Case Report: Histoplasmosis: First Autochthonous Case from Israel

Epidemiological, clinical, diagnostic, and therapeutic features of histoplasmosis: A systematic review

Histoplasmosis is a mycosis due to a dimorphic fungus Histoplasma capsulatum. This study aimed at providing an overview of histoplasmosis epidemiological, clinical, diagnostic, and therapeutic aspects from the last 30 years. This review was carried out using a systematic literature search on histoplasmosis from 1992 to 2021. We describe the clinical features, diagnostic methods and treatment. Empirical searches were conducted via the databases PubMed, Google Scholar and Science Direct. Between 1992 and 2021, 190 manuscripts were published and reported 212 cases of histoplasmosis. These publications included 115 and 97 cases of American and African histoplasmosis respectively. The number of publications increased over the last ten years with a maximum in 2020 (12.34 % of the cases reported). The disseminated forms of histoplasmosis were the most frequently reported cases as compared to the localized forms. This was the case with the American histoplasmosis (75.65 %) as well as with the African histoplasmosis (55.67 %). Itraconazole (31.17 %) and Amphotericin B (26.62 %) were the most used drugs in the management of these cases. American histoplasmosis is distributed worldwide whereas African histoplasmosis is mainly present in intertropical Africa. There is a critical need for setting up a global surveillance system, towards a better understanding of the disease.

Histoplasmosis Diagnosed in Europe and Israel: A Case Report and Systematic Review of the Literature from 2005 to 2020

Human histoplasmosis is a mycosis caused by two distinct varieties of a dimorphic fungus: Histoplasma capsulatum var. capsulatum and H. capsulatum var. duboisii. In Europe, it is usually imported by migrants and travellers, although there have been some autochthonous cases, especially in Italy; however, most European physicians are unfamiliar with its clinical and pathological picture, particularly among immunocompromised patients without HIV infection. This systematic review of all the cases of histoplasmosis reported in Europe and Israel between 2005 and 2020 identified 728 cases diagnosed in 17 European countries and Israel described in 133 articles. The vast majority were imported (mainly from Central and South America), but there were also seven autochthonous cases (six in Europe and one in Israel). The patients were prevalently males (60.4%), and their ages ranged from 2 to 86 years. The time between leaving an endemic region and the diagnosis of histoplasmosis varied from a few weeks to more than 40 years. Progressive disseminated histoplasmosis was the most frequent clinical picture among people living with HIV infection (89.5%) or a different immunocompromising condition (57.1%), but it was also recorded in 6.2% of immunocompetent patients. Twenty-eight cases were caused by Histoplasma duboisii. Immunocompromised patients without HIV infection had the worst outcomes, with a mortality rate of 32%.

Re-drawing the Maps for Endemic Mycoses

Endemic mycoses such as histoplasmosis, coccidioidomycosis, blastomycosis, paracoccidioidomycosis, and talaromycosis are well-known causes of focal and systemic disease within specific geographic areas of known endemicity. However, over the past few decades, there have been increasingly frequent reports of infections due to endemic fungi in areas previously thought to be “non-endemic.” There are numerous potential reasons for this shift such as increased use of immune suppressive medications, improved diagnostic tests, increased disease recognition, and global factors such as migration, increased travel, and climate change. Regardless of the causes, it has become evident that our previous understanding of endemic regions for these fungal diseases needs to evolve. The epidemiology of the newly described Emergomyces is incomplete; our understanding of it continues to evolve. This review will focus on the evidence underlying the established areas of endemicity for these mycoses as well as new data and reports from medical literature that support the re-thinking these geographic boundaries. Updating the endemic fungi maps would inform clinical practice and global surveillance of these diseases.

Environmental and Wilderness-Related Risk Factors for Histoplasmosis: More Than Bats in Caves

INTRODUCTION

Histoplasma capsulatum is a dimorphic fungus that causes histoplasmosis, a sporadic endemic mycosis with environmental, occupational, and wilderness exposure-related risk factors. The objectives of this review are to describe these risk factors, to alert clinicians to the different presenting manifestations of histoplasmosis, and to recommend effective management and prevention strategies.

METHODS

Internet search engines were queried with keywords to select articles for review over the study period, 1950 to 2018. Articles selected for review included case series, epidemiologic analyses of surveillance data, clinical and laboratory updates, immunologic investigations, and observational and longitudinal studies. Articles excluded from review included systemic mycosis reviews and clinicopathologic conference reports.

RESULTS

The principal transmission mechanism of histoplasmosis is by inhalation of spores aerosolized by soil disruption, resulting in pneumonic infections ranging from asymptomatic to disseminated. Although histoplasmosis is more common in endemic regions, nonendemic regions have reported increasing autochthonous and imported cases. Immunocompromised persons are at significantly increased risks of contracting histoplasmosis. Environmental and wilderness-related risk factors for histoplasmosis include bird and bat watching, cave and cave entrance exploration, and bamboo removal and burning. Occupational risk factors for histoplasmosis include road construction, roofing, bridge and water tower work, demolition, and masonry.

CONCLUSIONS

Histoplasmosis can result in considerable morbidity. Increased awareness of disease risk factors among the public and the international healthcare community will improve the timely diagnosis and treatment of histoplasmosis and prevent disease progression and dissemination.