Leprosy is an infectious disease that affects peripheral nerves and can lead to severe lifelong disabilities. Despite the availability of an effective cure, a fairly stable number of about 200,000... Show moreLeprosy is an infectious disease that affects peripheral nerves and can lead to severe lifelong disabilities. Despite the availability of an effective cure, a fairly stable number of about 200,000 new leprosy patients per year has been reported since 2010. This stagnation shows that the transmission of the mycobacteria that cause leprosy, Mycobacterium leprae and Mycobacterium lepromatosis, is still taking place. Timely diagnosis of leprosy patients is therefore vital, so that the time frame in which a person is contagious is shortened, but also irreversible nerve damage and leprosy-associated disabilities can be prevented. However, tools that confirm the diagnosis of leprosy are not yet available. This thesis investigated which factors in blood (the so-called biomarkers) can help to diagnose leprosy. The clinical signs of leprosy have a spectral character and are influenced by the immune response of the host. A combination of biomarkers is described that is able to identify patients with a lot of bacteria (multibacillary) as well as the more difficult to diagnose patients with few bacteria (paucibacillary). Subsequently, these biomarkers have been implemented in user-friendly lateral flow assays, which have been extensively validated in leprosy endemic areas. Show less
Leprosy is a multifactorial chronic disease caused by Mycobacterium leprae or Mycobacterium lepromatosis that affects the skin and nerves. More than 200.000 new cases are diagnosed per year; thus,... Show moreLeprosy is a multifactorial chronic disease caused by Mycobacterium leprae or Mycobacterium lepromatosis that affects the skin and nerves. More than 200.000 new cases are diagnosed per year; thus, transmission is still ongoing. The most likely way of transmission is the respiratory route form human-to-human; however, transmission is still not clearly understood. Early diagnosis of leprosy is crucial to reduce and avoid transmission as well as leprosy-associated disabilities, which are also a cause of stigma. Currently, diagnosis is performed based on clinical signs and symptoms and late- or mis-diagnosis are not uncommon.In this thesis, we combined the study of pathogen transmission with host transcriptomic and genomic biomarkers. To explore M. leprae transmission a One Health approach was followed, where human, animal and environmental samples were studied.The combination of demographic characteristics, pathogen detection, genetic and/or transcriptomic biomarkers can be applied in a multifactorial leprosy signature applicable for early diagnosis of leprosy and/or to guide intervention strategies. Identification of predictive biomarkers will in due course lead to prompt treatment, preventing leprosy-associated irreversible disabilities as well as reducing M. leprae transmission. Show less
Objectives: To identify patterns of spatial clustering of leprosy. Design: We performed a baseline survey for a trial on post-exposure prophylaxis for leprosy in Comoros and Madagascar. We screened... Show moreObjectives: To identify patterns of spatial clustering of leprosy. Design: We performed a baseline survey for a trial on post-exposure prophylaxis for leprosy in Comoros and Madagascar. We screened 64 villages, door-to-door, and recorded results of screening, demographic data and geographic coordinates. To identify clusters, we fitted a purely spatial Poisson model using Kulldorff's spatial scan statistic. We used a regular Poisson model to assess the risk of contracting leprosy at the individual level as a function of distance to the nearest known leprosy patient. Results: We identified 455 leprosy patients; 200 (4 4.0%) belonged to 2735 households included in a cluster. Thirty-eight percent of leprosy patients versus 10% of the total population live <25 m from another leprosy patient. Risk ratios for being diagnosed with leprosy were 7.3, 2.4, 1.8, 1.4 and 1.7, for those at the same household, at 1-<25 m, 25-<50 m, 50-<75 m and 75-<100 m as/from a leprosy patient, respectively, compared to those living at >100 m. Conclusions: We documented significant clustering of leprosy beyond household level, although 56% of cases were not part of a cluster. Control measures need to be extended beyond the household, and social networks should be further explored. (c) 2021 The Author(s). Published by Elsevier Ltd on behalf of International Society for Infectious Diseases. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-ncnd/4.0/). Show less
Tio-Coma, M.; Kielbasa, S.M.; Eeden, S.J.F. van den; Mei, H.L.; Roy, J.C.; Wallinga, J.; ... ; Geluk, A. 2021
Background: Leprosy, a chronic infectious disease caused by Mycobacterium leprae, is often late-or misdiag-nosed leading to irreversible disabilities. Blood transcriptomic biomarkers that... Show moreBackground: Leprosy, a chronic infectious disease caused by Mycobacterium leprae, is often late-or misdiag-nosed leading to irreversible disabilities. Blood transcriptomic biomarkers that prospectively predict those who progress to leprosy (progressors) would allow early diagnosis, better treatment outcomes and facilitate interventions aimed at stopping bacterial transmission. To identify potential risk signatures of leprosy, we collected whole blood of household contacts (HC, n=5,352) of leprosy patients, including individuals who were diagnosed with leprosy 4-61 months after sample collection.Methods: We investigated differential gene expression (DGE) by RNA-Seq between progressors before pres-ence of symptoms (n=40) and HC (n=40), as well as longitudinal DGE within each progressor. A prospective leprosy signature was identified using a machine learning approach (Random Forest) and validated using reverse transcription quantitative PCR (RT-qPCR). Findings: Although no significant intra-individual longitudinal variation within leprosy progressors was iden-tified, 1,613 genes were differentially expressed in progressors before diagnosis compared to HC. We identi-fied a 13-gene prospective risk signature with an Area Under the Curve (AUC) of 95.2%. Validation of this RNA-Seq signature in an additional set of progressors (n=43) and HC (n=43) by RT-qPCR, resulted ina final 4 -gene signature, designated RISK4LEP (MT-ND2, REX1BD, TPGS1, UBC) (AUC=86.4%).Interpretation: This study identifies for the first time a prospective transcriptional risk signature in blood pre-dicting development of leprosy 4 to 61 months before clinical diagnosis. Assessment of this signature in con-tacts of leprosy patients can function as an adjunct diagnostic tool to target implementation of interventions to restrain leprosy development. (C) 2021 The Author(s). Published by Elsevier B.V. Show less
Globally more than 200,000 people develop leprosy every year and 2-3 million people live with leprosy associated disabilities. Despite the availability of multi drug therapy, leprosy has continued... Show moreGlobally more than 200,000 people develop leprosy every year and 2-3 million people live with leprosy associated disabilities. Despite the availability of multi drug therapy, leprosy has continued affecting many individuals, including children because of the uninterrupted transmission in the population. Untreated multi bacillary cases as well as non-symptomatic M. leprae infected individuals in the population are believed to be the major sources of M. leprae infection and transmission. Leprosy reactions are also the major causes of disabilities. However, no tools are available to predict their occurrence. This thesis focuses on in vitro assessment of recombinant M. leprae proteins and synthetic peptides for their immunogenicity and specificity in populations with different genetic backgrounds by measuring cell mediated immunity and this has shown the presence of potential antigens. Further in depth analysis of the host immune responses against these unique antigens in leprosy patients, their household contacts and healthy endemic controls has led to identification of potential biomarkers with an immense importance in development of diagnostic tools for detection of M. leprae infection and early diagnosis of leprosy reactions. Currently, field friendly tests for early detection are developed at the LUMC using identified M. leprae antigens and host biomarkers with diagnostic potential. Show less
Mayboroda, O.A.; Hooij, A. van; Derks, R.; Eeden, S.J.F. van den; Dijkman, K.; Khadge, S.; ... ; Geluk, A. 2016
Conclusions: This study indicates that urinary metabolic profiles are promising host biomarkers for the detection of intra-individual changes during acute inflammation in leprosy and could... Show moreConclusions: This study indicates that urinary metabolic profiles are promising host biomarkers for the detection of intra-individual changes during acute inflammation in leprosy and could contribute to early treatment and prevention of tissue damage. (C) 2016 The Authors. Published by Elsevier Ltd on behalf of International Society for Infectious Diseases. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Show less
Inskip, S.A.; Taylor, G.M.; Zakrzewski, S.R.; Mays, S.A.; Pike, A.W.G.; Llewellyn, G.; et al 2015
We have examined a 5th to 6th century inhumation from Great Chesterford, Essex, UK. The incomplete remains are those of a young male, aged around 21–35 years at death. The remains show osteological... Show moreWe have examined a 5th to 6th century inhumation from Great Chesterford, Essex, UK. The incomplete remains are those of a young male, aged around 21–35 years at death. The remains show osteological evidence of lepromatous leprosy (LL) and this was confirmed by lipid biomarker analysis and ancient DNA (aDNA) analysis, which provided evidence for both multi-copy and single copy loci from the Mycobacterium leprae genome. Genotyping showed the strain belonged to the 3I lineage, but the Great Chesterford isolate appeared to be ancestral to 3I strains found in later medieval cases in southern Britain and also continental Europe. While a number of contemporaneous cases exist, at present, this case of leprosy is the earliest radiocarbon dated case in Britain confirmed by both aDNA and lipid biomarkers. Importantly, Strontium and Oxygen isotope analysis suggest that the individual is likely to have originated from outside Britain. This potentially sheds light on the origins of the strain in Britain and its subsequent spread to other parts of the world, including the Americas where the 3I lineage of M. leprae is still found in some southern states of America. Show less
