Probable zoonotic leprosy in the southern United States

Prevalence of Mycobacterium leprae and Mycobacterium lepromatosis in roadkill armadillos in Brazil

To evaluate the prevalence of Mycobacterium leprae and Mycobacterium lepromatosis in road killed armadillos identified along Brazilian regions, samples of liver, spleen, muscle, ear, nose and tail were collected on highways from 78 animals. The armadillos were of four different species, Cabassous tatouay, Dasypus novemcinctus, Dasypus septemcinctus and Euphractus sexcinctus. After DNA extraction from two tissues, specific primers were used for the detection of each pathogen using SYBR green qualitative Real-Time PCR, and amplicons were sequenced. The species with the highest prevalence was D. novemcinctus, mainly in the Central-West, South, and Southeast regions of Brazil. We detected M. leprae DNA in 32 (41 %) of the 78 individuals and M. lepromatosis DNA was not identified in any of the examined samples. The zoonotic component of leprosy may play a role in the transmission of the disease in endemic areas in which environmental conditions and contact with reservoirs must be investigated.

Molecular and Serological Surveillance for Mycobacterium leprae and Mycobacterium lepromatosis in Wild Red Squirrels (Sciurus vulgaris) from Scotland and Northern England

Leprosy is a poverty-associated infectious disease in humans caused by Mycobacterium leprae or M. lepromatosis, often resulting in skin and peripheral nerve damage, which remains a significant public health concern in isolated areas of low- and middle-income countries. Previous studies reported leprosy in red squirrels in the British Isles, despite the fact that autochthonous human cases have been absent for centuries in this region. To investigate the extent of M. leprae and M. lepromatosis presence in wild red squirrels in the northern UK, we analyzed 220 blood/body cavity fluid samples from opportunistically sampled red squirrels (2004-2023) for specific antibodies against phenolic glycolipid-I, a cell wall component specific for these leprosy bacilli. Additionally, we assessed bacillus-derived DNA by real-time PCR (qPCR) in 250 pinnae from the same cohort. M. lepromatosis and M. leprae DNA were detected by qPCR in 20.4% and 0.8% of the squirrels, respectively. No cases of co-detection were observed. Detectable levels of anti-PGL-I antibodies by UCP-LFA were observed in 52.9% of animals with the presence of M. lepromatosis determined by qPCR, and overall in 15.5% of all animals. In total, 22.6% (n = 296) of this UK cohort had at least some exposure to leprosy bacilli. Our study shows that leprosy bacilli persist in red squirrels in the northern UK, emphasizing the necessity for ongoing molecular and serological monitoring to study leprosy ecology in red squirrels, gain insight into potential zoonotic transmission, and to determine whether the disease has a conservation impact on this endangered species.

A Case of Lepromatous Leprosy (Lucio's Phenomenon) Presenting as Periorbital Edema

Despite low prevalence of leprosy worldwide, new cases continue to present and require swift evaluation and diagnosis to prevent complications. Here, we describe a case of lepromatous leprosy with Lucio's phenomenon initially presenting with facial and periorbital edema. A 38-year-old Brazilian woman presented to the emergency department with facial swelling and erythema, initially treated as cellulitis. Due to rapid worsening despite broad-spectrum antibiotics, she underwent soft tissue exploration and biopsy due to concern for necrotizing fasciitis. During her course, she also developed retiform purpura of bilateral upper and lower extremities. Periorbital and lower extremity pathological specimens ultimately revealed acid-fast bacilli consistent with Mycobacterium leprae , and the patient improved with multidrug therapy. This case illustrates the diagnostic difficulty of lepromatous leprosy with Lucio's phenomenon, which can initially present with periorbital edema.

Ancient Mycobacterium leprae genome reveals medieval English red squirrels as animal leprosy host

Leprosy, one of the oldest recorded diseases in human history, remains prevalent in Asia, Africa, and South America, with over 200,000 cases every year.1,2 Although ancient DNA (aDNA) approaches on the major causative agent, Mycobacterium leprae, have elucidated the disease's evolutionary history,3,4,5 the role of animal hosts and interspecies transmission in the past remains unexplored. Research has uncovered relationships between medieval strains isolated from archaeological human remains and modern animal hosts such as the red squirrel in England.6,7 However, the time frame, distribution, and direction of transmissions remains unknown. Here, we studied 25 human and 12 squirrel samples from two archaeological sites in Winchester, a medieval English city well known for its leprosarium and connections to the fur trade. We reconstructed four medieval M. leprae genomes, including one from a red squirrel, at a 2.2-fold average coverage. Our analysis revealed a phylogenetic placement of all strains on branch 3 as well as a close relationship between the squirrel strain and one newly reconstructed medieval human strain. In particular, the medieval squirrel strain is more closely related to some medieval human strains from Winchester than to modern red squirrel strains from England, indicating a yet-undetected circulation of M. leprae in non-human hosts in the Middle Ages. Our study represents the first One Health approach for M. leprae in archaeology, which is centered around a medieval animal host strain, and highlights the future capability of such approaches to understand the disease's zoonotic past and current potential.

High-Resolution Plasma Metabolomics Identifies Alterations in Fatty Acid, Energy, and Micronutrient Metabolism in Adults Across the Leprosy Spectrum

BACKGROUND

High-resolution metabolomics (HRM) is an innovative tool to study challenging infectious diseases like leprosy, where the pathogen cannot be grown with standard methods. Here, we use HRM to better understand associations between disease manifestations, nutrition, and host metabolism.

METHODS

From 2018 to 2019, adults with leprosy and controls were recruited in Minas Gerais, Brazil. Plasma metabolites were detected using an established HRM workflow and characterized by accurate mass, mass to charge ratio m/z and retention time. The mummichog informatics package compared metabolic pathways between cases and controls and between multibacillary (MB) and paucibacillary (PB) leprosy. Additionally, select individual metabolites were quantified and compared.

RESULTS

Thirty-nine cases (62% MB and 38% PB) and 25 controls were enrolled. We found differences (P < .05) in several metabolic pathways, including fatty acid metabolism, carnitine shuttle, retinol, vitamin D3, and C-21 steroid metabolism, between cases and controls with lower retinol and associated metabolites in cases. Between MB and PB, leukotrienes, prostaglandins, tryptophan, and cortisol were all found to be lower in MB (P < .05).

DISCUSSION

Metabolites associated with several nutrient-related metabolic pathways appeared differentially regulated in leprosy, especially MB versus PB. This pilot study demonstrates the metabolic interdependency of these pathways, which may play a role in the pathophysiology of disease.

New threats from an old foe: Evaluating the risk to the blood supply due to increasing incidence and endemicity of leprosy in the United States

Leprosy (i.e., Hansen's disease) is a chronic disease secondary to infection with either Mycobacterium leprae or M. lepromatosis. While the incidence of this disease is decreasing across the world, there is mounting evidence that it might be increasing, and becoming endemic, in the United States. Leprosy was once considered a potential threat to the blood supply, and while this threat has not borne out, it is worth revisiting the available data to assess whether it may pose a threat in the future. Herein, we discuss the evidence for and against the potential for transfusion-transmission of leprosy, and highlight future areas of research to further elucidate this possibility.

Half a Century in Hiding: A Unique Case of Tuberculoid Leprosy with an Unprecedented Incubation Period

BACKGROUND Leprosy, also known as Hansen's disease, is a neglected tropical disease with low prevalence in the United States. The disease's long incubation period can cause delayed presentation, and most affected individuals have a history of travel or work in leprosy-endemic regions. The immune response to Mycobacterium leprae determines the clinical characteristics of leprosy, with tuberculoid leprosy being characterized by well-defined granulomas and involvement of peripheral nerves. The recommended treatment is a combination of dapsone and rifampin for 12 months. CASE REPORT A 78-year-old man with a history of extensive travel to Africa and Asia 50 years ago, presented with a non-tender, non-pruritic, and hypopigmented skin lesion on his left knee. Biopsy results confirmed granulomatous inflammation and the presence of Mycobacterium leprae, leading to a diagnosis of tuberculoid/paucibacillary leprosy. The patient received dapsone and rifampin treatment, which resulted in symptom improvement. CONCLUSIONS The patient's long incubation period of 50 years between exposure and symptom onset is remarkable and possibly one of the longest reported for tuberculoid leprosy. It emphasizes the importance of considering leprosy in cases with an extensive travel history and long incubation periods. Our patient's case presented contradictory staining results, suggesting potential sampling variation or a rare mixed leprosy form. Based on his clinical findings, he was diagnosed with tuberculoid leprosy. Early diagnosis and treatment are crucial to prevent irreversible nerve damage and improve patient outcomes. Healthcare providers should be vigilant in acquiring a detailed travel history to facilitate early diagnosis and appropriate management of leprosy cases.

Auditory brainstem responses in the nine-banded armadillo (Dasypus novemcinctus)

The auditory brainstem response (ABR) to tone burst stimuli of thirteen frequencies ranging from 0.5 to 48 kHz was recorded in the nine-banded armadillo (Dasypus novemcinctus), the only extant member of the placental mammal superorder Xenarthra in North America. The armadillo ABR consisted of five main peaks that were visible within the first 10 ms when stimuli were presented at high intensities. The latency of peak I of the armadillo ABR increased as stimulus intensity decreased by an average of 20 μs/dB. Estimated frequency-specific thresholds identified by the ABR were used to construct an estimate of the armadillo audiogram describing the mean thresholds of the eight animals tested. The majority of animals tested (six out of eight) exhibited clear responses to stimuli from 0.5 to 38 kHz, and two animals exhibited responses to stimuli of 48 kHz. Across all cases, the lowest thresholds were observed for frequencies from 8 to 12 kHz. Overall, we observed that the armadillo estimated audiogram bears a similar pattern as those observed using ABR in members of other mammalian clades, including marsupials and later-derived placental mammals.

Multiplex PCR-based RFLP assay for early identification of prevalent Mycobacterium leprae genotypes

Mycobacterium leprae is classified into four SNP genotypes and 16 subtypes (from 1A to 4P) that exhibit phylogeographical association reported from around the world. Among them, genotypes 1D and 3I represent more than 60% of M. leprae strains. Here, we report a new method for M. leprae genotyping which identifies the genotypes 1D and 3I by combining multiplex PCR amplification and restriction fragment length polymorphism (RFLP) of a M. leprae DNA amplicons using AgeI restriction enzyme. Agarose gel electrophoresis showed a deletion of 11 bp only among 3I genotypes by electrophoresis. When this multiplex PCR reaction is subjected to AgeI digestion, successful restriction digestion shows three bands for all the genotypes except 1D where only two bands were observed due to loss of restriction site. This method gives us the advantage of 1-step identification of the two most prevalent strains of M. leprae without using specialized equipments such as the Sanger sequencing system or quantitative PCR.

Leprosy in a Patient With Lymphoma: A Challenge in the Twenty-First Century

Leprosy, or Hansen's disease, mistakenly considered a disease from the past by some, is still common nowadays, especially in tropical and subtropical regions. In the absence of appropriate medical treatment, it may progress and cause permanent damage to multiple organs. This case report illustrates the diagnostic challenge of a south-american adult man who had been living in Europe for over 14 years. He was referred to the Hematology department due to persistent lymphocytosis and a CD5+ B-cell lymphoproliferative disorder was identified. During clinical surveillance, the patient developed skin lesions in his limbs with associated hypoesthesia. A histological diagnosis of lepromatous leprosy was made, and he underwent a long-term three-drug therapeutic regimen (dapsone, rifampicin, and clofazimine). Adding to the complexity of the case, the patient progressed with splenomegaly and constitutional symptoms, more than 7 years after development of lymphocytosis. Through a comprehensive evaluation, a definitive diagnosis of mantle cell lymphoma was established and received 6-cycle R-CHOP induction, followed by maintenance rituximab. Importantly, prophylaxis for leprosy reactivation was not administered as there were no recommendations in available guidelines. Eventually, the patient experienced a leprosy relapse while on maintenance therapy, 58 months after completing the initial anti-leprous treatment. Clinical response was attained with a new treatment regimen consisting of rifampicin, clofazimine, and minocycline.  Although leprosy is primarily observed in tropical and subtropical regions, the long incubation period of this disease combined with the global flow of migrants, made us consider it. Despite being rare, leprosy relapses can occur even after a few decades. The contribution of rituximab or previously administered chemotherapeutic agents is still unknown. The question remains whether antibiotic prophylaxis should be performed in patients undergoing immunochemotherapy for malignant diseases.

Leprosy with type 1 reaction in a patient from Ontario, Canada without recent travel misdiagnosed as vasculitic neuropathy: a case report

BACKGROUND

Leprosy is rare within non-endemic countries such as Canada, where cases are almost exclusively imported from endemic regions, often presenting after an incubation period of as many as 20 years. Due to its rarity and prolonged incubation period, diagnosis is often delayed, which may result in neurologic impairment prior to the initiation of treatment. In this report we describe a case that is novel in its incubation period, which is the longest reported to-date and may have contributed to diagnostic delay. The case also uniquely demonstrates the challenges of distinguishing leprosy reactions from new rheumatologic manifestations in a patient with established autoimmune disease.

CASE PRESENTATION

We describe an 84-year-old male patient with rheumatoid arthritis on methotrexate and hydroxychloroquine, with no travel history outside Canada for 56 years, who presented in 2019 with new-onset paresthesias and rash. His paresthesias persisted despite a short course of prednisone, and his rash recurred after initial improvement. He underwent skin biopsy in May 2021, which eventually led to the diagnosis of leprosy. He was diagnosed with type 1 reaction and was started on rifampin, dapsone, clofazimine and prednisone, with which his rash resolved but his neurologic impairment remained.

CONCLUSION

This case report serves to highlight the potential for leprosy to present after markedly prolonged incubation periods. This is especially relevant in non-endemic countries that is home to an aging demographic of individuals who migrated decades ago from endemic countries. The importance of this concept is emphasized by the persistent neurologic impairment suffered by our case due to untreated type 1 reaction. We also demonstrate the necessity of skin biopsy in distinguishing this diagnosis from other autoimmune mimics in a patient with known autoimmune disease.

Effect of epidemic diseases on wild animal conservation

Under the background of global species extinction, the impact of epidemic diseases on wild animal protection is increasingly prominent. Here, we review and synthesize the literature on this topic, and discuss the relationship between diseases and biodiversity. Diseases usually reduce species diversity by decreasing or extinction of species populations, but also accelerate species evolution and promote species diversity. At the same time, species diversity can regulate disease outbreaks through dilution or amplification effects. The synergistic effect of human activities and global change is emphasized, which further aggravates the complex relationship between biodiversity and diseases. Finally, we emphasize the importance of active surveillance of wild animal diseases, which can protect wild animals from potential diseases, maintain population size and genetic variation, and reduce the damage of diseases to the balance of the whole ecosystem and human health. Therefore, we suggest that a background survey of wild animal populations and their pathogens should be carried out to assess the impact of potential outbreaks on the population or species level. The mechanism of dilution and amplification effect between species diversity and diseases of wild animals should be further studied to provide a theoretical basis and technical support for human intervention measures to change biodiversity. Most importantly, we should closely combine the protection of wild animals with the establishment of an active surveillance, prevention, and control system for wild animal epidemics, in an effort to achieve a win-win situation between wild animal protection and disease control.

Case Report of Leprosy in Central Florida, USA, 2022

Florida, USA, has witnessed an increased incidence of leprosy cases lacking traditional risk factors. Those trends, in addition to decreasing diagnoses in foreign-born persons, contribute to rising evidence that leprosy has become endemic in the southeastern United States. Travel to Florida should be considered when conducting leprosy contact tracing in any state.

Hi-plex deep amplicon sequencing for identification, high-resolution genotyping and multidrug resistance prediction of Mycobacterium leprae directly from patient biopsies by using Deeplex Myc-Lep

BACKGROUND

Expansion of antimicrobial resistance monitoring and epidemiological surveillance are key components of the WHO strategy towards zero leprosy. The inability to grow Mycobacterium leprae in vitro precludes routine phenotypic drug susceptibility testing, and only limited molecular tests are available. We evaluated a culture-free targeted deep sequencing assay, for mycobacterial identification, genotyping based on 18 canonical SNPs and 11 core variable-number tandem-repeat (VNTR) markers, and detection of rifampicin, dapsone and fluoroquinolone resistance-associated mutations in rpoB/ctpC/ctpI, folP1, gyrA/gyrB, respectively, and hypermutation-associated mutations in nth.

METHODS

The limit of detection (LOD) was determined using DNA of M. leprae reference strains and from 246 skin biopsies and 74 slit skin smears of leprosy patients, with genome copies quantified by RLEP qPCR. Sequencing results were evaluated versus whole genome sequencing (WGS) data of 14 strains, and versus VNTR-fragment length analysis (FLA) results of 89 clinical specimens.

FINDINGS

The LOD for sequencing success ranged between 80 and 3000 genome copies, depending on the sample type. The LOD for minority variants was 10%. All SNPs detected in targets by WGS were identified except in a clinical sample where WGS revealed two dapsone resistance-conferring mutations instead of one by Deeplex Myc-Lep, due to partial duplication of the sulfamide-binding domain in folP1. SNPs detected uniquely by Deeplex Myc-Lep were missed by WGS due to insufficient coverage. Concordance with VNTR-FLA results was 99.4% (926/932 alleles).

INTERPRETATION

Deeplex Myc-Lep may help improve the diagnosis and surveillance of leprosy. Gene domain duplication is an original putative drug resistance-related genetic adaptation in M. leprae.

FUNDING

EDCTP2 programme supported by the European Union (grant number RIA2017NIM-1847 -PEOPLE). EDCTP, R2Stop: Effect:Hope, The Mission To End Leprosy, the Flemish Fonds Wetenschappelijk Onderzoek.

[Overview of infectious and non-infectious diseases in French Guiana in 2022]

Source of many myths, French Guiana represents an exceptional territory due to the richness of its biodiversity and the variety of its communities. The only European territory in Amazonia, surrounded by the Brazilian giant and the little-known Suriname, Ariane 6 rockets are launched from Kourou while 50% of the population lives below the poverty line. This paradoxical situation is a source of health problems specific to this territory, whether they be infectious diseases with unknown germs, intoxications or chronic pathologies.Some infectious diseases such as Q fever, toxoplasmosis, cryptococcosis or HIV infection are in common with temperate countries, but present specificities leading to sometimes different management and medical reasoning. In addition to these pathologies, many tropical diseases are present in an endemic and / or epidemic mode such as malaria, leishmaniasis, Chagas disease, histoplasmosis or dengue. Besides, Amazonian dermatology is extremely varied, ranging from rare but serious pathologies (Buruli ulcer, leprosy) to others which are frequent and benign such as agouti lice (mites of the family Trombiculidae) or papillonitis. Envenomations by wild fauna are not rare, and deserve an appropriate management of the incriminated taxon. Obstetrical, cardiovascular and metabolic cosmopolitan pathologies sometimes take on a particular dimension in French Guiana that must be taken into account in the management of patients. Finally, different types of intoxication are to be known by practitioners, especially due to heavy metals.European-level resources offer diagnostic and therapeutic possibilities that do not exist in the surrounding countries and regions, thus allowing the management of diseases that are not well known elsewhere.Thanks to these same European-level resources, research in Guyana occupies a key place within the Amazon region, despite a smaller population than in the surrounding countries. Thus, certain pathologies such as histoplasmosis of the immunocompromised patient, Amazonian toxoplasmosis or Q fever are hardly described in neighboring countries, probably due to under-diagnosis linked to more limited resources. French Guiana plays a leading role in the study of these diseases.The objective of this overview is to guide health care providers coming to or practicing in French Guiana in their daily practice, but also practitioners taking care of people returning from French Guiana.

Allele-dependent interaction of LRRK2 and NOD2 in leprosy

Leprosy, caused by Mycobacterium leprae, rarely affects children younger than 5 years. Here, we studied a multiplex leprosy family that included monozygotic twins aged 22 months suffering from paucibacillary leprosy. Whole genome sequencing identified three amino acid mutations previously associated with Crohn’s disease and Parkinson’s disease as candidate variants for early onset leprosy: LRRK2 N551K, R1398H and NOD2 R702W. In genome-edited macrophages, we demonstrated that cells expressing the LRRK2 mutations displayed reduced apoptosis activity following mycobacterial challenge independently of NOD2. However, employing co-immunoprecipitation and confocal microscopy we showed that LRRK2 and NOD2 proteins interacted in RAW cells and monocyte-derived macrophages, and that this interaction was substantially reduced for the NOD2 R702W mutation. Moreover, we observed a joint effect of LRRK2 and NOD2 variants on Bacillus Calmette-Guérin (BCG)-induced respiratory burst, NF-κB activation and cytokine/chemokine secretion with a strong impact for the genotypes found in the twins consistent with a role of the identified mutations in the development of early onset leprosy.

Leprosy (Hansen's disease): An Update and Review

Leprosy (Hansen's disease) is caused by infection with bacilli of the Mycobacterium leprae complex. It is considered an exotic and rare diagnosis in Missouri. Past leprosy patients diagnosed locally have typically acquired it in areas of the world where leprosy is endemic. However, a recent case in a native Missourian that appears to be locally acquired suggests that leprosy may now be endemic in Missouri, possibly due to the expanded range of its zoonotic vector, the nine-banded armadillo. Health care providers in Missouri should be aware of how leprosy manifests and suspected cases referred to centers such as ours for evaluation and early institution of appropriate treatment.

Pathogenicity and virulence of Mycobacterium leprae

Leprosy is caused by Mycobacterium leprae (M. leprae) and M. lepromatosis, an obligate intracellular organism, and over 200,000 new cases occur every year. M. leprae parasitizes histiocytes (skin macrophages) and Schwann cells in the peripheral nerves. Although leprosy can be treated by multidrug therapy, some patients relapse or have a prolonged clinical course and/or experience leprosy reaction. These varying outcomes depend on host factors such as immune responses against bacterial components that determine a range of symptoms. To understand these host responses, knowledge of the mechanisms by which M. leprae parasitizes host cells is important. This article describes the characteristics of leprosy through bacteriology, genetics, epidemiology, immunology, animal models, routes of infection, and clinical findings. It also discusses recent diagnostic methods, treatment, and measures according to the World Health Organization (WHO), including prevention. Recently, the antibacterial activities of anti-hyperlipidaemia agents against other pathogens, such as M. tuberculosis and Staphylococcus aureus have been investigated. Our laboratory has been focused on the metabolism of lipids which constitute the cell wall of M. leprae. Our findings may be useful for the development of future treatments.

In vivo partial reprogramming by bacteria promotes adult liver organ growth without fibrosis and tumorigenesis

Ideal therapies for regenerative medicine or healthy aging require healthy organ growth and rejuvenation, but no organ-level approach is currently available. Using Mycobacterium leprae (ML) with natural partial cellular reprogramming capacity and its animal host nine-banded armadillos, we present an evolutionarily refined model of adult liver growth and regeneration. In infected armadillos, ML reprogram the entire liver and significantly increase total liver/body weight ratio by increasing healthy liver lobules, including hepatocyte proliferation and proportionate expansion of vasculature, and biliary systems. ML-infected livers are microarchitecturally and functionally normal without damage, fibrosis, or tumorigenesis. Bacteria-induced reprogramming reactivates liver progenitor/developmental/fetal genes and upregulates growth-, metabolism-, and anti-aging-associated markers with minimal change in senescence and tumorigenic genes, suggesting bacterial hijacking of homeostatic, regeneration pathways to promote de novo organogenesis. This may facilitate the unraveling of endogenous pathways that effectively and safely re-engage liver organ growth, with broad therapeutic implications including organ regeneration and rejuvenation.

The Acari Hypothesis, III: Atopic Dermatitis

Atopic dermatitis is a chronic relapsing dermatopathology involving IgE against allergenic materials present on mammalian epithelial surfaces. Allergens are as diverse as pet danders, and polypeptides expressed by microbes of the mammalian microbiome, e.g., Malassezia spp. The Acari Hypothesis posits that the mammalian innate immune system utilizes pathogen-bound acarian immune effectors to protect against the vectorial threat posed by mites and ticks. Per The Hypothesis, IgE-mediated allergic disease is a specious consequence of the pairing of acarian gastrointestinal materials, e.g., allergenic foodstuffs, with acarian innate immune effectors that have interspecies operability. In keeping with The Hypothesis, the IgE profile of atopic patients should include both anti-acarian antibodies and specious antibodies responsible for specific allergy. Further, the profile should inform on the diet and/or environment of the acarian vector. In this regard, the prevalence of Demodex and Dermatophagoides on the skin of persons suffering from atopic dermatitis is increased. Importantly, the diets of these mites correspond well with the allergens of affected patients. In this report, roles for these specific acarians in the pathogenesis of atopic dermatitis are proposed and elaborated.

Existence of viable Mycobacterium leprae in natural environment and its genetic profiling in a leprosy endemic region

Introduction

Molecular epidemiology of leprosy is very important to study leprosy transmission dynamics and to enhance our understanding of leprosy in endemic areas by utilizing the molecular typing method. Nowadays our understanding of leprosy transmission dynamics has been refined by SNP typing and VNTR marker analysis of M. leprae strains.

Objective

This study was carried out to find out the presence of viable M. leprae in the soil and water samples from residing areas of leprosy patients staying in different blocks of Purulia district of West Bengal, understanding their genotypes and compared with that of M. leprae present in patients.

Material and methods

Slit-skin smear (SSS) samples (n=112) were collected from the active multibacillary leprosy patients from different blocks of leprosy endemic area. Soil samples (n=1060) and water samples (n=620) were collected from residing areas of leprosy patients. SNP subtyping was performed by PCR followed by sequencing. Multiplex PCR was performed using fifteen ML-VNTR loci and results were analysed.

Results

We observed high PCR positivity in soil samples (344 out of 1060; 32%) and water samples (140 out of 620; 23%). These PCR positive samples when further screened for viability, it was observed that 150 soil samples (44%) and 56 water samples (40%) showed presence of 16S rRNA. SNP typing of M. leprae revealed presence of predominantly type 1. SNP subtype 1D (83%) was most prevalent in all the blocks of Purulia followed by subtype 1C (15%) and subtype 1A (2%). SNP subtype 2F was noted in only one sample. SNP and VNTR combination showed presence of similar strain type in certain pockets of Purulia region which was responsible for transmission.

Conclusion

Presence of viable M. leprae in the environment, and presence of SNP Type 1 M. leprae in patients and environment suggests both environment and patients play a role in disease transmission.

Confirming Multiplex RT-qPCR Use in COVID-19 with Next-Generation Sequencing: Strategies for Epidemiological Advantage

Rapid identification and tracking of emerging SARS-CoV-2 variants are critical for understanding the transmission dynamics and developing strategies for interrupting the transmission chain. Next-Generation Sequencing (NGS) is an exceptional tool for whole-genome analysis and deciphering new mutations. The technique has been instrumental in identifying the variants of concern (VOC) and tracking this pandemic. However, NGS is complex and expensive for large-scale adoption, and epidemiological monitoring with NGS alone could be unattainable in limited-resource settings. In this study, we explored the application of RT-qPCR-based detection of the variant identified by NGS. We analyzed a total of 78 deidentified samples that screened positive for SARS-CoV-2 from two timeframes, August 2020 and July 2021. All 78 samples were classified into WHO lineages by whole-genome sequencing and then compared with two commercially available RT-qPCR assays for spike protein mutation(s). The data showed good concordance between RT-qPCR and NGS analysis for specific SARS-CoV-2 lineages and characteristic mutations. RT-qPCR assays are quick and cost-effective and thus can be implemented in synergy with NGS for screening NGS-identified mutations of SARS-CoV-2 for clinical and epidemiological interest. Strategic use of NGS and RT-qPCR can offer several COVID-19 epidemiological advantages.

The Presence of Mycobacterium leprae in Wild Rodents

Leprosy is a chronic infection caused by Mycobacterium leprae. There is a lack of data regarding environmental reservoirs, which may represent a serious public health problem in Brazil, especially in the state of Pará, which occupies the fourth position in incidence of cases in the country. Previous studies report evidence of infection occurring among armadillos, mangabei monkeys, and chimpanzees. In the present study, wild animals were captured and tested for the presence of anti-PGL-1 antibodies and M. leprae DNA. Fieldwork was carried out from October to November of 2016 in the cities of Curionópolis and Canaã dos Carajás, southeast of Pará state. Small and medium-sized wild animals were captured using appropriate traps. A total of 15 animals were captured. Sera and viscera fragments were collected and tested by ELISA and PCR methods. The presence of M. leprae DNA was confirmed by sequencing of specific gyrase gene in three animals of two different species, including one Necromys lasiurus (liver sample) and two Proechimys roberti (kidney and liver samples). This unprecedented finding suggests that species other than those previously reported are responsible for maintaining M. leprae in nature.

Mycobacterium leprae Infection in a Wild Nine-Banded Armadillo, Nuevo León, Mexico

Nine-banded armadillos (Dasypus novemcinctus) are naturally infected with Mycobacterium leprae and are implicated in the zoonotic transmission of leprosy in the United States. In Mexico, the existence of such a reservoir remains to be characterized. We describe a wild armadillo infected by M. leprae in the state of Nuevo León, Mexico.

Human macrophage polarization in the response to Mycobacterium leprae genomic DNA

Infection with Mycobacterium leprae, the causative organism of leprosy, is still endemic in numerous parts of the world including the southwestern United States. The broad variation of symptoms in the leprosy disease spectrum range from the milder tuberculoid leprosy (paucibacillary) to the more severe and disfiguring lepromatous leprosy (multibacillary). The established thinking in the health community is that host response, rather than M. leprae strain variation, is the reason for the range of disease severity. More recent discoveries suggest that macrophage polarization also plays a significant role in the spectrum of leprosy disease but to what degree it contributes is not fully established. In this study, we aimed to analyze if different strains of M. leprae elicit different transcription responses in human macrophages, and to examine the role of macrophage polarization in these responses. Genomic DNA from three different strains of M. leprae DNA (Strains NHDP, Br4923, and Thai-53) were used to stimulate human macrophages under three polarization conditions (M1, M1-activated, and M2). Transcriptome analysis revealed a large number of differentially expressed (DE) genes upon stimulation with DNA from M. leprae strain Thai-53 compared to strains NHDP and Br4923, independent of the macrophage polarization condition. We also found that macrophage polarization affects the responses to M. leprae DNA, with up-regulation of numerous interferon stimulated genes. These findings provide a deeper understanding of the role of macrophage polarization in the recognition of M. leprae DNA, with the potential to improve leprosy treatment strategies.

Wild animal and zoonotic disease risk management and regulation in China: Examining gaps and One Health opportunities in scope, mandates, and monitoring systems

Emerging diseases of zoonotic origin such as COVID-19 are a continuing public health threat in China that lead to a significant socioeconomic burden. This study reviewed the current laws and regulations, government reports and policy documents, and existing literature on zoonotic disease preparedness and prevention across the forestry, agriculture, and public health authorities in China, to articulate the current landscape of potential risks, existing mandates, and gaps. A total of 55 known zoonotic diseases (59 pathogens) are routinely monitored under a multi-sectoral system among humans and domestic and wild animals in China. These diseases have been detected in wild mammals, birds, reptiles, amphibians, and fish or other aquatic animals, the majority of which are transmitted between humans and animals via direct or indirect contact and vectors. However, this current monitoring system covers a limited scope of disease threats and animal host species, warranting expanded review for sources of disease and pathogen with zoonotic potential. In addition, the governance of wild animal protection and utilization and limited knowledge about wild animal trade value chains present challenges for zoonotic disease risk assessment and monitoring, and affect the completeness of mandates and enforcement. A coordinated and collaborative mechanism among different departments is required for the effective monitoring and management of disease emergence and transmission risks in the animal value chains. Moreover, pathogen surveillance among wild animal hosts and human populations outside of the routine monitoring system will fill the data gaps and improve our understanding of future emerging zoonotic threats to achieve disease prevention. The findings and recommendations will advance One Health collaboration across government and non-government stakeholders to optimize monitoring and surveillance, risk management, and emergency responses to known and novel zoonotic threats, and support COVID-19 recovery efforts.

Detection of Mycobacterium leprae infection in family clusters from six leprosy-endemic regions in Colombia

BACKGROUND

Leprosy is a chronic infectious disease caused by Mycobacterium leprae, which continues to be endemic in tropical countries, making it necessary to implement strategies for its elimination. The objective of the current article was to detect M. leprae infection and associated factors through serological and epidemiological evaluation in family clusters of leprosy patients.

METHODS

Mycobacterium leprae infection was determined in 50 family clusters of leprosy patients from the departments of Bolívar, Atlántico, Santander, Boyacá, Chocó and Antioquia through the detection of antibodies (protein A, IgM, IgG) against anti-natural octyl disacharide-leprosy IDRI diagnostic (NDO-LID).

RESULTS

Higher seroconversion and elevated titers of these antibodies against NDO-LID were observed in the population of Chocó and Atlántico (p<0.05). Additionally, a higher frequency of infection was observed in large family groups that consumed armadillo meat and belonged to a low socioeconomic stratum (p<0.05). Multivariate analysis established that the main associated factors for a family cluster experiencing this infection were belonging to a vulnerable economic stratum and a large family group.

CONCLUSIONS

This study found that the set of social and demographic variables (i.e. armadillo consumption, geographic area, low socioeconomic status and belonging to a large family cluster) are related to the promotion of seropositivity in family clusters.

Mycobacterium leprae Infection in Ticks and Tick-Derived Cells

Leprosy is a zoonosis in the southern United States involving humans and wild armadillos. The majority of patients presenting with zoonotic strains of Mycobacterium leprae note extensive outdoor activity but only rarely report any history of direct contact with wild armadillos. Whether M. leprae is transmitted to new vertebrate hosts through the environment independently or with the aid of other organisms, e.g., arthropod vectors, is a fundamental question in leprosy transmission. The objectives of this study were to assess the potential for ticks to transmit M. leprae and to test if viable M. leprae can be maintained in tick-derived cells. To evaluate tick transmission, nymphal Amblyomma maculatum ticks were injected with isolated M. leprae. Infection and transmission were assessed by qPCR. Ticks infected as nymphs harbored M. leprae through vertical transmission events (nymph to adult and adult to progeny); and, horizontal transmission of M. leprae to a vertebrate host was observed. Mycobacterium leprae DNA was detected in multiple tick life cycle stages. Likewise, freshly isolated M. leprae (Thai-53) was used to infect a tick-derived cell line, and enumeration and bacterial viability were assessed at individual time points for up to 49 days. Evaluations of the viability of long-term cultured M. leprae (Thai-53 and Br4923) were also assessed in a mouse model. Tick-derived cells were able to maintain viable M. leprae over the 49-day course of infection and M. leprae remained infectious within tick cells for at least 300 days. The results of this study suggest that ticks themselves might serve as a vector for the transmission of M. leprae and that tick cells are suitable for maintenance of viable M. leprae for an extended period of time.

Detection and Monitoring of Mycobacterium leprae Infection in Nine Banded Armadillos (Dasypus novemcinctus) Using a Quantitative Rapid Test

Leprosy is an infectious disease caused by Mycobacterium leprae with tropism for skin and peripheral nerves. Incessant transmission in endemic areas is still impeding elimination of leprosy. Although detection of M. leprae infection remains a challenge in asymptomatic individuals, the presence of antibodies specific for phenolglycolipid-I (PGL-I) correlate with bacterial load. Therefore, serosurveillance utilizing field-friendly tests detecting anti-PGL-I antibodies, can be applied to identify those who may transmit bacteria and to study (reduction of) M. leprae transmission. However, serology based on antibody detection cannot discriminate between past and present M. leprae infection in humans, nor can it detect individuals carrying low bacillary loads. In humans, anti-PGL-I IgM levels are long-lasting and usually detected in more individuals than anti-PGL-I IgG levels. Inherent to the characteristically long incubation time of leprosy, IgM/IgG relations (antibody kinetics) in leprosy patients and infected individuals are not completely clear. To investigate the antibody response directly after infection, we have measured antibody levels by ELISA, in longitudinal samples of experimentally M. leprae infected, susceptible nine-banded armadillos (Dasypus novemcinctus). In addition, we assessed the user- and field-friendly, low-cost lateral flow assay (LFA) utilizing upconverting reporter particles (UCP), developed for quantitative detection of human anti-PGL-I IgM (UCP-LFA), to detect treatment- or vaccination-induced changes in viable bacterial load. Our results show that serum levels of anti-PGL-I IgM, and to a lesser extent IgG, significantly increase soon after experimental M. leprae infection in armadillos. In view of leprosy phenotypes in armadillos, this animal model can provide useful insight into antibody kinetics in early infection in the various spectral forms of human leprosy. The UCP-LFA for quantitative detection of anti-PGL-I IgM allows monitoring the efficacy of vaccination and rifampin-treatment in the armadillo leprosy model, thereby providing a convenient tool to evaluate the effects of drugs and vaccines and new diagnostics.

Autochthonous North American Leprosy: A Second Case in Canada

Autochthonous leprosy was reported in the Southern USA in 2011 and has comprised an average of 34% of new cases from 2015 to 2020 in that country. We report a similar case in a patient from Western Canada. A 50-year old male patient presented with a four-year history of a chronic rash. Pathology stains revealed acid-fast bacilli prompting specialist referral. Examination was suspicious for leprosy, which was confirmed on slit skin smears and molecular testing. The patient responded well to treatment. Genotypic testing mapped the organism to the 3I-2 SNP type, which is of European origin and is the type found in implicated armadillo species in North America.

One Health Approaches to Trace Mycobacterium leprae's Zoonotic Potential Through Time

Hansen's disease (leprosy), mainly caused by infection with Mycobacterium leprae, has accompanied humanity for thousands of years. Although currently rare in Europe, there are over 200,000 new infections annually in South East Asia, Africa, and South America. Over the years many disciplines - palaeopathology, ancient DNA and other ancient biomolecules, and history - have contributed to a better understanding of leprosy's past, in particular its history in medieval Europe. We discuss their contributions and potential, especially in relation to the role of inter-species transmission, an unexplored phenomenon in the disease's history. Here, we explore the potential of interdisciplinary approaches that understand disease as a biosocial phenomenon, which is a product of both infection with M. leprae and social behaviours that facilitate transmission and spread. Genetic evidence of M. leprae isolated from archaeological remains combined with systematic zooarchaeological and historical analysis would not only identify when and in what direction transmission occurred, but also key social behaviours and motivations that brought species together. In our opinion, this combination is crucial to understand the disease's zoonotic past and current potential.

BCG-induced immunity profiles in household contacts of leprosy patients differentiate between protection and disease

Leprosy is an infectious disease caused by Mycobacterium leprae leading to irreversible disabilities along with social exclusion. Leprosy is a spectral disease for which the clinical outcome after M. leprae infection is determined by host factors. The spectrum spans from anti-inflammatory T helper-2 (Th2) immunity concomitant with large numbers of bacteria as well as antibodies against M. leprae antigens in multibacillary (MB) leprosy, to paucibacillary (PB) leprosy characterised by strong pro-inflammatory, Th1 as well as Th17 immunity. Despite decades of availability of adequate antibiotic treatment, transmission of M. leprae is unabated. Since individuals with close and frequent contact with untreated leprosy patients are particularly at risk to develop the disease themselves, prophylactic strategies currently focus on household contacts of newly diagnosed patients. It has been shown that BCG (re)vaccination can reduce the risk of leprosy. However, BCG immunoprophylaxis in contacts of leprosy patients has also been reported to induce PB leprosy, indicating that BCG (re)vaccination may tip the balance between protective immunity and overactivation immunity causing skin/nerve tissue damage. In order to identify who is at risk of developing PB leprosy after BCG vaccination, amongst individuals who are chronically exposed to M. leprae, we analyzed innate and adaptive immune markers in whole blood of household contacts of newly diagnosed leprosy patients in Bangladesh, some of which received BCG vaccination. As controls, individuals from the same area without known contact with leprosy patients were similarly assessed. Our data show the added effect of BCG vaccination on immune markers on top of the effect already induced by M. leprae exposure. Moreover, we identified BCG-induced markers that differentiate between protective and disease prone immunity in those contacts.

Mycobacterium leprae diversity and population dynamics in medieval Europe from novel ancient genomes

BACKGROUND

Hansen's disease (leprosy), widespread in medieval Europe, is today mainly prevalent in tropical and subtropical regions with around 200,000 new cases reported annually. Despite its long history and appearance in historical records, its origins and past dissemination patterns are still widely unknown. Applying ancient DNA approaches to its major causative agent, Mycobacterium leprae, can significantly improve our understanding of the disease's complex history. Previous studies have identified a high genetic continuity of the pathogen over the last 1500 years and the existence of at least four M. leprae lineages in some parts of Europe since the Early Medieval period.

RESULTS

Here, we reconstructed 19 ancient M. leprae genomes to further investigate M. leprae's genetic variation in Europe, with a dedicated focus on bacterial genomes from previously unstudied regions (Belarus, Iberia, Russia, Scotland), from multiple sites in a single region (Cambridgeshire, England), and from two Iberian leprosaria. Overall, our data confirm the existence of similar phylogeographic patterns across Europe, including high diversity in leprosaria. Further, we identified a new genotype in Belarus. By doubling the number of complete ancient M. leprae genomes, our results improve our knowledge of the past phylogeography of M. leprae and reveal a particularly high M. leprae diversity in European medieval leprosaria.

CONCLUSIONS

Our findings allow us to detect similar patterns of strain diversity across Europe with branch 3 as the most common branch and the leprosaria as centers for high diversity. The higher resolution of our phylogeny tree also refined our understanding of the interspecies transfer between red squirrels and humans pointing to a late antique/early medieval transmission. Furthermore, with our new estimates on the past population diversity of M. leprae, we gained first insights into the disease's global history in relation to major historic events such as the Roman expansion or the beginning of the regular transatlantic long distance trade. In summary, our findings highlight how studying ancient M. leprae genomes worldwide improves our understanding of leprosy's global history and can contribute to current models of M. leprae's worldwide dissemination, including interspecies transmissions.

Leprosy in wild chimpanzees

Humans are considered as the main host for Mycobacterium leprae1, the aetiological agent of leprosy, but spillover has occurred to other mammals that are now maintenance hosts, such as nine-banded armadillos and red squirrels2,3. Although naturally acquired leprosy has also been described in captive nonhuman primates4-7, the exact origins of infection remain unclear. Here we describe leprosy-like lesions in two wild populations of western chimpanzees (Pan troglodytes verus) in Cantanhez National Park, Guinea-Bissau and Taï National Park, Côte d'Ivoire, West Africa. Longitudinal monitoring of both populations revealed the progression of disease symptoms compatible with advanced leprosy. Screening of faecal and necropsy samples confirmed the presence of M. leprae as the causative agent at each site and phylogenomic comparisons with other strains from humans and other animals show that the chimpanzee strains belong to different and rare genotypes (4N/O and 2F). These findings suggest that M. leprae may be circulating in more wild animals than suspected, either as a result of exposure to humans or other unknown environmental sources.

Simultaneous Determination of Mycobacterium leprae Drug Resistance and Single-Nucleotide Polymorphism Genotype by Use of Nested Multiplex PCR with Amplicon Sequencing

Mycobacterium leprae is the predominant cause of leprosy worldwide, and its genotypes can be classified into four single-nucleotide polymorphism (SNP) types and 16 subtypes. Determining M. leprae drug resistance and genotype is typically done by PCR and Sanger DNA sequencing, which require substantial effort. Here, we describe a rapid method involving multiplex PCR in combination with nested amplification and next-generation sequence analysis that allows simultaneous determination of M. leprae drug resistance and SNP genotype directly from clinical specimens. We used this method to analyze clinical samples from two paucibacillary, nine multibacillary, and six type-undetermined leprosy patients. Regions in folP1, rpoB, gyrA, and gyrB that determine drug resistance and those for 84 SNP-InDels in the M. leprae genome were amplified from clinical samples and their sequences determined. The results showed that seven samples were subtype 1A, three were 1D, and seven were 3K. Three samples of the subtype 3K had folp1 mutation. The method may allow more rapid genetic analyses of M. leprae in clinical samples.

Mycobacterium lepromatosis as a Second Agent of Hansen's Disease

Mycobacterium lepromatosis was identified as a new species and second causal agent of Hansen's disease (HD, or leprosy) in 2008, 150years after the disease was first attributed to Mycobacterium leprae. M. lepromatosis has been implicated in a small number of HD cases, and clinical aspects of HD caused by M. lepromatosis are poorly characterized. HD is a recognized zoonosis through transmission of M. leprae from armadillos, but the role of M. lepromatosis as a zoonotic agent of HD is unknown. M. lepromatosis was initially associated with diffuse lepromatous leprosy, but subsequent case reports and surveys have linked it to other forms of HD. HD caused by M. lepromatosis has been reported from three endemic countries: Brazil, Myanmar, and Philippines, and three non-endemic countries: Mexico, Malaysia, and United States. Contact with armadillos in Mexico was mentioned in 2/21 M. lepromatosis HD case reports since 2008. M. lepromatosis in animals has been investigated only in non-endemic countries, in squirrels and chipmunks in Europe, white-throated woodrats in Mexico, and armadillos in the United States. To date, there have only been a small number of positive findings in Eurasian red squirrels in Britain and Ireland. A single study of environmental samples found no M. lepromatosis in soil from a Scottish red squirrel habitat. Future studies must focus on endemic countries to determine the true proportion of HD cases caused by M. lepromatosis, and whether viable M. lepromatosis occurs in non-human sources.

Hansen Disease (Leprosy) and Armadillo Exposure in Arkansas: A Case Series

BACKGROUND

Although most cases of Hansen disease (HD) in the United States are imported from endemic areas, a subset of cases are relate to exposure to nine-banded armadillos. Several recent cases of HD in Arkansas occurred in patients who had not traveled to endemic areas and who reported variable degrees of armadillo exposure.

OBJECTIVE

The purpose of this study was to report 6 cases of HD diagnosed in Arkansas between 2004 and 2016. The secondary purpose was to explore the correlation between exposure to the nine-banded armadillo as it pertains to transmission of the disease.

METHODS

The referring clinician of each patient was contacted to gather information regarding the patient's clinical presentation, armadillo exposure, and travel history. In addition, the Arkansas Department of Health was consulted to review the demographics of individuals diagnosed with HD in the past 15 years and to review the distribution of HD throughout the state of Arkansas.

RESULTS

Six domestic cases of HD were associated with both direct and indirect exposure to armadillos.

LIMITATIONS

Armadillo exposure may be underreported in patients with HD because of fear of stigmatization and/or lack of access to care.

CONCLUSIONS

Direct exposure to armadillos does not appear to be required for transmission of HD making a soil-mediated mechanism of indirect exposure plausible.

Isolation of Mycobacterium lepromatosis and Development of Molecular Diagnostic Assays to Distinguish Mycobacterium leprae and M. lepromatosis

BACKGROUND

Mycobacterium leprae was thought to be the exclusive causative agent of leprosy until Mycobacterium lepromatosis was identified in a rare form of leprosy known as diffuse lepromatous leprosy (DLL).

METHODS

We isolated M. lepromatosis from a patient with DLL and propagated it in athymic nude mouse footpads. Genomic analysis of this strain (NHDP-385) identified a unique repetitive element, RLPM, on which a specific real-time quantitative polymerase chain reaction assay was developed. The RLPM assay, and a previously developed RLEP quantitative polymerase chain reaction assay for M. leprae, were validated as clinical diagnostic assays according to Clinical Laboratory Improvement Amendments guidelines. We tested DNA from archived histological sections, patient specimens from the United States, Philippines, and Mexico, and US wild armadillos.

RESULTS

The limit of detection for the RLEP and RLPM assays is 30 M. leprae per specimen (0.76 bacilli per reaction; coefficient of variation, 0.65%-2.44%) and 122 M. lepromatosis per specimen (3.05 bacilli per reaction; 0.84%-2.9%), respectively. In histological sections (n = 10), 1 lepromatous leprosy (LL), 1 DLL, and 3 Lucio reactions contained M. lepromatosis; 2 LL and 2 Lucio reactions contained M. leprae; and 1 LL reaction contained both species. M. lepromatosis was detected in 3 of 218 US biopsy specimens (1.38%). All Philippines specimens (n = 180) were M. lepromatosis negative and M. leprae positive. Conversely, 15 of 47 Mexican specimens (31.91%) were positive for M. lepromatosis, 19 of 47 (40.43%) were positive for M. leprae, and 2 of 47 (4.26%) contained both organisms. All armadillos were M. lepromatosis negative.

CONCLUSIONS

The RLPM and RLEP assays will aid healthcare providers in the clinical diagnosis and surveillance of leprosy.

Strategies for drug target identification in Mycobacterium leprae

Hansen's disease (HD), or leprosy, continues to be endemic in many parts of the world. Although multidrug therapy (MDT) is successful in curing a large number of patients, some of them abandon it because it is a long-term treatment. Therefore, identification of new drug targets in Mycobacterium leprae is considered of high importance. Here, we introduce an overview of in silico and in vitro studies that might be of help in this endeavor. The essentiality of M. leprae proteins is reviewed with discussion of flux balance analysis, gene expression, and knockout articles. Finally, druggability techniques are proposed for the validation of new M. leprae protein targets (see Fig. 1).

Susceptibility and resistance in leprosy: Studies in the mouse model

Leprosy is a chronic granulomatous infectious disease caused by the pathogen, Mycobacterium leprae, and the more recently discovered, M. lepromatosis. Described in 1873, M. leprae was among the first microorganisms to be proposed as a cause of a human infectious disease. As an obligate intracellular bacterium, it has still not thus far been reproducibly cultivated in axenic medium or cell cultures. Shepard's mouse footpad assay, therefore, was truly a breakthrough in leprosy research. The generation of immunosuppressed and genetically engineered mice, along with advances in molecular and cellular techniques, has since offered more tools for the study of the M. leprae–induced granuloma. While far from perfect, these new mouse models have provided insights into the immunoregulatory mechanisms responsible for the spectrum of this complex disease.

Zoonotic risk of Hansen's disease from community contact with wild armadillos: A systematic review and meta-analysis

Understanding and quantifying the risk of Hansen's disease (HD) through zoonotic transmission of Mycobacterium leprae infection from wild armadillos is important because hunting, handling and consumption of these animals is widespread in communities where HD is endemic, posing a potential threat to the health of individuals and to HD elimination. We conducted a systematic review (PROSPERO CRD42019159891) of publications in MEDLINE, EMBASE, Global Health, Scopus, LILACS, Biblioteca Digital Brasileira de Teses e Dissertações, Catálogo de Teses e Dissertações de CAPES, and Biblioteca Virtual em Saúde up to 09/05/2020 using Mesh and text terms in English, Portuguese, Spanish and French. Random effects meta-analyses were performed including of subgroups by endemicity and type of exposure. Seven of the nine included studies were case-control, four from Brazil and three from the USA, comprising 1,124 cases and 2,023 controls in total. The other two studies, one from Brazil and one from Colombia, were cross-sectional. The overall summary estimate (odds ratio, OR) for the relative odds of HD comparing people who had direct contact with armadillos and/or had eaten armadillo meat with those who had not was OR = 2.60 (95% CI 1.78-3.80, p < .001) with a predictive interval of OR = 1.10-6.17. Summary odds ratios for specific exposures were as follows: indirect contact, OR = 1.39 (95% CI 1.02, 1.89) (p = .04); eating, OR = 2.29 (95% CI 1.13, 4.66) (p = .02); hunting, OR = 2.54 (95% CI 1.21, 5.33) (p = .01). Most of the included studies had moderate risk of bias. Crude estimates were reduced by up to 24% when adjusted for confounders (where reported). Direct contact with wild armadillos was strongly associated with an increased risk of HD, whilst evidence for an increased risk of HD from indirect contact was weaker. The fraction of HD in endemic countries attributable to zoonotic transmission from armadillos remains unknown, but the precautionary principle needs to be adopted to protect public health.

Hansen's Disease and Complications among Marshallese Persons Residing in Northwest Arkansas, 2003-2017

Persons from the Republic of the Marshall Islands have among the highest rates of Hansen's disease (HD) in the world; the largest Marshallese community in the continental United States is in northwest Arkansas. In 2017, the HD Ambulatory Care Clinic in Springdale, Arkansas, informed the Arkansas Department of Health (ADH) that Marshallese persons with HD had severe disease with frequent complications. To characterize their illness, we reviewed ADH surveillance reports of HD among Marshallese persons in Arkansas treated during 2003-2017 (n = 42). Hansen's Disease prevalence among Marshallese in Arkansas (11.7/10,000) was greater than that in the general U.S. population. Complications included arthritis (38%), erythema nodosum leprosum (21%), and prolonged treatment lasting > 2 years (40%). The majority (82%) of patients treated for > 2 years had documented intermittent therapy. Culturally appropriate support for therapy and adherence is needed in Arkansas.

Zoonotic parasites infecting free-living armadillos from Brazil

Armadillos are specialist diggers and their burrows are used to find food, seek shelter and protect their pups. These burrows can also be shared with dozens of vertebrate and invertebrate species and; consequently, their parasites including the zoonotics. The aim of this study was to diagnose the presence of zoonotic parasites in four wild-caught armadillo species from two different Brazilian ecosystems, the Cerrado (Brazilian savanna) and the Pantanal (wetland). The investigated parasites and their correspondent diseases were: Toxoplasma gondii (toxoplasmosis), Trypanosoma cruzi (Chagas disease), Leishmania spp., (leishmaniasis), Paracoccidioides brasiliensis (Paracoccidioidomicosis) and Mycobacterium leprae (Hansen's disease). Forty-three free-living armadillos from Pantanal and seven road-killed armadillos from the Cerrado were sampled. Trypanosoma cruzi DTU TcIII were isolated from 2 out of 43 (4.65%) armadillos, including one of them also infected with Trypanosoma rangeli. Antibodies anti-T. gondii were detected in 13 out of 43 (30.2%) armadillos. All seven armadillos from Cerrado tested positive for P. brasiliensis DNA, in the lungs, spleen, liver fragments. Also, by molecular analysis, all 43 individuals were negative for M. leprae and Leishmania spp. Armadillos were infected by T. cruzi, T. rangeli, P. brasiliensis and presented seric antibodies to T. gondii, highlighting the importance of those armadillos could have in the epidemiology of zoonotic parasites.

Multi-omic detection of Mycobacterium leprae in archaeological human dental calculus

Mineralized dental plaque (calculus) has proven to be an excellent source of ancient biomolecules. Here we present a Mycobacterium leprae genome (6.6-fold), the causative agent of leprosy, recovered via shotgun sequencing of sixteenth-century human dental calculus from an individual from Trondheim, Norway. When phylogenetically placed, this genome falls in branch 3I among the diversity of other contemporary ancient strains from Northern Europe. Moreover, ancient mycobacterial peptides were retrieved via mass spectrometry-based proteomics, further validating the presence of the pathogen. Mycobacterium leprae can readily be detected in the oral cavity and associated mucosal membranes, which likely contributed to it being incorporated into this individual's dental calculus. This individual showed some possible, but not definitive, evidence of skeletal lesions associated with early-stage leprosy. This study is the first known example of successful multi-omics retrieval of M. leprae from archaeological dental calculus. Furthermore, we offer new insights into dental calculus as an alternative sample source to bones or teeth for detecting and molecularly characterizing M. leprae in individuals from the archaeological record.

This article is part of the theme issue ‘Insights into health and disease from ancient biomolecules’.

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.

Morphological features of lower respiratory tract of nine-banded armadillo (Dasypus novemcinctus, Linnaeus, 1758)

The nine-banded armadillo (Dasypus novemcinctus) is a mammal of the Xenarthra Superorder, which inhabits Central, South and North America. Few morphological descriptions are observed in this species, including the respiratory tract; therefore, the objective of this study was to describe morphologically the lower respiratory tract of the nine-banded armadillo. Five animals were dissected, and the macroscopic and microscopic aspects were analysed. In the anatomical analysis, the perfusion technique was performed with vinyl acetate and the fragments of tissue from respiratory organs (trachea, bronchi, bronchioles and pulmonary lobes) were stained with haematoxylin-eosin for visualization under optical microscopy. Containing about 30 cartilage rings, the trachea is lined internally with ciliated pseudostratified epithelial tissue. The lungs are subdivided into lobes by deep interlobar fissures, with two lobes in the right lung and three lobes in the left lung. Microscopically, the primary, secondary and tertiary bronchi have non-ciliated pseudostratified epithelium with goblet cells. It was found that macro- and microscopically the respiratory tract of this species is similar to existing xenarthras and other excavator animals. These data provide subsidies for the clinic and preservation of this species.

Host Diversity and Origin of Zoonoses: The Ancient and the New

Simple Summary

There is a wide variety of diseases caused by bacteria, viruses, and parasites that are transmitted to humans by different routes from other animals. These diseases, known as zoonoses, represent 75% of new or reemerging infectious diseases. There is a considerable impact of these diseases on the economy and health at local and global levels, including zoonotic diseases caused by the ingestion of food and products derived from animals. The wide range of animal species that host these disease-causing organisms include all groups of mammals. Birds are the second significant animal group to act as hosts for zoonoses. Much progress has been made in understanding disease evolution and animal origin, with important contributions from fields such as paleopathology and analysis of DNA, applied to ancient human bone remains. The study of ancient diseases such as brucellosis and tuberculosis benefits from these approaches. More research is needed as new diseases emerge causing pandemics and some previously eradicated reemerge in some regions. Global efforts are focused, based on evidence generated by research, on the prevention of new pandemics.

Abstract

Bacterial, viral, and parasitic zoonotic diseases are transmitted to humans from a wide variety of animal species that act as reservoir hosts for the causative organisms. Zoonoses contribute an estimated 75% of new or reemerging infectious diseases in humans. All groups of mammals have been shown to act as hosts for transmission of different organisms that cause zoonoses, followed in importance by birds; with both wild and domestic species identified as hosts in specific cases. There has been considerable research progress leading to a better understanding of the host range, animal origin, evolution, and transmission of important zoonoses, including those caused by the ingestion of food and products derived from animals. Paleopathology studies of ancient human bone lesions, in combination with ancient DNA analysis of the causative pathogen, have contributed to our understanding of the origin of zoonotic diseases, including brucellosis and mycobacterial zoonoses. However, there are still knowledge gaps and new confirmed and potential hosts are reported locally with some frequency. Both the economic cost and burden of disease of zoonoses are substantial at local and global levels, as reflected by recent coronavirus pandemics that spread rapidly around the world. Evidence-based prevention strategies are currently a global priority increasingly recognized, especially in zoonoses-affected regions.