Leprosy Case Detection Research Articles

Correlation between the spatial distribution of leprosy and socioeconomic indicators in the city of Vitória, State of ES, Brazil

Leprosy is a disease that is directly linked to poverty. The number of cases in Vit6ria, the capital city of Espírito Santo, has been decreasing in recent years, but the disease remains highly endemic. This research aimed to identify relationships between the epidemiological status of leprosy and socioeconomic indicators during the period from 2005 to 2009. An ecological study was performed based on the spatial distribution of leprosy in Vit6ria, Espírito Santo, between 2005 and 2009. The source data used were records available at the Secretary of State for Health of the Espírito Santo. We used the Urban Quality Index (IQU) as the leprosy-associated socioeconomic variable. The data were analysed with covariate and spatial effects by the WinBugs programme (Version 1.4) and R (Version 2.12). The spatial distribution of leprosy in the district is not uniform. By studying the geographic distribution of leprosy cases, and the risks estimated by the complete Bayesian model, it was possible to gain further insight into the distribution of leprosy cases. It was noted that neighbourhoods with a low IQU have a higher leprosy case detection rate than neighbourhoods with a higher IQU. This result reinforced the theory that a low IQU is associated with the emergence of leprosy. The model methodology adopted enabled the verification of the effect of the influence of covariates related to the social determinants of health as well as the spatial structure, in contrast to the gross rate method that does not aggregate this information. The results obtained suggest that leprosy control may be promoted by improving the socioeconomic indicators of neighbourhoods, and highlights the need for implementation of health policies aimed at people who live in areas where they are at greatest risk of getting sick.

Whole-Blood Nested-PCR Amplification of M. leprae-Specific DNA for Early Diagnosis of Leprosy

We evaluated the sensitivity and specificity of a nested-polymerase chain reaction (PCR) method for detection of Mycobacterium leprae DNA from whole blood. Whole-blood specimens were subjected to nested-PCR amplification of M. leprae repeat DNA sequences in 49 multibacillary (MB) and 30 paucibacillary (PB) leprosy patients, 96 household contacts (HHCs), 18 tuberculosis (TB) patients, and 35 normal healthy individuals. M. leprae DNA was detected in 95.92% (47/49) of MB, 70% (21/30) of PB, and 6.25% (6/96) of HHC, but it was not detected in 18 TB or 35 normal controls. The sensitivities of the anti-bovine serum albumin (ND-O-BSA) immunoglobulin M (IgM) and antifusion protein of ML0405-ML2331 IgG for MB were 97.96% and 89.8%, and these values for PB were 70% and 53.33%. However, the ND-O-BSA enzyme-linked immunosorbent assay (ELISA) had lower specificity, with relatively high false-positive results for TB patients (16.67%) and normal healthy controls (10%). Based on these promising findings, we propose the use of nested PCR of whole-blood samples along with ELISA test for early detection of leprosy cases.

The potential for vaccination in leprosy elimination: new tools for targeted interventions

Despite the huge effort and massive advances toward the elimination of leprosy over the last two decades, the disease has proven stubborn; new case detection rates have stabilised over the last few years and leprosy remains endemic in a number of localised regions. The American Leprosy Missions and Infectious Disease Research Institute have undertaken a large research effort aimed at developing new tools and a vaccine to continue the push for leprosy elimination. In this paper, we outline our strategy for the integration of rapid diagnostic tests and lab-based assays to facilitate the detection of early or asymptomatic leprosy cases, as well as the efficient and focused implementation of chemoprophylaxis and immunisation to intervene in leprosy development and transmission.

Trends in leprosy case detection in Rwanda 1995-2011: analysis of 17 years

Background: Leprosy, or Hansen's disease, is a chronic, infectious disease caused by Mycobacterium leprae. It remains one of the leading causes of deformity and physical disability. We analyzed the laboratory records to assess trends in prevalence rate (PR) and case detection rate (CDR) in Rwanda. Methods: A retrospective laboratory records review of detected leprosy cases over a 17-year period (1995–2011) was conducted at the National Reference Laboratory. Skin biopsy samples were analyzed microscopically using Ziehl Neelsen (ZN) staining technique to identify Hansen's bacilli. Results: Cumulatively 266 suspected cases were reported between 1995 and 2011. Among suspected cases, 77 (28.9%) were laboratory confirmed as having leprosy. Among detected cases,76.6% were males and 23.4% females. The male-female ratio is 3:1. The registered leprosy cases over the past 17 years are 77 cases and the prevalence rate (PR) is 0.005/10,000 population. A graudual decrease of PR was oberved over the eight (8) past years from 0.015 per 10,000 population in 2003 to 0.003 per 10,000 population in 2010. From 1995 to 2011 CDR did not exceed 1 per 10,000 population. Multibacillary (MB) patients having bacteriological index ranging from 1+ to 4+ were highly represented (94.4%) in the last five (5) years while the paucibacillary patients were less represented 5.6%. Conclusion: Laboratory review demonstrates a considerable tendency of decline in PR and CDR trends up to date. Early case detection and sustainable leprosy control program remains the cornerstone to reduce physical and socioeconomic burden of leprosy in the country.

Analysis of newly detected leprosy in Sohag Governorate, Upper Egypt, 2004–2008

Leprosy is a chronic and complex infectious illness; the new-case detection rate is better than prevalence as an indicator of disease trends. This study presents an analysis of pattern of new cases of leprosy detected annually from 2004 to 2008 in Sohag Governorate, Upper Egypt. Data about patients with newly diagnosed leprosy were collected from Sohag leprosy hospital, the main referral centre in the governorate. Case detection rates (CDR) were calculated for each year by dividing the newly diagnosed cases by mid-year populations for the same year. 587 patients were newly diagnosed between 2004 and 2008. The mean age of patients at diagnosis was 34 years, 62% were males, and 11% were children below 15 years of age. The overall leprosy case detection rate was 3-1/100,000 population and it decreased from 3.4/100,000 population in 2004 to 2.8/100,000 population in 2008. Ninety three percent were classified as multibacillary, and 20.4% had Grade 2 disability at diagnosis. Leprosy remains a health problem in Sohag Governorate. It is possible that new cases are being detected late owing to inadequate community awareness of the disease. Leprosy control activities should be provided in primary health care units in order to detect new cases, and continued surveillance is required to detect relapses and to ensure good patient compliance with treatment.

Clusters of leprosy transmission and of late diagnosis in a highly endemic area in Brazil: focus on different spatial analysis approaches

The Brazilian National Hansen's Disease Control Program recently identified clusters with high disease transmission. Herein, we present different spatial analytical approaches to define highly vulnerable areas in one of these clusters. The study area included 373 municipalities in the four Brazilian states Maranhão, Pará, Tocantins and Piauí. Spatial analysis was based on municipalities as the observation unit, considering the following disease indicators: (i) rate of new cases/100,000 population, (ii) rate of cases <15 years/100,000 population, (iii) new cases with grade-2 disability/100,000 population and (iv) proportion of new cases with grade-2 disabilities. We performed descriptive spatial analysis, local empirical Bayesian analysis and spatial scan statistic. A total of 254 (68.0%) municipalities were classified as hyperendemic (mean annual detection rates >40 cases/100,000 inhabitants). There was a concentration of municipalities with higher detection rates in Pará and in the center of Maranhão. Spatial scan statistic identified 23 likely clusters of new leprosy case detection rates, most of them localized in these two states. These clusters included only 32% of the total population, but 55.4% of new leprosy cases. We also identified 16 significant clusters for the detection rate <15 years and 11 likely clusters of new cases with grade-2. Several clusters of new cases with grade-2/population overlap with those of new cases detection and detection of children <15 years of age. The proportion of new cases with grade-2 did not reveal any significant clusters. Several municipality clusters for high leprosy transmission and late diagnosis were identified in an endemic area using different statistical approaches. Spatial scan statistic is adequate to validate and confirm high-risk leprosy areas for transmission and late diagnosis, identified using descriptive spatial analysis and using local empirical Bayesian method. National and State leprosy control programs urgently need to intensify control actions in these highly vulnerable municipalities.

Leprosy decline in Amazonas State, Brazil

To analyse the leprosy case detection rates in Amazonas State, Brazil, by age group from 1980 to 2009. The historical data series of leprosy cases by age group from 1980 to 2009 were fitted as a function of time using Poisson regression models. Relative annual reduction in the detection rate (RAR) by age group was estimated as one minus the exponential of the estimated regression coefficient for time. To compare the regression coefficients, we used their 95% confidence interval. The relative annual reduction varied from 9% in the age group of 0-4 years to 1% in the age group of 60-69 years. There was a declining trend of the RAR in the younger age groups that disappeared after 29 years of age. The detection rate in people >29 years old declined very little over time, with no statistically significant difference between age groups. Our findings show a reduction in the infection risk in the last 30 years and a birth cohort effect: cohorts born in more recent years faced smaller risks of leprosy infection than older cohorts.

PMD28 Cost-Effectiveness Analysis of Three Leprosy Case Detection Methods in Northern Nigeria

Case detection is key to identifying leprosy disease early in its development for more effective prevention of progression to permanent disability. The study evaluated the costs and cost-effectiveness of three leprosy case detection methods in Nigeria's north-eastern states of Adamawa and Gombe; namely Rapid Village Survey (RVS), Household Contact Examination (HCE) and Traditional Healer's (THs) incentive approach The study was cross-sectional and explorative, undertaken in routine practice setting, targeting endemic and non-endemic communities selected randomly. Primary and secondary data were collected from routine practice records and the Nigerian Leprosy Elimination Programme 2009. All costs were measured from both providers' and patients' perspectives. Effectiveness was measured as new cases detected and outcome expressed as cost per case detected. Incremental approach, using routine passive case detection method as a reference was used to estimate the costs and effects by comparing each method against the routine practise; to measure additional cost per new case detected, as incremental cost-effectiveness ratio (ICER). Univariate sensitivity analysis was carried out to evaluate uncertainties around the ICER. All costs were converted to US Dollars at the 2010 exchange rate. HCE generated a total of $2416 at the lowest rate of $142 per additional case detected at all contact levels, as the most cost-effective method while the RVS was dominated by THs method which generated a total of $4447 at $193 per new case detected.Variation of diagnostic accuracy and subsistent wage for valuing unpaid time did not significantly change the results. From both perspectives and at all contact levels, the Household Contact Examination, complementing routine practice demonstrated the most cost-effective approach to identifying new leprosy cases for effective prevention and control of leprosy in Nigeria. It will be necessary to carry out implementation studies to establish the feasibility and acceptability of the method in other leprosy areas.

The Long Term Effect of Current and New Interventions on the New Case Detection of Leprosy: A Modeling Study

BackgroundAlthough the number of newly detected leprosy cases has decreased globally, a quarter of a million new cases are detected annually and eradication remains far away. Current options for leprosy prevention are contact tracing and BCG vaccination of infants. Future options may include chemoprophylaxis and early diagnosis of subclinical infections. This study compared the predicted trends in leprosy case detection of future intervention strategies.MethodsSeven leprosy intervention scenarios were investigated with a microsimulation model (SIMCOLEP) to predict future leprosy trends. The baseline scenario consisted of passive case detection, multidrug therapy, contact tracing, and BCG vaccination of infants. The other six scenarios were modifications of the baseline, as follows: no contact tracing; with chemoprophylaxis; with early diagnosis of subclinical infections; replacement of the BCG vaccine with a new tuberculosis vaccine ineffective against Mycobacterium leprae (“no BCG”); no BCG with chemoprophylaxis; and no BCG with early diagnosis.FindingsWithout contact tracing, the model predicted an initial drop in the new case detection rate due to a delay in detecting clinical cases among contacts. Eventually, this scenario would lead to new case detection rates higher than the baseline program. Both chemoprophylaxis and early diagnosis would prevent new cases due to a reduction of the infectious period of subclinical cases by detection and cure of these cases. Also, replacing BCG would increase the new case detection rate of leprosy, but this effect could be offset with either chemoprophylaxis or early diagnosis.ConclusionsThis study showed that the leprosy incidence would be reduced substantially by good BCG vaccine coverage and the combined strategies of contact tracing, early diagnosis, and treatment of infection and/or chemoprophylaxis among household contacts. To effectively interrupt the transmission of M. leprae, it is crucial to continue developing immuno- and chemoprophylaxis strategies and an effective test for diagnosing subclinical infections.

Perceptions, health seeking behaviour and access to diagnosis and treatment initiation among previously undetected leprosy cases in rural Maharashtra, India

To study sociodemographic profiles, perceptions about leprosy and health seeking patterns among adult leprosy patients and parents of children with leprosy detected through a prevalence survey conducted earlier, in rural areas of Panvel tehsil in Maharashtra. The study was cross-sectional and used mixed (qualitative and quantitative) methods. Of the 97 confirmed rural leprosy cases who had been detected through the initial prevalence survey, 58 newly detected adult leprosy cases and parents of 22 children detected with leprosy were interviewed with a semistructured interview schedule between May 2008 and March 2009. The study revealed that most of the leprosy patients belonged to the poor socioeconomic strata. Nearly 58% of the adult patients reported that they had been detected through the survey within 3 months of noticing their symptom(s) for the first time. Despite having been diagnosed and receiving treatment, only 48% of adult cases knew their condition as leprosy, reflecting their poor knowledge of the disease and lack of communication between providers and patients. The symptom 'patch on the skin' seems to have percolated in the community. Despite approaching the private or public sector for help in the first instance, many patients and children remained undiagnosed and untreated for leprosy. Active surveys for leprosy case detection should substitute the self-reporting approach until IEC measures are sufficiently effective to achieve a significant impact on transmission. Nevertheless both approaches will need the presence of staff with active diagnostic skills and optimal drug availability at PHCs.

Trends in new leprosy case detection over 57 years (1952–2008) in Yuxi, Yunnan Province of Southwest China

Leprosy control and management in China was maintained via a vertical system. Despite substantial achievements in leprosy control in the past decades, leprosy has not been completely eliminated in several endemic areas of Yunnan Province, China. To report the epidemiological trends and management of leprosy in Yuxi, Yunnan Province from 1952 to 2008. Diagnosis, control, and treatment data for 2223 leprosy cases detected from 1952 to 2008 were analysed. Two large-scale house-to-house surveys were launched in 1957-1958 and 1964-1965, and a remarkable number of new cases were identified during these two surveys. The overall prevalence rate of leprosy in the Yuxi region presented a roughly unimodal distribution between 1952 and 2008, with a peak (9.27 per 10000 population) in 1965. This reflects a combination of case detection and duration of treatment. Overall, the age distribution of the patients changed dramatically over the years, and there were only two childhood cases between 1995 and 2008 (both occurring in 1998). Nearly half of the total cases (49.1%) were classified as multibacillary leprosy type. With the introduction and ubiquitous coverage of the WHO multi-drug therapy (MDT) in this area, leprosy elimination was achieved in 1992. In recent years, the majority of cases (> 80%) were detected by passive approaches, and there is an increasing tendency to find multibacillary leprosy patients. Our results provide an overall profile of our 57-year effort regarding the leprosy control in the Yuxi region. The trend in detection of new cases in recent years suggested that the transmission of leprosy has stopped in the area or, at least, dramatically declined.

わが国のハンセン病患者の動向

We aimed to elucidate the patterns and trends of autochthonous leprosy in Japan from 1964 to 2009, to compare them with the findings from other studies of leprosy in decline. Data on registered leprosy cases in Japan in the period 1964-2009 were analysed with reference to trends in case detection, geographical distribution, age at diagnosis, sex, classification and family history. A consistent decline in leprosy case detection was observed in all areas of the country over the period 1964-2009. Highest incidence was consistently in Okinawa. Autochthonous leprosy has not been reported in anyone born in Japan since 1980. Increasing average age and a shift towards lower latitudes were demonstrated throughout the period. Analyses of data on autochthonous cases revealed patterns similar to those reported in other countries with declining leprosy. Okinawa has had the highest incidence of leprosy in all of Japan since the first national survey in 1900. Several possible explanations include the difference of leprosy control history between Okinawa and the rest of Japan, Okinawa's unique geographical condition, large-scale problem of stigma and discrimination against leprosy patients and delayed improvement of socio-economic conditions.

Different mechanisms for heterogeneity in leprosy susceptibility can explain disease clustering within households.

The epidemiology of leprosy is characterized by heterogeneity in susceptibility and clustering of disease within households. We aim to assess the extent to which different mechanisms for heterogeneity in leprosy susceptibility can explain household clustering as observed in a large study among contacts of leprosy patients.We used a microsimulation model, parameterizing it with data from over 20,000 contacts of leprosy patients in Bangladesh. We simulated six mechanisms producing heterogeneity in susceptibility: (1) susceptibility was allocated at random to persons (i.e. no additional mechanism), (2) a household factor, (3, 4) a genetic factor (dominant or recessive), or (5, 6) half a household factor and half genetic. We further assumed that a fraction of 5%, 10%, and 20% of the population was susceptible, leading to a total of 18 scenarios to be fitted to the data. We obtained an acceptable fit for each of the six mechanisms, thereby excluding none of the possible underlying mechanisms for heterogeneity of susceptibility to leprosy. However, the distribution of leprosy among contacts did differ between mechanisms, and predicted trends in the declining leprosy case detection were dependent on the assumed mechanism, with genetic-based susceptibility showing the slowest decline. Clustering of leprosy within households is partially caused by an increased transmission within households independent of the leprosy susceptibility mechanism. Even a large and detailed data set on contacts of leprosy patients could not unequivocally reveal the mechanism most likely responsible for heterogeneity in leprosy susceptibility.

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

BackgroundImplementation 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.MethodsA 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.Results83.4% 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.ConclusionThe 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.

The decline of leprosy in Japan: patterns and trends 1964–2008

Our purpose was to elucidate the patterns and trends of autochthonous leprosy in Japan from 1964 to 2008, to compare them with the findings from other studies of leprosy in decline, and to determine whether M. leprae transmission persists in Japan. Data on registered leprosy cases in Japan in the period 1964-2008 were analysed with reference to trends in case detection, geographical distribution, age at diagnosis, sex, classification, family history and broad correlation with socioeconomic conditions. A consistent decline in leprosy case detection was observed in all areas of the country over the period 1964-2008. Highest incidence was consistently in Okinawa, the southernmost part of Japan. Autochthonous leprosy has not been reported in anyone born in Japan since 1980. Increasing average age and a shift towards lower latitudes were demonstrated throughout the period. There was an inverse association between regional measures of wealth and leprosy incidence. Leprosy has declined throughout the past century in Japan. Autochthonous transmission has probably stopped in mainland Japan, but may still occur at a low level in Okinawa, the country's southernmost region. Analyses of data on autochthonous cases revealed patterns similar to those reported in other countries with declining leprosy. Detailed comparisons between countries with very low leprosy incidence may help us to better understand the epidemiology of leprosy.

Detection of previously undetected leprosy cases in a defined rural and urban area of Maharashtra, Western India

Leprosy has been a major public health problem in India for centuries. In India, between 2001 and 2005, the prevalence of leprosy was reduced by 80%. This sharp decline in the prevalence of leprosy alongside the cessation of active surveillance for detection of leprosy cases has raised a sense of alarm in the scientific community. This is a total population survey aiming to estimate the prevalence of undetected active cases of leprosy in the community in defined rural (Panvel Taluka, Raigad District) and urban (M-East Ward, Mumbai) areas by health workers from Kushth Nivaran Samiti (Panvel) and Lok Seva Sangam (Mumbai). Those provisionally diagnosed with leprosy were subjected to an independent verification using clinical, bacteriological and histopathological investigations at the Foundation for Medical Research. A population of 196,694 and 600,247 was covered in defined rural and urban areas respectively. In the rural area on examining 178,646 individuals, 120 provisionally diagnosed leprosy cases were detected, of which 65 were paucibacillary (PB) and 55 were multibacillary (MB) based on the WHO operational classification used by health workers at field level. In the urban area, of the 512,434 individuals who were examined, 134 provisionally diagnosed leprosy cases were detected with 92 PB and 42 MB cases. Among the clinically confirmed cases, 35.6% (32/90) and 34.9% (36/109) in rural and urban areas respectively were children. There are large numbers of undetected leprosy cases in the community with a high proportion of MB patients and children among them. This indicates active transmission pointing to the need for a paradigm shift in leprosy care services and control programme.

Analysis on value of household contact survey in case detection of leprosy at a low endemic situation in China

Leprosy is at a low endemic situation in China, the value of house contact survey in case detection of leprosy becoming a dispute. To evaluate the value of household contact survey in the case detection of leprosy at a low endemic situation in China. A study was carried out using a designed questionnaire in a retrospective method to analyze the value of household contact survey in case detection in Southwest and East China. A total of 2135 index leprosy patients were collected from January 1, 1996 to December 31, 2005 in six provinces of China. The number of index patients accounted for 22.0 and 14.1% of newly registered patients in the Southwest and East of China, respectively. The household contact survey (36.1%) and the skin clinic (62.0%) ranked first in methods of case detection in Southwest and East China, respectively. Within 5 years after primary leprosy patients were detected, 24.8 and 16.1% of the index patients in Southwest China and East China had been detected, respectively. The authors conclude that at the time of a low leprosy endemic situation, the household contact survey is still a useful method for case detection in China.

Global collaborations in leprosy research – the future is connected

Collaboration between endemic and non-endemic partners has always been essential for leprosy research: patients and clinical knowledge are mainly found in endemic countries, whereas technical advances and opportunities are usually first available in non-endemic countries. During the period 1976–1995 the WHO IMMLEP and THELEP Special Programmes provided forums for the melding of basic and field research and resulted in great advances, particular in the application of immunological and molecular approaches to control of leprosy. However, nowadays the opportunities for leprosy researchers involved in more basic research to interact are few with a limited number of dedicated meetings. Even at the International Congresses held every 5 years, the balance is quite rightly in favour of leprosy control over basic research. Meanwhile leprosy research has been facing two major challenges. Firstly, the decline in global leprosy case detection rates has had the same effect on leprosy research funding as on the provision of leprosy diagnostic services: dedicated leprosy research funding is thin on the ground, although invaluable support is still provided by the non-governmental anti-leprosy organisations represented in the International Federation of Anti-Leprosy Associations (ILEP). Secondly, there has been a huge increase in funding for tuberculosis research. With the similarities between Mycobacterium tuberculosis and Mycobacterium leprae, many researchers who previously worked exclusively on leprosy have found the balance of their research on mycobacteria tipping increasingly towards tuberculosis. In the last 10 years there has been another change occurring in the funding of infectious diseases research. Smaller European Community-funded mycobacterial research networks

Enquête sur la qualité du diagnostic de lèpre à Madagascar

By 2005, Madagascar had not achieved its goal of eliminating leprosy. During reexamination of leprosy patients, rates of diagnostic error ranged from 4.5 to 62%, casting doubt on the reported prevalence of leprosy. We therefore decided to carry out a survey of the quality of leprosy diagnosis. The survey consisted in reexamination of a sample of 102 new cases of leprosy (treated for less than three months). The sample was obtained from clusters of six patients, randomly drawn from the 111 districts in the country's six provinces. Two reexamination teams visited the target districts. Each team included at least three medical doctors: a doctor from the National Program, a WHO consultant and a dermatologist from partner NGOs in the program. The mean false-positive rate was 27.5%, ranging from 5.6 to 44.4% in the different provinces. The quality of leprosy diagnosis was found to be very poor, particularly in districts with a marked decrease in annual detection of leprosy cases. The high rate of false-positives during this survey could be due to the incompetence of peripheral health workers. This incompetence could be partly attributed to the decrease in leprosy detection, resulting in reduced familiarity of these health staff with leprosy diagnosis. Recommendations were made to the country concerning review of the leprosy case detection network and improvement of the quality of leprosy diagnosis in the field. Health workers involved in leprosy detection must have basic dermatological knowledge.

Future prevalence of WHO grade 2 impairment in relation to incidence trends in leprosy: an exploration

To explore the relationship between leprosy incidence trends and the future prevalence of World Health Organization (WHO) grade 2 impairment caused by leprosy. Three scenarios were defined to estimate incidences and prevalences of leprosy impairment beyond 2000, assuming 6%, 12% and 18% annual declines in case detection rate respectively, and 6% impairment among new patients. Case detection data from 1985 to 2000 were used for projecting leprosy incidences up to 2020. To estimate future prevalences of WHO grade 2 impairment, the survival of existing and new impaired individuals was calculated. In the 6% scenario, 410 000 new patients will be detected in 2010 and 250 000 in 2020. The number of people living with WHO grade 2 impairment in these years will be 1.3 and 1.1 million, respectively. The 12% scenario predicts that 210 000 new patients will be detected in 2010 and 70 000 in 2020. The grade 2 prevalences will be 1.2 and 0.9 million, respectively. In the 18% scenario, the incidence will be 110 000 in 2010 and 20 000 in 2020, and the grade 2 prevalences will be 1.1 and 0.8 million, respectively. Declines in numbers of people living with grade 2 impairment lag behind trends in leprosy incidence. The prevalence of people with grade 2 decreases much slower than leprosy incidence and case detection in all three scenarios. This implies that a substantial number of people will live with impairment and will need support, training in self-care and other prevention of disability interventions in the next decades.