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PLoS Neglected Tropical Diseases Jan 2018Histoplasmosis in Africa has markedly increased since the advent of the HIV/AIDS epidemic but is under-recognised. Pulmonary histoplasmosis may be misdiagnosed as... (Review)
Review
Histoplasmosis in Africa has markedly increased since the advent of the HIV/AIDS epidemic but is under-recognised. Pulmonary histoplasmosis may be misdiagnosed as tuberculosis (TB). In the last six decades (1952-2017), 470 cases of histoplasmosis have been reported. HIV-infected patients accounted for 38% (178) of the cases. West Africa had the highest number of recorded cases with 179; the majority (162 cases) were caused by Histoplasma capsulatum var. dubuosii (Hcd). From the Southern African region, 150 cases have been reported, and the majority (119) were caused by H. capsulatum var. capsulatum (Hcc). There have been 12 histoplasmin skin test surveys with rates of 0% to 35% positivity. Most cases of Hcd presented as localised lesions in immunocompetent persons; however, it was disseminated in AIDS patients. Rapid diagnosis of histoplasmosis in Africa is only currently possible using microscopy; antigen testing and PCR are not available in most of Africa. Treatment requires amphotericin B and itraconazole, both of which are not licensed or available in several parts of Africa.
Topics: Africa; Antifungal Agents; Communicable Diseases, Emerging; Diagnostic Tests, Routine; Histoplasma; Histoplasmosis; Humans; Neglected Diseases; Topography, Medical
PubMed: 29346384
DOI: 10.1371/journal.pntd.0006046 -
Virulence 2015Fungi are among the most common microbes encountered by humans. More than 100, 000 fungal species have been described in the environment to date, however only a few... (Review)
Review
Fungi are among the most common microbes encountered by humans. More than 100, 000 fungal species have been described in the environment to date, however only a few species cause disease in humans. Fungal infections are of particular importance to immunocompromised hosts in whom disease is often more severe, especially in those with impaired cell-mediated immunity such as individuals with HIV infection, hematologic malignancies, or those receiving TNF-α inhibitors. Nevertheless, environmental disturbances through natural processes or as a consequence of deforestation or construction can expose immunologically competent people to a large number of fungal spores resulting in asymptomatic acquisition to life-threatening disease. In recent decades, the significance of the innate immune system and more importantly the role of dendritic cells (DC) have been found to play a fundamental role in the resolution of fungal infections, such as in dimorphic fungi like Histoplasma and Paracoccidioides. In this review article the general role of DCs will be illustrated as the bridge between the innate and adaptive immune systems, as well as their specific interactions with these 2 dimorphic fungi.
Topics: Animals; Dendritic Cells; Histoplasma; Histoplasmosis; Host-Pathogen Interactions; Humans; Immunity, Cellular; Immunity, Innate; Paracoccidioides; Paracoccidioidomycosis
PubMed: 25933034
DOI: 10.4161/21505594.2014.965586 -
Revue Scientifique Et Technique... Dec 1999Epizootic lymphangitis is a relatively common infectious disease of horses and other liquids in certain parts of the world. The infection rate varies according to the... (Review)
Review
Epizootic lymphangitis is a relatively common infectious disease of horses and other liquids in certain parts of the world. The infection rate varies according to the geographic area and the age of the animal. The disease is most commonly characterised by a cord-like appearance of the subcutaneous lymphatic and cutaneous pyogranulomas, the discharge from which contains spherical or pear-shaped bodies of the causal agent, Histoplasma farciminosum. Diagnosis can be made by the demonstration of typical organisms in stained smears, culture and tissue sections. Serological tests and a skin hypersensitivity test have been described. Amphotericin B is the drug of choice for the treatment of clinical cases. An attenuated vaccine and a killed formalized vaccine are available and can be used in endemic areas to control the disease.
Topics: Animals; Diagnosis, Differential; Disease Outbreaks; Histoplasma; Histoplasmosis; Horse Diseases; Horses; Lymphangitis
PubMed: 10588013
DOI: No ID Found -
Microbes and Infection Jul 2008Histoplasma capsulatum is the most common cause of invasive fungal pulmonary disease worldwide. The interaction of H. capsulatum with a host is a complex, dynamic... (Review)
Review
Histoplasma capsulatum is the most common cause of invasive fungal pulmonary disease worldwide. The interaction of H. capsulatum with a host is a complex, dynamic process. Severe disease most commonly occurs in individuals with compromised immunity, and the increasing utilization of immunomodulators in medicine has revealed significant risks for reactivation disease in patients with latent histoplasmosis. Fortunately, there are well developed molecular tools and excellent animal models for studying H. capsulatum virulence and numerous recent advances have been made regarding the pathogenesis of this fungus that will improve our capacity to combat disease.
Topics: Antibodies, Monoclonal; Databases, Genetic; Fungal Vaccines; Histoplasma; Histoplasmosis; Host-Pathogen Interactions; Humans
PubMed: 18672088
DOI: 10.1016/j.micinf.2008.07.011 -
BMC Veterinary Research May 2021Histoplasma (H.) capsulatum is a dimorphic fungus, and infection is typically via inhalation of microconidia. After conversion to the yeast phase within the lung, the...
BACKGROUND
Histoplasma (H.) capsulatum is a dimorphic fungus, and infection is typically via inhalation of microconidia. After conversion to the yeast phase within the lung, the organism is subsequently disseminated to other tissues by macrophages. Nasal histoplasmosis appears to be a rare condition in dogs.
CASE PRESENTATION
We report the clinical case of a 4.5-year-old male neutered Cocker spaniel/Poodle mix, 7.7 kg, body condition score 6/9, that presented with a 3-month history of sneezing and left-sided mucoid nasal discharge. The history also included a mild swelling (transient) of the right carpus with a lameness (grade II-III/IV), coinciding with the onset of sneezing and nasal discharge. The dog lived primarily indoors in the Texas Gulf Coast area. On physical examination, the dog was febrile, and the left nostril was swollen, ulcerative, deformed, and hypopigmented. Mandibular lymph nodes were firm and mildly enlarged bilaterally. Mild lymphopenia, thrombocytopenia, and hyperglobulinemia were noted. Thoracic radiographs were unremarkable. Computed tomography and rhinoscopy revealed swelling of the rostral portion of the left and right nasal passages. Cytology and histology of biopsies of the affected nasal tissue showed pyogranulomatous inflammation and yeast organisms consistent with H. capsulatum. Weak antigenuria was detected on the MVista H. capsulatum antigen test. Treatment with oral itraconazole led to a resolution of the nasal signs and normalization of the appearance of the nostril over 13 weeks, and neither antigenuria nor antigenemia was detected on several recheck examinations. The dog remained in good general and physical condition and showed no signs of disease recurrence more than 6 years after the last examination.
CONCLUSION
We report a rare case of nasal mucocutaneous histoplasmosis in an immunocompetent dog, with an excellent clinical response to oral itraconazole. This case documents that histoplasmosis in dogs can affect primarily the nasal cavity, which responds rapidly to triazole antifungal therapy and has a good prognosis. A similar case has only been reported in human medicine in a young adult.
Topics: Animals; Antifungal Agents; Dog Diseases; Dogs; Histoplasma; Histoplasmosis; Itraconazole; Male; Nasal Cavity; Texas
PubMed: 33985507
DOI: 10.1186/s12917-021-02896-9 -
Proceedings of the National Academy of... Aug 2000The success of Histoplasma capsulatum as an intracellular pathogen depends completely on successful conversion of the saprophytic mycelial (mold) form of this fungus to... (Review)
Review
The success of Histoplasma capsulatum as an intracellular pathogen depends completely on successful conversion of the saprophytic mycelial (mold) form of this fungus to a parasitic yeast form. It is therefore not surprising that yeast phase-specific genes and gene products are proving to be important for survival and proliferation of H. capsulatum within macrophages. In this study, we have focused on the role and regulation of two yeast-specific characteristics: alpha-(1,3)-glucan, a cell wall polysaccharide modulated by cell-density (quorum) sensing, and a secreted calcium-binding protein (CBP) that is essential for pathogenicity.
Topics: Calcium-Binding Proteins; Cell Wall; Gene Expression Regulation; Glucans; Histoplasma; Phenotype; Virulence
PubMed: 10922037
DOI: 10.1073/pnas.97.16.8794 -
Medical Mycology Journal 2014
Review
Topics: Animals; Histoplasma; Histoplasmosis; Humans; Immunity, Innate; Lysosomes; Macrophages, Alveolar; Mice; Phagocytosis
PubMed: 25902570
DOI: 10.3314/mmj.55.E57 -
Virulence Dec 2022Histoplasmosis is a systemic mycosis caused by the thermally dimorphic fungus . Although healthy individuals can develop histoplasmosis, the disease is particularly... (Review)
Review
Histoplasmosis is a systemic mycosis caused by the thermally dimorphic fungus . Although healthy individuals can develop histoplasmosis, the disease is particularly life-threatening in immunocompromised patients, with a wide range of clinical manifestations depending on the inoculum and virulence of the infecting strain. In this review, we discuss the established virulence factors and pathogenesis traits that make highly adapted to a wide variety of hosts, including mammals. Understanding and integrating these mechanisms is a key step toward devising new preventative and therapeutic interventions.
Topics: Animals; Humans; Histoplasma; Histoplasmosis; Virulence; Adaptation, Physiological; Virulence Factors; Mammals
PubMed: 36266777
DOI: 10.1080/21505594.2022.2137987 -
Frontiers in Immunology 2021As there are more than 6 million human deaths due to mycoses each year, there is an urgent need to develop fungal vaccines. Moreover, given the similarities among...
As there are more than 6 million human deaths due to mycoses each year, there is an urgent need to develop fungal vaccines. Moreover, given the similarities among pathogenic fungi, it may be possible to create a multi-fungi vaccine. In this study, we combined immunoproteomic and immunopeptidomic methods, for which we have adapted a technique based on co-immunoprecipitation (Co-IP) that made it possible to map epitopes for the first time in a natural context using murine dendritic cells (DCs) and macrophages (Mφ). Although polysaccharide epitopes exist, this research focused on mapping protein epitopes as these are more immunogenic. We used different algorithms to screen proteins and peptides identified by two-dimensional electrophoresis (2-D) and Co-IP. Seventeen proteins were revealed by 2-D gels, and 45 and 24 peptides from distinct proteins were presented by DCs and Mφ, respectively. We then determined which epitopes were restricted to MHC-I and II from humans and mice and showed high promiscuity, but lacked identity with human proteins. The 4 most promising peptides were synthesized, and the peptides with and without incorporation into glucan particles induced CD4+ and CD8+ T cell proliferation and produced a Th1 and Th17 response marked by the secretion of high levels of IFN-γ, IL-17 and IL-2. These epitopes were from heat shock protein 60, enolase, and the ATP-dependent molecular chaperone HSC82, and they each have a high degree of identity with proteins expressed by other medically important pathogenic fungi. Thus, the epitopes described in this study have the potential for use in the development of vaccines that could result in cross-protection among fungal species.
Topics: Animals; Epitope Mapping; Fungal Vaccines; Histoplasma; Male; Mice; Mice, Inbred C57BL; Peptidomimetics; Proteomics
PubMed: 34880863
DOI: 10.3389/fimmu.2021.764501 -
Emerging Infectious Diseases Mar 2021In Europe, pulmonary histoplasmosis is rarely diagnosed except in travelers. We report a probable autochthonous case of severe chronic pulmonary histoplasmosis in an...
In Europe, pulmonary histoplasmosis is rarely diagnosed except in travelers. We report a probable autochthonous case of severe chronic pulmonary histoplasmosis in an immunocompetent man in Switzerland without travel history outside of Europe. Diagnosis was achieved by histopathology, fungal culture, and serology, but the source of the infection remains speculative.
Topics: Europe; Histoplasma; Histoplasmosis; Humans; Lung Diseases, Fungal; Male; Switzerland
PubMed: 33622462
DOI: 10.3201/eid2703.191831