Hot spots of leprosy in the endemic area of São Luís, Maranhão State, Northeastern Brazil

Spatio-temporal analysis of leprosy risks in a municipality in the state of Mato Grosso-Brazilian Amazon: results from the leprosy post-exposure prophylaxis program in Brazil

BACKGROUND

Leprosy post-exposure prophylaxis (LPEP) with single dose rifampicin (SDR) can be integrated into different leprosy control program set-ups once contact tracing has been established. We analyzed the spatio-temporal changes in the distribution of index cases (IC) and co-prevalent cases among contacts of leprosy patients (CP) over the course of the LPEP program in one of the four study areas in Brazil, namely the municipality of Alta Floresta, state of Mato Grosso, in the Brazilian Amazon basin.

METHODS

Leprosy cases were mapped, and socioeconomic indicators were evaluated to explain the leprosy distribution of all leprosy cases diagnosed in the period 2016-2018. Data were obtained on new leprosy cases [Notifiable diseases information system (Sinan)], contacts traced by the LPEP program, and socioeconomic variables [Brazilian Institute of Geography and Statistics (IBGE)]. Kernel, SCAN, factor analysis and spatial regression were applied to analyze changes.

RESULTS

Overall, the new case detection rate (NCDR) was 20/10 000 inhabitants or 304 new cases, of which 55 were CP cases among the 2076 examined contacts. Changes over time were observed in the geographic distribution of cases. The highest concentration of cases was observed in the northeast of the study area, including one significant cluster (Relative risk = 2.24; population 27 427, P-value < 0.001) in an area characterized by different indicators associated with poverty as identified through spatial regression (Coefficient 3.34, P-value = 0.01).

CONCLUSIONS

The disease distribution was partly explained by poverty indicators. LPEP influences the spatial dynamic of the disease and results highlighted the relevance of systematic contact surveillance for leprosy elimination.

[Combined use of serologic markers and spatial analysis for epidemiological surveillance of leprosyUso conjunto de los marcadores serológicos y del análisis espacial en la vigilancia epidemiológica de la lepra]

Objective

To evaluate the combined use of serologic markers and spatial analysis to increase the sensitivity of leprosy epidemiological surveillance.

Method

This cross-sectional study was performed with neighbors of leprosy cases and neighbors and family members of schoolchildren with a positive anti-phenolic glycolipid I (PGL-I) test in Diamantina, state of Minas Gerais, Brazil. Neighbors were those living within a 100-m radius of schoolchildren or leprosy cases. Data collection included a semi-structured interview, dermatologic examination, and rapid ML Flow test. All residential addresses were georeferenced. Multivariate regression and spatial analysis were performed with anti-PGL-I seropositivity as the dependent variable.

Results

The study included 1 491 individuals: 1 009 (67.7%) family members and neighbors of schoolchildren with positive serology test and 482 (32.3%) neighbors of leprosy cases. Of the total, 421 (28.2%) were positive for anti-PGL-I. Seropositivity was higher among family members and neighbors of seropositive schoolers (P < 0.001), among people with family income of 1 minimum wage (P < 0.001), among the youngest participants (P < 0.001), and among those living in homes with one to five rooms (P = 0.007). The seropositivity rate was higher in the geographic area corresponding to seropositive schoolchildren (P < 0.001), that is, the spot with the highest number of cases was different from the spot with the highest rate of seropositivity.

Conclusions

The combined use of serologic markers and spatial analysis allowed us to easily identify operational weaknesses of services and a possible occult leprosy endemism in the municipality's urban census tracts. Tracing of social contact and neighbors, active search, educational campaigns, school surveys, and territorial analyses facilitate the early diagnosis of leprosy.

Measuring endemicity and burden of leprosy across countries and regions: A systematic review and Delphi survey

BACKGROUND

Leprosy is a chronic infectious disease caused by Mycobacterium leprae, the annual new case detection in 2019 was 202,189 globally. Measuring endemicity levels and burden in leprosy lacks a uniform approach. As a result, the assessment of leprosy endemicity or burden are not comparable over time and across countries and regions. This can make program planning and evaluation difficult. This study aims to identify relevant metrics and methods for measuring and classifying leprosy endemicity and burden at (sub)national level.

METHODS

We used a mixed-method approach combining findings from a systematic literature review and a Delphi survey. The literature search was conducted in seven databases, searching for endemicity, burden and leprosy. We reviewed the available evidence on the usage of indicators, classification levels, and scoring methods to measure and classify endemicity and burden. A two round Delphi survey was conducted to ask experts to rank and weigh indicators, classification levels, and scoring methods.

RESULTS

The literature review showed variation of indicators, levels, and cut-off values to measure leprosy endemicity and/or burden. The most used indicators for endemicity include new case detection rate (NCDR), new cases among children and new cases with grade 2 disability. For burden these include NCDR, MB cases, and prevalence. The classification levels 'high' and 'low' were most important. It was considered most relevant to use separate scoring methods for endemicity and burden. The scores would be derived by use of multiple indicators.

CONCLUSION

There is great variation in the existing method for measuring endemicity and burden across countries and regions. Our findings contribute to establishing a standardized uniform approach to measure and classify leprosy endemicity and burden at (sub)national level, which would allow effective communication and planning of intervention strategies.

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.

Molecular epidemiology of leprosy: An update

Molecular epidemiology investigations are notoriously challenging in the leprosy field mainly because the inherent characteristics of the disease as well as its yet uncultivated causative agents, Mycobacterium leprae and M. lepromatosis. Despite significant developments in understanding the biology of leprosy bacilli through genomic approaches, the exact mechanisms of transmission is still unclear and the factors underlying pathological variation of the disease in different patients remain as major gaps in our knowledge about leprosy. Despite these difficulties, the last two decades have seen the development of genotyping procedures based on PCR-sequencing of target loci as well as by the genome-wide analysis of an increasing number of geographically diverse isolates of leprosy bacilli. This has provided a foundation for molecular epidemiology studies that are bringing a better understanding of strain evolution associated with ancient human migrations, and phylogeographical insights about the spread of disease globally. This review discusses the advantages and drawbacks of the main tools available for molecular epidemiological investigations of leprosy and summarizes various methods ranging from PCR-based genotyping to genome-typing techniques. We also describe their main applications in analyzing the short-range and long-range transmission of the disease. Finally, we summarise the current gaps and challenges that remain in the field of molecular epidemiology of leprosy.