Different Skin Layers: An Accuracy Study and Track of the Transmission Potential of Multibacillary and Paucibacillary Leprosy Patients

The development of new molecular techniques is essential for the early diagnosis of leprosy. Studies in the field have failed to elucidate the performance of these tests in clinical practice. We aimed to design a new primer pair for the repetitive element (RLEP) target of Mycobacterium leprae and to test the accuracy of SYBR green-based real-time PCR through the evaluation of different thresholds for different skin layers. We also aimed to track the transmission potential of multibacillary and paucibacillary leprosy patients. The in vitro validation of our reaction resulted in a quantification limit of 0.03 bacilli. We then conducted a cross-sectional/cohort-based study of diagnostic accuracy. Patients were included, and skin samples were divided into four layers: epidermis, superior dermis, inferior dermis, and hypodermis. We also quantified M. leprae in nasal swabs of the included patients and compared the results to the number of household contacts also diagnosed with leprosy. One hundred patients with a clinical presentation compatible with leprosy were allocated to the leprosy or control group. Although the parasite load was greater in the superior and inferior dermis, M. leprae DNA was found in all skin layers. The best sensitivity was observed for the superior dermis using the presence of any quantifiable bacillus DNA as the threshold [sensitivity=59.26% (95% CI=45.97–71.32)]. In the epidermis, setting 1 quantifiable bacillus as the threshold resulted in 100% specificity (95% CI=92.29–100). The number of bacilli found in nasal swabs was not significantly related to the number of household contacts also diagnosed with leprosy. Paucibacillary patients tested positive only for bacillus fragments in nasal swabs but not for the entire bacilli. We can conclude that superficial biopsies might result in sensitivity loss, although different skin sample types will have little influence on the final accuracy. In contrast, threshold changes greatly influence these properties. Paucibacillary patients may not be a relevant source of disease transmission.

Laboratory diagnosis of leprosy: Two staining methods from bacilloscopy and rapid ml flow test

Background

The diagnosis of leprosy is based on the characteristic signs and symptoms of the disease, subsidized by laboratory tests. When positive, the bacilloscopy closes the diagnosis for leprosy. Phenolic glycolipid-I, or PGL-I, is a molecule in the bacillus cell wall that confers a greater immune response. The ML Flow test is an immunochromatographic test for the detection of anti-PGL-I IgM in human blood or serum.

Methods

A prospective study with data collection and biological materials in patients with suspected leprosy from August 2020 to May 2021. For microscopy, intradermal smears were stained with Auramine O, and after reading under a fluorescence microscope, reviewed by Ziehl-Neelsen. The ML flow test was performed according to the Bührer-Sékula protocol. To assess the agreement between the methods, the Kappa index was estimated.

Results

Of the 94 suspected leprosy patients, 31 (32.9%) were diagnosed with leprosy. There was moderate agreement between the results of the ML Flow and Auramine O tests (Kappa = 0.58) and substantial agreement between the ML Flow and Ziehl-Neelsen microscopy (Kappa = 0.72). In paucibacillary cases, serology was positive in 100% of patients.

Conclusions

This study concluded that the Ziehl-Neelsen technique remains the best option for standard leprosy staining, and the ML flow test is more positive among the three techniques evaluated and can be an effective tool in the early diagnosis of leprosy cases.

[Combined use of serologic markers and spatial analysis for epidemiological surveillance of leprosyUso conjunto de los marcadores serológicos y del análisis espacial en la vigilancia epidemiológica de la lepra]

Objective

To evaluate the combined use of serologic markers and spatial analysis to increase the sensitivity of leprosy epidemiological surveillance.

Method

This cross-sectional study was performed with neighbors of leprosy cases and neighbors and family members of schoolchildren with a positive anti-phenolic glycolipid I (PGL-I) test in Diamantina, state of Minas Gerais, Brazil. Neighbors were those living within a 100-m radius of schoolchildren or leprosy cases. Data collection included a semi-structured interview, dermatologic examination, and rapid ML Flow test. All residential addresses were georeferenced. Multivariate regression and spatial analysis were performed with anti-PGL-I seropositivity as the dependent variable.

Results

The study included 1 491 individuals: 1 009 (67.7%) family members and neighbors of schoolchildren with positive serology test and 482 (32.3%) neighbors of leprosy cases. Of the total, 421 (28.2%) were positive for anti-PGL-I. Seropositivity was higher among family members and neighbors of seropositive schoolers (P < 0.001), among people with family income of 1 minimum wage (P < 0.001), among the youngest participants (P < 0.001), and among those living in homes with one to five rooms (P = 0.007). The seropositivity rate was higher in the geographic area corresponding to seropositive schoolchildren (P < 0.001), that is, the spot with the highest number of cases was different from the spot with the highest rate of seropositivity.

Conclusions

The combined use of serologic markers and spatial analysis allowed us to easily identify operational weaknesses of services and a possible occult leprosy endemism in the municipality's urban census tracts. Tracing of social contact and neighbors, active search, educational campaigns, school surveys, and territorial analyses facilitate the early diagnosis of leprosy.

Primary neural leprosy: clinical, neurophysiological and pathological presentation and progression

Disability in leprosy is a direct consequence of damage to the peripheral nervous system which is usually worse in patients with no skin manifestations, an underdiagnosed subtype of leprosy known as primary neural leprosy. We evaluated clinical, neurophysiological and laboratory findings of 164 patients with definite and probable primary neural leprosy diagnoses. To better understand the disease progression and to improve primary neural leprosy clinical recognition we compared the characteristics of patients with short (≤ 12 months) and long (> 12 months) disease duration. Positive and negative symptoms mediated by small-fibre were frequent at presentation (∼95%), and symptoms tend to manifest first in the upper limbs (∼68%). There is a consistent phenotypic variability between the aforementioned groups. Deep sensory modalities were spared in patients evaluated within the first 12 months of the disease, and were only affected in patients with longer disease duration (∼12%). Deep tendon reflexes abnormalities were most frequent in patients with longer disease duration (p < 0,001), as well as motor deficits (p = 0,002). Damage to large fibres (sensory and motor) is a latter event in primary neural leprosy. Grade-2 disability and nerve thickening was also more frequent in cases with long disease duration (p < 0,001). Primary neural leprosy progress over time and there is a marked difference in clinical phenotype between patients with short and long disease duration. Patients assessed within the first 12 months of symptom onset had a non-length-dependent predominant small-fibre sensory neuropathy, whilst patients with chronic disease presented an asymmetrical all diameter sensory-motor neuropathy and patchily decreased/absent deep tendon reflexes.

Lucio's phenomenon: A systematic literature review of definition, clinical features, histopathogenesis and management

Leprosy is a chronic disease with clinical presentations according to the immunologic spectrum. Lepromatous form is the most advanced, with the highest transmissibility and risk of causing disabilities. Lucio's phenomenon is a rare manifestation among lepromatous patients with a rapid and severe evolution and high mortality. It is difficult to differentiate from ulcerative/necrotic erythema nodosum leprosum and has no consensus on how it should be treated. This article is a qualitative review of the literature after the introduction of multidrug therapy, aiming to bring consensus related to the clinical, laboratory and histopathological diagnostic criteria of the disease and its management.

Non-tuberculous cutaneous mycobacterioses

Non-tuberculous mycobacteriosis, previously known as atypical, anonymous, opportunistic, or unclassified mycobacteriosis, refers to pathogenic mycobacterioses other than those caused by Mycobacterium tuberculosis and Mycobacterium leprae. These mycobacteria are known for their environmental distribution, mainly in water and soil. The incidence of non-tuberculous mycobacteriosis has been increasing in all countries and skin infections are being increasingly studied, mainly with the increase in immunosuppressive conditions and the development of new medications that affect immunological function. In the present article, a detailed narrative review of the literature is carried out to study the main non-tuberculous mycobacteriosis that cause diseases of the skin and appendages. The article also aims to present a historical context, followed by epidemiological, microbiological, and clinical characteristics of these diseases. Practical considerations about the diagnosis and treatment of non-tuberculous mycobacteriosis are detailed.

Innovative tracking, active search and follow-up strategies for new leprosy cases in the female prison population

BACKGROUND

Regarding the leprosy transmission through the upper airways, overcrowded locations such as prisons can become a risk to get sick. Like the leprosy hidden endemic demonstrated in male prison population, being interesting to assess the leprosy scene also among confined women.

METHODS

A prospective descriptive study conducted at Female Penitentiary, Brazil. Leprosy Suspicion Questionnaire (LSQ) were applied to the participants, and submitted to specialized dermatoneurological exam, peripheral nerve ultrasonography, and anti-PGL-I serology.

FINDINGS

404 female inmates were evaluated, 14 new cases were diagnosed (LG-leprosy group), a new case detection rate (NCDR) of 3.4%, 13 multibacillary, while another 390 constituted the Non-Leprosy group (NLG). Leprosy cases were followed up during multidrug therapy with clinical improvement. The confinement time median was 31 months in LG, similar to NLG, less than the time of leprosy incubation. Regarding LSQ, the neurological symptoms reached the highest x2 values as Q1-numbness (5.6), Q3-anesthetizes areas in the skin (7.5), Q5-Stinging sensation (5.8), and Q7-pain in the nerves (34.7), while Q4-spots on the skin was 4.94. When more than one question were marked in the LSQ means a 12.8-fold higher to have the disease than a subject who marked only one or none. The high 34% rate of anti-PGL-I seropositivity in the penitentiary, higher levels in LG than NLG. Three additional leprosy cases each were diagnosed on the second (n = 66) and third (n = 14) reevaluations 18 and 36 months after the initial one. Semmes-Weinstein monofilaments demonstrated lower limbs (32.2%) more affected than the upper limbs (25%) with improvement during the follow-up.

INTERPRETATION

The NCDR in this population showed an hidden endemic of leprosy as well as the efficacy of a search action on the part of a specialized team with the aid of the LSQ and anti-PGL-I serology as an auxiliary tracking tools.

The influence of leprosy-related clinical and epidemiological variables in the occurrence and severity of COVID-19: A prospective real-world cohort study

BACKGROUND

Protective effects of Bacillus Calmette-Guérin (BCG) vaccination and clofazimine and dapsone treatment against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection have been reported. Patients at risk for leprosy represent an interesting model for assessing the effects of these therapies on the occurrence and severity of coronavirus disease 2019 (COVID-19). We assessed the influence of leprosy-related variables in the occurrence and severity of COVID-19.

METHODOLOGY/PRINCIPAL FINDINGS

We performed a 14-month prospective real-world cohort study in which the main risk factor was 2 previous vaccinations with BCG and the main outcome was COVID-19 detection by reverse transcription polymerase chain reaction (RT-PCR). A Cox proportional hazards model was used. Among the 406 included patients, 113 were diagnosed with leprosy. During follow-up, 69 (16.99%) patients contracted COVID-19. Survival analysis showed that leprosy was associated with COVID-19 (p<0.001), but multivariate analysis showed that only COVID-19-positive household contacts (hazard ratio (HR) = 8.04; 95% CI = 4.93-13.11) and diabetes mellitus (HR = 2.06; 95% CI = 1.04-4.06) were significant risk factors for COVID-19.

CONCLUSIONS/SIGNIFICANCE

Leprosy patients are vulnerable to COVID-19 because they have more frequent contact with SARS-CoV-2-infected patients, possibly due to social and economic limitations. Our model showed that the use of corticosteroids, thalidomide, pentoxifylline, clofazimine, or dapsone or BCG vaccination did not affect the occurrence or severity of COVID-19.

Active search strategies, clinicoimmunobiological determinants and training for implementation research confirm hidden endemic leprosy in inner São Paulo, Brazil

Background

This study evaluates implementation strategies for leprosy diagnosis based on responses to a Leprosy Suspicion Questionnaire (LSQ), and analyzes immunoepidemiological aspects and follow-up of individuals living in a presumptively nonendemic area in Brazil.

Methodology/Principal findings

Quasi-experimental study based on LSQ throughout Jardinópolis town by community health agents, theoretical-practical trainings for primary care teams, dermatoneurological examination, anti-PGL-I serology, RLEP-PCR, and spatial epidemiology. A Leprosy Group (LG, n = 64) and Non-Leprosy Group (NLG, n = 415) were established. Overall, 3,241 LSQs were distributed; 1,054 (32.5%) LSQ were positive for signs/symptoms (LSQ+). Among LSQ+ respondents, Q2-Tingling (pricking)? (11.8%); Q4-Spots on the skin? (11.7%); Q7-Pain in the nerves? (11.6%); Q1-Numbness in your hands and/or feet? (10.7%) and Q8-Swelling of hands and feet? (8.5%) were most frequently reported symptoms. We evaluated 479 (14.8%) individuals and diagnosed 64 new cases, a general new case detection rate (NCDR) of 13.4%; 60 were among 300 LSQ+ (NCDR-20%), while 4 were among 179 LSQ negative (NCDR-2.23%). In LG, Q7(65%), Q2(60%), Q1(45%), Q4(40%) and Q8(25%) were most frequent. All 2x2 crossings of these 5 questions showed a relative risk for leprosy ranging from 3 to 5.8 compared with NLG. All patients were multibacillary and presented hypochromatic macules with loss of sensation. LG anti-PGL-I titers were higher than NLG, while 8.9% were positive for RLEP-PCR. The leprosy cases and anti-PGL-I spatial mappings demonstrated the disease spread across the town.

Conclusions/Significance

Implementation actions, primarily LSQ administration focused on neurological symptoms, indicate hidden endemic leprosy in a nonendemic Brazilian state.

The prevalence of leprosy in the world and in Brazil is unknown. Although Brazil has effective disease notification systems, the data do not capture reality in the field, due to decreasing leprosy awareness, both in the community and among health professionals. Schools have decreased or stopped teaching about the disease, likely as a result of a massive campaign to eliminate leprosy as a public health problem around the world that focused almost exclusively on dermatological manifestations. The disease is primarily neural, affects mainly the reproductive-age population, and can generate disabilities leading to serious economic impacts on the individual and society. Despite modern diagnostic approaches, diagnosis of leprosy is still focused on clinical observation, given the scarcity of laboratory tests with good performance in terms of sensitivity and specificity. This makes leprosy diagnosis a challenge, especially for mild forms; Mycobacterium leprae can grow slowly and interact variably with the host, making leprosy as a highly complex disease. Only when the leprosy care policy in Jardinópolis municipality, São Paulo state inner, Brazil, was changed to hire a leprosy specialist for surveillance, was it possible to modify leprosy indicators revealing the hidden epidemic in the municipality. This study confirms hidden endemic leprosy in the municipality and informs implementation strategies for primary health teams using the Leprosy Suspicion Questionnaire (LSQ) on symptoms and signs of leprosy. LSQ is a low-cost, highly effective instrument to promote leprosy health education among community health agents and other health team workers, and among communities about the neurological symptoms that precede dermatological leprosy signs. This technique increases the likelihood of early diagnosis and treatment, avoiding disabilities, and consequently effectively halting disease transmission. The LSQ is an effective, low-cost screening tool for detecting new leprosy cases and increasing awareness of leprosy. The LSQ alerts community members and health professionals to detect even mild symptoms/signs of leprosy, a primarily neurological disease. Our data also demonstrate the importance of the leprosy specialist role to train and to supervise health teams to investigate incidence in communities that have long been established as nonendemic. The assumption of nonendemicity can and should change, due to the increase in the number of cases initially, and in view of the chronicity of leprosy and slow future decline. This change will in fact facilitate the much-desired elimination of leprosy as a global public health problem.

Social inequalities and their association with the leprosy burden in a Brazilian city of low endemicity: An ecological study

OBJECTIVE

To analyse the association between social inequalities and the leprosy burden in a low endemicity scenario in the state of São Paulo, Brazil.

METHODS

This ecological study was carried out in the city of Ribeirão Preto, state of São Paulo, Brazil, considering leprosy cases notified from 2006 to 2016. Regarding social inequalities, dimensions related to high household density, literacy, home occupation conditions, health conditions, household income, ethnicity and age were considered. The generalised additive model for location, scale and shape (GAMLSS) was used to verify the association between the social inequalities and leprosy burden.

RESULTS

The increase in men and women with no education and people with an income of 1 to 2 minimum wages was associated with a relative increase in the number of leprosy cases (7.37%, 7.10% and 2.44%, respectively). Regarding the ethnicity variables, the increase in the proportion of men (black) and women (mixed race) with no schooling was associated with a relative increase in the number of cases of the disease (10.77% and 4.02%, respectively). Finally, for people of mixed race or ethnicity, the increase in the proportion of households with 1/2 to 1 minimum wage was related to a relative decrease in the total number of cases (-4.90%).

CONCLUSION

The results show that the determinants associated with the increase in leprosy cases are similar to those in Brazilian hyperendemic regions, and that even in cities with low endemicity, social inequality is one of the main determinants of the disease.

Latent leprosy infection identified by dual RLEP and anti-PGL-I positivity: Implications for new control strategies

The number of new cases of leprosy reported worldwide has remained essentially unchanged for the last decade despite continued global use of free multidrug therapy (MDT) provided to any diagnosed leprosy patient. In order to more effectively interrupt the chain of transmission, new strategies will be required to detect those with latent disease who contribute to furthering transmission. To improve the ability to diagnose leprosy earlier in asymptomatic infected individuals, we examined the combined use of two well-known biomarkers of M. leprae infection, namely the presence of M. leprae DNA by PCR from earlobe slit skin smears (SSS) and positive antibody titers to the M. leprae-specific antigen, Phenolic Glycolipid I (anti-PGL-I) from leprosy patients and household contacts living in seven hyperendemic cities in the northern state of Pará, Brazilian Amazon. Combining both tests increased sensitivity, specificity and accuracy over either test alone. A total of 466 individuals were evaluated, including 87 newly diagnosed leprosy patients, 52 post-treated patients, 296 household contacts and 31 healthy endemic controls. The highest frequency of double positives (PGL-I+/RLEP+) were detected in the new case group (40/87, 46%) with lower numbers for treated (12/52, 23.1%), household contacts (46/296, 15.5%) and healthy endemic controls (0/31, 0%). The frequencies in these groups were reversed for double negatives (PGL-I-/RLEP-) for new cases (6/87, 6.9%), treated leprosy cases (15/52, 28.8%) and the highest in household contacts (108/296, 36.5%) and healthy endemic controls (24/31, 77.4%). The data strongly suggest that household contacts that are double positive have latent disease, are likely contributing to shedding and transmission of disease to their close contacts and are at the highest risk of progressing to clinical disease. Proposed strategies to reduce leprosy transmission in highly endemic areas may include chemoprophylactic treatment of this group of individuals to stop the spread of bacilli to eventually lower new case detection rates in these areas.

Leprosy detection rate in patients under immunosuppression for the treatment of dermatological, rheumatological, and gastroenterological diseases: a systematic review of the literature and meta-analysis

Background

Recently developed immunosuppressive drugs, especially TNF antagonists, may enhance the risk of granulomatous infections, including leprosy. We aimed to evaluate the leprosy detection rate in patients under immunosuppression due to rheumatological, dermatological and gastroenterological diseases.

Methods

We performed a systematic review of the literature by searching the PubMed, EMBASE, LILACS, Web of Science and Scielo databases through 2018. No date or language restrictions were applied. We included all articles that reported the occurrence of leprosy in patients under medication-induced immunosuppression.

Results

The search strategy resulted in 15,103 articles; finally, 20 articles were included, with 4 reporting longitudinal designs. The detection rate of leprosy ranged from 0.13 to 116.18 per 100,000 patients/year in the USA and Brazil, respectively. In the meta-analysis, the detection rate of cases of leprosy per 100,000 immunosuppressed patients with rheumatic diseases was 84 (detection rate = 0.00084; 95% CI = 0.0000–0.00266; I² = 0%, p = 0.55).

Conclusion

Our analysis showed that leprosy was relatively frequently detected in medication-induced immunosuppressed patients suffering from rheumatological diseases, and further studies are needed. The lack of an active search for leprosy in the included articles precluded more precise conclusions.

Trial registration

This review is registered in PROSPERO with the registry number CRD42018116275.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06041-7.

Leprosy in a prison population: A new active search strategy and a prospective clinical analysis

BACKGROUND

This study evaluates an active search strategy for leprosy diagnosis based on responses to a Leprosy Suspicion Questionnaire (LSQ), and analyzing the clinical, immunoepidemiological and follow-up aspects for individuals living in a prison population.

METHODS

A cross-sectional study based on a questionnaire posing 14 questions about leprosy symptoms and signs that was distributed to 1,400 prisoners. This was followed by dermatoneurological examination, anti-PGL-I serology and RLEP-PCR. Those without leprosy were placed in the Non-leprosy Group (NLG, n = 1,216) and those diagnosed with clinical symptoms of leprosy were placed in the Leprosy Group (LG, n = 34).

FINDINGS

In total, 896 LSQ were returned (64%), and 187 (20.9%) of the responses were deemed as positive for signs/symptoms, answering 2.7 questions on average. Clinically, 1,250 (89.3%) of the prisoners were evaluated resulting in the diagnosis of 34 new cases (LG), based on well-accepted clinical signs and symptoms, a new case detection rate of 2.7% within this population, while the NLG were comprised of 1,216 individuals. The confinement time medians were 39 months in the LG while it was 36 months in the NLG (p>0.05). The 31 leprosy cases who responded to the questionnaire (LSQ+) had an average of 1.5 responses. The symptoms "anesthetized skin area" and "pain in nerves" were most commonly mentioned in the LG while "tingling, numbness in the hands/feet", "sensation of pricks and needles", "pain in nerves" and "spots on the skin" responses were found in more than 30% of questionnaires in the NLG. Clinically, 88.2% had dysesthetic macular skin lesions and 97.1% presented some peripheral nerve impairment, 71.9% with some degree of disability. All cases were multibacillary, confirming a late diagnosis. Anti-PGL-I results in the LG were higher than in the NLG (p<0.0001), while the RLEP-PCR was positive in 11.8% of the patients.

INTERPRETATION

Our findings within the penitentiary demonstrated a hidden prevalence of leprosy, although the individuals diagnosed were likely infected while living in their former communities and not as a result of exposure in the prison. The LSQ proved to be an important screening tool to help identify leprosy cases in prisons.

Prospects for new leprosy diagnostic tools, a narrative review considering ELISA and PCR assays

Slit skin smear and histopathological examinations are currently the main laboratory tools used to aid the diagnosis of leprosy. However, their sensitivity is low, and many cases are not detected. New methodologies have been studied to develop more accurate tests. This narrative review aims to raise attention to the results of molecular (polymerase chain reaction) and serological (Enzyme-Linked Immunosorbent Assay) tests applied to the diagnosis of leprosy, and to summarize the available information about the former. Original scientific articles published in indexed international journals, whose study involved aspects of the diagnosis and classification of leprosy cases or home contacts, were selected. The data were extracted independently using a standardized method that dictated the inclusion of the following information: diagnosis in Paucibacillary and Multibacillary cases and in household contacts; sample number; sample type; study design; studied variables; statistical analysis employed; main results; and limitations identified. In clinical practice, the results from molecular and serological tests are assessed separately, with moderate sensitivity and specificity. However, an integrated study of these methodologies has been suggested for greater accuracy in diagnosis.

Leprosy surveillance study in a highly endemic Brazilian area using leprosy specific serologic tests and IFNγ whole blood assay

This surveillance study evaluated leprosy-serologic tests and the IFNγ whole-blood-assay/WBA as adjunct diagnostic tools. Previously diagnosed leprosy index cases, intradomiciliary, peridomiciliary contacts from a Brazilian endemic area were enrolled during domiciliary visits. Physical evaluation was performed by trained nurses and leprosy diagnosis confirmed by expert dermatologist. ELISA detected IgM anti-PGL-I, IgG anti-LID-1, and IgM/IgG anti-ND-O-LID antibodies. Heparinized WBA plasma stimulated with LID-1, 46f + LID-1, ML0276 + LID-1 (24 h, 37 °C, 5% CO₂₎ was tested for human IFNγ (QuantiFERON®-TB Gold/QFT-G; Qiagen). The survey included 1731 participants: 44 leprosy index cases, 64 intradomiciliary, 1623 peridomiciliary contacts. Women represented 57.7%, median age was 32 years, 72.2% had BCG scar. Leprosy prevalence was higher in intradomiciliary (8.57%) versus peridomiciliary contacts (0.67%), p < 0.001. Among 23 suspects, five leprosy cases were confirmed: 4 multibacillary/MB and 1 paucibacillary/PB. Leprosy incidence was 0.30%: 1.56% in intradomiciliary versus 0.25% in peridomiciliary (p = 0.028). Seropositivity rates were 1.9% to PGL-I, 4.9% to LID-1, and 1.0% to ND-O-LID. LID-1 positivity was higher in all groups; incident cases were LID-1 seropositive. ND-O-LID positivity was higher in intra- versus peridomiciliary contacts (p = 0.022). IFNγ WBA (40 index cases, 19 suspects, 35 intradomiciliary, 74 peridomiciliary contacts) showed higher LID-1/WBA positivity in peridomiciliary contacts (p > 0.05); significant differences among groups were seen with 46f + LID-1 but 0276 + LID-1 induced higher IFNγ levels. Incident cases were LID-1 seropositive, while IFNγ-WBA had marginal diagnostic application. As seropositivity indicates exposed individuals at higher risk of disease development, the utility of serologic screening for surveillance and prophylactic measures remains to be demonstrated.

Association between NDO-LID and PGL-1 for leprosy and class I and II human leukocyte antigen alleles in an indigenous community in Southwest Amazon

The frequencies of the Human leukocyte antigen (HLA) alleles in the Puyanawa indigenous reserve population and their association with the NDO-LID and ELISA PGL-1 rapid serological test was assessed. This was a cross-sectional study with an epidemiological clinical design conducted in two indigenous communities in the state of Acre, Brazil. Blood was collected in a tube with EDTA to identify HLA alleles and perform serological tests. DNA was obtained using the salting out procedure. The LabType™ technique (One-Lambda-USA) was used for HLA class I (loci A*, B* and C*) and II (loci DRB1*, DQA1* and DQB1*) typing. Allele frequency was obtained by direct count, and the chi-square test was used to assess the association with the NDO-LID and PGL-1 tests. The most frequent alleles in the two communities were: HLA-A*02:01, HLA-B*40:02, HLA-DRB1*16:02, HLA-DQA1*05:05 and HLA-DQB1*03:01. The allele HLA-C*04:01 was the most common in the Barão community, and the allele HLA-C*07:01 in Ipiranga. Among individuals who presented seropositivity to the NDO-LID test, the association with alleles HLA-A*02 (43.18% vs 24.8%, p = 0.03, OR = 2.35) and HLA-B*53 (6.83% vs 0.0%, p = 0.03, OR = 8.95) was observed in the Barão community. HLA-B*15 was associated with non-seroconversion to the NDO-LID test in Ipiranga. In both communities, HLA-B*40 and HLA-C*03 were associated with positive serological response to ELISA PGL-1. The HLA class I and II alleles most frequently found in this study have already been described among Terena indigenous groups, and HLA class I contributes to seroconversion to NDO-LID and PGL-1 tests in inhabitants of the Barão and Ipiranga communities.

The interference of polypharmacy and the importance of clinical pharmacy advice in the treatment of leprosy: a case-control study

INTRODUCTION:

Although supervised doses are essential for reducing leprosy treatment failure, the impact of specific drug interactions has rarely been assessed. This study aimed to estimate the risk of leprosy treatment suspension in patients receiving polypharmacy.

METHODS

We performed this case-control study in which the primary outcome was defined as the need to discontinue multibacillary leprosy treatment for at least one supervised dose, and the main risk factor was the detection of polypharmacy. Multivariate analysis by logistic regression was used for calculating odds ratio (OR).

RESULTS:

This study included 103 patients, of whom 43 needed to discontinue leprosy treatment (hemolysis = 26, hepatitis = 2, hemolysis associated with hepatitis = 6, and suspected treatment resistance = 9) and the rest did not. The severity of drug interactions had no effect on treatment discontinuation. Patients who used five or more drugs in addition to leprosy treatment had almost a 4-fold greater risk of treatment suspension (OR, 3.88; 95% confidence interval: 1.79-9.12; p < 0.001). The number of drugs used also positively influenced the occurrence of hemolysis (p < 0.001). No patient presented evidence of molecular resistance to rifampicin, dapsone, or ofloxacin treatment, as evidenced by genetic sequencing detection of rpoB, folp1, and gyrA mutations.

CONCLUSIONS:

Polypharmacy has deleterious effects on the already difficult-to-adhere-to treatment of leprosy and polypharmacy induces hemolysis. Additional measures must be taken to avoid the undesirable effects of inadequate polypharmacy.

Biotechnological and Immunological Platforms Based on PGL-I Carbohydrate-Like Peptide of Mycobacterium leprae for Antibodies Detection Among Leprosy Clinical Forms

Phenolic glycolipid I (PGL-I) is an abundant antigen on the Mycobacterium leprae cell wall, commonly used for operational classification of leprosy patients. Our aim was to develop PGL-I mimotopes with similar characteristics and functions of the native antigen. We have used a random peptide phage display (PD) library for selections against the monoclonal antibody anti-PGL-I. After three selection cycles, six peptides were identified. All sequences were interspersed by a spacer generating a chimeric peptide (PGLI-M3) that was artificially synthesized. The highly reactive peptide was submitted to a reverse PD selection with a single-chain Fv (scFv) antibody fragment combinatorial library. The most reactive scFv was then validated by enzyme-linked immunosorbent assay (ELISA) against both native PGL-I and two derived synthetic (NDO and ND-O-HSA). We have further proved the scFv specificity by detecting M. leprae bacilli in leprosy lesions through immunohistochemistry. We then described its applicability in ELISA for all clinical forms and household contacts (HC). Afterward, we showed differential binding affinities of PGLI-M3 to sera (anti-PGL-I IgM) from all leprosy clinical forms through surface plasmon resonance (SPR). ELISA IgM detection showed 89.1% sensitivity and 100% specificity, considering all clinical forms. Positivity for anti-PGL-I IgM was twofold higher in both HC and patients with paucibacillary forms in hyperendemic regions than in endemic ones. The SPR immunosensor was able to differentiate clinical forms with 100% accuracy. This is the first time that a PGL-I mimotope has efficiently mimicked the carbohydrate group of the M. leprae antigen with successful immunoassay applications and may become a substitute for the native antigen.

Development of LepReact, a defined skin test for paucibacillary leprosy and low-level M. leprae infection

The persistence of new leprosy cases in endemic areas such as India, Brazil, Bangladesh, and the Philippines has encouraged studies of chemoprophylaxis among contacts of patients. Epidemiological screening tools to enable early detection of infected individuals in endemic populations would be critical to target individuals most in need of intervention. Despite decades of attempts, however, there still are no tests available for the early detection of low-level infection with Mycobacterium leprae. In this report, we describe the development of a leprosy skin test using M. leprae-specific antigens. We selected the chimeric LID-1 fusion protein, formulated to achieve maximum performance at a minimal dose, as a skin test candidate based on its ability to elicit delayed-type hypersensitivity (DTH) reactions in M. leprae immune guinea pigs in a sensitive and specific manner, i.e., with no cross-reactivity observed with other mycobacterial species. Importantly, evaluations in armadillos indicated that intradermal inoculation of formulated LID-1 could distinguish uninfected from M. leprae-infected animals manifesting with symptoms distinctly similar to the PB presentation of patients. Together, our data provide strong proof-of-concept for developing an antigen-specific skin test to detect low-level M. leprae infection. Such a test could, when applied with appropriate use of chemo- and/or immunoprophylaxis, be instrumental in altering the evolution of clinical disease and M. leprae transmission, thus furthering the objective of zero leprosy.

Recombinant polypeptide of Mycobacterium leprae as a potential tool for serological detection of leprosy

Current prevention methods for the transmission of Mycobacterium leprae, the causative agent of leprosy, are inadequate as suggested by the rate of new leprosy cases reported. Simple large-scale detection methods for M. leprae infection are crucial for early detection of leprosy and disease control. The present study investigates the production and seroreactivity of a recombinant polypeptide composed of various M. leprae protein epitopes. The structural and physicochemical parameters of this construction were assessed using in silico tools. Parameters like subcellular localization, presence of signal peptide, primary, secondary, and tertiary structures, and 3D model were ascertained using several bioinformatics tools. The resultant purified recombinant polypeptide, designated rMLP15, is composed of 15 peptides from six selected M. leprae proteins (ML1358, ML2055, ML0885, ML1811, ML1812, and ML1214) that induce T cell reactivity in leprosy patients from different hyperendemic regions. Using rMLP15 as the antigen, sera from 24 positive patients and 14 healthy controls were evaluated for reactivity via ELISA. ELISA-rMLP15 was able to diagnose 79.17% of leprosy patients with a specificity of 92.86%. rMLP15 was also able to detect the multibacillary and paucibacillary patients in the same proportions, a desirable addition in the leprosy diagnosis. These results summarily indicate the utility of the recombinant protein rMLP15 in the diagnosis of leprosy and the future development of a viable screening test.

Serological and molecular detection of infection with Mycobacterium leprae in Brazilian six banded armadillos (Euphractus sexcinctus)

Leprosy was recognized as a zoonotic disease, associated with nine-banded armadillos (Dasypus novemcinctus) in the Southern United States of America in 2011. In addition, there is growing evidence to support a role for armadillos in zoonotic leprosy in South America. The current study evaluated twenty specimens of the six-banded armadillo (Euphractus sexcinctus), collected from rural locations in the state of Rio Grande do Norte (RN), Brazil for evidence of infection with Mycobacterium leprae. Serum was examined using two "in-house" enzyme-linked immunosorbent assays (ELISAs) and via two commercially available (ML flow and NDO-LID®) immunochromatographic lateral flow (LF) tests, for detection of the PGL-I and/or LID-1 antigens of the bacterium. The presence of M. leprae DNA in liver tissue was examined using the multi-copy, M. leprae-specific repetitive element (RLEP), as target in conventional and nested PCR assays. Molecular and anti-PGL-I-ELISA data indicated that 20/20 (100 %) of the armadillos were infected with M. leprae. The corresponding detection levels recorded with the LF tests were 17/20 (85 %) and 16/20 (85 %), for the NDO-LID® and ML flow tests, respectively. Our results indicate that, in common with D. novemcinctus, six banded armadillos (a species hunted and reared as a food-source in some regions of Brazil, including RN), represent a potential reservoir of M. leprae and as such, their role in a possible zoonotic cycle of leprosy within Brazil warrants further investigation.

Policy Lessons From Quantitative Modeling of Leprosy

Recent mathematical and statistical modeling of leprosy incidence data provides estimates of the current undiagnosed population and projections of diagnosed cases, as well as ongoing transmission. Furthermore, modeling studies have been used to evaluate the effectiveness of proposed intervention strategies, such as postleprosy exposure prophylaxis and novel diagnostics, relative to current approaches. Such modeling studies have revealed both a slow decline of new cases and a substantial pool of undiagnosed infections. These findings highlight the need for active case detection, particularly targeting leprosy foci, as well as for continued research into innovative accurate, rapid, and cost-effective diagnostics. As leprosy incidence continues to decline, targeted active case detection primarily in foci and connected areas will likely become increasingly important.

PGL-1 and LID-1 antibody levels in HIV-infected and HIV-uninfected individuals in a Hansen's disease (leprosy) endemic area of Brazil

Serological tests for subclinical Mycobacterium leprae infection based on antibodies to phenolic glycolipid-1 (PGL-1) and leprosy IDRI diagnostic-1 (LID-1) have not been compared in HIV-infected and uninfected individuals. PGL-1 seropositivity by ELISA was 6.0 % (21/350) in HIV-infected compared with 29.1 % (102/350) in HIV-uninfected individuals (p < 0.001); LID-1 seropositivity was 45.4 % (159/350) in HIV-infected compared with 50.3 % (153/304) in HIV-uninfected individuals (p = 0.21). In HIV-infected individuals, LID-1 but not PGL-1 antibody levels were inversely associated with CD4+ cell count (p = 0.02). These differential associations of HIV infection and CD4 count with PGL-1 and LID-1 have implications for M leprae immunodiagnostic tools and require replication.

A novel integrated molecular and serological analysis method to predict new cases of leprosy amongst household contacts

Background

Early detection of Mycobacterium leprae is a key strategy for disrupting the transmission chain of leprosy and preventing the potential onset of physical disabilities. Clinical diagnosis is essential, but some of the presented symptoms may go unnoticed, even by specialists. In areas of greater endemicity, serological and molecular tests have been performed and analyzed separately for the follow-up of household contacts, who are at high risk of developing the disease. The accuracy of these tests is still debated, and it is necessary to make them more reliable, especially for the identification of cases of leprosy between contacts. We proposed an integrated analysis of molecular and serological methods using artificial intelligence by the random forest (RF) algorithm to better diagnose and predict new cases of leprosy.

Methods

The study was developed in Governador Valadares, Brazil, a hyperendemic region for leprosy. A longitudinal study was performed, including new cases diagnosed in 2011 and their respective household contacts, who were followed in 2011, 2012, and 2016. All contacts were diligently evaluated by clinicians from Reference Center for Endemic Diseases (CREDEN-PES) before being classified as asymptomatic. Samples of slit skin smears (SSS) from the earlobe of the patients and household contacts were collected for quantitative polymerase chain reaction (qPCR) of 16S rRNA, and peripheral blood samples were collected for ELISA assays to detect LID-1 and ND-O-LID.

Results

The statistical analysis of the tests revealed sensitivity for anti-LID-1 (63.2%), anti-ND-O-LID (57.9%), qPCR SSS (36.8%), and smear microscopy (30.2%). However, the use of RF allowed for an expressive increase in sensitivity in the diagnosis of multibacillary leprosy (90.5%) and especially paucibacillary leprosy (70.6%). It is important to report that the specificity was 92.5%.

Conclusion

The proposed model using RF allows for the diagnosis of leprosy with high sensitivity and specificity and the early identification of new cases among household contacts.

Leprosy is a chronic infectious disease caused by Mycobacterium leprae (M. leprae) that can infect cells in the skin and nerves. Despite efforts to eliminate leprosy, the number of M. leprae infected individuals who develop leprosy is still substantial in the world. The diagnosis relies mainly on clinical parameters. Histopathological and bacteriological analysis help to classify clinical forms of patients. Serology and polymerase chain reaction (PCR) assays are claimed by health professionals as auxiliary tools, but until now these tests have been used almost exclusively in research, with minor use in leprosy reference centers throughout Brazil. Here, we tested quantitative PCR (qPCR) designed to amplify specific M. leprae targets and ELISA assays to detect antibody response to recombinant antigens (LID-1, ND-O-LID). All results were analyzed by multivariate analysis based in artificial intelligence. We chose random forest as a classification algorithm to aid in the diagnosis and the monitoring of contacts. The results allowed us to diagnose cases of leprosy with high sensitivity and specificity and the early identification of new cases among household contacts.

Diagnostic accuracy of tests for leprosy: a systematic review and meta-analysis

OBJECTIVES

Owing to difficulties in the clinical diagnosis of leprosy, several complementary tests have been developed and used. The aim was to systematically summarize the accuracy of diagnostic tests for leprosy.

METHODS

We searched for relevant articles in Embase, Medline, and Global Health databases, until June 2017. Studies evaluating the accuracy of any diagnostic techniques for differentiating between people with and without leprosy were included. Studies solely focusing on differentiating between the separate forms of leprosy were excluded. Our protocol was registered on PROSPERO (CRD42017071803). We assessed study quality using the QUADAS-2 checklist. A bivariate random effects regression model was used for the meta-analyses.

RESULTS

We included 78 studies, most of those evaluating the detection of IgM antibodies against phenolic glycolipid I using ELISA. Sensitivity of the 39 studies evaluating ELISA was 63.8% (95% CI 55.0-71.8); specificity 91.0% (95% CI 86.9-93.9). The lateral flow test (nine studies) and the agglutination test (five studies) had a slightly higher sensitivity and a slightly lower specificity. Sensitivity of qPCR was (five studies) 78.5% (95% CI 61.9-89.2) and specificity 89.3% (95% CI 61.4-97.8). Sensitivity of conventional PCR was (17 studies) 75.3% (95% CI 67.9-81.5) and specificity 94.5% (95% CI 91.4-96.5).

CONCLUSIONS

Although the test accuracy looks reasonable, the studies suffered from heterogeneity and low methodological quality.

Accuracy of Enzyme-Linked Immunosorbent Assays (ELISAs) in Detecting Antibodies against Mycobacterium leprae in Leprosy Patients: A Systematic Review and Meta-Analysis

IgM against Mycobacterium leprae may be detected by enzyme-linked immunosorbent assays (ELISAs) based on phenolic glycolipid I (PGL-I) or natural disaccharide octyl bovine serum albumin (ND-O-BSA) as antigens, and the IgG response can be detected by an ELISA based on lipid droplet protein 1 (LID-1). The titers of antibodies against these antigens vary with operational classification. The aim of this study was to compare the accuracy of ELISAs involving PGL-I and ND-O-BSA with that involving LID-1. We included studies that analyze multibacillary and paucibacillary leprosy cases and evaluate the diagnostic accuracy of ELISAs based on LID-1 and/or PGL-I or ND-O-BSA as antigens to measure antibody titers against M. leprae. Studies were found via PubMed, the Virtual Health Library Regional Portal, Literatura Latino-Americana e do Caribe em Ciências da Saúde, Índice Bibliográfico Espanhol de Ciências de Saúde, the Brazilian Society of Dermatology, National Institute for Health and Clinical Excellence, Cochrane Library, Embase (the Elsevier database), and Cumulative Index to Nursing and Allied Health Literature. The Quality Assessment of Diagnostic Accuracy Studies served as a methodological validity tool. Quantitative data were extracted using the Standards for Reporting of Diagnostic Accuracy. Sensitivity, specificity, and a diagnostic odds ratio were calculated, and a hierarchical summary receiver-operating characteristic curve and forest plots were constructed. The protocol register code for this meta-analysis is PROSPERO 2017: CRD42017055983. Nineteen studies were included. ND-O-BSA showed better overall performance in terms of sensitivity, specificity, positive and negative likelihood ratios, and diagnostic odds ratio when compared with PGL-I and LID-1. The multibacillary group showed better performance on these parameters (than the paucibacillary group did), at 94%, 99%, 129, 0.05, and 2293, respectively. LID-1 did not provide any advantage regarding the overall estimate of sensitivity in comparison with PGL-I or ND-O-BSA.

Leprosy in children under 15 years of age in Brazil: A systematic review of the literature

Background

Leprosy is a chronic infectious disease neglected, caused by Mycobacterium leprae, considered a public health problem because may cause permanent physical disabilities and deformities, leading to severe limitations. This review presents an overview of the results of epidemiological studies on leprosy occurrence in childhood in Brazil, aiming to alert health planners and managers to the actual need to institute special control strategies.

Methodology/Principal findings

Data collection consisted of an electronic search for publications in eight databases: Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS), Scientific Electronic Library Online (SciELO), PuBMed, Biblioteca Virtual em Saúde (BVS), SciVerse Scopus (Scopus), CAPES theses database, CAPES journals database and Web of Science of papers published up to 2016. After apply selection criteria, twenty-two papers of studies conducted in four different regions of Brazil and published between 2001 and 2016 were included in the review. The leprosy detection rate ranged from 10.9 to 78.4 per 100,000 inhabitants. Despite affecting both sexes, leprosy was more common in boys and in 10-14-year-olds. Although the authors reported a high cure proportion (82–90%), between 1.7% and 5.5% of the individuals developed a disability resulting from the disease.

Conclusions/Significance

The findings of this review shows that leprosy situation in Brazilian children under 15 years is extremely adverse in that the leprosy detection rate remains high in the majority of studies. The proportion of cases involving disability is also high and reflects the difficulties and the poor effectiveness of actions aimed at controlling the disease. The authors suggest the development of studies in spatial clusters of leprosy, where beyond the routine actions established, are included news strategies of active search and campaigns and actions of educations inside the clusters of this disease. The new agenda needs to involve the precepts of ethical, humane and supportive care, in order to achieve a new level of leprosy control in Brazil.

Leprosy remains as a severe health problem in Brazil and its transmission in children under 15 years of age occurs mainly through intradomiciliary contacts. The number of leprosy cases in this age group is considered an important indicator for the surveillance of this disease. To understand how the epidemiological studies in Brazil have shown the situation of young people affected by leprosy, we performed a systematic review of the literature, searching for published articles about the situation of leprosy in this age group. We reviewed 22 studies published during 2001 to 2016 and concluded that the negative effects of leprosy still remain high in most of studied places in Brazil. This disease was more common in boys, aged between 10 to 14 years old, with a remarkable proportion of disabilities due to leprosy. These disabilities can limit their routine activities and reflect failure in the public medical care. We hope that our review should contribute to arguments in order to improve the control of this disease in children.

Evaluation of antigen-specific immune responses for leprosy diagnosis in a hyperendemic area in China

OBJECTIVE

To evaluate antigen-specific immune responses for leprosy diagnosis in a hyperendemic area in China.

METHODS

Eighty-three leprosy patients and 161 non-leprosy controls were enrolled from Hani-yi Autonomous Prefecture of Honghe, Yunnan Province, China. Leprosy patients were divided into multibacillary (MB, n = 38), paucibacillary (PB, n = 23), and post-multi-drug therapy (MDT, n = 22) groups. Controls were divided into the following groups: healthy household contacts (HHC, n = 119), tuberculosis (TB, n = 11), and endemic controls (EC, n = 31). The NDO-LID Rapid Test, M. leprae antigen-specific ELISA and antigen-specific IFN-γ secretion in a whole blood assay (WBA) were used to evaluate these subjects.

RESULTS

The NDO-LID Rapid Test achieved higher positive response rates in MB than in PB patients[94.7%(36/38) vs 65.2%(15/23)], and these rates were higher than those observed by ELISA using anti-LID-1[92.1%(35/38) vs 52.2%(12/23)], anti-NDO-LID[92.1%(35/38) vs 47.8% (11/23)], and anti-ND-O-BSA[89.5%(34/38) vs 60.9%(14/23)]. However, the NDO-LID Rapid Test also showed a higher positive response rate in the EC group (33.3%,10/31), which was higher than the rates observed for anti-NDO-LID (12.9%,4/31) and anti-ND-O-BSA (16.1%,5/31). M. leprae antigen-specific ELISA demonstrated relatively high specificity (86.84-97.37%) but low sensitivity (15.97-72.73%) in discriminating between leprosy patients and non-leprosy controls by ROC curve analysis. In contrast, M. leprae antigen-specific IFN-γ secretion detection achieved higher positive response rates in PB than in MB patients (positive ratio of MB vs PB: 40% vs 56% for LID-1, 28.6% vs 47.8% for ML89, 31.4% vs 60.7% for ML2044, and 31.4 vs 47.8% for ML2028) and could distinguish MB from EC when stimulated with ML89(AUC = 0.6664) and PB fromTB when stimulated with ML2044 and ML2028(AUC = 0.7549 and 0.7372, respectively).

CONCLUSION

The NDO-LID Rapid Test and M. leprae antigen-specific ELISA are useful tools to assist in the diagnosis of leprosy patients, especially MB patients, although the former had higher sensitivity but lower specificity than the latter. M. leprae antigen-specific IFN-γ release assessed by WBA has diagnostic value for distinguishing PB from TB but not for distinguishing PB from HHC or EC. Screening novel M. leprae-specific antigens, combining different M. leprae antigens and a multi-cytokine analyte model may be needed for more effective diagnosis of leprosy.

Monitoring and detection of leprosy patients in Southwest China: A retrospective study, 2010-2014

More than 100 counties, mainly in southwest China, report incidence rates of leprosy >1/100,000. The current study analysed the epidemiology of leprosy in southwest China to improve our understanding of the transmission pattern and improve control programs. 207 counties were selected in southwest China. Leprosy patients and their household contacts were recruited. The data from the medical interview and the serological antileprosy antibody of the leprosy patients were analysed. A total of 2,353 new cases of leprosy were interviewed. The distribution of leprosy patients was partly associated with local natural and economic conditions, especially several pocket areas. A total of 53 from 6643 household contacts developed leprosy, and the incidence rate of leprosy in the household contacts was 364/100,000 person-years. We found that NDO-BSA attained higher positive rates than MMP-II and LID-1 regardless of clinical types, disability and infection time in leprosy patients. By means of combination of antigens, 88.4% patients of multibacillary leprosy were detected, in contrast to 59.9% in paucibacillary leprosy. Household contacts should be given close attention for the early diagnosis, disruption of disease transmission and precise control. Applications of serology for multi-antigens were recommended for effective coverage and monitoring in leprosy control.

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

Background

The high rate of leprosy cases among children under 15 years of age in Brazil indicates ongoing transmission within the community. The identification of the new leprosy cases among contacts can help identify the source of infection and interrupt the transmission chain. This study aims to determine the detection rate of previously undiagnosed cases of leprosy among schoolchildren who are under 15 years of age living in Manaus, Amazonas, Brazil, and their possible source of infection by contact tracing.

Methodology/Principal findings

This was a school-based, cross-sectional study in which the identification of active leprosy cases was conducted in 277 out of 622 randomly selected public schools in Manaus, Amazonas, Brazil. Suspected cases of leprosy were referred to the Alfredo da Matta Foundation, a reference center for leprosy in Manaus. A total of 34,547 schoolchildren were examined, and 40 new leprosy cases were diagnosed. Among new cases, 57.5% were males, and 80.0% demonstrated paucibacillary leprosy. A total of 196 of 206 registered contacts were screened, and 52.5% of the newly diagnosed children’s cases had at least one positive household contact. In these contacts, grandparents (52.4%) were the most common co-prevalent cases, while 14.3% were uncles, 9.5% were parents and 9.5% were granduncles. Seven contacts (5.0%), including four siblings of child patients were newly diagnosed. Our data indicate that the prevalence is 11.58 per 10,000, which is 17 times higher than the registered rate.

Conclusions/Significance

This study suggests that the detection rate of leprosy among schoolchildren may have remained unchanged over the past thirty years. It also indicates that that active case finding is necessary for reaching the World Health Organization’s goals of zero detection among children, especially in endemic areas where the prevalence of leprosy is obscure. Moreover, we assert that all children must have their household contacts examined in order to identify the possible source of infection and interrupt the disease’s transmission. Novel strategies to reinforce contact tracing associated with large-scale strategies of chemo- and immune-prophylaxis should be expanded to prevent the perpetuation of the disease cycle.

Leprosy is a disease that has long since been eradicated in the developed world, but it still affects poor people in developing countries, such as India, Brazil, and Indonesia. Because the causative agent of the disease may involve the skin and peripheral nerves, the disease can cause physical disabilities and deformities. Although leprosy affects all ages, children under 15 years of age are an important epidemiological marker because infection in that age group indicates active transmission within the community. In our work, we examined 34,547 children from public schools in Manaus, a city in the north of Brazil. In this population, we found 40 new cases of leprosy that were further confirmed by clinical and laboratorial tests. We also examined 196 people who had familiar or close non-familiar contact with the affected children. Among them, we identified the possible source of infection of 21 affected children and found seven new cases of leprosy. Overall, our findings revealed a detection rate of leprosy cases that was 17 times higher than the registered number. This indicates the necessity of identifying active cases of leprosy in order to improve case detection and effectively control the disease.

Evidence of hidden leprosy in a supposedly low endemic area of Brazil

OBJECTIVES

Show that hidden endemic leprosy exists in a municipality of inner São Paulo state (Brazil) with active surveillance actions based on clinical and immunological evaluations.

METHODS

The study sample was composed by people randomly selected by a dermatologist during medical care in the public emergency department and by active surveillance carried out during two days at a mobile clinic. All subjects received a dermato-neurological examination and blood sampling to determine anti-PGL-I antibody titers by enzyme-linked immunosorbent assay (ELISA).

RESULTS

From July to December 2015, 24 new cases of leprosy were diagnosed; all were classified as multibacillary (MB) leprosy, one with severe Lucio's phenomenon. Seventeen (75%) were found with grade-1 or 2 disability at the moment of diagnosis. Anti-PGL-I titer was positive in 31/133 (23.3%) individuals, only 6/24 (25%) were positive in newly diagnosed leprosy cases.

CONCLUSIONS

During the last ten years before this study, the average new case detection rate (NCDR) in this town was 2.62/100,000 population. After our work, the NCDR was raised to 42.8/100,000. These results indicate a very high number of hidden leprosy cases in this supposedly low endemic area of Brazil.