Bayesian model, ecological factors & transmission of leprosy in an endemic area of South India

Prediction of the occurrence of leprosy reactions based on Bayesian networks

Introduction

Leprosy reactions (LR) are severe episodes of intense activation of the host inflammatory response of uncertain etiology, today the leading cause of permanent nerve damage in leprosy patients. Several genetic and non-genetic risk factors for LR have been described; however, there are limited attempts to combine this information to estimate the risk of a leprosy patient developing LR. Here we present an artificial intelligence (AI)-based system that can assess LR risk using clinical, demographic, and genetic data.

Methods

The study includes four datasets from different regions of Brazil, totalizing 1,450 leprosy patients followed prospectively for at least 2 years to assess the occurrence of LR. Data mining using WEKA software was performed following a two-step protocol to select the variables included in the AI system, based on Bayesian Networks, and developed using the NETICA software.

Results

Analysis of the complete database resulted in a system able to estimate LR risk with 82.7% accuracy, 79.3% sensitivity, and 86.2% specificity. When using only databases for which host genetic information associated with LR was included, the performance increased to 87.7% accuracy, 85.7% sensitivity, and 89.4% specificity.

Conclusion

We produced an easy-to-use, online, free-access system that identifies leprosy patients at risk of developing LR. Risk assessment of LR for individual patients may detect candidates for close monitoring, with a potentially positive impact on the prevention of permanent disabilities, the quality of life of the patients, and upon leprosy control programs.

Factors Influencing Leprosy Incidence: A Comprehensive Analysis of Observations in Wenshan of China, Nepal, and Other Global Epidemic Areas

Leprosy remains endemic in some regions and is a global health concern. However, the possible causes and risk factors of the disease remain unclear. Data in Wenshan, China were collected from the Wenshan Institute of Dermatology (1986-2015); data in Nepal were obtained from the Leprosy Control Division, Department of Health Services, Nepal (2011 to 2015); and data from Indonesia, India, and Brazil were collected from WHO records. We assessed the epidemiological trends of leprosy in Wenshan and compared the features of possible causes and risk factors with those of other countries. We then performed a descriptive and statistical analysis to make our study more purposeful and definitive. A total of 3,376 cases were detected in Wenshan from 1986 to 2015. The overall prevalence rate (PR) of leprosy presented a decreasing trend with a peak (4.9/10,000 population) in 1986. The detection of new leprosy cases was higher in males than in females. Visible deformity increased every year since 2005 with a disability of 34.8% in 2015 among new cases. In Nepal, 2,461 leprosy patients received multi-drug therapy (MDT) in 2015 which corresponded to the PR of 0.89/10,000 population. Geographic latitude and socio-economic situations appeared to be the main causes of leprosy, and the healthcare condition was an important factor associated with leprosy incidence. The introduction of MDT effectively reduced leprosy prevalence worldwide. Wenshan (China), Nepal, and other countries share similarities in various aspects with respect to socio-cultural features, geographical distribution, environmental factors, and economic situation, which may contribute to leprosy being endemic in these areas.

COMPARING SOCIO-ECONOMIC CONDITIONS OF MOTHER AND CHILDREN WITH LEPROSY IN ENDEMIC AND NON-ENDEMIC AREAS IN EAST JAVA, INDONESIA

Background

Leprosy is a disease that causes social, psychological, and economic issues. Failure to treat the causes of the immune system dysregulation in endemic areas of leprosy conditions makes the transmission of the bacteria easier. This paper aims to analyze the comparison of family income, occupation types of mothers and fathers, number of children, access to health facilities, and education of mothers, fathers, and children in mothers and children with leprosy in endemic and non-endemic areas.

Materials and Methods

A cross sectional study by survey was done in both an endemic and a non-endemic area of leprosy in Tuban Regency, East Java, Indonesia. Retrieval of research data was done using interview techniques. Respondents who participated in this study were 106 pairs of mother and child respondents who met the research restriction criteria. Subjects were divided into 5groups based on diagnosis of leprosy and area of living. Bivariate analysis was performed by comparing the independent variables in each group A, B, C, and D with group E.

Results

It was found that the variables that differed significantly between the endemic and non-endemic areas were the variable number of children with a p-value=0.004, family income with a p-value=0.049 and the variable mother's education with a p-value=0.016. Meanwhile, other variables do not have significant difference.

Conclusions

We found significant difference on the number of children, father's education, mother's education, and family income. These variables can be a risk factor for leprosy. To make efforts to prevent the transmission of leprosy, stakeholders should consider these factors.

Spatial analysis of epidemiological and quality indicators of health services for leprosy in hyperendemic areas in Northeastern Brazil

Leprosy is a public health problem due to the physical disabilities and deformities it causes. This study aimed to describe new leprosy cases using an operational classification and analyzing spatial patterns by means of epidemiological and quality indicators of health services in Pernambuco State, Brazil, between 2005 and 2014. This was an ecological study performed in 184 municipalities grouped into 12 health regions units for analysis. To analyze spatial patterns, the Bayesian local empirical method and Moran's spatial autocorrelation indicator were applied and box and Moran maps were used. Individuals aged ≥15 years old, grade zero physical disability and complete remission as the treatment outcome were predominant in both paucibacillary and multibacillary cases, the only difference was the predominance of females (n=9,286; 63.00%) and males (n=8,564; 60.70%), respectively. These variables were correlated (p<0.05) with the operational classification. The overall detection rate showed three high-priority areas; the indicator rate of grade 2 physical disability revealed clusters in regions IV, V, and VI; and the indicator rate of cases with some degree of disability showed precarious municipalities in seven health regions. Pernambuco maintains an active chain of transmission and ongoing endemicity of leprosy. Therefore, spatial analysis methods allow the identification of priority areas for intervention, thereby supporting the disease elimination strategy.

Cutaneous Mycobacterial Infections

Humans encounter mycobacterial species due to their ubiquity in different environmental niches. In many individuals, pathogenic mycobacterial species may breach our first-line barrier defenses of the innate immune system and modulate the activation of phagocytes to cause disease of the respiratory tract or the skin and soft tissues, sometimes resulting in disseminated infection. Cutaneous mycobacterial infections may cause a wide range of clinical manifestations, which are divided into four main disease categories: (i) cutaneous manifestations of Mycobacterium tuberculosis infection, (ii) Buruli ulcer caused by Mycobacterium ulcerans and other related slowly growing mycobacteria, (iii) leprosy caused by Mycobacterium leprae and Mycobacterium lepromatosis, and (iv) cutaneous infections caused by rapidly growing mycobacteria. Clinically, cutaneous mycobacterial infections present with widely different clinical presentations, including cellulitis, nonhealing ulcers, subacute or chronic nodular lesions, abscesses, superficial lymphadenitis, verrucous lesions, and other types of findings. Mycobacterial infections of the skin and subcutaneous tissue are associated with important stigma, deformity, and disability. Geography-based environmental exposures influence the epidemiology of cutaneous mycobacterial infections. Cutaneous tuberculosis exhibits different clinical phenotypes acquired through different routes, including via extrinsic inoculation of the tuberculous bacilli and dissemination to the skin from other sites, or represents hypersensitivity reactions to M. tuberculosis infection. In many settings, leprosy remains an important cause of neurological impairment, deformity, limb loss, and stigma. Mycobacterium lepromatosis, a mycobacterial species related to M. leprae, is linked to diffuse lepromatous leprosy of Lucio and Latapí. Mycobacterium ulcerans produces a mycolactone toxin that leads to subcutaneous tissue destruction and immunosuppression, resulting in deep ulcerations that often produce substantial disfigurement and disability. Mycobacterium marinum, a close relative of M. ulcerans, is an important cause of cutaneous sporotrichoid nodular lymphangitic lesions. Among patients with advanced immunosuppression, Mycobacterium kansasii, the Mycobacterium avium-intracellulare complex, and Mycobacterium haemophilum may cause cutaneous or disseminated disease. Rapidly growing mycobacteria, including the Mycobacterium abscessus group, Mycobacterium chelonei, and Mycobacterium fortuitum, are increasingly recognized pathogens in cutaneous infections associated particularly with plastic surgery and cosmetic procedures. Skin biopsies of cutaneous lesions to identify acid-fast staining bacilli and cultures represent the cornerstone of diagnosis. Additionally, histopathological evaluation of skin biopsy specimens may be useful in identifying leprosy, Buruli ulcer, and cutaneous tuberculosis. Molecular assays are useful in some cases. The treatment for cutaneous mycobacterial infections depends on the specific pathogen and therefore requires a careful consideration of antimicrobial choices based on official treatment guidelines.

Unsolved matters in leprosy: a descriptive review and call for further research

Leprosy, a chronic mycobacterial infection caused by Mycobacterium leprae, is an infectious disease that has ravaged human societies throughout millennia. This ancestral pathogen causes disfiguring cutaneous lesions, peripheral nerve injury, ostearticular deformity, limb loss and dysfunction, blindness and stigma. Despite ongoing efforts in interrupting leprosy transmission, large numbers of new cases are persistently identified in many endemic areas. Moreover, at the time of diagnosis, most newly identified cases have considerable neurologic disability. Many challenges remain in our understanding of the epidemiology of leprosy including: (a) the precise mode and route of transmission; (b) the socioeconomic, environmental, and behavioral factors that promote its transmission; and