The geographical distribution and socioeconomic risk factors of COVID-19, tuberculosis and leprosy in Fortaleza, Brazil.

BACKGROUND: Fortaleza (Brazil) is high endemic for coronavirus disease 2019 (COVID-19), tuberculosis (TB) and leprosy. These three diseases share respiratory droplets through coughing or sneezing as the main mode of transmission but differ in incubation time, with COVID-19 having a short and leprosy a long incubation time. Consequently, contacts of a patient are at higher risk of infection and developing these diseases. There might be scope for combined preventive measures, but a better understanding of the geographical distribution and relevant socioeconomic risk factors of the three diseases is needed first. This study aims to describe the geographic distribution of COVID-19, TB and leprosy incidence and to identify common socioeconomic risk factors. METHODS: The total number of new cases of COVID-19, TB and leprosy, as well as socioeconomic and demographic variables, were retrieved from official registers. The geographical distribution of COVID-19, TB and leprosy rates per neighbourhood was visualised in Quantum GIS, and spatial autocorrelation was measured with Moran's I in GeoDa. A spatial regression model was applied to understand the association between COVID-19, TB, leprosy rates, and socioeconomic factors. RESULTS: COVID-19 and TB showed a more homogenous distribution, whereas leprosy is located more in the south and west of Fortaleza. One neighbourhood (Pedras) in the southeast was identified as high endemic for all three diseases. Literacy was a socioeconomic risk factor for all three diseases: a high literacy rate increases the risk of COVID-19, and a low literacy rate (i.e., illiteracy) increases the risk of TB and leprosy. In addition, high income was associated with COVID-19, while low income with TB. CONCLUSIONS: Despite the similar mode of transmission, COVID-19, TB and leprosy show a different distribution of cases in Fortaleza. In addition, associated risk factors are related to wealth in COVID-19 and to poverty in TB and leprosy. These findings may support policymakers in developing (partially combined) primary and secondary prevention considering the efficient use of resources.

Determining target populations for leprosy prophylactic interventions: a hotspot analysis in Indonesia.

BACKGROUND: Leprosy incidence remained at around 200,000 new cases globally for the last decade. Current strategies to reduce the number of new patients include early detection and providing post-exposure prophylaxis (PEP) to at-risk populations. Because leprosy is distributed unevenly, it is crucial to identify high-risk clusters of leprosy cases for targeting interventions. Geographic Information Systems (GIS) methodology can be used to optimize leprosy control activities by identifying clustering of leprosy cases and determining optimal target populations for PEP. METHODS: The geolocations of leprosy cases registered from 2014 to 2018 in Pasuruan and Pamekasan (Indonesia) were collected and tested for spatial autocorrelation with the Moran's I statistic. We did a hotspot analysis using the Heatmap tool of QGIS to identify clusters of leprosy cases in both areas. Fifteen cluster settings were compared, varying the heatmap radius (i.e., 500 m, 1000 m, 1500 m, 2000 m, or 2500 m) and the density of clustering (low, moderate, and high). For each cluster setting, we calculated the number of cases in clusters, the size of the cluster (km2), and the total population targeted for PEP under various strategies. RESULTS: The distribution of cases was more focused in Pasuruan (Moran's I = 0.44) than in Pamekasan (0.27). The proportion of total cases within identified clusters increased with heatmap radius and ranged from 3% to almost 100% in both areas. The proportion of the population in clusters targeted for PEP decreased with heatmap radius from > 100% to 5% in high and from 88 to 3% in moderate and low density clusters. We have developed an example of a practical guideline to determine optimal cluster settings based on a given PEP strategy, distribution of cases, resources available, and proportion of population targeted for PEP. CONCLUSION: Policy and operational decisions related to leprosy control programs can be guided by a hotspot analysis which aid in identifying high-risk clusters and estimating the number of people targeted for prophylactic interventions.

Introducing leprosy post-exposure prophylaxis into the health systems of India, Nepal and Indonesia: a case study.

BACKGROUND: Leprosy has a wide range of clinical and socio-economic consequences. India, Indonesia and Nepal contribute significantly to the global leprosy burden. After integration, the health systems are pivotal in leprosy service delivery. The Leprosy Post Exposure Prophylaxis (LPEP) program is ongoing to investigate the feasibility of providing single dose rifampicin (SDR) as post-exposure prophylaxis (PEP) to the contacts of leprosy cases in various health systems. We aim to compare national leprosy control programs, and adapted LPEP strategies in India, Nepal and Indonesia. The purpose is to establish a baseline of the health system's situation and document the subsequent adjustment of LPEP, which will provide the context for interpreting the LPEP results in future. METHODS: The study followed the multiple-case study design with single units of analysis. The data collection methods were direct observation, in-depth interviews and desk review. The study was divided into two phases, i.e. review of national leprosy programs and description of the LPEP program. The comparative analysis was performed using the WHO health system frameworks (2007). RESULTS: In all countries leprosy services including contact tracing is integrated into the health systems. The LPEP program is fully integrated into the established national leprosy programs, with SDR and increased documentation, which need major additions to standard procedures. PEP administration was widely perceived as well manageable, but the additional LPEP data collection was reported to increase workload in the first year. CONCLUSIONS: The findings of our study led to the recommendation that field-based leprosy research programs should keep health systems in focus. The national leprosy programs are diverse in terms of organizational hierarchy, human resource quantity and capacity. We conclude that PEP can be integrated into different health systems without major structural and personal changes, but provisions are necessary for the additional monitoring requirements.

Social contact patterns and leprosy disease: a case-control study in Bangladesh.

Socioeconomic and culturally defined social contact patterns are expected to be an important determinant in the continuing transmission of Mycobacterium leprae in leprosy-endemic areas. In a case-control study in two districts in Bangladesh, we assessed the association between social contact patterns and the risk of acquiring clinical leprosy. Social contacts of 90 recently diagnosed patients were compared to those of 199 controls. Leprosy was associated with a more intensive social contact pattern in the home [odds ratio (OR) 1·09, 95% confidence interval (CI) 1·00-1·19, P = 0·043] and in the nearby neighbourhood (OR 1·07, 95% CI 1·03-1·11, P = 0·001). Although it is known that M. leprae spreads most easily within households of infected persons, in endemic areas social contacts within the neighbourhood, village or urban ward, also appear to be important for transmission. We advise that disease control measures in leprosy-endemic areas should not be limited to households, but include high-risk groups in the nearby neighbourhood of patients.

MUSIDH, multiple use of simulated demographic histories, a novel method to reduce computation time in microsimulation models of infectious diseases.

Microsimulation of infectious diseases requires simulation of many life histories of interacting individuals. In particular, relatively rare infections such as leprosy need to be studied in very large populations. Computation time increases disproportionally with the size of the simulated population. We present a novel method, MUSIDH, an acronym for multiple use of simulated demographic histories, to reduce computation time. Demographic history refers to the processes of birth, death and all other demographic events that should be unrelated to the natural course of an infection, thus non-fatal infections. MUSIDH attaches a fixed number of infection histories to each demographic history, and these infection histories interact as if being the infection history of separate individuals. With two examples, mumps and leprosy, we show that the method can give a factor 50 reduction in computation time at the cost of a small loss in precision. The largest reductions are obtained for rare infections with complex demographic histories.

Social distance and spatial distance are not the same, observations on the use of GIS in leprosy epidemiology.

Contacts of leprosy patients have a higher risk of developing clinical leprosy. Being a contact is defined socially, but with the introduction of geographical information systems (GIS) in infectious disease epidemiology, it is necessary to relate spatial distance to social distance. We measured the distances between patients and their socially defined contacts in northwest Bangladesh. Contact categories differ in mean distance to the index patients. Sixty-seven per cent of the high-risk contacts lived within 10 metres (m), while all low-risk contacts lived >10 m from the index patient. Classification based on intervals of spatial distance creates categories that contain contacts of different socially defined categories, illustrated by a category of people living between 10 m and 20 m consisting of 47% of high-risk contacts and 52% low-risk contacts. Classification of contacts based on the spatial distance, as performed with GIS techniques, produces other groups than with social definitions.

Corticosteroids for treating nerve damage in leprosy.

BACKGROUND: Leprosy causes nerve damage which can result in nerve function impairment and disability. Corticosteroids are commonly used for treating nerve damage, although the long-term effect is uncertain. OBJECTIVES: To assess the effects of corticosteroids on nerve damage in leprosy. SEARCH STRATEGY: We searched the Cochrane Neuromuscular Disease Group Register, the Cochrane Central Register of Controlled Trials (Issue 4), MEDLINE (from 1966), EMBASE (from 1980), CINAHL (from 1980), LILACS (from 1982) in January 2006. We checked reference lists of the studies identified, the Current Controlled Trials Register (www.controlled-trials.com), conference proceedings and contacted trial authors. SELECTION CRITERIA: Randomised and quasi-randomised controlled trials of corticosteroids for nerve damage in leprosy. DATA COLLECTION AND ANALYSIS: The primary outcome was improvement in sensory and motor nerve function after one year. Secondary outcomes were improvement in nerve function after two years, change in nerve pain and tenderness, and adverse events. Two authors independently extracted data and assessed trial quality. We contacted trial authors for additional information. We collected adverse effects and cost effectiveness information from the trials and non-randomised studies. MAIN RESULTS: We included three randomised controlled trials involving 513 people. Two trials compared prednisolone with placebo. One trial treated mild sensory impairment of less than six months duration and the other trial treated nerve function impairment of 6 to 24 months duration. Both trials examined an effect twelve months from the start of treatment. There was no significant difference in nerve function improvement between people treated with prednisolone or with placebo. The third trial compared three corticosteroid regimens for severe type 1 reactions. This trial did not report the prespecified outcomes. However, after 12 months, a significantly higher proportion of individuals on a 3-month course of prednisolone required extra corticosteroids compared to the groups with a high-dose and low-dose regimen of five months duration. Diabetes and peptic or infected ulcer were sometimes reported as serious adverse events in the placebo-controlled trials, but not significantly more often in the corticosteroid than placebo groups. AUTHORS' CONCLUSIONS: Corticosteroids are used for treating acute nerve damage in leprosy, but evidence from randomised controlled trials does not show a significant long-term effect. Randomised controlled trials are needed to establish their effectiveness, the optimal regimens and to examine new therapies.

Trabajos científicos y colaboraciones. Factores de riesgo para el desarrollo de lepra clínica entre contactos y su importancia como objetivos de intervención / No disponible

Se revisan los conocimiento actuales sobre factores de riesgo para contraer lepra entre contactos de casos confirmados para intentar identificar los factores asociados con la enfermedad que entre los contactos presentan potencial para ser objetivos de intervenciones en los programas de control de la lepra. Se han utilizado distintas definiciones para el termino “contacto” aunque la mayoría de estudios emplean el de conviviente. Sin embargo, hay estudios que indican que otro tipo de contacto distinto al conviviente también esta en peligro de contraer la enfermedad. El tipo de lepra y su carga bacilar son los dos factores mas implicados en la transmisión pero los contactos de pacientes PB presentan mayor riesgo de contraer la lepra que los individuos de la población general. Los factores de contacto más importantes son: la cercanía e intensidad de contacto y la susceptibilidad heredada mientras que el sexo y la edad de los contactos junto a los factores socio-económicos no están muy claros. Tampoco están definidos los conceptos de marcadores inmunológicos y moleculares en cuanto al riesgo de transmitir o desarrollar la enfermedad pero existen evidencia de que contactos PGL1 seropositivos están en mayor riesgo. La presencia de cicatriz BCG parece apuntar hacia un menor riesgo. Las analogías con tuberculosis parecen indicar la similitud del concepto de “ondas en el estanque” en las dos enfermedades. Se sabe que pacientes esputo negativos pueden transmitir la tuberculosis, por tanto se debe extender este concepto de riesgo a los contactos de pacientes PB. La conclusión es que los contactos de pacientes MB y PB, tanto convivientes como no, deben ser objeto de intervenciones dirigidas sobre todo cuando están relacionadas genéticamente

Existing knowledge on risk factors the development of clinical leprosy among contacts of know leprosy patients is reviewed with the aim to identify factors associated with leprosy among contacts that have potential or developing effective targeted interventions in leprosy control. Different definitions of “contact” have been used and most study on this subject were among so-called household members. Yet several studies indicate that contacts found in other places that the household are also at risk of developing leprosy. The type of leprosy and the bacterial index are the main patient-related factors involved in transmission, but also contacts of PB patients have a higher risk of contracting leprosy as compared to general population. The most important contact-related factors are the closeness and intensity of the contact and inherited susceptibility, while the role of age and sex of the contacts is not clear. The role of socio-economic factors is also vague. The significance of immunological and molecular markers in relation to risk of transmitting or developing leprosy is not yet fully understood, but there is an indication that contacts who are sero-positive for anti-PGL-I antibodies are at increased risk of developing clinical leprosy. The presence of BCG scar is likely to be related to a lower risk. Analogies with tuberculosis suggest that the “stone-in-the-pond” approach to control may be applicable to leprosy too. Sputum smear negative tuberculosis patients are known to spread the bacteria to other. This analogy strengthens the suggestion that the contacts of paucibacillary leprosy cases should also be included in contact tracing and examination. It is included that targeted interventions should be aimed at close contacts of both MB and PB patients inside and outside the household, particularly when genetically related

Estudio sobre la transmisión y un ensayo quimioprofiláctico en contactos de pacientes de lepra: resultados de Colep / No disponible

En este trabajo se describe el modelo metodológico y hallazgos del estudio COLEP. Los objetivos del estudio son determinar la efectividad de la quimioprofilaxis con una dosis única de rifampicina e la prevención de la lepra entre contactos de pacientes de lepra y hallar características de los grupos de contacto en mayor riesgo de desarrollar lepra clínica. Estas características deben resultar útiles para los programas de control de lepra. El COLEP es un ensayo agrupado y aleatorio, a dobe ciego y controlado por placebo para determinar factores de riesgo que caracterizan los subgrupos en mayor riesgo entre el grupo contacto total de un paciente y un estudio de cohortes utilizando un grupo de referencia de entre la población general para determinar la prevalencia e incidencia de la lepra en la zona de la población estudiada. El período de seguimiento fue de 4 años. Se desarrolló un sistema de codificación explicando la distancia física y genética del contacto al paciente. Este estudio de Bangladesh incluye 1037 pacientes recién diagnosticados y sin tratamiento previo y sus 21,867 contactos. La prevalencia de la lepra entre los contactos era de 7-3 por 1000. Un total de 21,708 contactos sin rasgos ni síntomas de lepra clínica se incluyeron en un ensayo quimioprofiláctico con una dosis única de rifampicina y aleatorio a nivel del grupo de contacto en cuanto tratamiento y placebo. Los resultados de este ensayo estarán disponibles en algunos años

In this article, we describe the design, methodology and recruitment findings of the COLEP study. The objectives of this study were to determine the effective-ness of chemoprophylaxis with a single dose of rifampicin in the prevention of leprosy among contacts of leprosy patients, and to find characteristics of contact groups most at risk to develop clinical leprosy. These characteristics should be usable by routine leprosy control programmes. COLEP consists of a cluster randomized, double-blind and placebo-controlled trial, a cohort study to determine risk factors characterizing the sub-groups most at risk within the total contact group of a patient, and a cohort study using a reference group from the general population to determine the prevalence and incidence of leprosy in the total population of the study area. The follow-up period will be 4 years. A coding system was developed describing the physical and genetic distance of the contact person to the patient. This study in Bangladesh includes 1.037 newly diagnosed and previously untreated leprosy patients and their 21.867 contacts. The prevalence of leprosy among contacts was 7.3 per 1.000. a total of 21.708 contacts without sings and symptoms of clinical leprosy are included in a trial of chemoprophylaxis with single dose rifampicin, and randomized at contact group level in treatment and placebo arms. The results of this large field trial will become available in the years to come

Risk factors for the development of clinical leprosy among contacts, and their relevance for targeted interventions.

Existing knowledge on risk factors for the development of clinical leprosy among contacts of known leprosy patients is reviewed with the aim to identify factors associated with leprosy among contacts that have potential for developing effective targeted interventions in leprosy control. Different definitions of 'contact' have been used and most studies on this subject were among so-called household members. Yet several studies indicate that contacts found in other places than the household are also at risk of developing leprosy. The type of leprosy and the bacterial index are the main patient-related factors involved in transmission, but also contacts of PB patients have a higher risk of contracting leprosy as compared to the general population. The most important contact-related factors are the closeness and intensity of the contact and inherited susceptibility, while the role of age and sex of the contacts is not clear. The role of socio-economic factors is also vague. The significance of immunological and molecular markers in relation to risk of transmitting or developing leprosy is not yet fully understood, but there is an indication that contacts who are sero-positive for anti-PGL-I antibodies are at increased risk of developing clinical leprosy. The presence of a BCG scar is likely to be related to a lower risk. Analogies with tuberculosis suggest that the 'stone-in-the-pond' approach to control may be applicable to leprosy too. Sputum smear negative tuberculosis patients are known to spread the bacteria to others. This analogy strengthens the suggestion that the contacts of paucibacillary leprosy cases should also be included in contact tracing and examination. It is concluded that targeted interventions should be aimed at close contacts of both MB and PB patients inside and outside the household, particularly when genetically related.

A study on transmission and a trial of chemoprophylaxis in contacts of leprosy patients: design, methodology and recruitment findings of COLEP.

In this article, we describe the design, methodology and recruitment findings of the COLEP study. The objectives of this study were to determine the effectiveness of chemoprophylaxis with a single dose of rifampicin in the prevention of leprosy among close contacts of leprosy patients, and to find characteristics of contact groups most at risk to develop clinical leprosy. These characteristics should be usable by routine leprosy control programmes. COLEP consists of a cluster randomized, double-blind and placebo-controlled trial, a cohort study to determine risk factors characterizing the sub-groups most at risk within the total contact group of a patient, and a cohort study using a reference group from the general population to determine the prevalence and incidence of leprosy in the total population of the study area. The follow-up period will be 4 years. A coding system was developed describing the physical and genetic distance of the contact person to the patient. This study in Bangladesh includes 1037 newly diagnosed and previously untreated leprosy patients and their 21,867 contacts. The prevalence of leprosy among contacts was 7.3 per 1000. A total of 21,708 contacts without signs and symptoms of clinical leprosy are included in a trial of chemoprophylaxis with single dose rifampicin, and randomized at contact group level in treatment and placebo arms. The results of this large field trial will become available in the years to come.

Sensory testing in leprosy: comparison of ballpoint pen and monofilaments.

The 10 g monofilament has been replaced by the ballpoint pen in routine sensory testing of nerves in leprosy control in Ethiopia. Results of sensory testing between the ballpoint pen and different monofilaments on hands and feet were compared. Ballpoint pen underdiagnosis of loss of sensation was defined to occur when the pen was felt and the monofilament was not. Differences were evaluated both for individual test points (test point level) and for the test points of extremities collectively (extremity level). An extremity (either a hand or a foot) was defined as having sensory nerve function impairment (SNFI) if a supplying nerve had SNFI, which was the case when sensation was absent in two or more test points in the area supplied by that nerve. At test point level, the percentages with ballpoint pen underdiagnosis relative to the 2, 10, 20 and 50 g monofilaments were 40, 21, 9 and 7%, respectively, in the hands, and 47, 30, 15 and 7% in the feet. Ballpoint pen underdiagnosis percentages of SNFI at extremity level were 32, 18, 8 and 9% in the hands, and 37, 26, 14 and 6% in the feet. The risk of ballpoint pen underdiagnosis appears to be higher in extremities without visible damage. In conclusion, substantial levels of underdiagnosis of sensory loss with the ballpoint pen were observed. However, the consequences for the prognosis of treatment with corticosteroids in patients with the more subtle sensation loss noted here need to be established. Development and testing of guidelines is a prerequisite for the use of the ballpoint pen.

Delay in presentation, an indicator for nerve function status at registration and for treatment outcome--the experience of the Bangladesh Acute Nerve Damage Study cohort.

The objective of our research was to relate delay in presentation in the Bangladesh Acute Nerve Damage Study cohort to intake status and to treatment outcome. The Bangladesh Acute Nerve Damage Study (BANDS) is a prospective cohort study of 2664 consecutive newly registered patients at clinics run by the Danish-Bangladesh Mission Leprosy (DBLM) project in Nilphamari, northern Bangladesh. The 1-year intake began in April 1995. Three-year follow-up for PB cases and 5 years for MB cases was completed in 2001. Delay in presentation in the BANDS cohort is associated with increased signs of nerve function impairment at registration. Individuals presenting with no nerve impairment and maintaining nerve function to the end of follow-up had the shortest mean delays. Individuals presenting with impairment that did not improve during follow-up had the longest mean delays. Discussion focuses on the value of setting a threshold value defining early presentation. Since the WHO Grade 2 disability rate effectively sanctions lengthy delays where there is no impairment, an indicator relating directly to delay is preferred as an indicator for good practice in leprosy control.

The hand-foot impairment score as a tool for evaluating prevention of disability activities in leprosy: an exploration in patients treated with corticosteroids.

The hand-foot (HF) impairment score in leprosy patients is the sum of the WHO disability grades for hands and feet. This retrospective study explored the possibility of using the HF score for evaluation of the effectiveness of corticosteroid treatment programmes for nerve function impairment (NFI). Changes in the score were compared with changes in sensory testing (ST) and voluntary muscle testing (VMT) for 42 leprosy patients who received corticosteroid treatment. The WHO grade did not change in 30/60 (50%) of extremities gaining, and in 4/10 (40%) extremities losing sensation and/or muscle strength. However, 18/24 (75%) patients with a definite gain in function improved in HF score, while the HF score remained unchanged in 10/11 (91%) patients with no change in nerve function. Five patients with impairment in multiple extremities showed both gain and loss of sensation and/or muscle strength in the same or different extremities. Overall, improvement, deterioration and absence of change in NFI, as indicated by changes in ST and VMT were reflected correctly by the HF score in 28 (76%) of the remaining 37 patients. It was also shown that the HF score does not give appropriate information on the extent of the effect of corticosteroid treatment. This study illustrates that the HF score can not be used to support management of corticosteroid treatment of individual patients, but indicates this score to be a promising device for the evaluation of the effectiveness of corticosteroid treatment programmes. This study used the HF score because information on (changes in) eye impairment was not considered reliable. However, in principle, we consider the EHF score, which is the sum of the WHO disability grades for hands, feet and eyes, preferable for evaluation purposes. We strongly recommend further validation of the EHF score as a tool for evaluation of corticosteroid treatment programmes for patient groups with different distributions of NFI through prospective studies.

The treatment of acute nerve function impairment in leprosy: results from a prospective cohort study in Bangladesh.

In this paper, the outcome of 132 patients having acute nerve function impairment (NFI) is reported at 4 and 12 months after the start of prednisolone treatment. In all, 68% of sensory nerves and 67% of motor nerves showed improvement at 12 months, with no statistical difference in responsiveness of various nerves to prednisolone. Duration and severity of impairment were not found significant predictors of treatment outcome. A core of 32% of impaired nerves did not respond to prednisolone, and 12% of impaired nerves had functional deterioration despite treatment. The mean eye-hand-foot (EHF) score improved from 2.02 to 1.33 in the treatment group (median score improved from 2 to 1). Approximately one-third of all patients requiring prednisolone treatment did not receive it, an important reason being that some patients developed new NFI against a background of chronic impairment, and were thus overlooked. The 'unjustly untreated' group of patients had a spontaneous sensory nerve function improvement rate of 62% and a motor nerve function improvement rate of 33% at 12 months from onset of NFI. The EHF score showed no statistically significant improvement.

A clinical prediction rule for nerve-function impairment in leprosy patients.

BACKGROUND: Nerve-function impairment (NFI) commonly occurs during or after chemotherapy in leprosy and is the key pathological process leading to disability and handicap. We describe the development of a simple clinical prediction rule for estimating the risk of NFI occurrence. METHODS: New leprosy cases who presented to a centre in Bangladesh were recruited and followed up for 2 years in a field setting. We used multivariable regression analysis by Cox's proportional hazards model to identify predictive variables for NFI. Discriminative ability was measured by a concordance statistic. Internal validity was assessed with bootstrap resampling techniques. FINDINGS: 2510 patients were followed up for 2 years, 166 developed NFI. A simple model was developed with leprosy group (either paucibacillary leprosy [PB] or multibacillary leprosy [MB]) and the presence of any nerve-function loss at registration as predictive variables. Patients with PB leprosy and no nerve-function loss had a 1.3% (95% CI 0.8-1.8%) risk of developing NFI within 2 years of registration; patients with PB leprosy and nerve-function loss, or patients with MB leprosy and no nerve-function loss had a 16.0% (12-20%) risk; and patients with MB leprosy with nerve-function loss had a 65% (56-73%) risk. INTERPRETATION: Our prediction rule can be used to plan surveillance of new leprosy patients. Patients at low risk of NFI may need no follow-up beyond their course of chemotherapy (6 months); patients with intermediate risk need a minimum of 1 year of surveillance; and patients with high risk should have at least 2 years of surveillance for new NFI. Current recommendations for surveillance of patients with leprosy (for the duration of chemotherapy only) exclude an important group of patients who are at risk of developing NFI after completion of treatment.

Incidence rates of acute nerve function impairment in leprosy: a prospective cohort analysis after 24 months (The Bangladesh Acute Nerve Damage Study).

In this paper, the incidence rates and cumulative incidence of nerve function impairment (NFI) and leprosy reactions over 24 months follow-up of the prospective cohort of 2664 new leprosy cases are presented. Graphs showing the cumulative incidence of NFI relative to time since registration are presented. Hazard ratios (HRs) for the development of NFI for four variables are given. The majority of patients who developed NFI after registration did so in the first year (67% of multibacillary (MB) patients, and 91% of paucibacillary (PB) patients who developed NFI). Thirty-three percent of all MB patients who developed NFI after registration did so in the second year of follow-up. No PB patients developed NFI for the first time in the last 6 months of follow-up. However, seven NFI events occurred amongst PB patients in that period, amongst those who had already had one NFI event. The incidence rate (IR) of NFI amongst MB patients was 24/100 person-years at risk (PYAR), and amongst PB patients was 1.3/100 PYAR. The HR for the development of NFI amongst MB patients compared with PB patients was 16 using univariate analysis. Amongst patients who had long-standing NFI present at registration, the IR was 27/100 PYAR compared with 1.7/100 PYAR amongst those who did not have long-standing NFI. The HR for developing acute NFI amongst those with long-standing NFI present at registration compared with those without was 14 using univariate analysis. When multivariate regression analysis is applied, the apparently significant univariate HRs for sex and age disappeared. The resultant multivariate HR for leprosy group is 8.8, and 6.1 for the presence/absence of long-standing NFI at registration. In all, 142/166 (86%) of all new NFI events were silent, underlining the need for regular nerve function testing. IRs are presented for the four 6-month periods of the 24-month follow-up. They show a clear stepwise reduction over the total period. The IRs amongst MB patients and those with long-standing NFI present at registration are very high at 34 and 41/100 PYAR, respectively, for the first 6 months of follow-up. Even during the final 6-month period, the IR is maintained at a moderately high level (18 and 15/100 PYAR, respectively).

Nerve function impairment in leprosy: design, methodology, and intake status of a prospective cohort study of 2664 new leprosy cases in Bangladesh (The Bangladesh Acute Nerve Damage Study).

The Bangladesh Acute Nerve Damage Study (BANDS) is a prospective cohort study designed to investigate epidemiological, diagnostic, therapeutic and operational aspects of acute nerve function impairment in leprosy. The study is based at a single centre in Bangladesh, in an area with a high prevalence of leprosy. The centre, Danish Bangladesh Leprosy Mission, has a well-established vertical leprosy control programme. In this paper, the study design and methodology are described, together with definitions of nerve function impairment (NFI) used in this and subsequent papers. The study recruited 2664 new leprosy cases in a 12-month period. The male:female ratio is 1.25:1, and 17.61% of the cohort are under 15 years of age. In all, 83.33% of the cohort are paucibacillary (PB), and 16.67% multibacillary (MB). However, the MB rate amongst males is 19.72%, and amongst females is 12.85%, despite an equal period of delay to diagnosis. 55% of patients presented for treatment within 12 months of developing symptoms 6.12% of the total number of cases were smear positive, and 36.71% of the MB cases were smear positive. 9.61% of the total number of cases were graded as having World Health Organisation (WHO) disability grade 1, and 5.97% had grade 2. Amongst MB cases, 27.48% had WHO grade 1 disability present, and 18.24% had grade 2 present, compared with 6.04% and 3.51%, respectively, amongst PB cases. A total of 11.90% of the cohort had sensory NFI of any kind, and 7.39% had motor NFI. Ninety patients presented with NFI needing treatment (3.38%), and of these, 61 (67.78%) had silent NFI. MB patients had a prevalence of reaction/NFI needing treatment nearly 7 times higher than PB cases (15.32% amongst MB; 2.30% amongst PB), and males nearly double that of females (5.67% amongst males, 2.96% amongst females). The most commonly affected nerve by function impairment was the posterior tibial (sensory) with 6.46% of nerves affected (9.38% of patients), followed by the ulnar nerve with 3.23% of nerves impaired (5.56% of patients). Future research and publications, building on this foundation, will focus on the following areas: the incidence of NFI and reactive events, the risk factors for developing NFI, and the response to treatment of patients developing acute NFI.

Case detection, gender and disability in leprosy in Bangladesh: a trend analysis.

A trend analysis is presented of all newly detected leprosy cases over an 18-year period (1979-1996) in a highly leprosy endemic area of Bangladesh. A total of 23,678 new cases were registered, with an average of 860 new cases per year in the first 12 years, and increasing to around 3000 in 1996. The male:female (M:F) ratio decreased from 2.3 to 1.4. The proportions of newly detected cases with MB leprosy and of newly detected cases with any disability decreased over time. These reductions were more marked in the higher age groups of both sexes. The reduction in disability was primarily attributable to a decline in grade 2 disability. New case detection rates (NCDR) of all leprosy patients per 10,000 general population increased for males from 3 to 6; and for females from 1 to 4, while the NCDR of MB leprosy decreased in males from 1.4 to 0.6, and in females fluctuated around 0.45. The NCDRs of leprosy patients with disabilities showed an initial decrease in the first period, especially in males, but later showed an increase. The NCDR of males with disability was about twice as high as that of females. Finally, female NCDRs in the ages between 15 and 30 were low by comparison with the male NCDRs at the same time. This may be due to the sociocultural characteristics of the Bangladeshi society, with gender differences in exposure, health seeking behaviour and opportunities for case detection. Operational changes in the control programme have contributed to the changed profile of newly detected cases. This study shows that the application of general population statistics is essential for understanding the dynamics in leprosy control programmes under changing operational conditions. Combining case detection figures with such statistics helps to identify population groups that are possibly not benefiting sufficiently from the services provided, and to clarify the dynamics in control programmes and the future trends and programme requirements.