Histoplasmosis in Montreal During the Fall of 1963, with Observations on Erythema Multiforme

Although Montreal is in an endemic area, significant clinical histoplasmosis with systemic manifestations has been, until recently, infrequently diagnosed. However, since the autumn of 1963, 31 cases of clinically significant histoplasmosis have been seen by the authors. These were divided into two groups: (1) patients in whom the diagnosis was established on the basis of histological and/or cultural demonstration of the fungus; (2) patients in whom the diagnosis was based on a positive histoplasmin skin test, a complement fixation antibody titre of 1:32 or greater and compatible clinical and radiological findings. An additional group of 11 patients who presented with erythema multiforme was investigated and a heretofore unrecognized relationship between histoplasmosis and erythema multiforme was established.     

Indigenous Case of Disseminated Histoplasmosis from the <Emphasis Type="Italic">Penicillium marneffei</Emphasis> Endemic Area of China

This is the first indigenous case of disseminated histoplasmosis reported from the Penicillium marneffei endemic area in southern China. It was diagnosed by histopathology of tissue, gross and microscopic morphology of the culture and PCR assay of the isolated fungus. Successful antifungal treatment was with itraconazole 400 mg/day for 5 months. This case suggests that histoplasmosis should be an important differential diagnosis in immunocompromised patients in southern China and South East Asia (the only endemic area for P. marneffei).     

Epididymal histoplasmosis diagnosed by isolation ofHistoplasma capsulatum from semen

An autochthonous case of epididymal histoplasmosis masquerading as tuberculosis in a 55-year-old male patient is reported from India. It was diagnosed by culture ofHistoplasma capsulatum from semen and by demonstration of the fungus upon re-examination of epididymal biopsy sections previously misinterpreted as tuberculous granuloma. The patient's main complaints were painful epididymal swelling, occasional fever and cough. He was treated successfully by excision of epididymis and vas deferens combined with amphotericin B therapy. This is believed to be the first case of epididymal histoplasmosis to be reported outside the American continent and the fourth of its type reported in the English literature. The case is also noteworthy in thatH. capsulatum was isolated for the first time from semen, and it underlines the importance of mycological culture of semen specimens for diagnosis of genitourinary infections of obscure etiology.Presented at the XII Congress of the International Society for Human and Animal Mycology, Adelaide, Australia, March 13–18, 1994.     

Histoplasmosis in Africa: Current perspectives,knowledge gaps,and research priorities

BackgroundHistoplasmosis 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.MethodsA 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.FindingsIn 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.ConclusionsDespite 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.     

How I Treat Histoplasmosis

Histoplasmosis is an endemic mycosis caused by the dimorphic fungus Histoplasma capsulatum. Some important manifestations of infection include acute or chronic pulmonary disease, histoplasmomas, progressive disseminated histoplasmosis, and central nervous system infection. Depending on the clinical presentation, site of infection and severity of disease, either amphotericin B preparations followed by itraconazole, or itraconazole alone have become the preferred treatments. Because prolonged therapy (6 weeks to 24 months) may be required, careful monitoring for nephrotoxicity in patients on amphotericin B preparations is necessary. In addition, in patients receiving itraconazole, vigilance for drug interactions and pharmacokinetic properties is warranted. Histoplasma antigen testing has improved rapidity of diagnosis and the ability of long-term monitoring for clinical response in patients with histoplasmosis.     

Ocular Histoplasmosis

Case reports of three residents of Ontario with clinical histoplasmic chorioretinitis are presented. The diagnosis was made on the basis of the clinical appearance, the presence of calcified lesions in the chest, a negative skin test to tuberculin, and a positive skin test to toxoplasmin. All patients were treated with intravenous amphotericin B. Except for transitory elevation of blood urea nitrogen, there were no serious complications from the drug and in all cases the lesions in the eyes were improved. Histologic or cultural proof of the presence of fungus in the eye is not available, but clinical and laboratory findings can combine to point to the diagnosis of histoplasmosis. In such cases, since vision is at stake, treatment with amphotericin B should be considered.     

Chronic Cavitary Histoplasmosis of the Lung

Four main clinical types of disease result from infection by the fungus Histoplasma capsulatum: (1) the primary complex; (2) acute pulmonary histoplasmosis; (3) chronic cavitary pulmonary histoplasmosis; (4) disseminated systemic histoplasmosis.Chronic cavitary histoplasmosis of the lung is indistinguishable clinically and radiographically from pulmonary tuberculosis. In this disease, however, the histoplasmin skin test and the histoplasmin complement fixation test are positive in more than 80% of cases and sputum cultures are usually positive for Histoplasma capsulatum. The mortality rate of the chronic cavitary type is greater than 30%. The antibiotic, amphotericin B, is the most effective drug in treatment. If surgical resection of the cavitary lesion is feasible, under amphotericin coverage, this is the treatment of choice.During the past year, two patients with chronic cavitary histoplasmosis illustrating the aforementioned features were diagnosed at the Toronto Hospital for Tuberculosis.     

Coccidioidomycosis and other endemic mycoses in Mexico

The endemic mycoses traditionally include coccidioidomycosis, histoplasmosis, blastomycosis and paracoccidioidomycosis. Although sporotrichosis and chromomycosis are technically not included among the endemic mycoses, they are frequently diagnosed in Mexico. Most systemic endemic mycoses are a consequence of inhaling the fungi, while subcutaneous mycoses are acquired through the inoculation of vegetable matter or soil containing the organism. Coccidioidomycosis is caused by Coccidioides spp., a dimorphic pathogenic fungus. Approximately 60% of exposures result in asymptomatic infection; in the rest there are protean manifestations that range from a benign syndrome also known as "Valley Fever" to progressive pulmonary or extrapulmonary disease. Histoplasmosis, caused by the dimorphic fungus Histoplasma capsulatum, is endemic to the Americas. Pulmonary histoplasmosis manifestations are protean, ranging from a brief period of malaise to a severe, prolonged illness. The spectrum of illness in disseminated histoplasmosis ranges from a chronic, intermittent course to an acute and rapidly fatal infection. Paracoccidioidomycosis is a chronic, granulomatous systemic disease caused by Paracoccidioides brasiliensis that characteristically produces a primary pulmonary infection, often asymptomatic, and then disseminates to form ulcerative granulomata of the oral, nasal and occasionally the gastrointestinal mucosa. Sporotrichosis, caused by Sporothrix schenckii, has diverse clinical manifestations; the most frequent is the lymphocutaneous form. Generally, infection results from inoculation of the fungus through thorns, splinters, scratches and small traumas. Chromomycosis (Chromoblastomycosis) is a slowly progressive cutaneous and subcutaneous mycosis attributed to various saprophyte Hypomycetes fungi. The primary lesion is also thought to develop as a result of percutaneous traumatic inoculation.     

High prevalence and mortality due to Histoplasma capsulatum in the Brazilian Amazon: An autopsy study

BackgroundHistoplasmosis is acquired by inhalation of spores of the dimorphic fungus Histoplasma spp. Although this pathogen is distributed worldwide, it is more prevalent in the Americas. However, the real burden of histoplasmosis remains undefined in many endemic regions.MethodologyWe conducted a series of 61 autopsies to individuals who died in a hospital in the Brazilian Amazon focused on infectious diseases. We performed a detailed histological and microbiological evaluation with genetic characterization of Histoplasma strains with the aim to evaluate the contribution of histoplasmosis to morbidity and mortality. Additionally, we assessed the clinicopathological correlation.Principal findingsEvidence of Histoplasma infection was detected in 21 patients (34%). Eight cases were disseminated infections, all of them occurred in HIV-positive patients. Six cases were localized histoplasmosis, limited to the lungs. In seven patients Histoplasma DNA was detected by PCR in patients with no histological lesions. Histoplasma infection was detected in 38% of HIV-positive patients and was a major contributor to death in 22% of them. Lungs, liver and spleen were affected in all cases of disseminated histoplasmosis. Phylogenetic analysis of the strains suggested a high diversity of Histoplasma species circulating in the Brazilian Amazon. Histoplasmosis was clinically missed in 75% of the disseminated infections.ConclusionsThe high incidence of histoplasmosis, the low index of clinical suspicion, and the severity of the disseminated disease highlight the need of proactively implementing sensitive routine screening methods for this pathogen in endemic areas. Antifungal prophylaxis against Histoplasma should be encouraged in the severely immunocompromised HIV patients in these areas. In conclusion, substantial mortality is associated with disseminated histoplasmosis among HIV-positive patients in the Brazilian Amazon.     

Disseminated histoplasmosis in an English patient with diabetes mellitus.

Histoplasma capsulatum is not endemic in Britain. We report a case of disseminated histoplasmosis in an English man who had not ventured out of northern Europe for 30 years. The disease presented as painful mouth ulcers and hepatosplenomegaly six months after he had developed maturity-onset diabetes. The origin of the infecting fungus may have been from within the United Kingdom or alternatively it may have existed as an intraoral saprophyte for over 30 years.     

Efficacy of cell-free antigens in evaluating cell immunity and inducing protection in a murine model of histoplasmosis

Histoplasma capsulatum is a dimorphic pathogenic fungus that causes a wide spectrum of disease when mycelial fragments are inhaled. Resistance to H. capsulatum is dependent on cellular immunity mediated by T cells and macrophages. Here we standardized the production of extracts containing cell-free antigens (CFAgs) and observed their efficacy in evaluating cellular immunity during murine histoplasmosis. CFAgs induced a more potent delayed-type hypersensitivity (DTH) response in H. capsulatum-infected mice than did histoplasmin-a classical antigen. This DTH response to CFAgs is able to determine the immune status of infected mice and to predict their death. Moreover, CFAgs stimulated spleen cells from immune mice to produce higher amounts of gamma interferon (IFN-gamma) in vitro. Finally, immunization with CFAgs protected against a lethal inoculum of H. capsulatum. These results demonstrate that CFAgs may be useful for the evaluation of cellular immune response and as a potential source for the development of a vaccine against histoplasmosis.     

Histoplasma capsulatum in the environment of sporadic histoplasmosis cases

Conclusions 1. Acute pulmonary histoplasmosis in adults is demonstrated to be associated with exogenous sources of infection in one-half of a series of cases. 2. No exogenous sources of infection were found in chronic pulmonary histoplasmosis in adults by methods comparable to those used in acute pulmonary histoplasmosis. 3. The significance of these findings for the pathogenesis of the three clinical forms of histoplasmosis is discussed. 4. In acute pulmonary histoplasmosis in adults, the isolation ofH. capsulatum from the environment at sites of exposure aided in specific diagnosis.Two acute pulmonary histoplasmosis cases were reported previously (2–3).     

Disseminated histoplasmosis with lesions restricted to the larynx in a patient with AIDS. Report of a case and review of the literature

Histoplasmosis is an endemic and systemic mycosis, caused by the dimorphic fungus Histoplasma capsulatum var capsulatum. Disseminated disease in immunocompromised patients generally results from the reactivation of latent foci after a prolonged period of asymptomatic infection. We report a case of laryngeal histoplasmosis as the unique clinical manifestation of a progressive form of the disease in a patient with advanced HIV/AIDS disease. Histopathological analysis of laryngeal biopsy smears revealed granulomas containing Histoplasma-like organisms. Treatment with amphotericin B followed by itraconazole resulted in complete remission of laryngeal lesions. To our knowledge, this is the third case report of laryngeal histoplasmosis in a patient with AIDS.     

Biological function and molecular mapping of M antigen in yeast phase of Histoplasma capsulatum

Histoplasmosis, due to the intracellular fungus Histoplasma capsulatum, can be diagnosed by demonstrating the presence of antibodies specific to the immunodominant M antigen. However, the role of this protein in the pathogenesis of histoplasmosis has not been elucidated. We sought to structurally and immunologically characterize the protein, determine yeast cell surface expression, and confirm catalase activity. A 3D-rendering of the M antigen by homology modeling revealed that the structures and domains closely resemble characterized fungal catalases. We generated monoclonal antibodies (mAbs) to the protein and determined that the M antigen is present on the yeast cell surface and in cell wall/cell membrane preparations. Similarly, we found that the majority of catalase activity was in extracts containing fungal surface antigens and that the M antigen is not significantly secreted by live yeast cells. The mAbs also identified unique epitopes on the M antigen. The localization of the M antigen to the cell surface of H. capsulatum yeast and the characterization of the protein's major epitopes have important implications since it demonstrates that although the protein may participate in protecting the fungus against oxidative stress it is also accessible to host immune cells and antibody.     

HIV-Associated Histoplasmosis Early Mortality and Incidence Trends: From Neglect to Priority

Background

Histoplasmosis is an endemic fungal infection in French Guiana. It is the most common AIDS-defining illness and the leading cause of AIDS-related deaths. Diagnosis is difficult, but in the past 2 decades, it has improved in this French overseas territory which offers an interesting model of Amazonian pathogen ecology. The objectives of the present study were to describe the temporal trends of incidence and mortality indicators for HIV-associated histoplasmosis in French Guiana.

Methods

A retrospective study was conducted to describe early mortality rates observed in persons diagnosed with incident cases of HIV-associated Histoplasma capsulatum var. capsulatum histoplasmosis admitted in one of the three main hospitals in French Guiana between 1992 and 2011. Early mortality was defined by death occurring within 30 days after antifungal treatment initiation. Data were collected on standardized case report forms and analysed using standard statistical methods.

Results

There were 124 deaths (45.3%) and 46 early deaths (16.8%) among 274 patients. Three time periods of particular interest were identified: 1992–1997, 1998–2004 and 2005–2011. The two main temporal trends were: the proportion of early deaths among annual incident histoplasmosis cases significantly declined four fold (χ2, p<0.0001) and the number of annual incident histoplasmosis cases increased three fold between 1992–1997 and 1998–2004, and subsequently stabilized.

Conclusion

From an occasional exotic diagnosis, AIDS-related histoplasmosis became the top AIDS-defining event in French Guiana. This was accompanied by a spectacular decrease of early mortality related to histoplasmosis, consistent with North American reference center mortality rates. The present example testifies that rapid progress could be at reach if awareness increases and leads to clinical and laboratory capacity building in order to diagnose and treat this curable disease.     

宏基因组学诊断播散型组织胞浆菌病1例

播散型组织胞浆菌病是一种进行性肺外疾病好发于免疫缺陷者。该病诊断的应结合组织胞浆菌病的高危因素(免疫抑制剂、高龄、高风险的暴露等)与临床表现。本文报道一例播散型组织胞浆菌病但免疫功能健全的病例,其表现为亚急性起病,后期病程进展迅速,骨髓涂片及宏基因测序诊断为播散型组织胞浆菌病。予以两性霉素B去氧胆酸盐及伊曲康唑治疗后病情明显好转。     

Advances in the serodiagnosis of blastomycosis

Blastomyces dermatitidis, the etiologic agent of blastomycosis, is endemic to certain areas of North America and other continents and can cause a variety of clinical manifestations that range from subclinical to life-threatening infections. Delineation of its ecology and epidemiology has been difficult because of the lack of rapid, sensitive, and specific noninvasive diagnostic tests. Despite efforts to develop such tests for clinical use, diagnosis of infection is still based on direct visualization of the organism in histopathologic or cytologic specimens and growth in the microbiologic laboratory. Serologic tests and skin testing have been hampered by low sensitivity and specificity caused by cross-reactivity with other endemic mycoses and are not commercially available. An antigen assay is now commercially available, but it also has significant cross-reactivity with other mycoses, especially histoplasmosis. The keys to diagnosis remain a high index of suspicion and knowledge of the disease’s varied clinical manifestations.     

Disseminated histoplasmosis with hemophagocytic syndrome in a patient with AIDS: description of one case and review of the Spanish literature

We report a case of disseminated histoplasmosis in a 33-year old Ecuadorian patient with AIDS and a CD4 lymphocyte count of 39 cells/microl. He presented with prolonged fever and cough, was diagnosed with hemophagocytic syndrome and multiple organ failure and died 18 days after admission. Histoplasma capsulatum was isolated post-mortem from bone marrow biopsy and blood culture. In a literature review we found 22 published cases of disseminated histoplasmosis in patients with AIDS in Spain since 1988. All but two were men under 50 years old. Nineteen had been born or had lived in endemic areas. The diagnosis of histoplasmosis was established by culture of bone marrow biopsy in 10 cases. Itraconazole was introduced as a second drug after amphotericin B in ten of the thirteen patients who survived.     

Evaluation of a Microtiter Latex Agglutination Test for Histoplasmosis

Experiments were designed to evaluate a Microtiter latex agglutination (Micro-LA) test, as a serological aid in the diagnosis of histoplasmosis, and to compare this test with the conventional microtiter-complement fixation (CF) test for histoplasmosis. Sera tested were from cases of acute and chronic pulmonary and disseminated histoplasmosis, as well as from individuals not having histoplasmosis. Ninety-seven percent of the cases of acute pulmonary histoplasmosis had positive Micro-LA tests, whereas 91% had positive CF tests. Ninety-six percent of the patients having chronic pulmonary histoplasmosis showed positive Micro-LA tests and 91% had positive CF tests. In contrast, 64% of the cases of disseminated histoplasmosis had positive Micro-LA tests, whereas 82% had positive CF tests. None of these differences was statistically significant. Although there were no significant differences in complement fixing and agglutinating antibody cross-reactivity with Blastomyces antigens, more patients demonstrated CF titers than Micro-LA titers. Sera from patients with acute and chronic histoplasmosis showed higher Micro-LA titers than CF titers, whereas sera from cases of disseminated histoplasmosis showed higher CF titers. Histoplasmin skin testing has less of a boosting effect on agglutinating antibodies than on CF antibodies to histoplasmin. Anticomplementary sera can be used in the Micro-LA test. This test is simple to perform, and results can be obtained in 2 to 4 hr.