Lobomycosis: a therapeutic challenge

Fungal Density in Lobomycosis in French Guiana: A Proposal for a New Clinico-Histological and Therapeutic Classification

BACKGROUND

Lobomycosis is a rare cutaneous tropical neglected disease caused by the fungal agent Lacazia loboi, recently renamed Paracoccidioides lobogeorgii. Our objectives were to present all cases of lobomycosis diagnosed in French Guiana, to offer a precise description of their histopathological features and to propose a new clinico-histological prognostic classification.

METHODS

All cases of lobomycosis diagnosed in French Guiana between 1959 and 2022 were included. We looked for associations between the occurrence of relapses and the clinic-histological form.

RESULTS

31 patients diagnosed with lobomycosis were included. An epidemiological shift was observed in the 2000s as Brazilian patients became the most important ethnic group. Gold mining, forestry and fishing/sailing were reported as professional exposures. New histological features, such as inflammatory "rosettes" formations were described. We describe two clinic-histological patterns: a major form (high fungal density and/or multifocal lesions) and a minor form (low fungal density, unifocal lesions, association with fewer relapses).

CONCLUSIONS

The changing epidemiology of lobomycosis in French Guiana is characterized by a shift towards Brazilian patients, mostly gold miners. Minor forms should be treated with surgery, major forms with a combination of surgery followed by nultiple drug therapy (MDT) or posaconazole.

Dermatopathology and the Diagnosis of Fungal Infections

Diagnosis of superficial/cutaneous fungal infections from skin, hair and nail samples is generally achieved using microscopy and culture in a microbiology laboratory, however, any presentation that is unusual or subcutaneous is sampled by taking a biopsy. Using histological techniques a tissue biopsy enables a pathologist to perform a full examination of the skin structure, detect any inflammatory processes or the presence of an infectious agent or foreign body. Histopathological examination can give a presumptive diagnosis while a culture result is pending, and may provide valuable diagnostic information if culture fails. This review demonstrates how histopathology contributes to the diagnosis of fungal infections from the superficial to the life threatening.

Lobomycosis Epidemiology and Management: The Quest for a Cure for the Most Neglected of Neglected Tropical Diseases

Lobomycosis is a chronic disease caused by Lacazia loboi, which is endemic to the Amazon rainforest, where it affects forest dwellers in Brazil. There is no disease control program and no official therapeutic protocol. This situation contributes to an unknown disease prevalence and unmet needs of people disabled by this disease who seek access to treatment. This review provides an update on the subject with an emphasis on therapeutic advances in humans. All relevant studies that addressed epidemiology, diagnosis, or therapeutics of lobomycosis were considered. Seventy-one articles published between 1931 and 2021 were included for a narrative literature review on the epidemiology and quest for a cure. An effective therapy for lobomycosis has been found following decades of research led by the State Dermatology Program of Acre in the Amazon rainforest, where the largest number of cases occur. This discovery opened new avenues for future studies. The main recommendations here, addressed to the Brazilian Ministry of Health, are for lobomycosis to become a reportable disease to ensure that disease prevalence is measured, and that it be prioritized such that affected individuals may access treatment free-of-charge.

Lobomycosis: exuberant presentation with malignant transformation

Lobomycosis is a chronic granulomatous infection caused by the yeast Lacazia loboi, typically found in tropical and subtropical geographical areas. Transmission occurs through traumatic inoculation into the skin, especially in exposed areas, of men who work in contact with the soil. Lesions are restricted to the skin and subcutaneous tissue, with a keloid-like appearance in most cases. The occurrence of squamous cell carcinoma on skin lesions with a long evolution is well known; however, there are scarce reports of lobomycosis that developed into squamous cell carcinoma. The authors report a patient from the Brazilian Amazon region, with lobomycosis and carcinomatous degeneration, with an unfavorable outcome, due to late diagnosis.

Natural-Product-Based Solutions for Tropical Infectious Diseases

About half of the world's population and 80% of the world's biodiversity can be found in the tropics. Many diseases are specific to the tropics, with at least 41 diseases caused by endemic bacteria, viruses, parasites, and fungi. Such diseases are of increasing concern, as the geographic range of tropical diseases is expanding due to climate change, urbanization, change in agricultural practices, deforestation, and loss of biodiversity. While traditional medicines have been used for centuries in the treatment of tropical diseases, the active natural compounds within these medicines remain largely unknown. In this review, we describe infectious diseases specific to the tropics, including their causative pathogens, modes of transmission, recent major outbreaks, and geographic locations. We further review current treatments for these tropical diseases, carefully consider the biodiscovery potential of the tropical biome, and discuss a range of technologies being used for drug development from natural resources. We provide a list of natural products with antimicrobial activity, detailing the source organisms and their effectiveness as treatment. We discuss how technological advancements, such as next-generation sequencing, are driving high-throughput natural product screening pipelines to identify compounds with therapeutic properties. This review demonstrates the impact natural products from the vast tropical biome have in the treatment of tropical infectious diseases and how high-throughput technical capacity will accelerate this discovery process.

Subcutaneous Mycoses in Travelers

Purpose of Review

The increase in international travel in recent decades has contributed to the risk of acquiring diseases considered endemic to a region or country and the change in the epidemiology of these diseases. Endemic mycoses that may be acquired by travelers in the short or long term are endemic subcutaneous mycoses such as sporotrichosis and lobomycosis, while endemic systemic mycoses are a group of serious diseases including histoplasmosis and coccidioidomycosis. Herein, we review the current knowledge and highlight the most important aspects of these fungal infections in travelers.

Recent Findings

The most relevant advances in the study of these mycoses involve the epidemiological distribution; human mycoses can be fatal and there are few antifungal drugs available, increasing drug resistance, and a risk of emerging fungal diseases associated with climate change, as well as the increasing virulence, and the diagnostic strategies that may be limited in many countries.

Summary

Although endemic mycoses are relatively rare, they should be considered as potentially travel-related illnesses. A recent or late trip to an endemic country may guide the clinical suspicion, an early diagnosis, and the institution of effective therapy.

Multidrug Therapy for Leprosy Can Cure Patients with Lobomycosis in Acre State, Brazil: A Proof of Therapy Study

Lobomycosis, also referred to as lacaziosis, is an endemic cutaneous and subcutaneous fungal disease that mainly affects Amazonian forest dwellers in Brazil. There is no disease control program in place in Brazil, and antifungal therapy failures are common, and the therapy is inaccessible to most patients. We performed a randomized, unblinded clinical trial testing the cure rate of multiple drug therapy (MDT) for leprosy with surgical excision, with or without itraconazole. A control arm consisted of patients who did not adhere to either therapeutic regimens but continued to be followed up. Multiple drug therapy consisted of monthly supervised doses of 600 mg rifampicin, 300 mg clofazimine, and 100 mg dapsone, in addition to daily doses of 50 mg clofazimine and 100 mg dapsone. The patients in the MDT plus itraconazole arm also received itraconazole 100 mg twice daily. We followed up 54 patients from the MDT group and 26 patients from the MDT plus itraconazole group for an average of 4 years and 9 months. The 23 controls were followed up for 6 months on average. The following endpoints were observed: 1) unchanged (no apparent improvement), 2) improved (reduction in lesion size and/or pruritus), and 3) cured (complete remission of the lesions, no viable fungi, and no relapse for 2 years after the end of the drug treatment). The results indicated a significantly greater likelihood of cure associated with the use of multidrug therapy for leprosy with or without itraconazole when compared with the control group. The addition of itraconazole to MDT was not associated with improved outcomes, suggesting that MDT alone is effective.

Epidemiologic and Clinical Progression of Lobomycosis among Kaiabi Indians, Brazil, 1965-2019

Lobomycosis is a rare granulomatous skin disease with a high prevalence in the Amazon region. The Kaiabi Indians are an especially affected group. We studied the current epidemiologic and clinical progression of lobomycosis among the Kaiabi in Brazil, from initial case reports in 1965 through 2019. A total of 60 lobomycosis cases had been reported among the Kaiabi, and we identified 3 new cases in our review. Of 550 cases of lobomycosis ever reported worldwide, 11.5% were among the Kaiabi. We note a high incidence among female Kaiabi and a precocious onset of disease in this indigenous population. Male Kaiabi frequently are infected with the multicentric form and women more frequently exhibit the localized form. Ulcerated lesions are observed more often in the multicentric form. The prevalence among this indigenous group could be explained by genetic susceptibility and lifestyle, which exposes them to a particular agent in the habitats in which they live.

Lobomycosis in Soldiers, Colombia

Lobomycosis is a disease that is endemic to the Amazon rainforest and is caused by the still uncultured fungus Lacazia loboi. This disease occurs in loggers, farmers, miners, fishermen, and persons living near coastal rivers of this region. We report 6 soldiers in Colombia in whom lobomycosis developed after military service in the Amazon area. The patients had nodular and keloid-like lesions on the face, neck, trunk, and limbs. The duration of illness ranged from 2 years to 15 years. The initial diagnosis was leishmaniasis on the basis of clinical manifestations and direct smear results, but biopsies confirmed the final diagnosis of lobomycosis. Treatment with surgical excision, itraconazole and clofazimine was satisfactory. However, the follow-up time was short. Healthcare professionals responsible for the diagnosis and treatment of skin diseases need to be able to recognize the clinical signs of lobomycosis and differentiate them from those of cutaneous leishmaniasis.