Leprosy in French Polynesia

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.

Unravelling the determinants of human health in French Polynesia: the MATAEA project

Background

French Polynesia is a French overseas collectivity in the Southeast Pacific, comprising 75 inhabited islands across five archipelagoes. The human settlement of the region corresponds to the last massive migration of humans to empty territories, but its timeline is still debated. Despite their recent population history and geographical isolation, inhabitants of French Polynesia experience health issues similar to those of continental countries. Modern lifestyles and increased longevity have led to a rise in non-communicable diseases (NCDs) such as obesity, diabetes, hypertension, and cardiovascular diseases. Likewise, international trade and people mobility have caused the emergence of communicable diseases (CDs) including mosquito-borne and respiratory diseases. Additionally, chronic pathologies including acute rheumatic fever, liver diseases, and ciguatera, are highly prevalent in French Polynesia. However, data on such diseases are scarce and not representative of the geographic fragmentation of the population.

Objectives

The present project aims to estimate the prevalence of several NCDs and CDs in the population of the five archipelagoes, and identify associated risk factors. Moreover, genetic analyses will contribute to determine the sequence and timings of the peopling history of French Polynesia, and identify causal links between past genetic adaptation to island environments, and present-day susceptibility to certain diseases.

Methods

This cross-sectional survey is based on the random selection of 2,100 adults aged 18-69 years and residing on 18 islands from the five archipelagoes. Each participant answered a questionnaire on a wide range of topics (including demographic characteristics, lifestyle habits and medical history), underwent physical measurements (height, weight, waist circumference, arterial pressure, and skin pigmentation), and provided biological samples (blood, saliva, and stool) for biological, genetic and microbiological analyses.

Conclusion

For the first time in French Polynesia, the present project allows to collect a wide range of data to explore the existence of indicators and/or risk factors for multiple pathologies of public health concern. The results will help health authorities to adapt actions and preventive measures aimed at reducing the incidence of NCDs and CDs. Moreover, the new genomic data generated in this study, combined with anthropological data, will increase our understanding of the peopling history of French Polynesia.

Clinical trial registration

https://clinicaltrials.gov/, identifier: NCT06133400.

[Epidemiology of leprosy in Chad from 2015 to 2019]

INTRODUCTION

leprosy is a disease found and unevenly distributed in Chad. Since 1997, the annual national prevalence has been less than 1/10000 inhabitants, the elimination threshold set by the World Health Organization (WHO). The purpose of this study is to describe epidemiological trends of leprosy in Chad between 2015 and 2019, in order to provide the necessary data for the development of more effective strategies for leprosy control.

METHODS

we conducted a retrospective, descriptive study of patients with leprosy diagnosed between 2015 and 2019 at national level. Data were collected from the database of the National Program for the Control of Leprosy in Chad (NPCLC).

RESULTS

a total of 1896 new cases of leprosy were detected in Chad between 2015 and 2019. The rates of patients aged 15 to 70 years and children under 15 years were 92.08% and 7.92% respectively. Sex ratio (M/F) was 1.68. The annual average detection rate was 2.6/100 000, with an average rate of multi-bacillary leprosy of 83.10% and degree 2 disability (2DD) of 20.38%. The average rate of degree 2 disability in children under 15 years of age was 0.92% . However, our study identified five districts as endemic (Adré, Abéché, Aboudeia, Koukou, et Bebedjia) in 2019, where the prevalence rate was above 1/10000 inhabitants.

CONCLUSION

epidemiological trends are in favor of the persistence of the disease and a delay in diagnosis and in the management of leprosy cases.

Fecal Excretion of Mycobacterium leprae, Burkina Faso

Mycobacterium leprae was detected by optical microscopy, fluorescent in situ hybridization, and molecular detection in feces collected for the diagnosis of Entamoeba coli enteritis in a leprosy patient in Burkina Faso. This observation raises questions about the role of fecal excretion of M. leprae in the natural history and diagnosis of leprosy.

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.

Fluorescent Hybridization of Mycobacterium leprae in Skin Samples Collected in Burkina Faso

Leprosy is caused by Mycobacterium leprae, and it remains underdiagnosed in Burkina Faso. We investigated the use of fluorescent in situ hybridization (FISH) for detecting M. leprae in 27 skin samples (skin biopsy samples, slit skin samples, and skin lesion swabs) collected from 21 patients from Burkina Faso and three from Côte d'Ivoire who were suspected of having cutaneous leprosy. In all seven Ziehl-Neelsen-positive skin samples (four skin biopsy samples and three skin swabs collected from the same patient), FISH specifically identified M. leprae, including one FISH-positive skin biopsy sample that remained negative after testing with PCR targeting the rpoB gene and with the GenoType LepraeDR assay. Twenty other skin samples and three negative controls all remained negative for Ziehl-Neelsen staining, FISH, and rpoB PCR. These data indicate the usefulness of a microscopic examination of skin samples after FISH for first-line diagnosis of cutaneous leprosy. Accordingly, FISH represents a potentially useful point-of-care test for the diagnosis of cutaneous leprosy.