No abstract present
When non-scientific people are interviewed about the most dangerous fungus in
the world, most instinctively cite the—so famous—death cap amanita
(Amanita phalloides). However, this macroscopic species related to the
Basidiomycota division, largely widespread in Europe and subsequently imported to
all other continents, actually causes only few dozens of deaths per year. The real threat is rather microscopic and is responsible for a heavy
burden in worldwide public health. According to the GAFFI (Global Action Fund for
Fungal Infection) website (https://gaffi.org/), 13,500,000 people are currently
suffering from common life-threatening fungal infections and
Summarizing representation of the relative burden for the most common fungal infections (according to the data of the GAFFI website (https://gaffi.org/). For each one, the global current prevalence and the annual related deaths are showed by the means of a radar graph, and compared to those caused by tuberculosis and human immunodeficiency virus (HIV) infection, according to a logarithmic scale.
Fungal infection is described in both high and low resources countries, but their relative representations are variable therein [1]. In addition to the influence of numerous factors, their respective prevalence notably depends on the local climate, demographics and healthcare situation and habits, e.g., prevalence of tuberculosis and human immunodeficiency virus (HIV) infection, easy access to cancer chemotherapy, practice of transplantation, distribution of novel immunosuppressive regimens like monoclonal antibodies… [2]. For instance, tropical areas are mostly concerned by endemic infections, e.g., mycetoma in the Saharan band from Senegal to Sudan, Penicillium marneffei talaromycosis in Southeast Asia, or histoplasmosis in central and South America: all these entities are associated with poverty, underlying infectious diseases and certain temperatures. In contrast, Northern and Western countries are rather interested in opportunistic diseases induced by iatrogenic processes, e.g., candidiasis following solid organ transplantation or surgery, aspergillosis associated to hematopoietic stem-cell transplantation or intensive anticancer chemotherapy [1].
Nowadays, historic infections like Pneumocystis pneumonia or
Cryptococcus meningitis in HIV-positive patients are becoming less
incident (especially because of the advent of highly active antiretroviral
therapies), as illustrated by the –14.3% decrease per year in France
during the 2001–2010 period for the former [3], and the 3 to 4-fold reduction in
Africa over the last decade for the latter [4]. They have been progressively
replaced by other fungal diseases that have been newly emergent or just
relatively more represented. For instance, numbers of candidemia and invasive
aspergillosis were 89.5% and 63.6% increased in France, during the same
aforementioned period [3]. Several causes linked to the medical advances can
explain these findings: the diversification of the medical procedures and the
arrival of new immunosuppressive drugs on the market, but also the prolongation
of the overall survival of patients (so that consequently the exposure risks are
proportionally increased). Currently, around 400,000 new cases of candidemia
occur annually worldwide, primarily in intensive care units (ICU), but not
exclusively [1]. The incidence rose up by
Diversification of the panel of the underlying chronic diseases, as well as the increasing absolute number of concerned patients, also plays a major role in the global burden of fungal infections. Thus, it is thought that at least 3,000,000 subjects are affected by chronic aspergillosis among those with debilitated terrain, like chronic obstructive pulmonary disease [COPD], alcoholic cirrhosis, sarcoidosis, or corticosteroid treatments [15]. More specifically, its prevalence was evaluated at about 1.2 million cases in the context of ancient tuberculosis [16]. Case fatality rate approaches 15–40%. All over the world, more than 23,500,000 individuals are currently concerned by allergic fungal diseases, whatever the pathophysiology, like severe asthma with fungal sensitization (SAFS) in 5–20% asthmatics [17] and allergic bronchopulmonary aspergillosis (ABPA) in 15% adults with cystic fibrosis (teenagers and kids are usually less affected) [18].
In tropical countries, the actual burden of endemic fungal diseases is tough to assess, primarily because the access to efficient diagnostics still lacks in rural areas. Incidence rate of histoplasmosis is likely ~100,000 cases per year [19], and the cumulated prevalence close to 50 million over time, although the infection remains most often asymptomatic [1]. According to a recent study, the number of deaths related to histoplasmosis in Latin America was estimated at range of 671 to 9394 during one unique year, so that they were somewhat equivalent to the 5062 deceases related to tuberculosis meantime [20]. Like chromoblastomycosis (in all, 7740 cases have been reported worldwide, but this fungal entity is mostly present in Madagascar with prevalence up to 14/100,000 inhabitants, and in Brazil) [21], mycetoma have been recently listed among the neglected tropical diseases by the World Health Organization (WHO). In the world, almost 20,000 cases of mycetoma have been reported in the literature in more than 100 countries. Notably, mycetoma is now described far outside the tropics, including for example Italy, China, Australia and USA [22]. Sporotrichosis is mainly found in central and South America: a new epidemic wave has spread from Rio de Janeiro to the North through cat transmission [23]. Only in China, talaromycosis is supposed to concern 20% HIV-positive subjects geographically exposed, resulting in 0.35 cases per 100,000 inhabitants, whereas its worldwide incidence is supposed to be close to 10,000 new cases per year [24]. Coccidioidomycosis due to Coccidioides immitis is largely underestimated: the actual incidence is likely closer to 140,000–150,000 cases per year, most occurring asymptomatically in America [1]. In California, 7466 workers were contaminated in 2017 subsequently to digging agricultural works and creation of embankments in the ground [25].
Finally, we can also cite the burden represented by superficial fungal
infection, like tinea corporis, capitis, pedis or
unguium that altogether probably count for a prevalence of one billion
persons [26]. All people categories can be concerned, but tinea pedis,
or athlete’s foot, is more common in young sportsmen (-women), while
tinea unguigum, or onychomycosis, is increasingly more prevalent in
elderly, up to 50% individuals
In conclusion in the light of all the aforementioned rates (although they are
probably significantly underestimated), one could legitimately acknowledge that
mycologists and specialists of infectious diseases still have a lot of efforts to
provide in order to better diagnose and treat the fungal diseases. The direct
costs related to the care for managing fungal infections were estimated at
GD was at the origin of the text and wrote it; AC reviewed and edited the document.
Not applicable.
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This research received no external funding.
The authors declare no conflict of interest. GD was specifically invited by the editorial board to write this manuscript for the special issue dedicated to fungal diseases.