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Current Topics in Microbiology and... 2019Histoplasmosis, caused by the dimorphic environmental fungus Histoplasma capsulatum, is a major mycosis on the global stage. Acquisition of the fungus by mammalian hosts... (Review)
Review
Histoplasmosis, caused by the dimorphic environmental fungus Histoplasma capsulatum, is a major mycosis on the global stage. Acquisition of the fungus by mammalian hosts can be clinically silent or it can lead to life-threatening systemic disease, which can occur in immunologically intact or deficient hosts, albeit severe disease is more likely in the setting of compromised cellular immunity. H. capsulatum yeast cells are highly adapted to the mammalian host as they can effectively survive within intracellular niches in select phagocytic cells. Understanding the biological response by both the host and H. capsulatum will facilitate improved approaches to prevent and/or modify disease. This review presents our current understanding of the major pathogenic mechanisms involved in histoplasmosis.
Topics: Animals; Histoplasma; Histoplasmosis; Humans; Virulence
PubMed: 30043340
DOI: 10.1007/82_2018_114 -
Clinical Infectious Diseases : An... Apr 2023The dimorphic mycoses (DMs) of the United States-Histoplasma, Coccidioides, and Blastomyces-commonly known as endemic mycoses of North America (in addition to...
BACKGROUND
The dimorphic mycoses (DMs) of the United States-Histoplasma, Coccidioides, and Blastomyces-commonly known as endemic mycoses of North America (in addition to Paracoccidioides) are increasingly being diagnosed outside their historical areas of endemicity. Despite this trend, the maps outlining their geographic distributions have not been updated in more than half a century using a large, nationwide database containing individual-patient-level data.
METHODS
This was a retrospective analysis of >45 million Medicare fee-for-service beneficiaries from 1 January 2007 through 31 December 2016. Diagnoses of histoplasmosis, coccidioidomycosis, and blastomycosis were defined by International Classification of Diseases, Ninth/10th Revision, codes. The primary outcome was the incidence of histoplasmosis, coccidioidomycosis, and blastomycosis for each US county. Clinically meaningful thresholds for incidence were defined as 100 cases/100 000 person-years for histoplasmosis and coccidioidomycosis and 50 cases/100 000 person-years for blastomycosis.
RESULTS
There were 79 749 histoplasmosis, 37 726 coccidioidomycosis, and 6109 blastomycosis diagnoses in unique persons from 2007-2016 across 3143 US counties. Considering all US states plus Washington, DC, 94% (48/51) had ≥1 county above the clinically relevant threshold for histoplasmosis, 69% (35/51) for coccidioidomycosis, and 78% (40/51) for blastomycosis.
CONCLUSIONS
Persons with histoplasmosis, coccidioidomycosis, and blastomycosis are diagnosed in significant numbers outside their historical geographic distributions established >50 years ago. Clinicians should consider DM diagnoses based on compatible clinical syndromes with less emphasis placed on patients' geographic exposure. Increased clinical suspicion leading to a subsequent increase in DM diagnostic testing would likely result in fewer missed diagnoses, fewer diagnostic delays, and improved patient outcomes.
Topics: Aged; Humans; United States; Blastomycosis; Coccidioidomycosis; Histoplasmosis; Retrospective Studies; Medicare; Mycoses
PubMed: 36366776
DOI: 10.1093/cid/ciac882 -
Head and Neck Pathology Dec 2017A 44-year-old female presented to her general dentist with the chief complaint of a painful mouth sore of 2 weeks duration. Clinical examination revealed an irregularly...
A 44-year-old female presented to her general dentist with the chief complaint of a painful mouth sore of 2 weeks duration. Clinical examination revealed an irregularly shaped ulcer of the buccal and lingual attached gingiva of the anterior mandible. A biopsy was performed and microscopic evaluation revealed histoplasmosis. Histoplasmosis, caused by Histoplasma capsulate, is the most common fungal infection in the United States. Oral lesions of histoplasmosis are generally associated with the disseminated form of histoplasmosis and may present as a fungating or ulcerative lesion of the oral mucosa. The histologic findings and differential diagnosis for oral histoplasmosis are discussed.
Topics: Adult; Female; Histoplasmosis; Humans; Mouth Diseases
PubMed: 28220360
DOI: 10.1007/s12105-017-0797-y -
PLoS Neglected Tropical Diseases Feb 2022Histoplasmosis is a chronic granulomatous disease caused by the thermally dimorphic fungus Histoplasma capsulatum. The 2 variants Histoplasma capsulatum var. capsulatum... (Review)
Review
BACKGROUND
Histoplasmosis is a chronic granulomatous disease caused by the thermally dimorphic fungus Histoplasma capsulatum. The 2 variants Histoplasma capsulatum var. capsulatum (Hcc) and Histoplasma capsulatum var. duboisii (Hcd) causes infection in humans and commonly termed classical or American histoplasmosis and African histoplasmosis, respectively. Histoplasma capsulatum var. farciminosum (Hcf) affects equines. In recent times, there have been heightened sensitization on fungal infections such as histoplasmosis in Africa, aimed at improving awareness among relevant stakeholders, particularly healthcare workers. This effort is expected to be paralleled with increased detection of both classical and African histoplasmosis, which has remained underdiagnosed over the years. In this narrative review, we describe the current perspectives of histoplasmosis in Africa, identify knowledge gaps, and suggest research priorities.
METHODS
A PubMed, Google Scholar, and Africa Journal Online (AJOL) literature search was conducted for studies on histoplasmosis in Africa between 2000 and 2020. Histoplasmosis essays in medical mycology textbooks were also consulted. This narrative review was prepared from the data gathered.
FINDINGS
In the past 2 decades, histoplasmosis in general has seen a relative increase in case detection in some Africa countries, probably attributable to the gradually increasing medical mycology advocacy efforts in Africa. Histoplasmosis cases are dominated by African histoplasmosis mostly in Western and Central Africa, while classical histoplasmosis is more common in Southern and Northern Africa. Although both classical and African histoplasmosis are common in Africa, the latter is more restricted to Africa, and cases outside the continent usually have a travel history to the continent. Despite the clinical and laboratory difference between African histoplasmosis and classical histoplasmosis, it is not straightforward to distinguish them. The typical manifestation of African histoplasmosis is the appearance of lesions affecting the skin, bones, and lymph nodes and unusually linked to human immunodeficiency virus (HIV)/AIDS. By contrast, classical histoplasmosis mostly affects the lungs and is often associated with immunosuppression, mainly HIV/AIDS. The present perspectives of histoplasmosis in Africa highlight unclear details on the true burden, strain diversity, infection route and genetic basis of African histoplasmosis, availability of specie-specific diagnostic tools, and compliance with recommended antifungal therapy. These knowledge gaps represent research questions that require scientific exploration.
CONCLUSIONS
Despite a subtle increase in identifying histoplasmosis cases in Africa, it remains underdiagnosed and neglected in some parts of the continent. Increasing awareness and training among healthcare workers, bridging diagnostic and therapeutic gaps, and encouraging more research in Africa are crucial to improve the current perspectives of histoplasmosis in Africa.
Topics: Africa; Animals; Awareness; Health Knowledge, Attitudes, Practice; Histoplasma; Histoplasmosis; Humans; Research
PubMed: 35202403
DOI: 10.1371/journal.pntd.0010111 -
The American Journal of Tropical... Feb 2023
Topics: Humans; Histoplasmosis; Lung Diseases, Fungal; Histoplasma; Pneumonia
PubMed: 36623482
DOI: 10.4269/ajtmh.22-0541 -
Jornal Brasileiro de Pneumologia :... Nov 2009Histoplasmosis is systemic mycosis caused by a small fungus, Histoplasma capsulatum var. capsulatum, whose natural habitat is soil contaminated by bat or bird excrement.... (Review)
Review
Histoplasmosis is systemic mycosis caused by a small fungus, Histoplasma capsulatum var. capsulatum, whose natural habitat is soil contaminated by bat or bird excrement. The incidence of histoplasmosis is worldwide. In Brazil, the disease is found in all regions; however, the state of Rio de Janeiro is responsible for most of the microepidemics described. Human infection occurs when airborne spores of H. capsulatum are inhaled. The most common clinical presentation is asymptomatic. The symptoms of acute or epidemic histoplasmosis are high fever, cough, asthenia and retrosternal pain, as well as enlargement of the cervical lymph nodes, liver and spleen. The most common radiological findings are diffuse reticulonodular infiltrates in both lungs, as well as hilar and mediastinal lymph node enlargement. In chronic pulmonary histoplasmosis, the clinical and radiological manifestations are identical to those of reinfection with pulmonary tuberculosis. Histoplasmosis is diagnosed by means of the identification or culture growth of the fungus in sputum or fiberoptic bronchoscopy specimens. Histopathological examination reveals the fungus itself within or surrounding macrophages, as well as granulomatous lesions with or without caseous necrosis. Double agar gel immunodiffusion is the most easily used and readily available serologic test for making the immunological diagnosis. Acute histoplasmosis with prolonged symptoms requires treatment, as do the disseminated or chronic pulmonary forms of the disease. The drug of choice is itraconazole.
Topics: Histoplasmosis; Humans; Lung Diseases, Fungal
PubMed: 20011851
DOI: 10.1590/s1806-37132009001100013 -
Journal of Clinical Microbiology Jun 2017The diagnosis of histoplasmosis is based on a multifaceted approach that includes clinical, radiographic, and laboratory evidence of disease. The gold standards for... (Review)
Review
The diagnosis of histoplasmosis is based on a multifaceted approach that includes clinical, radiographic, and laboratory evidence of disease. The gold standards for laboratory diagnosis include demonstration of yeast on pathological examination of tissue and isolation of the mold in the culture of clinical specimens; however, antigen detection has provided a rapid, noninvasive, and highly sensitive method for diagnosis and is a useful marker of treatment response. Molecular methods with improved sensitivity on clinical specimens are being developed but are not yet ready for widespread clinical use. This review synthesizes currently available laboratory diagnostics for histoplasmosis, with an emphasis on complexities of testing and performance in various clinical contexts.
Topics: Clinical Laboratory Techniques; Histoplasmosis; Humans
PubMed: 28275076
DOI: 10.1128/JCM.02430-16 -
The New England Journal of Medicine Mar 2019
Topics: AIDS-Related Opportunistic Infections; Adult; CD4 Lymphocyte Count; Fatal Outcome; HIV Infections; Histoplasma; Histoplasmosis; Humans; Male
PubMed: 30865801
DOI: 10.1056/NEJMicm1809792 -
Revista Da Sociedade Brasileira de... 2009Histoplasmosis is a fungal infection caused by the dimorphic fungus Histoplasma capsulatum. It is classically considered an endemic mycosis, even though the fungus has... (Review)
Review
Histoplasmosis is a fungal infection caused by the dimorphic fungus Histoplasma capsulatum. It is classically considered an endemic mycosis, even though the fungus has an opportunistic behavior in immunocompromised patients. People acquired the infection through the inhalation of conidial forms present in the environmental, such as caves dwelling bats and soils inhabited by chickens. The clinical features may vary from asymptomatic infections to disseminated severe forms that affect patients with acquired immunodeficiency syndrome or hematological malignancies and allograft recipients. The diagnosis is based on the detection of the fungus in organic fluids (sputum, blood, liquor) or tissues (histopathological assays), in the culture of biological samples and serological assays. The treatment of severe chronic respiratory acute or localized forms can be performed with oral azolic (itraconazol) and in the disseminated forms, the amphotericin B (preferentially the lipidic formulations) consists in the elected drug to initiate the therapy. Nowadays, histoplasmosis represents one of the most important systemic mycosis in the Americas, with broad distribution in all regions of Brazil.
Topics: AIDS-Related Opportunistic Infections; Acute Disease; Chronic Disease; Histoplasma; Histoplasmosis; Humans; Lung Diseases, Fungal
PubMed: 19448941
DOI: 10.1590/s0037-86822009000200020 -
Clinical and Vaccine Immunology : CVI Nov 2017Heat shock proteins (Hsps) are highly conserved biomolecules that are constitutively expressed and generally upregulated in response to various stress conditions (biotic... (Review)
Review
Heat shock proteins (Hsps) are highly conserved biomolecules that are constitutively expressed and generally upregulated in response to various stress conditions (biotic and abiotic). Hsps have diverse functions, categorizations, and classifications. Their adaptive expression in fungi indicates their significance in these diverse species, particularly in dimorphic pathogens. and species are dimorphic fungi that are the causative agents of histoplasmosis and paracoccidioidomycosis, respectively. This minireview focuses on the pathobiology of Hsps, with particular emphasis on their roles in the morphogenesis and virulence of and and the potential roles of active and passive immunization against Hsps in protection against infection with these fungi.
Topics: Fungal Proteins; Heat-Shock Proteins; Histoplasma; Histoplasmosis; Humans; Immunization, Passive; Immunotherapy; Paracoccidioides; Paracoccidioidomycosis; Vaccination; Virulence
PubMed: 28903987
DOI: 10.1128/CVI.00221-17