Lobomycosis. Literature review and future perspectives

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.

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.

Seroprevalence of Antibodies Against Paracoccidioides Spp. in Captive Dolphins from Three Aquaria in Japan

The skin disease paracoccidioidomycosis ceti occurs in several dolphin species globally. Infection by the unculturable fungi Paracoccidioides brasilensis or other Paracoccidioides spp. results in chronic cutaneous and granulomatous lesions. In this study we used immunohistochemistry to investigate the seroprevalence of antibodies to Paracoccidioides spp. in captive dolphins from three aquaria in Japan. We had previously reported that there were serological cross-reactions for Paracoccidioides spp. with related species in the order Onygenales. We hypothesized that the degree of serological cross-reactions for Paracoccidioides spp. might be lower in areas, such as Japan, where the fungal diseases coccidiodomycosis and paracoccidiodomycosis are not endemic. Sera from 41 apparently healthy dolphins, including 20 Atlantic bottlenose dolphins (BD: Tursiops truncatus), 6 Indo-Pacific bottlenose dolphins (IPBD: Tursiops aduncus), 2 F1 generation of a cross between BD and IPBD (F1), 3 Pacific white-sided dolphins (PWD: Lagenorhynchus obliquidens), 2 pantropical spotted dolphins (PSD: Stenella attenuata), 6 false killer whales (FKW: Pseudorca crassidens), and 2 rough-toothed dolphins (RTD: Steno bredanensis) were investigated. Sera from three dolphins with paracoccidioidomycosis ceti were used as a positive control. The yeast-form cells of Paracoccidioides spp. in the cutaneous tissue sample derived from the first Japanese paracoccidioidomycosis ceti case were used as the antigen for the immunohistochemistry. Of the 41 dolphins tested, 61.0% had antibodies against Paracoccidioides spp. This indicates that dolphins of several species in Japanese aquaria have likely been exposed to the pathogen Paracoccidioides spp.

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.

Bedside diagnostics in dermatology: Viral, bacterial, and fungal infections

Viral, bacterial, and fungal infections are frequently encountered in clinical practice, resulting in numerous cutaneous manifestations. Although diagnosis of these infections has changed over time because of technological advancements, such as polymerase chain reaction, bedside diagnostic techniques still play an important role in diagnosis and management, enabling rapid and low-cost diagnosis and implementation of appropriate therapies. This 2-part article will review both common and infrequent uses of bedside diagnostic techniques that dermatologists can incorporate into daily practice. This article examines the utility of bedside tests for the diagnosis of viral, bacterial, and fungal infections. The second article in this series reviews the use of bedside diagnostics for parasitic and noninfectious disorders.

Trichosporon asteroides Isolated from Cutaneous Lesions of a Suspected Case of "paracoccidioidomycosis ceti" in a Bottlenose Dolphin (Tursiops truncatus)

"Paracoccidioidomycosis ceti" is a rare zoonotic fungal infection affecting dolphins and is endemic worldwide. The causative agents are Paracoccidioides species; however, it is impossible to isolate the fungal species. We isolated Trichosporon asteroides from multifocal, irregularly raised skin lesions on a female bottlenose dolphin (Tursiops truncatus) captured off coast of Japan, which was suspected to have "paracoccidioidomycosis ceti." An abundance of round, yeast-like cells was detected in a potassium hydroxide direct-mount specimen of the skin samples; however, nested PCR targeting the partial sequence of 43-kDa glycoprotein-coding gene correspondent to Paracoccidioides sp. was negative. Biopsied tissue samples were cultured on brain heart infusion agar plates supplemented with chloramphenicol, 1% yeast extract, and 4% sodium chloride (4% NaCl-BHI), on Mycosel agar with 4% sodium chloride (4% NaCl-Mycosel), and on potato dextrose agar supplemented with chloramphenicol (CPDA) at 35 °C for 4 weeks. Cream-colored and wrinkled colonies consisting of hyphae and arthroconidia grew on 4% NaCl-BHI and CPDA, while film-like colonies composed of arthroconidia and round yeast-like cells developed on 4% NaCl-Mycosel. Although these primary cultures resembled fresh isolates of P. brasiliensis, they were identified as Trichosporon asteroides based on routine mycological studies and the internal transcribed spacer regions of ribosomal RNA sequences. The results suggested that trichosporonosis caused by T. asteroides might remain latent among cases of "paracoccidioidomycosis ceti" diagnosed without cultures and molecular biological analysis.

DNA damage in BALB/c mice infected with Lacazia loboi and its relation to nutritional status

Background

Jorge Lobo’s disease, also known as lacaziosis, is a cutaneous-subcutaneous mycosis with chronic evolution. It is caused by the fungus Lacazia loboi. Herein we report a study that relates the genotoxicity caused by L. loboi in isogenic mice with nutritional status, through a normal or restricted diet.

Methods

DNA damage was assessed in the peripheral blood by the comet assay (tail intensity).

Results

The results for leukocytes showed increases in the mean tail intensity in mice under dietary restriction, in infected mice under dietary restriction and in infected mice ingesting a normal diet.

Conclusion

These results indicate that dietary restriction and L. loboi infection may increase DNA damage levels in mice, as detected by the comet assay.

Analysis of microvasculature phenotype and endothelial activation markers in skin lesions of lacaziosis (Lobomycosis)

Jorge Lobo's disease is a rare mycosis characterized by chronic inflammation, which causes skin lesions in the absence of visceral dissemination. The disease occurs mainly in hot and humid climates and most cases have been registered in the Brazilian Amazon region. This study investigated possible microvascular alterations in skin lesions caused by infection with Lacazia loboi which may interfere with the clinical progression of the disease. Immunohistochemistry was used to evaluate the density of blood and lymphatic vessels, as well as expression of the cell adhesion molecules ICAM-1, VCAM-1 and E-selectin. The results showed a reduced number of blood (62.66 ± 20.30 vessels/mm(2)) and lymphatic vessels (3.55 ± 5.84 vessels/mm(2)) in Jorge Lobo's disease when compared to control skin (169.66 ± 66.38 blood vessels/mm(2) and 8 ± 2.17 lymphatic vessels/mm(2)). There were a larger number of vessels expressing ICAM-1 (27.58 ± 15.32 vessels/mm(2)) and VCAM-1 (7.55 ± 6.2 vessels/mm(2)). No difference was observed in the expression of E-selectin (4.66 ± 11 vessels/mm(2)). Taken together, the results indicate changes in the local microvasculature which may interfere with the development of an efficient cell-mediated immune response and may explain restriction of the fungus to the site of injury.

Lobomycosis: epidemiology, clinical presentation, and management options

Lobomycosis is a subcutaneous mycosis of chronic evolution caused by the Lacazia loboi fungus. Its distribution is almost exclusive in the Americas, and it has a particularly high prevalence in the Amazon basin. Cases of lobomycosis have been reported only in dolphins and humans. Its prevalence is higher among men who are active in the forest, such as rubber tappers, bushmen, miners, and Indian men. It is recognized that the traumatic implantation of the fungus on the skin is the route by which humans acquire this infection. The lesions affect mainly exposed areas such as the auricles and upper and lower limbs and are typically presented as keloid-like lesions. Currently, surgical removal is the therapeutic procedure of choice in initial cases. Despite the existing data and studies to date, the active immune mechanisms in this infection and its involvement in the control or development of lacaziosis have not been fully clarified. In recent years, little progress has been made in the appraisal of the epidemiologic aspects of the disease. So far, we have neither a population-based study nor any evaluation directed to the forest workers.

Two Cases of Lacaziosis in Bottlenose Dolphins (Tursiops truncatus) in Japan

Lacaziosis, formerly called lobomycosis, caused byLacazia loboi, is a zoonotic mycosis found in humans and dolphins and is endemic in the countries on the Atlantic Ocean. Although the Japanese coast is not considered an endemic area, photographic records of lacaziosis-like skin lesions were found in bottlenose dolphins (Tursiops truncatus) that were migrating in the Goto Islands (Nagasaki Prefecture, Japan). We diagnosed 2 cases of lacaziosis in bottlenose dolphins captured simultaneously at the same coast within Japanese territory on the basis of clinical characteristics, cytology, histopathology, immunological tests, and detection of partial sequences of a 43 kDa glycoprotein coding gene (gp43) with a nested-PCR system. The granulomatous skin lesions from the present cases were similar to those found in animals from endemic areas, containing multiple budding and chains of round yeast cells and positive in the immune-staining with anti-Paracoccidioides brasiliensisserum which is a fungal species related toL. loboi; however, thegp43gene sequences derived from the present cases showed 94.1% homology toP. brasiliensisand 84.1% toL. loboi. We confirmed that the causative agent at the present cases was different genotype ofL. loboifrom Amazon area.

Lobomycosis: A case from Southeastern Europe and review of the literature

BACKGROUND

Lobomycosis, also known as Jorge Lobo's disease, represents a rare chronic subcutaneous mycosis caused by the fungus Lacazia loboi, an organism that is found within lesions but has not been cultured to date. The natural reservoir of L. loboi is unknown but it is believed to be aquatic, or associated with soil and vegetation. More than 550 human cases have been reported, especially in patients with a history of travel or residence in endemic areas (Central and South America, particularly Brazil) or in communities along rivers.

MAIN OBSERVATIONS

We describe a 64-year-old Greek female farmer living in a coastal region, who presented with an erythematous plaque on her left inner thigh resembling a keloid. The diagnosis was based on the triad: 1) absence of fungal growth in cultures, 2) positive direct microscopic examination of the lesion and 3) histopathology, all consistent with lobomycosis. Particularly, skin biopsy showed deep cutaneous fungal infection with granulomatous reaction. Fungal cells were found inside giant cells. The fungi were thick-walled with some budding, isolated or in short chains. Dermal fibrosis was present. Our patient had a medical history of common variable immunodeficiency but no history of travel to South or Central America. She probably acquired this rare infection by injury during her agricultural works.

CONCLUSION

Our case represents probably the first documented case of human lobomycosis in Southeastern Europe. This case is unusual due to the rarity of lobomycosis in Mediterranean countries, particularly in Southeastern Europe.

Genus paracoccidioides: Species recognition and biogeographic aspects

BACKGROUND

Paracoccidioidomycosis is a systemic mycosis caused by Paracoccidioides brasiliensis (species S1, PS2, PS3), and Paracoccidioides lutzii. This work aimed to differentiate species within the genus Paracoccidioides, without applying multilocus sequencing, as well as to obtain knowledge of the possible speciation processes.

METHODOLOGY/PRINCIPAL FINDINGS

Single nucleotide polymorphism analysis on GP43, ARF and PRP8 intein genes successfully distinguished isolates into four different species. Morphological evaluation indicated that elongated conidia were observed exclusively in P. lutzii isolates, while all other species (S1, PS2 and PS3) were indistinguishable. To evaluate the biogeographic events that led to the current geographic distribution of Paracoccidioides species and their sister species, Nested Clade and Likelihood Analysis of Geographic Range Evolution (LAGRANGE) analyses were applied. The radiation of Paracoccidioides started in northwest South America, around 11-32 million years ago, as calculated on the basis of ARF substitution rate, in the BEAST program. Vicariance was responsible for the divergence among S1, PS2 and P. lutzii and a recent dispersal generated the PS3 species, restricted to Colombia. Taking into account the ancestral areas revealed by the LAGRANGE analysis and the major geographic distribution of L. loboi in the Amazon basin, a region strongly affected by the Andes uplift and marine incursions in the Cenozoic era, we also speculate about the effect of these geological events on the vicariance between Paracoccidioides and L. loboi.

CONCLUSIONS/SIGNIFICANCE

The use of at least 3 SNPs, but not morphological criteria, as markers allows us to distinguish among the four cryptic species of the genus Paracoccidioides. The work also presents a biogeographic study speculating on how these species might have diverged in South America, thus contributing to elucidating evolutionary aspects of the genus Paracoccidioides.

Molecular diagnosis of lobomycosis-like disease in a bottlenose dolphin in captivity

We report the diagnosis and molecular characterization of lobomycosis-like lesions in a captive bottlenose dolphin. The clinical picture and the absence of growth in conventional media resembled the features associated with Lacazia loboi. However sequencing of ribosomal DNA and further phylogenetic analyses showed a novel sequence more related to Paracoccidioides brasilensis than to L. loboi. Moreover, the morphology of the yeast cells differed from those L. loboi causing infections humans. These facts suggest that the dolphin lobomycosis-like lesions might have been be caused by different a different fungus clustered inside the order Onygenales. A successful treatment protocol based on topic and systemic terbinafine is also detailed.

Lacaziosis and lacaziosis-like prevalence among wild, common bottlenose dolphins Tursiops truncatus from the west coast of Florida, USA

Lacaziosis (lobomycosis; Lacazia loboi) is a fungal skin disease that naturally occurs only in humans and dolphins. The first reported case of lacaziosis in a bottlenose dolphin Tursiops truncatus occurred in 1970 in Sarasota Bay, Florida, USA, and subsequent photo-ID monitoring of the Sarasota Bay dolphin population has revealed persistence of the disease. The objectives of this study were to estimate lacaziosis prevalence (P) in 2 bottlenose dolphin populations on the west coast of Florida (Sarasota Bay and Charlotte Harbor) and compare disease occurrence to other published estimates of lacaziosis in dolphin populations across the globe. Historic photographic records of dolphins captured and released for health assessment purposes (Sarasota Bay) and photo-ID studies (Charlotte Harbor) were screened for evidence of lesions consistent with lacaziosis. Health assessment data revealed a prevalence of lacaziosis in the Sarasota Bay bottlenose dolphin population between 2 and 3%, and analyses of photo-ID data provided a lacaziosis-like prevalence estimate of 2% for Charlotte Harbor dolphins. With the exception of lacaziosis prevalence estimates for dolphins inhabiting the Indian River Lagoon (P = 0.068; P = 0.12), no statistically significant differences were seen among Sarasota Bay, Charlotte Harbor, and other published estimates. Although lacaziosis is a rare disease among these dolphin populations, studies that assess disease burden among different populations can assist with the surveillance of this zoonotic pathogen.

Giant keloid of left buttock treated with post-excisional radiotherapy

Keloids are defined as excessive scar tissue formation extending beyond the area of the original skin injury and occurring in predisposed individuals. While no single treatment has proven widely effective, several series report excellent outcomes for keloids with post-surgery radiation therapy as described in the literature. We present a patient with recurrent giant keloid of left buttock after several surgical removals, that at physical examination shows the size of 40×22×10 cm in the largest dimension. Patient underwent a surgical excision of gluteal lesion and postoperative radiotherapy using photons at 8 MV of linear accelerator: the total dose delivered was 22 Gy in 11 days, with a daily fraction of 2 Gy. No relapse was showed at 36 months post-therapy. Several methods seem unsatisfactory for preventing keloid recurrence. The combination of surgery and adjuvant radiotherapy seems an excellent strategy to prevent recurrent disease.