[Leprosy epidemiology in a cohort of household contacts in Rio de Janeiro (1987-1991)]

The State of Affairs in Post-Exposure Leprosy Prevention: A Descriptive Meta-Analysis on Immuno- and Chemo-Prophylaxis

OBJECTIVE

Annually, over 200,000 people are diagnosed with leprosy, also called Hansen's disease. This number has been relatively stable over the past years. Progress has been made in the fields of chemoprophylaxis and immunoprophylaxis to prevent leprosy, with a primary focus on close contacts of patients. In this descriptive meta-analysis, we summarize the evidence and identify knowledge gaps regarding post-exposure prophylaxis against leprosy.

METHODS

A systematic literature search according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology was conducted by searching the medical scientific databases Cochrane, Embase, Pubmed/MEDLINE, Research Gate, Scopus and Web of Science on Jan. 22, 2020, using a combination of synonyms for index terms in four languages: "leprosy" and "population" or "contacts" and "prevention" or "prophylaxis." Subsequently, Infolep.org and Google Scholar were searched and the "snowball method" was used to retrieve other potentially relevant literature. The found articles were screened for eligibility using predetermined inclusion and exclusion criteria.

RESULTS

After deduplication, 1,515 articles were screened, and 125 articles were included in this descriptive meta-analysis. Immunoprophylaxis by bacillus Calmette-Guérin (BCG) vaccination is known to provide protection against leprosy. The protection it offers is higher in household contacts of leprosy patients compared with the general population and is seen to decline over time. Contact follow-up screening is important in the first period after BCG administration, as a substantial number of new leprosy patients presents three months post-vaccination. Evidence for the benefit of re-vaccination is conflicting. The World Health Organization (WHO) included BCG in its Guidelines for the Diagnosis, Treatment and Prevention of Leprosy by stating that BCG at birth should be maintained in at least all leprosy high-burden regions. Literature shows that several vaccination interventions with other immunoprophylactic agents demonstrate similar or slightly less efficacy in leprosy risk reduction compared with BCG. However, most of these studies do not exclusively focus on post-exposure prophylaxis. Two vaccines are considered future candidates for leprosy prophylaxis: Mycobacterium indicus pranii (MiP) and LepVax. For chemoprophylaxis, trials were performed with dapsone/acedapsone, rifampicin, and ROM, a combination of rifampicin, ofloxacin, and minocycline. Single-dose rifampicin is favored as post-exposure prophylaxis, abbreviated as SDR-PEP. It demonstrated a protective effect of 57% in the first two years after administration to contacts of leprosy patients. It is inexpensive, and adverse events are rare. The risk of SDR-PEP inducing rifampicin resistance is considered negligible, but continuous monitoring in accordance with WHO policies should be encouraged. The integration of contact screening and SDR-PEP administration into different leprosy control programs was found to be feasible and well accepted. Since 2018, SDR-PEP is included in the WHO Guidelines for the Diagnosis, Treatment and Prevention of Leprosy.

CONCLUSION

Progress has been made in the areas of chemoprophylaxis and immunoprophylaxis to prevent leprosy in contacts of patients. Investing in vaccine studies, like LepVax and MiP, and increasing harmonization between tuberculosis (TB) and leprosy research groups is important. SDR-PEP is promising as a chemoprophylactic agent, and further implementation should be promoted. More chemoprophylaxis research is needed on: enhanced medication regimens; interventions in varying (epidemiological) settings, including focal mass drug administration (fMDA); specific approaches per contact type; combinations with screening variations and field-friendly rapid tests, if available in the future; community and health staff education; ongoing antibiotic resistance surveillance; and administering chemoprophylaxis with SDR-PEP prior to BCG administration. Additionally, both leprosy prophylactic drug registration nationally and prophylactic drug availability globally at low or no cost are important for the implementation and further upscaling of preventive measures against leprosy, such as SDR-PEP and new vaccines.

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.

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.

Interruption of persistent exposure to leprosy combined or not with recent BCG vaccination enhances the response to Mycobacterium leprae specific antigens

Household contacts of multibacillary leprosy patients (HCMB) constitute the group of individuals at the highest risk of developing leprosy. Early diagnosis and treatment of their index cases combined with Bacille Calmette-Guerin (BCG) immunization remain important strategies adopted in Brazil to prevent HCMB from evolving into active disease. In the present study, we assessed the impact of these measures on the immune response to Mycobacterium leprae in HCMB. Peripheral blood mononuclear cells (PBMC) from HCMB (n = 16) were obtained at the beginning of leprosy index case treatment (T0). At this time point, contacts were vaccinated (n = 13) or not (n = 3) in accordance with their infancy history of BCG vaccination and PBMCs were recollected at least 6 months later (T1). As expected, a significant increase in memory CD4 and CD8 T cell frequencies responsive to M. leprae whole-cell sonicate was observed in most contacts. Of note, higher frequencies of CD4⁺ T cells that recognize M. leprae specific epitopes were also detected. Moreover, increased production of the inflammatory mediators IL1-β, IL-6, IL-17, TNF, IFN-γ, MIP1-β, and MCP-1 was found at T1. Interestingly, the increment in these parameters was observed even in those contacts that were not BCG vaccinated at T0. This result reinforces the hypothesis that the continuous exposure of HCMB to live M. leprae down regulates the specific cellular immune response against the pathogen. Moreover, our data suggest that BCG vaccination of HCMB induces activation of T cell clones, likely through “trained immunity”, that recognize M. leprae specific antigens not shared with BCG as an additional protective mechanism besides the expected boost in cell-mediated immunity by BCG homologues of M. leprae antigens.

Leprosy remains a global public health issue with an annual new case detection of approximately 200,000–250,000 patients. The current study targets leprosy patient contacts, who constitute the group of individuals at highest risk of developing the disease. Treatment of the index case (patient) and BCG vaccination of his/her contacts are among the measures known to decrease the risk of household leprosy contacts contracting the disease. In the present work, the impact of these two measures on the immune response of contacts to mycobacterial antigens was investigated, showing improvement in the cellular immune response to both specific and shared M. leprae antigens and an increase in secretion of proinflammatory mediators, which likely explains the protective effect of these measures against leprosy.

CHEMOPROPHYLAXIS TO CONTROL LEPROSY AND THE PERSPECTIVE OF ITS IMPLEMENTATION IN BRAZIL: A PRIMER FOR NON-EPIDEMIOLOGISTS

The occurrence of leprosy has decreased in the world but the perspective of its elimination has been questioned. A proposed control measure is the use of post-exposure chemoprophylaxis (PEP) among contacts, but there are still questions about its operational aspects. In this text we discuss the evidence available in literature, explain some concepts in epidemiology commonly used in the research on this topic, analyze the appropriateness of implementing PEP in the context of Brazil, and answer a set of key questions. We argue some points: (1) the number of contacts that need to receive PEP in order to prevent one additional case of disease is not easy to be generalized from the studies; (2) areas covered by the family health program are the priority settings where PEP could be implemented; (3) there is no need for a second dose; (4) risk for drug resistance seems to be very small; (5) the usefulness of a serological test to identify a higher risk group of individuals among contacts is questionable. Given that, we recommend that, if it is decided to start PEP in Brazil, it should start on a small scale and, as new evidence can be generated in terms of feasibility, sustainability and impact, it could move up a scale, or not, for a wider intervention.

Geographical heterogeneity in the analysis of factors associated with leprosy in an endemic area of Brazil: are we eliminating the disease?

Background

The leprosy transmission chain is very complex and, in order to intervene in this transmission, more must be known about the factors linked to falling ill. There are doubts as to the influence of population size, population density and the disease’s magnitude in detection rate trends. This paper aimed to identify factors associated with detection of leprosy in an endemic municipality of Rio de Janeiro State, Brazil.

Methods

This ecological study in Duque de Caxias municipality, Rio de Janeiro State, Brazil, used neighbourhoods (bairros) as the unit of analysis. Selecting new cases of leprosy detected from 1998 to 2006, the analysis examined clinical, socioeconomic and service variables using a Poisson log-Normal model.

Results

In the municipality overall, 2572 new cases were detected, a rate of 3.70 cases/10,000 inhabitants. The results describe a heterogeneous distribution of cases and rates in the municipality. The final model displayed a significant association with indeterminate clinical form (β = 2.599), proportion of homes with running water (β = -2.334) and presence of a decentralised health care unit (β = 0.524).

Conclusion

Although the results indicate progress towards elimination of the disease in the municipality, high rates continue to be detected in municipal sub-regions. The following question can thus be posed: over how wide a geographical area could the disease be thoroughly eliminated, given this heterogeneity within a small municipality?

Epidemiological situation of leprosy in Salvador from 2001 to 2009

Mycobacterium leprae was first described as the bacillus that causes leprosy, a chronic granulomatous infectious disease, in 1873 by Amauer Hansen. Leprosy is part of a group of 10 neglected diseases and Bahia has endemic levels of this illness, varying between high and very high. The detection of 52 new cases of leprosy in children under 15 years old in Salvador in 2006 is alarming, and suggests an early contact with the disease. The aim of this review is to analyze the epidemiological situation, the detection rate and evaluate the clinical and epidemiological profile of leprosy in Salvador, in the period 2001-2009. A retrospective cross-sectional study was performed using secondary data collected at Notifiable Diseases Information System Database (SINAN) through the notification of patients with leprosy. Over these nine years 3,226 patients were reported, with a predominance of: females (51.5%), and clinical multibacillary forms in the general population (51.7%), but when we analyze those under 15 years old, paucibacillary forms (tuberculoid + indeterminate) prevailed. The tuberculoid form was the most diagnosed type of presentation. The annual detection rate in Salvador remained at a very high level of endemicity during the studied period and for those under 15 years old it ranged between high and very high. Grade 2 disabilities both at the time of diagnosis and at discharge after cure, varied between low and medium. Based on these data we conclude that the high levels of leprosy detection rates in the general population, plus the variation between high and very high levels in those under 15 years old, associated with the medium level of grade 2 disabilities at the time of diagnosis and discharge, demonstrate the need for improvement on the existing services, investment in active case finding and training of the healthcare professionals in Salvador.

Leprosy exposure, infection and disease: a 25-year surveillance study of leprosy patient contacts

Contact surveillance is a valuable strategy for controlling leprosy. A dynamic cohort study of leprosy contacts was initiated in 1987 at Oswaldo Cruz Foundation. The objective of this work was to review the data on the major risk factors leading up to the infectious stage of the disease, estimate incidence rates of leprosy in the cohort and characterise the risk factors for the disease among the contacts under surveillance. The incidence rate of leprosy among contacts of leprosy patients was estimated at 0.01694 cases per person-year in the first five years of follow-up. The following factors were associated with acquiring the disease: (i) not receiving the BCG vaccine, (ii) a negative Mitsuda reaction and (iii) contact with a patient with a multibacillary clinical form of leprosy. The contacts of index patients who had high bacilloscopic index scores > 1 were at especially high risk of infection. The following factors were associated with infection, which was defined as a seropositive reaction for anti-phenolic glicolipid-1 IgM: (i) young age (< 20 years), (ii) a low measured Mitsuda reaction (< 5 mm) and (iii) contact with an index patient who had a high bacilloscopic index. BCG vaccination and re-vaccination were shown to be protective among household contacts. The main conclusions of this study indicate an urgent need for additional leprosy control strategies in areas with a high incidence of the disease.

Impact of PGL-I seropositivity on the protective effect of BCG vaccination among leprosy contacts: a cohort study

Background

Contacts of leprosy patients are at increased risk of developing leprosy and need to be targeted for early diagnosis. Seropositivity to the phenolic glycolipid I (PGL-I) antigen of Mycobacterium leprae has been used to identify contacts who have an increased risk of developing leprosy. In the present study, we studied the effect of seropositivity in patient contacts, on the risk of developing leprosy, stratified by Bacille Calmette Guerin (BCG) vaccination after index case diagnosis.

Methodology/Principal Findings

Leprosy contacts were examined as part of the surveillance programme of the Oswaldo Cruz Institute Leprosy Outpatient Clinic in Rio de Janeiro. Demographic, social, epidemiological and clinical data were collected. The presence of IgM antibodies to PGL-I in sera and BCG vaccination status at the time of index case diagnosis were evaluated in 2,135 contacts. During follow-up, 60 (2.8%; 60/2,135) leprosy cases were diagnosed: 41 among the 1,793 PGL-I-negative contacts and 19 among the 342 PGL-I-positive contacts. Among PGL-I-positive contacts, BCG vaccination after index case diagnosis increased the adjusted rate of developing clinical manifestations of leprosy (Adjusted Rate Ratio (aRR) = 4.1; 95% CI: 1.8–8.2) compared with the PGL-I-positive unvaccinated contacts (aRR = 3.2; 95% CI: 1.2–8.1). The incidence density was highest during the first year of follow-up for the PGL-I-positive vaccinated contacts. However, all of those contacts developed PB leprosy, whereas most MB cases (4/6) occurred in PGL-I-positive unvaccinated contacts.

Conclusion

Contact examination combined with PGL-I testing and BCG vaccination remain important strategies for leprosy control. The finding that rates of leprosy cases were highest among seropositive contacts justifies targeting this specific group for close monitoring. Furthermore, it is recommended that PGL-I-positive contacts and contacts with a high familial bacteriological index, regardless of serological response, should be monitored. This group could be considered as a target for chemoprophylaxis.

Although leprosy has become a neglected disease, it is an important cause of disability, and 250,000 new cases are still diagnosed worldwide every year. The current study was carried out in Brazil, where almost 40,000 new cases of leprosy are diagnosed every year. The study targeted contacts of leprosy patients, who are at the highest risk of contracting the disease. We studied 2,135 contacts who were diagnosed at the Leprosy Outpatient Clinic at the Oswaldo Cruz Foundation in Rio de Janeiro, RJ, Brazil, between 1987 and 2007. The presence of antibodies against a specific Mycobacterium leprae antigen (PGL-I) at the first examination and BCG vaccination status were evaluated. PGL-I-positive contacts had a higher risk of developing leprosy than PGL-I-negative contacts. Among the former, vaccinated contacts were at higher risk than unvaccinated contacts. Our results indicate that contact examination combined with PGL-I testing and BCG vaccination appears to justify the targeting of PGL-I-positive individuals for enhanced surveillance. Furthermore, it is highly recommended that PGL-I-positive contacts and contacts with a high familial bacterial index (i.e., the sum of results from index and co-prevalent cases), regardless of serological response, should be monitored. This group could be considered as a target for chemoprophylaxis.

Assessment of integration of the leprosy program into primary health care in Aracaju, state of Sergipe, Brazil

INTRODUCTION

The aim of this study was to assess the epidemiological and operational characteristics of the Leprosy Program before and after its integration into the Primary healthcare Services of the municipality of Aracaju-Sergipe, Brazil.

METHODS

Data were drawn from the national database. The study periods were divided into preintegration (1996-2000) and postintegration (2001-2007). Annual rates of epidemiological detection were calculated. Frequency data on clinico-epidemiological variables of cases detected and treated for the two periods were compared using the Chi-squared (χ²) test adopting a 5% level of significance.

RESULTS

Rates of detection overall, and in subjects younger than 15 years, were greater for the postintegration period and were higher than rates recorded for Brazil as a whole during the same periods. A total of 780 and 1,469 cases were registered during the preintegration and postintegration periods, respectively. Observations for the postintegration period were as follows: I) a higher proportion of cases with disability grade assessed at diagnosis, with increase of 60.9% to 78.8% (p < 0.001), and at end of treatment, from 41.4% to 44.4% (p < 0.023); II) an increase in proportion of cases detected by contact examination, from 2.1% to 4.1% (p < 0.001); and III) a lower level of treatment default with a decrease from 5.64 to 3.35 (p < 0.008). Only 34% of cases registered from 2001 to 2007 were examined.

CONCLUSIONS

The shift observed in rates of detection overall, and in subjects younger than 15 years, during the postintegration period indicate an increased level of health care access. The fall in number of patients abandoning treatment indicates greater adherence to treatment. However, previous shortcomings in key actions, pivotal to attaining the outcomes and impact envisaged for the program, persisted in the postintegration period.

Pathogen-specific epitopes as epidemiological tools for defining the magnitude of Mycobacterium leprae transmission in areas endemic for leprosy

During recent years, comparative genomic analysis has allowed the identification of Mycobacterium leprae-specific genes with potential application for the diagnosis of leprosy. In a previous study, 58 synthetic peptides derived from these sequences were tested for their ability to induce production of IFN-γ in PBMC from endemic controls (EC) with unknown exposure to M. leprae, household contacts of leprosy patients and patients, indicating the potential of these synthetic peptides for the diagnosis of sub- or preclinical forms of leprosy. In the present study, the patterns of IFN-γ release of the individuals exposed or non-exposed to M. leprae were compared using an Artificial Neural Network algorithm, and the most promising M. leprae peptides for the identification of exposed people were selected. This subset of M. leprae-specific peptides allowed the differentiation of groups of individuals from sites hyperendemic for leprosy versus those from areas with lower level detection rates. A progressive reduction in the IFN-γ levels in response to the peptides was seen when contacts of multibacillary (MB) patients were compared to other less exposed groups, suggesting a down modulation of IFN-γ production with an increase in bacillary load or exposure to M. leprae. The data generated indicate that an IFN-γ assay based on these peptides applied individually or as a pool can be used as a new tool for predicting the magnitude of M. leprae transmission in a given population.

Leprosy among patient contacts: a multilevel study of risk factors

BACKGROUND

This study aimed to evaluate the risk factors associated with developing leprosy among the contacts of newly-diagnosed leprosy patients.

METHODOLOGY/PRINCIPAL FINDINGS

A total of 6,158 contacts and 1,201 leprosy patients of the cohort who were diagnosed and treated at the Leprosy Laboratory of Fiocruz from 1987 to 2007 were included. The contact variables analyzed were sex; age; educational and income levels; blood relationship, if any, to the index case; household or non-household relationship; length of time of close association with the index case; receipt of bacillus Calmette-Guérin (BGG) vaccine and presence of BCG scar. Index cases variables included sex, age, educational level, family size, bacillary load, and disability grade. Multilevel logistic regression with random intercept was applied. Among the co-prevalent cases, the leprosy-related variables that remained associated with leprosy included type of household contact, [odds ratio (OR) = 1.33, 95% confidence interval (CI): 1.02, 1.73] and consanguinity with the index case, (OR = 1.89, 95% CI: 1.42-2.51). With respect to the index case variables, the factors associated with leprosy among contacts included up to 4 years of schooling and 4 to 10 years of schooling (OR = 2.72, 95% CI: 1.54-4.79 and 2.40, 95% CI: 1.30-4.42, respectively) and bacillary load, which increased the chance of leprosy among multibacillary contacts for those with a bacillary index of one to three and greater than three (OR = 1.79, 95% CI: 1.19-2.17 and OR: 4.07-95% CI: 2.73, 6.09), respectively. Among incident cases, household exposure was associated with leprosy (OR = 1.96, 95% CI: 1.29-2.98), compared with non-household exposure. Among the index case risk factors, an elevated bacillary load was the only variable associated with leprosy in the contacts.

CONCLUSIONS/SIGNIFICANCE

Biological and social factors appear to be associated with leprosy among co-prevalent cases, whereas the factors related to the infectious load and proximity with the index case were associated with leprosy that appeared in the incident cases during follow-up.

Multiplex PCR technique could be an alternative approach for early detection of leprosy among close contacts--a pilot study from India

Background

Implementation of Multi drug Therapy (MDT) regimen has resulted in the decline of the total number of leprosy cases in the world. Though the prevalence rate has been declining, the incidence rate remains more or less constant and high in South East Asian countries particularly in India, Nepal, Bangladesh, Pakistan and Srilanka. Leprosy, particularly that of multibacillary type spreads silently before it is clinically detected. An early detection and treatment would help to prevent transmission in the community. Multiplex PCR (M-PCR) technique appears to be promising towards early detection among contacts of leprosy cases.

Methods

A total of 234 paucibacillary (PB) and 205 multibacillary (MB) leprosy cases were studied in a community of an endemic area of Bankura district of West Bengal (Eastern India). They were assessed by smear examination for acid-fast bacilli (AFB) and M-PCR technique. These patients were treated with Multidrug Therapy (MDT) as prescribed by WHO following detection. A total of 110 MB and 72 PB contacts were studied by performing M-PCR in their nasal swab samples.

Results

83.4% of MB patients were observed to be positive by smear examination for AFB and 89.2% by M-PCR. While 22.2% of PB patients were found to be positive by smear examination for AFB, 80.3% of these patients were positive by M-PCR. Among leprosy contacts (using M-PCR), 10.9% were found to be positive among MB contacts and 1.3% among PB contacts. Interestingly, two contacts of M-PCR positive MB cases developed leprosy during the period of two years follow up.

Conclusion

The M-PCR technique appears to be an efficient tool for early detection of leprosy cases in community based contact tracing amongst close associates of PB and MB cases. Early contact tracing using a molecular biology tool can be of great help in curbing the incidence of leprosy further.

Estudo epidemiológico de 107 focos familiares de hanseníase no município de Duque de Caxias - Rio de Janeiro, Brasil

FUNDAMENTOS - Os pacientes multibacilares (MB) são a principal fonte de infecção na hanseníase e esse risco é maior nos contatos domiciliares dos pacientes MB do que nos contatos dos paucibacilares (PB) e na população em geral. Entretanto, os contatos domiciliares são os mais próximos do caso-índice (CI), em termos genéticos. OBJETIVO: Analisar dados epidemiológicos das variáveis: sexo, idade, anos de estudo, grau de parentesco com o CI e tipo de contato residencial (intradomiciliar ou peridomiciliar) com o CI em 107 famílias de hanseníase. MÉTODOS: Foram realizadas visitas domiciliares para exame clínico dos familiares. Os prontuários dos CIs e de seus coprevalentes (contatos familiares que também tiveram hanseníase) foram revistos. RESULTADOS: A análise controlada das variáveis tipo de contato e grau de parentesco revelou que o contato domiciliar e o parentesco de primeiro grau estão independentemente associados a uma probabilidade maior de adoecer. CONCLUSÃO: Os contatos domiciliares, em geral, são os mais próximos do caso, em termos genéticos, e aferir a magnitude desses riscos separadamente tem sido um desafio nos estudos de vigilância de contatos em hanseníase. Os resultados deste estudo confirmam os dados da literatura, demonstrando a influência genética no desfecho da hanseníase per se.

BCG vaccination and leprosy protection: review of current evidence and status of BCG in leprosy control

The bacillus Calmette-Guérin (BCG) vaccine, initially developed to provide protection against TB, also protects against leprosy; and the magnitude of this effect varies. Previous meta-analyses did not provide a summary estimate of the efficacy due to the heterogeneity of the results. We conducted a meta-analysis of published data including recently published studies (up to June 2009) to determine the efficacy of BCG protection on leprosy and to investigate whether age at vaccination, clinical form, number of doses, type of study, the latitude of study area and year of publication influence the degree of efficacy and explain the variation. In the light of the results, we argue for more emphasis on the role of BCG vaccination in leprosy control and research.

[Leprosy in Espírito Santo State, Brazil: a growing endemic?]

This study provides a trend analysis of leprosy among patients in the State of Espírito Santo, Brazil, from 1980 to 2003. Using temporal series statistical models, an upward trend was identified throughout the period in the overall detection rate (p<0.05), with an apparent stabilization at the end of the period. We also observed an upward trend for the following periods: (i) 1980-1987 in the <15 and >or=50-year age groups and for paucibacillary forms; (ii) 1988-1995 for the 15-19, 20-29, and >or=50-year groups and for multibacillary forms; and (iii) 1996-2003 in the 20-29-year group and paucibacillary forms. The indicators for evaluation of the endemic indicate: stable levels in grade 2 disability (mean of 6%); a proportion of less than 10% of cases in individuals<15 years of age; and a treatment dropout rate of approximately 6%. Prevalence showed a sharp decline. The upward trend can be explained partially by greater surveillance sensitivity, but the high proportion of individuals<15 highlights the need for studies aimed at better knowledge of residual sources of infection, especially in the household.

[Detection of Mycobacterium leprae DNA in nasal swab]

Studies have demonstrated high sensibility of the polimerase chain reaction (PCR) technique in the identification of the Mycobacterium leprae DNA . This study aimed to evalue the PCR sensibility at the detection of the M. leprae DNA in nasal swab of leprosy patients and to compare the results with the bacilloscopy and multibacillary (MBs) and paucibacilares (PBs) forms. Nasal secretion samples of 24 leprosy patients were collected, and were preserved in one and two lise's solution. The PCR results were highly significant (p <0.0000) and they revealed grater sensibility than bacilloscopy, in several clinical forms. Nevertheless, still different studies are necessary, testing new markers and preservatives, with the purpose of lifting up the sensibility of this technique, in nasal secretion samples.

Hanseníase em populações indígenas do Amazonas, Brasil: um estudo epidemiológico nos municípios de Autazes, Eirunepé e São Gabriel da Cachoeira (2000 a 2005)

O Estado do Amazonas, Brasil, apresentou, em 2005, coeficientes hiperendêmicos de detecção de hanseníase e prevalência de média endemicidade. O estado detém a maior população indígena no país, mas inexistem informações sobre o perfil da hanseníase nesses grupos. O estudo objetivou a descrição e análise das características epidemiológicas das notificações de hanseníase nos municípios de Autazes, Eirunepé e São Gabriel da Cachoeira, comparando achados entre indígenas e não indígenas, segundo variáveis de interesse. Foram analisados os casos notificados no SINAN, no período de 2000 a 2005. Do total de 386 casos notificados, verificaram-se coeficientes médios de detecção de 3,55, 14,94 e 2,13/10 mil (entre os não indígenas) e de 10,95, 1,93 e 0,78/10 mil (para os indígenas), para Autazes, Eirunepé e São Gabriel da Cachoeira, respectivamente. Houve predomínio de casos paucibacilares em indígenas e em não indígenas, no entanto, a forma dimorfa representou 1/3 das notificações. Apesar das limitações de cobertura e do sub-registro, os achados sugerem que a hanseníase representa importante problema de saúde pública para os indígenas no Amazonas. A classificação segundo "raça/etnicidade" se constituiu em ferramenta útil para elucidar desigualdades em saúde.

[Leprosy: control of household contacts in the municipality of Londrina-PR for a ten-year period]

The purpose of this descriptive study is to analyze variables related to leprosy patients' household contacts who received treatment in Londrina-PR-Brazil for a ten-year period. The data analysis was based on the health service's records and from a system of infectious disease. Out of 1055 leprosy's patients, it was recorded 3394 contacts with an average of 3,2. The most exposed individuals were those aged up to 40 (71,5%); son/daughter (40.6%) and husband/wife (17.8%). Of the1731 contacts (51.0%) examined, 183 showed some signs of the disease: there were 16 confirmed cases, 47 were excluded and 120 did not finish the clinical investigation. Most of the contacts (51.6%) were exposed to the multibacillary forms and 12.8% proved they were vaccinated with two doses of BCG. It is possible to conclude that the follow-up of the contacts was not adequate.

Hanseníase no município de Fortaleza, CE, Brasil: aspectos epidemiológicos e operacionais em menores de 15 anos (1995-2006)

Estudo transversal que objetiva analisar a ocorrência de casos de hanseníase em menores de 15 anos de idade residentes no Município de Fortaleza e notificados no SINAN. Os indicadores epidemiológicos nesta população mostram hiperendemicidade. Operacionalmente observa-se a manutenção da concentração de atendimento em algumas unidades de referência, apesar de alguns avanços. Diagnóstico tardio, elevado grau de incapacidade no diagnóstico e baixo grau de avaliação de contatos registrados revelam a fragilidade das ações de controle. Ressalta-se a possibilidade de erro diagnóstico frente às características da infecção nesta população. A ocorrência de casos de hanseníase nesta população representa um indicador epidemiológico de grande relevância e sua análise amplia a discussão sobre problemas operacionais na rede de serviços de saúde.

Avaliação e controle de contatos faltosos de doentes com hanseníase

Estudo descritivo, com variáveis qualitativas, realizado no Ambulatório Regional de Especialidades de Taubaté, com objetivo de resgatar e avaliar contatos faltosos de doentes de hanseníase. Analisou-se 36 prontuários de casos novos, no período de janeiro de 2003 a julho de 2004. Identificou-se 92 contatos, sendo 64,1% faltosos, tendo 25% entre 20 a 29 anos e 58,5% do sexo feminino. Destes, 61% foram submetidos à consulta de enfermagem no domicilio. Relataram não adesão ao controle por esquecimento (66,6%), e falta de tempo (11,1%); 4 contatos tinham sintomas de hanseníase, e 1 foi confirmado (forma transmissível - Dimorfa). Sem atingir 100% da cobertura de busca ativa, sugerimos, para assegurar a meta de eliminação da doença, parcerias e descentralização das ações de controle.

[The impact of leprosy elimination strategy on an endemic municipality in Rio de Janeiro State, Brazil]

Various strategies for eliminating leprosy as a public health problem have evolved in the last 20 years. In some countries, especially highly endemic ones, the WHO target rate for leprosy elimination fell far short. The current study aimed to analyze the impact of different strategies for reducing leprosy prevalence in Duque de Caxias, a highly endemic municipality in Rio de Janeiro State, Brazil. The study observed the evolution of traditional operational indicators for the disease and their trends in the last 14 years. The indicators were calculated using the National Communicable Diseases Database (SINAN). Strategies that focused on decentralization of patient care and/or localized campaigns were associated with earlier case detection, reduction in prevalence, and shorter patient time in the active registry. An increase in the annual detection rate could be related to the existence of hidden prevalence or individuals with asymptomatic infection. New complementary strategies are needed to eliminate the disease in Duque de Caxias.

Single lesion as an indicator to monitor the leprosy trend to elimination in hyperendemic areas

INTRODUCTION: Prevalence and detection rates of leprosy are not sufficient to show the real magnitude of changes in epidemiological patterns. OBJECTIVES: Evaluate the feasibility and usefulness of the proportion of new leprosy patients with a single skin lesion (SSL) as a potential indicator of the elimination of leprosy. METHODS: We conducted a retrospective study based on secondary data analyzing newly reported cases of leprosy between 1997 and 2002, in the city of Palmas, Tocantins, Brazil. Patients with a single lesion were compared to remaining patients, and the odds ratio was used as measure of association. RESULTS: Out of the 1,303 new cases of leprosy, 481 (36.9%) had a SSL. An increasing time-trend was observed in the proportion of new cases detected with a single lesion, which grew from 20.3% in 1999 to 49.1% in 2002 (linear trend p<.001) while a reduction in the number of new cases was observed simultaneously after 1999. The proportion of patients with a single lesion was higher in women, young age, paucibacillary, tuberculoid and indeterminate clinical forms, residents of urban areas, those with negative baciloscopy, with macular lesions, without physical disabilities, and mainly detected in primary health care units. CONCLUSIONS: These findings confirm that the proportion of patients with a SSL can be used as a sensitive and feasible indicator to assess the progress of the elimination of leprosy in hyperendemic areas.

Estudo de 20 focos familiares de hanseníase no município de Duque de Caxias, Rio de Janeiro

FUNDAMENTOS: O conhecimento da transmissão da hanseníase ainda apresenta lacunas devido ao longo período de incubação e ao fato de poucas pessoas expostas adoecerem. Além da exposição ao M. leprae, a susceptibilidade genética é um importante fator de risco para o adoecimento. OBJETIVO: Caracterizar a transmissão da hanseníase em focos familiares de área endêmica urbana no segundo distrito de Duque de Caxias, Rio de Janeiro, RJ. MÉTODOS: Estudo de 20 famílias, a partir de 20 casos índices (CI), diagnosticados no segundo distrito de Duque de Caxias que apresentaram mais de um caso de hanseníase (co-prevalência), com intervalo de até 10 anos entre os diagnósticos. Foi realizado inquérito domiciliar com preenchimento de questionário estruturado e exame dermatoneurológico. RESULTADOS: Houve predominância da consangüinidade entre os que adoeceram (69/75). A possibilidade de adoecer entre os consangüíneos foi 2,8 vezes maior do que a verificada entre os não consangüíneos. Apenas três cônjuges foram acometidos entre os seis doentes não consangüíneos contra 14 filhos. Em duas famílias os casos foram restritos a uma única geração, em cinco houve acometimento de três gerações, e em 13, de duas gerações. CONCLUSÃO: Embora existam outros fatores de risco envolvidos na transmissão da doença (ambientais, sociais, epidemiológicos), não abordados neste estudo, a consangüinidade mostra associação estatística positiva e reforça a importância da vigilância do núcleo familiar, intra e extradomiciliar, considerando as diferentes situações de convivência. São apresentados aqui dados preliminares do estudo de 70 famílias. A inclusão de um maior número de famílias e o estudo do polimorfismo genético deverá aproximar os estudiosos da complexidade desse tema.

Abandono do tratamento da tuberculose pulmonar em Cuiabá - MT - Brasil

OBJETIVO: Analisar os fatores preditivos de abandono do tratamento da tuberculose pulmonar. MÉTODOS: Estudo de coorte histórica a partir da análise de 481 pacientes bacilíferos, de um total de 529 casos inscritos no Programa de Controle de Tuberculose de Cuiabá (MT), de 1998 a 2000. Os dados foram obtidos do livro de registro do programa e dos prontuários médicos. Para o cálculo das taxas de incidência utilizou-se o método de densidade de incidência. Na análise bivariada utilizou-se o teste do qui-quadrado para razões de taxas de abandono (risco relativo) - Cornfield, ou o exato de Fisher. Foi construído um modelo de regressão logística multivariada visando a identificar as variáveis mais relevantes como preditoras da variável resposta (p < 0,05). RESULTADOS: A incidência global de abandono foi de 27,3%, equivalente a 5,1 abandonos por 100 pessoas/mês, com maior freqüência entre o segundo e o terceiro meses de tratamento. No modelo final, pela regressão logística, foram considerados preditores para o abandono: tratamento não supervisionado (razão de chance: 2,58; intervalo de confiança 95%: 1,64 - 4,06; p < 0,001), ter realizado tratamento em 1998 e 1999 (razão de chance:1,43; intervalo de confiança 95%:1,14 - 1,80; p = 0,002), ser do sexo masculino (razão de chance:1,39; intervalo de confiança 95%:1,10 - 1,76; p = 0,005) e ter abandonado previamente tratamentos anteriores (razão de chance: 1,37; intervalo de confiança 95%:1,06 - 1,78; p = 0,017). CONCLUSÃO: Os resultados indicam elevada incidência de abandono, sendo considerados preditores: tratamento não supervisionado, ano de tratamento, sexo masculino e abandono prévio.

[Assessment of a leprosy control program in a hyperendemic county in the State of Maranhão, Brazil, 1991-1995]

This is a descriptive study to assess the leprosy control program in the municipality of Buriticupu in Maranhão State, Brazil. The records of 214 patients with different forms of leprosy were studied. Patients were treated at a health center of the Federal University in Maranhão located in the above-mentioned municipality. The study population was comprised of 110 cases with paucibacillary leprosy (PB) and 104 with multibacillary leprosy (MB). The patients were registered between January 1991 and December 1995. Data on the form of the disease, number of contacts registered, examined, and assessed, degree of disability at the beginning and end of treatment, and the register's status were collected on a form designed specifically for this purpose. Analysis of results was based on operational guidelines developed by the Ministry of Health. There was a slight predominance of the PB form. Observation of patients with physical disabilities at the beginning and end of treatment was low, as were levels of successful treatment and examined contacts. There was a high dropout level. The program was considered "low-level performance" for all indicators used in the study.

Endemias e epidemias brasileiras, desafios e perspectivas de investigação científica: hanseníase

A endemia hansênica apresenta-se, na virada do milênio, no limiar da sua eliminação como problema global de saúde pública. O Brasil é o único país da América Latina onde a doença não foi eliminada, tendo sido a meta de eliminação postergada para 2005. Neste artigo discute-se o declínio da prevalência após a introdução da poliquimioterapia (PQT) para o tratamento da hanseníase, não acompanhada pela redução da incidência no mesmo período. Os progressos na área de imunologia, biologia molecular e seqüenciamento genômico do M. leprae são apresentados enquanto perspectivas de pesquisa e de aplicação potencial para diagnóstico, prognóstico e vigilância na hanseníase. Apesar do êxito das atuais estratégias de controle tem-se observado com preocupação a redução do interesse e do apoio financeiro em pesquisa na hanseníase e na desestruturação dos serviços de saúde frente ao atual cenário de eliminação. A exclusão da hanseníase da lista de doenças prioritárias é prematura, representando um perigo concreto de não se eliminar a doença, mas a pesquisa em hanseníase. Fica evidente a necessidade de investir na produção de conhecimentos de áreas básica e aplicada que viabilizem uma maior compreensão dos mecanismos de transmissão da infecção, da efetividade dos métodos de prevenção e controle, serão essenciais na "erradicação" da infecção pelo M. leprae.

[Empirical bayesian model applied to the spatial analysis of leprosy occurrence]

OBJECTIVE

To analyze the spatial distribution of leprosy, identify areas of potential case underreporting or high transmission risk, and to assess the ecological association of leprosy distribution with multibacillary cases.

METHODS

This study was carried out in 94 neighborhoods of Recife, Brazil. Data was obtained from the Ministry of Health's Disease Reporting System. An ecological approach with the empirical Bayesian method was applied for local rate flattening, using data from a neighborhood matrix.

RESULTS

The mean annual occurrence was 17.3% of new cases in individuals under the age of 15 (28.3% corresponded to multibacillary forms), revealing an intense disease transmission. The spatial distribution of leprosy indicated three areas where there was a concentration of high detection rates and low-income neighborhoods.

CONCLUSIONS

The Bayesian method allowed to reassess epidemiological indicators based on data from neighboring spatial units. This enabled to identify areas that should be prioritized in municipal control programs, either because of underreporting of cases or the higher number of occurrences related to multibacillary forms in individuals under 15.

Immunological cytokine correlates of protective immunity and pathogenesis in leprosy

The in vitro production of interferon (IFN)-gamma, interleukin (IL)-5, tumour necrosis factor (TNF)-alpha and IL-10 by blood mononuclear cells in response to whole Mycobacterium leprae and polyclonal stimulii of 23 individuals, representing a variety of conditions in relation to exposure/susceptibility to M. leprae, was assayed. In most cases, healthy household contacts of newly diagnosed multibacillary leprosy patients, designated exposed household contacts (EC), showed low-to-undetectable in vitro IFN-gamma production in addition to substantial TNF-alpha production in response to M. leprae. In contrast, peripheral blood mononuclear cells from previously exposed contacts (R) regarded as resistant-to-leprosy released low-to-moderate levels of IFN-gamma together with a mixed cytokine profile resembling a T helper (Th)0-type response. TNF-alpha/IL-10 ratios in response to M. leprae and Concanavalin A were significantly higher in EC than in R contacts suggesting a role for the TNF-alpha/IL-10 ratio in restraining mycobacteria proliferation and spreading early in infection. The cytokine profiles of leprosy patients were taken as reference points. Post-treatment lepromatous leprosy patients secreted relatively high levels of IL-10 in response to M. leprae, whereas one self-cured tuberculoid leprosy patient produced simultaneously high levels of IFN-gamma and TNF-alpha. In addition, the quantitative changes in the cytokines released by peripheral blood mononuclear cells in EC contacts after Bacille Calmette-Guérin (BCG) vaccination were investigated. Vaccination induced amplification of IFN-gamma production with a concomitant decrease in TNF-alpha/IL-10 ratios that resembled the cytokine pattern observed in R contacts. IFN-gamma production was observed in response to both a cross-reactive antigen (Ag 85) and a M. leprae-specific protein (MMP-I), which attests to a BCG nonspecific stimulation of the immune system, thereby casting these antigens as likely candidates for inclusion in a subunit vaccine against leprosy. Finally, a model for protective x pathologic response to mycobacteria is presented.