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

High-risk spatiotemporal patterns of leprosy in the southeastern region of Yunnan province from 2010 to 2022: an analysis at the township level

BACKGROUND

Despite being preventable and curable, leprosy remains endemic in some undeveloped regions, including China. Wenshan Zhuang and Miao Autonomous Prefecture (Wenshan prefecture) currently bears the highest leprosy burden in China. In this ecological study, we aimed to analyze the epidemiological characteristics as well as identify and visualize the high-risk townships of Wenshan prefecture using the most updated leprosy data from 2010 to 2022.

METHODS

Geographical information system combined with spatial scan statistics was used for newly detected leprosy cases abstracted from the Leprosy Management Information System in China. Global Moran's I index was used to uncover the spatial pattern of leprosy at the township level. Spatial scan statistics, encompassing purely temporal, purely spatial, spatial variation in temporal trends, and space-time analysis, were implemented for detecting the risk clusters.

RESULTS

Between 2010 and 2022, Wenshan prefecture detected 532 new leprosy cases, comprising 352 (66.17%) males and 180 (33.83%) females. The aggregated time primarily occurred between October 2010 and March 2014. The distribution pattern of newly detected leprosy cases was spatially clustered. We identified four high-risk spatial clusters encompassing 54.51% of the new cases. Furthermore, spatial variation in temporal trends highlighted one cluster as a potential high-risk area. Finally, two space-time clusters were detected, and the most likely cluster was predominantly located in the central and northwest regions of Wenshan prefecture, spanning from January 2010 to September 2013.

CONCLUSIONS

In this ecology study, we characterized the epidemiological features and temporal and spatial patterns of leprosy in Wenshan prefecture using the most recent leprosy data between 2010 and 2022. Our findings offer scientific insights into the epidemiological profiles and spatiotemporal dynamics of leprosy in Wenshan prefecture. Clinicians and policymakers should pay particular attention to the identified clusters for the prevention and control of leprosy.

Any resurgence of leprosy cases in the Togo's post-elimination period? Trend analysis of reported leprosy cases from 2010 to 2022

BACKGROUND

Leprosy, or Hansen's disease, is a chronic infectious disease caused by Mycobacterium leprae. Togo achieved the target of eliminating leprosy as a public health problem in 2000 (less than 1 case/10 000 population). However, new cases of leprosy are still being reported. The aim of this study was to describe and map trends of leprosy cases notified in Togo from 2010 to 2022.

METHODS

This was a descriptive cross-sectional study covering a thirteen-year period from January 1, 2010, to December 31, 2022. The data of the study were leprosy surveillance system's data collected monthly between 2010 and 2022. The estimated number of leprosy cases and the incidence rate of leprosy cases were reported for the whole population by region, by district, by calendar year (2010-2022) and by target sub-population (children under 15, women and people with disabilities). Observed case incidence rates were mapped by health district and by year.

RESULTS

From January 1, 2010, to December 31, 2022, 1031 new cases of leprosy were diagnosed in Togo. The median age of subjects was 46 years (interquartile range: 33-60), with extremes from 4 to 96 years. Half the subjects were women (50.7%). Variations in the leprosy incidence rate by year show an increase between 2010 and 2022, from 0.7 cases /100,000 population to 1.1 /100,000 population respectively. From 2010 to 2022, the proportion of cases in children remained low, between 0 and 9%. The proportion of women fluctuated between 39.7% and 67.2% between 2010 and 2017, then stabilized at an average of 50% between 2018 and 2022. The proportion of multi-bacillary leprosy cases increased quasi-linearly between 2010 and 2022, from 70 to 96.6%. Mapping of leprosy cases showed that leprosy was notified in all Togo health districts during the study period, apart from the Lacs district, which reported no leprosy cases.

CONCLUSION

Togo has achieved the elimination of leprosy as a public health problem. However, the increase in the number of new leprosy cases and the proportion of leprosy cases in children indicate that transmission of the disease is continuing and that supplementary measures are needed.

Spatiotemporal pattern of leprosy in southwest China from 2010 to 2020: an ecological study

BACKGROUND

Despite many efforts to control leprosy worldwide, it is still a significant public health problem in low- and middle-income regions. It has been endemic in China for thousands of years, and southwest China has the highest leprosy burden in the country.

METHODS

This observational study was conducted with all newly detected leprosy cases in southwest China from 2010 to 2020. Data were extracted from the Leprosy Management Information System (LEPMIS) database in China. The Joinpoint model was used to determine the time trends in the study area. Spatial autocorrelation statistics was performed to understand spatial distribution of leprosy cases. Spatial scan statistics was applied to identify significant clusters with high rate.

RESULTS

A total of 4801 newly detected leprosy cases were reported in southwest China over 11 years. The temporal trends declined stably. The new case detection rate (NCDR) dropped from 4.38/1,000,000 population in 2010 to 1.25/1,000,000 population in 2020, with an average decrease of 12.24% (95% CI: -14.0 to - 10.5; P < 0.001). Results of global spatial autocorrelation showed that leprosy cases presented clustering distribution in the study area. Most likely clusters were identified during the study period and were frequently located at Yunnan or the border areas between Yunnan and Guizhou Provinces. Secondary clusters were always located in the western counties, the border areas between Yunnan and Sichuan Provinces.

CONCLUSIONS

Geographic regions characterized by clusters with high rates were considered as leprosy high-risk areas. The findings of this study could be used to design leprosy control measures and provide indications to strengthen the surveillance of high-risk areas. These areas should be prioritized in the allocation of resources.

Molecular epidemiological characteristics of Mycobacterium leprae in highly endemic areas of China during the COVID-19 epidemic

Objectives

The present study analyzed the impact of the COVID-19 pandemic on the prevalence and incidence of new leprosy cases, as well as the diversity, distribution, and temporal transmission of Mycobacterium leprae strains at the county level in leprae-endemic provinces in Southwest China.

Methods

A total of 219 new leprosy cases during two periods, 2018-2019 and 2020-2021, were compared. We genetically characterized 83 clinical isolates of M. leprae in Guizhou using variable number tandem repeats (VNTRs) and single nucleotide polymorphisms (SNPs). The obtained genetic profiles and cluster consequences of M. leprae were compared between the two periods.

Results

There was an 18.97% decrease in the number of counties and districts reporting cases. Considering the initial months (January-March) of virus emergence, the number of new cases in 2021 increased by 167% compared to 2020. The number of patients with a delay of >12 months before COVID-19 (63.56%) was significantly higher than that during COVID-19 (48.51%). Eighty-one clinical isolates (97.60%) were positive for all 17 VNTR types, whereas two (2.40%) clinical isolates were positive for 16 VNTR types. The (GTA)9, (TA)18, (TTC)21 and (TA)10 loci showed higher polymorphism than the other loci. The VNTR profile of these clinical isolates generated five clusters, among which the counties where the patients were located were adjacent or relatively close to each other. SNP typing revealed that all clinical isolates possessed the single SNP3K.

Conclusion

COVID-19 may have a negative/imbalanced impact on the prevention and control measures of leprosy, which could be a considerable fact for official health departments. Isolates formed clusters among counties in Guizhou, indicating that the transmission chain remained during the epidemic and was less influenced by COVID-19 preventative policies.

Single-Dose Rifapentine in Household Contacts of Patients with Leprosy

BACKGROUND

Previous studies have suggested that a single dose of rifampin has protective effects against leprosy in close contacts of patients with the disease. Rifapentine was shown to have greater bactericidal activity against Mycobacterium leprae than rifampin in murine models of leprosy, but data regarding its effectiveness in preventing leprosy are lacking.

METHODS

We conducted a cluster-randomized, controlled trial to investigate whether single-dose rifapentine is effective in preventing leprosy in household contacts of patients with leprosy. The clusters (counties or districts in Southwest China) were assigned to one of three trial groups: single-dose rifapentine, single-dose rifampin, or control (no intervention). The primary outcome was the 4-year cumulative incidence of leprosy among household contacts.

RESULTS

A total of 207 clusters comprising 7450 household contacts underwent randomization; 68 clusters (2331 household contacts) were assigned to the rifapentine group, 71 (2760) to the rifampin group, and 68 (2359) to the control group. A total of 24 new cases of leprosy occurred over the 4-year follow-up, for a cumulative incidence of 0.09% (95% confidence interval [CI], 0.02 to 0.34) with rifapentine (2 cases), 0.33% (95% CI, 0.17 to 0.63) with rifampin (9 cases), and 0.55% (95% CI, 0.32 to 0.95) with no intervention (13 cases). In an intention-to-treat analysis, the cumulative incidence in the rifapentine group was 84% lower than that in the control group (cumulative incidence ratio, 0.16; multiplicity-adjusted 95% CI, 0.03 to 0.87; P = 0.02); the cumulative incidence did not differ significantly between the rifampin group and the control group (cumulative incidence ratio, 0.59; multiplicity-adjusted 95% CI, 0.22 to 1.57; P = 0.23). In a per-protocol analysis, the cumulative incidence was 0.05% with rifapentine, 0.19% with rifampin, and 0.63% with no intervention. No severe adverse events were observed.

CONCLUSIONS

The incidence of leprosy among household contacts over 4 years was lower with single-dose rifapentine than with no intervention. (Funded by the Ministry of Health of China and the Chinese Academy of Medical Sciences; Chinese Clinical Trial Registry number, ChiCTR-IPR-15007075.).

Epidemiological characteristics of leprosy during the period 2005-2020: A retrospective study based on the Chinese surveillance system

Background

Jiangsu Province is located in the Yangtze River Delta region, with a total area of 107,200 square kilometers. Since 1949, over 55,000 cases have been registered, with Taixing accounting for the highest number of patients. The proportion of new cases with MB and G2D was higher compared to other regions. As a result, Jiangsu has been considered a priority area for public health interventions in China.

Methods

This paper mainly described the population, time, and spatial distribution of the newly detected leprosy cases in Jiangsu Province between 2005 and 2020. In this study, all the data were entered into Microsoft Excel and SPSS for the descriptive analysis. ArcGIS was applied to create statistical maps, and Geoda was used to conduct spatial autocorrelation analysis with local Moran's I statistics (LISA). The epidemiological data were obtained from LEPMIS. In addition, population data were obtained from the Statistical Yearbook of Jiangsu Province.

Results

During the study period, 363 new cases were reported. Of these, 232 were men and 131 were women (1.77:1). The mean age at diagnosis was 60.56 years, and no adolescent cases were identified. Three hundred and twenty-seven (90.08%) were diagnosed with MB and 36 (9.92%) with PB. 31.68% (115/363) of the patients presented with G2D. Farmers accounted for 74.9%, and most cases were identified in skin clinics (248, 68.32%). We observed a decreasing trend in detection rate, with a higher concentration of new cases diagnosed between July and October. Spatial analysis showed that the new cases were primarily distributed in the northwest of Jiangsu province, and Suqian has the highest incidence of leprosy. Special attention should be paid to Wuzhong, a county with a potential risk of inter-provincial transmission. Furthermore, 55 new cases came from other Chinese provinces but lived in Jiangsu.

Conclusion

The NCDR of leprosy decreased, but the new cases showed disabilities, a sign of the late diagnosis. The results indicated that some regions were still suffering from the burden of leprosy. Thus, we recommend that the government should adopt effective strategies to promote leprosy control. The main priorities for eliminating new cases were to provide sustainable financial support, improve the quality of clinical services, strengthen preventive intervention and rehabilitation services for disabilities, provide health education among high-risk populations, and explore new approaches.

Oscillatory properties of class C notifiable infectious diseases in China from 2009 to 2021

Background

Epidemics of infectious diseases have a great negative impact on people's daily life. How it changes over time and what kind of laws it obeys are important questions that researchers are always interested in. Among the characteristics of infectious diseases, the phenomenon of recrudescence is undoubtedly of great concern. Understanding the mechanisms of the outbreak cycle of infectious diseases could be conducive for public health policies to the government.

Method

In this study, we collected time-series data for nine class C notifiable infectious diseases from 2009 to 2021 using public datasets from the National Health Commission of China. Oscillatory power of each infectious disease was captured using the method of the power spectrum analysis.

Results

We found that all the nine class C diseases have strong oscillations, which could be divided into three categories according to their oscillatory frequencies each year. Then, we calculated the oscillation power and the average number of infected cases of all nine diseases in the first 6 years (2009-2015) and the next 6 years (2015-2021) since the update of the surveillance system. The change of oscillation power is positively correlated to the change in the number of infected cases. Moreover, the diseases that break out in summer are more selective than those in winter.

Conclusion

Our results enable us to better understand the oscillation characteristics of class C infectious diseases and provide guidance and suggestions for the government's prevention and control policies.

Utility of Multi-target Nested PCR and ELISPOT Assays for the Detection of Paucibacillary Leprosy: A Possible Conclusion of Clinical Laboratory Misdiagnosis

The diagnosis of paucibacillary (PB) leprosy often possesses a diagnostic challenge, especially for pure neuritic and lesser skin lesions with the zero bacillary load, requiring a sensitive and accurate diagnostic tool. We have included 300 clinically diagnosed new leprosy cases (comprising 98 PB cases) and analyzed the sensitivity and specificity of PB leprosy cases by nested PCR with folP, gyrA, rpoB, RLEP, and 16SrRNA and Enzyme-linked Immunospot Assay test (ELISPOT) with MMPII, NDO-BSA, and LID-1 antigens by detecting interferon gamma (IFN-γ) release. The overall positivity rates of genes tested in 300 clinical specimens were identified as 55% of 16SrRNA, 59% of RLEP, 59.3% of folP, 57.3% of rpoB, 61% of gyrA while 90% of nested folP, 92.6% of nested rpoB, and 95% of nested gyrA, and 285 (95%) of at least one gene positive cases. For PB specimens, 95% PCR positivity was achieved by three tested genes in nested PCR. The data obtained from ELISPOT for three antigens were analyzed for IFN-γ expression with 600 subjects. Among 98 PB leprosy cases, the sensitivity of MMP II, LID-1, and NDO-BSA was 90%, 87%, and 83%, respectively, and the specificity was 90%, 91%, and 86%, respectively. The total number of cases positive for at least one antigen was 90 (91.8%) in PB, which is significantly higher than that in multibacillary (MB) leprosy (56.7%). The combination of multi-targets nested PCR and ELISPOT assay provides a specific tool to early clinical laboratory diagnosis of PB leprosy cases. The two assays are complementary to each other and beneficial for screening PB patients.

The state of the leprosy epidemic in Yunnan, China 2011-2020: A spatial and spatiotemporal analysis, highlighting areas for intervention

BACKGROUND

Despite public health efforts to reduce the leprosy burden in Yunnan, China, leprosy remains an important public health problem in some specific areas. We analyzed the epidemiological characteristics and spatial distribution of leprosy in Yunnan, China, and provide data to guide disease prevention and control efforts.

METHODOLOGY/PRINCIPAL FINDINGS

The surveillance data of newly detected leprosy cases in Yunnan, China, during 2011-2020 were extracted from the LEPROSY MANAGEMANT INFORMATION SYSTEM IN CHINA (LEPMIS), and spatial distribution analysis, spatial autocorrelation analysis, and spatiotemporal scanning were performed with ArcGIS 10.6.1, GeoDa 1.8.8, and SaTScan 9.4.3 software, respectively. A total of 1907 newly detected leprosy cases were reported in Yunnan, China, during 2011-2020. The new case detection rate (NCDR) decreased from 0.62 in 2011 to 0.25 in 2020, with an annual incidence of 0.41/100,000 population. The proportions of multibacillary (MB) cases, cases in female patients, cases causing grade 2 physical disability (G2D), and cases in pediatric patients were 67.07%, 33.93%, 17.99%, and 2.83%, respectively. The number of counties with an incidence above 1/100,000 population decreased from 30 in 2011 to 8 in 2020. The Moran's I of leprosy in Yunnan, China, during 2011-2020 ranged from 0.076 to 0.260, indicating the presence of spatial clusters. Local spatial autocorrelation (LSA) analysis showed that high-high cluster areas (hot spots) were mainly distributed in the southeastern, northern, and northwestern regions. Spatiotemporal scanning showed three clusters with high NCDRs. The probably primary clusters, occurring during January 1, 2011-December 31, 2015, covered 11 counties in the southeastern region (RR = 5.046515, LRR = 271.749664, P = 0.000).

CONCLUSION

The number of leprosy cases in Yunnan decreased overall, although some high-NCDR regions remained. Geographic information system (GIS) analysis coupled with spatial analysis indicated regions with leprosy clusters. Continuous leprosy prevention and control strategies in Yunnan Province should be established, and interventions in high-risk regions should be prioritized and further strengthened.

Evaluation of antibody detection against the NDO-BSA, LID-1 and NDO-LID antigens as confirmatory tests to support the diagnosis of leprosy in Yunnan province, southwest China

Although multidrug therapy (MDT) has been widely used for the treatment of leprosy for nearly 40 y, the disease remains a public health concern in some areas. The early detection of leprosy cases is vital to interrupt Mycobacterium leprae transmission, but currently diagnosis is typically achieved during the recognition of clinical symptoms by professional staff performing physical examinations in conjunction with microbiological assessment of slit skin smears (SSSs) and histopathology. In the last 10 y, serum antibody detection tests have emerged to aid leprosy diagnosis. Here we evaluated the ability of antigens NDO-BSA and LID-1 (ML0405 and ML2331) and the conjugate of these, NDO-LID, to detect antibodies in the sera of 113 leprosy patients and 166 control individuals in Yunnan province in southwest China. We found that each antigen was readily detected by sera from multibacillary (MB) patients, with sensitivities of 97.3%, 97.3% and 98.6% for NDO-BSA, LID-1 and NDO-LID, respectively. Even among paucibacillary (PB) patients the antigens detected antibodies in 74.4%, 56.4% and 69.2% of serum samples, respectively. Receiver operating characteristics (ROC) curve analysis indicated that, irrespective of the leprosy case classification as MB or PB, the detection efficiency obtained with NDO-LID was better than that obtained with the other two antigens (with LID-1 being a slightly better than NDO-BSA). Our results indicate the utility of NDO-LID in assisting in the diagnosis of PB and MB leprosy patients and that these antibody detection assays represent powerful diagnostic tools. We suggest that could be implemented into the procedures of local health centres in leprosy-endemic regions to assist in earlier diagnosis.

Internal Migration and Leprosy in Shanghai from 2000 to 2019: an Epidemiological Study of New Cases

Leprosy is a chronic infectious disease caused by Mycobacterium leprae. Massive internal migration from rural to urban areas poses new challenges for leprosy control in Shanghai, China. This retrospective epidemiological study examined new cases of leprosy diagnosed in Shanghai from 2000 to 2019, with emphasis on internal migration cases. There were 145 cases of leprosy in the study period; the majority of cases (89.0%) were internal migrants. Migrant cases had a mean of 25.4 months lag time from onset of symptoms to diagnosis, which was significantly longer than that of resident cases (mean 10.8 months, p < 0.001). Greater lag time from the first visit to diagnosis was observed in migrant cases (mean 23.2 months) compared with resident cases (mean 9.4 months, p < 0.001). A large majority of cases (91.0%) had been misdiagnosed. Internal migrant cases were responsible for most incidences of leprosy in Shanghai. They often did not receive timely diagnosis and treatment, which may have an adverse impact on the prevention of epidemic leprosy.

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

Importance

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

Objective

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

Design, Setting, and Participants

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

Exposures

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

Main Outcomes and Measures

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

Results

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

Conclusions and Relevance

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

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

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

Trends of the leprosy control indicators in Benin from 2006 to 2018

BACKGROUND

Leprosy, or Hansen's disease, is a chronic infectious disease caused by Mycobacterium leprae. The purpose of this study was to describe the epidemiological characteristics of leprosy in Benin from 2006 to 2018.

METHODS

This descriptive retrospective study included data from January 2006 to December 2018. The data of all patients treated in the leprosy treatment centres (LTCs) of the Republic of Benin were obtained from the LTC registers and analysed using Stata/SE 11.0 software. Quantum GIS (Geographic Information System) version 2.18.23 software was used for mapping. The main indicators of leprosy were calculated according to the World Health Organization (WHO) recommendations.

RESULTS

During the study period, a total of 2785 (annual average of 214) new cases of leprosy were diagnosed. The median age of the patients was 38 years, with extremes ranging from 6 to 88 years. The sex ratio (males/females) was 1.18 (1509/1276). The departments of Plateau, Atacora, and Zou were the most endemic; their leprosy detection rate per 100,000 population during these thirteen years were 6.46 (479/7414297), 5.38 (534/9932880) and 5.19 (526/10134877), respectively. The leprosy detection rate declined from 3.8 to 1.32 per 100,000 inhabitants. The proportion of paediatric cases varied from 8.56 to 2.67% as the proportion of multibacillary forms increased from 72.95 to 90%. From 2006 to 2018, 622 leprosy patients detected had grade 2 disability (G2D) at screening, indicating an average rate of 5.06 (622/122877474) cases with G2D per million population. The proportion of grade 2 disabilities increased from 21.23 to 32% during the study period. The majority of new leprosy cases among foreign-born persons were Nigerian (85.71%). The completion of multidrug therapy (MDT) for paucibacillary (PB) and multibacillary (MB) leprosy cases ranged from 96.36 to 95.65% and from 90.53 to 94.12%, respectively.

CONCLUSION

In Benin, leprosy remains a major health challenge; it is important to revitalize the epidemiological surveillance system to achieve its elimination by 2030.

Leprosy in the North and Northeast regions of Brazil: an integrated spatiotemporal approach

OBJECTIVE

To analyse the spatiotemporal patterns of leprosy occurrence in the North and Northeast regions of Brazil from 2001 to 2017.

METHODS

Mixed population-based ecological study with spatial and temporal trend analysis of epidemiological indicators based on new cases reported to the Information System for Notifiable Diseases of the Ministry of Health occurring in individuals residing in North and Northeast states of Brazil.

RESULTS

A total of 396 987 new cases were analysed; 9.2% of these involved children <15 years of age, and 5.4% involved individuals with grade 2 disability (G2D). The Northeast region recorded 66.4% of the new cases. Most cases involved males between 15 and 59 years of age and of brown race/colour. The temporal trend showed a reduction in most of the indicators and study variables. The G2D rate did not have trends over time in the Northeast Region, in individuals 0-14 years of age, or in municipalities with 'very high' social vulnerability indexes. The spatial and spatiotemporal analysis showed the presence of hyperendemic foci with high detection risk involving municipalities in the states of Tocantins, Pará and Maranhão.

CONCLUSION

Leprosy in the North and Northeast regions of Brazil persists as a critical public health problem. Temporal and spatiotemporal patterns identified in this study confirm that leprosy remains epidemiologically relevant in vulnerable areas. Surveillance and control interventions are needed in municipalities with low detection in the general population, in children and in individuals with G2D, to reduce late diagnosis.

Develop and Field Evolution of Single Tube Nested PCR, SYBRGreen PCR Methods, for the Diagnosis of Leprosy in Paraffin-embedded Formalin Fixed Tissues in Yunnan Province, a Hyper endemic Area of Leprosy in China

BACKGROUND

Detection and pathology analysis of Mycobacterium leprae using skin biopsy tissues are essential for leprosy diagnosis and monitoring response to treatment. Although formalin fixation of patient tissues may not be ideal for molecular studies, biopsy samples are the most accessible material from suspected cases. Therefore, clinical molecular laboratories must be able to utilize formalin-fixed, paraffin-embedded (FFPE) material.

OBJECTIVE

To determine the best molecular method for diagnosing and monitoring leprosy in FFPE specimens, we developed a single-tube nested PCR (STNPCR) (131 bp) and SYBRGreen PCR (101 bp) assay using primers for the M. leprae-specific repetitive element (RLEP) gene and evaluated the results compared to those using previously established RLEP primers (372 bp).

METHODS

FFPE biopsy samples obtained from 145 leprosy patients (during or after multidrug therapy (MDT)) and patients with 29 other confounding dermatoses were examined by the bacteria index (BI) and by simple PCR, STNPCR, and SYBRGreen PCR using primers amplifying a 372-bp, 131-bp or 101-bp fragment of RLEP, respectively.

RESULTS

In leprosy patients receiving MDT, STNPCR showed a highest specificity of 100% and a positive predictive value (PPV) of 100%. For multibacillary (MB), paucibacillary (PB) and all leprosy patients, the highest sensitivities were 91.42%, 39.13%, and 67.92%, negative predictive values (NPVs) were 8.57%, 60.36%, and 32.07%, and the highest accuracies were 93.93%, 62.67%, and 74.81%, respectively, higher than the results of SYBRGreen PCR and simple PCR. For post-MDT leprosy patients, SYBRGreen PCR showed the highest sensitivity of 50.0%, highest specificity of 100%, a PPV of 100%, an NPV of 100% and the highest accuracy of 83.72% for MB patients, which were higher than those of STNPCR and simple PCR. STNPCR showed the highest sensitivity of 26.66% and 34.48%, highest specificity of 100% and 100%, a PPV of 100% and 100%, NPV of 72.50% and 60.21%, and highest accuracy of 75.00% and 67.24% for PB and leprosy patients, respectively, higher than those of SYBRGreen PCR and simple PCR.

CONCLUSIONS

These findings suggest that STNPCR or SYBRGreen PCR (131-bp and 101-bp fragment amplification, respectively) for RLEP using FFPE specimens performs better as a diagnostic test and for monitoring response to MDT than does simple PCR based on 372-bp fragment amplification. Additionally, STNPCR showed increased sensitivity for PB diagnosis using FFPE specimens, which can be transferred remotely or retrieved from previous leprosy patients.