Re-drawing the Maps for Endemic Mycoses

Updating the epidemiology of blastomycosis and histoplasmosis in the United States, using national electronic health record data, 2013 - 2023

Introduction

Where surveillance data are limited, nationally-representative electronic health records allow for geographic, temporal, and demographic characterization of the fungal diseases blastomycosis and histoplasmosis.

Methods

We identified incident blastomycosis and histoplasmosis cases from 2013 to 2023 within Oracle EHR Real-World Data, which comprises 1.6 billion healthcare encounters nationally. To characterize geographic and temporal incidence rates, we used weighted generalized estimating equations adjusting for non-representativeness of EHR-reporting facilities. We computed standardized incidence rate ratios (sIRRs), which relay relative differences in standardized incidence rates among region, race/ethnicity, gender, and age subgroups and the national population.

Results

National incidence rates in 2023 were 2.4 (95% CI: 1.6-3.5) and 1.9 times (95% CI: 1.6-2.2) rates in 2013, for blastomycosis and histoplasmosis, respectively. Blastomycosis incidence rates among Hispanic/Latino and non-Hispanic Black individuals were 60% (sIRR: 1.6 [95% CI: 1.0-2.4]) and 30% (sIRR: 1.3 [95% CI: 1.0-1.6]) higher than the standardized national incidence rate. Histoplasmosis incidence rates were elevated among non-Hispanic White patients (sIRR: 1.05 [95% CI: 1.02-1.08]). Standardized incidence rates of both diseases were higher among older and male patients and were elevated in the Upper Midwest (sIRR: blastomycosis: 5.1 [95% CI: 3.7-6.8]; histoplasmosis: 1.7 [95% CI: 1.5-1.9]) and Ohio Valley regions (sIRR: blastomycosis: 2.0 [95% CI: 1.7-2.3]; histoplasmosis: 2.3 [95% CI: 2.2-2.5], and increased in the Northern Rockies and Plains from 2013 to 2023.

Discussion

This analysis revealed increasing incidence rates of blastomycosis and histoplasmosis and expansion outside of historically endemic regions, with notable differences in incidence by race/ethnicity, gender, and age.

High Genetic Diversity of Histoplasma in the Amazon Basin, 2006-2017

Histoplasmosis is one of the most common pulmonary mycosis diseases in the world. Genome sequencing has revealed that Histoplasma, the cause of histoplasmosis, is composed of several phylogenetic species. The genetic diversity of the pathogen remains largely unknown, especially in the tropics. We sequenced the genomes of 91 Histoplasma isolates from the Amazon basin of South America and used phylogenomics and population genetic evidence to measure the genetic variation of the genus in South America. We report a previously unidentified clade of Histoplasma endemic to the Amazon basin. The lineage is widespread across the continent and contains 5 lineages that are sufficiently differentiated to be considered phylogenetic species. We found the geographic range of those lineages is largely but not completely overlapping. Finally, we found that the patient median age and sex ratio differs among species, suggesting differences in the epidemiology of histoplasmosis caused by each Histoplasma lineage.

A cautionary tale of false-positive histoplasma urine antigen in an HIV patient: a case report

Introduction. Coccidioidomycosis, or Valley fever, is a fungal disease caused by Coccidioides species, prevalent in parts of the southwestern United States. It usually results from inhaling spores from soil and is a common cause of pneumonia in these regions. Case Presentation. We present a unique case of coccidioidomycosis in an immunodeficient male patient secondary to human immunodeficiency virus infection with poor adherence to anti-retroviral treatment. After presenting with non-specific symptoms and pre-syncope, he was initially diagnosed with pneumonia based on chest X-ray findings, but his symptoms failed to improve with antibiotics. He was treated for presumed pulmonary histoplasmosis following a positive histoplasma urine antigen test. However, the patient worsened clinically. Following a computed tomography scan demonstrating a large necrotic lung consolidation, fungal stain and culture of tissue biopsied through endobronchial ultrasound confirmed coccidioidomycosis. The patient received 2 weeks of liposomal amphotericin with clinical improvement before discharge with itraconazole. Conclusion. The histoplasma antigen test can be falsely positive due to cross-reaction with other fungal infections like blastomycosis, paracoccidioidomycosis or talaromycosis, and less frequently, coccidioidomycosis or aspergillosis. Diagnosis of coccidioidomycosis requires a high index of suspicion outside the expected geographic distribution in the appropriate clinical setting. Our case highlights the risk of false-positive antigen test results and the importance of invasive diagnostics, including bronchoscopy to obtain fungal cultures, if the diagnosis remains uncertain.

Practical Guidance for Clinical Microbiology Laboratories: Antibody and antigen detection methods for dimorphic fungal infections

SUMMARYAntibody and antigen detection assays continue to play a significant role in the diagnosis of dimorphic fungal pathogens, including Blastomyces dermatitidis complex, Coccidioides immitis/posadasii, Paracoccidioides species, Histoplasma species, Sporothrix species, and Talaromyces marneffei. The performance characteristics of serologic and antigen detection assays for these pathogens are variable, however, influenced by multiple factors, including sample type, disease presentation, patient immunostatus, and timing of specimen collection relative to symptom onset. As a result, there is a need for a centralized document summarizing the accuracy of currently available antibody and antigen detection assays for each of these agents, including discussion of individual assay nuances and caveats that should be considered by clinicians and laboratorians alike. In addition, this review provides expert recommendations for the utilization and interpretation of serologic and antigen detection assays for these dimorphic pathogens.

A role in intracellular K+ in protecting pathogenic dimorphic fungi against induced cell death by bioinspired antimicrobial peptides

Antimicrobial peptides (AMPs) are promising drugs, though their fungal combat mechanisms remain partly unclear. We designed three AMPs (dAMPs) based on the γ-core of the Vu-Def1 seed defensin from Vigna unguiculata L. Walp. named RR, D-RR, and WR, and assessed their actions on Candida tropicalis and Candida albicans. Amidst their actions are cell shrinkage caused by K+ efflux from fungal cells. K+ involvement in fungal death by these peptides was explored. We assessed cell shrinkage, oxidative stress, mitochondria hyperpolarization, membrane permeabilization, medium acidification, antimicrobial activity under hypoosmotic conditions, and cellular degradation. Viability assays were performed with channel blockers and K+ addition at various times. The interactions of dAMPs with salts and fungal cells were analyzed using circular dichroism and microscopy. K+ and Cl- channels were not directly involved in dAMPs-induced death. Supplementation with K+ protected fungal cells from death. In tests, cations often deactivated them through charge neutralization. Peptides maintained their conformation with K+ and were found in cell cytoplasm indicating K+ did not neutralize charges. K+ did not prevent oxidative stress, but protected from cell shrinkage and mitochondria hyperpolarization. dAMPs rapidly stimulated medium acidification, followed by inhibition after 1 min, and K+ prevented acidification. Membrane permeabilization occurred after 20 min, faster with WR, explaining lack of protection from blockers. Fungal death was accelerated under hypoosmotic conditions. Electrophoresis revealed protein degradation, while ultrastructural analysis of the cells showed vacuolization, indicative of cytoplasmic degradation. Thus, K+ prevented cell death by maintaining internal levels, averting activation of cell degradation process.

Disseminated coccidioidomycosis presenting as eosinophilic ascites

A man in his 50s with a self-reported history of liver cirrhosis was admitted to the hospital for the treatment of suspected spontaneous bacterial peritonitis (SBP). Initial imaging revealed a mildly nodular liver, a large volume of ascites and omental thickening. He was treated empirically for SBP. Ascitic fluid analysis from paracentesis demonstrated eosinophils and a low serum-ascites albumin gradient. He was discharged from the hospital with a diagnosis of peritoneal carcinomatosis pending work-up for an unknown primary malignancy. An extensive malignancy work-up was negative, but an omental biopsy revealed coccidioidomycosis by culture and histopathology. With high-dose fluconazole therapy, his abdominal pain improved, and his ascites completely resolved. Eosinophilia in ascitic fluid is uncommon and should prompt consideration of rare diagnoses, such as peritoneal coccidioidomycosis, tuberculosis, helminthic infections or eosinophilic gastrointestinal diseases.

High genetic diversity of Histoplasma in the Amazon basin, 2006-2017

Genome sequencing has revealed that Histoplasma, the etiological agent of histoplasmosis is composed of several phylogenetic species. Nonetheless, the genetic diversity of the pathogen remains largely unknown, especially in the tropics. We sequenced the genome for 91 Histoplasma isolates from the Amazon basin, and used phylogenomics, and population genetic evidence to measure the genetic variation of the genus in South America. We report a previously unidentified clade of Histoplasma endemic to the Amazon basin. The lineage is widespread across the continent and contains five lineages that are sufficiently differentiated to be considered phylogenetic species. We find that the geographic range of these lineages is largely but not completely overlapping. Finally, we find that the patient median age and sex ratio differs among species suggesting differences in the epidemiology of histoplasmosis caused by each Histoplasma lineage.

Transcriptomic atlas throughout Coccidioides development reveals key phase-enriched transcripts of this important fungal pathogen

Coccidioides spp. are highly understudied but significant dimorphic fungal pathogens that can infect both immunocompetent and immunocompromised people. In the environment, they grow as multicellular filaments (hyphae) that produce vegetative spores called arthroconidia. Upon inhalation by mammals, arthroconidia undergo a process called spherulation. They enlarge and undergo numerous nuclear divisions to form a spherical structure, and then internally segment until the spherule is filled with multiple cells called endospores. Mature spherules rupture and release endospores, each of which can form another spherule, in a process thought to facilitate dissemination. Spherulation is unique to Coccidioides, and its molecular determinants remain largely unknown. Here, we report the first high-density transcriptomic analyses of Coccidioides development, defining morphology-dependent transcripts and those whose expression is regulated by RYP1, a major regulator required for spherulation and virulence. Of approximately 9,000 predicted transcripts, we discovered 273 transcripts with consistent spherule-associated expression, 82 of which are RYP1-dependent, a set likely to be critical for Coccidioides virulence. ChIP-Seq revealed two distinct regulons of Ryp1: one shared between hyphae and spherules and the other unique to spherules. Spherulation regulation was elaborate, with the majority of 227 predicted transcription factors in Coccidioides displaying spherule-enriched expression. We identified provocative targets, including 20 transcripts whose expression is endospore-enriched and 14 putative secreted effectors whose expression is spherule-enriched, of which six are secreted proteases. To highlight the utility of these data, we selected a cluster of Ryp1-dependent, arthroconidia-associated transcripts and found that they play a role in arthroconidia cell wall biology, demonstrating the power of this resource in illuminating Coccidioides biology and virulence.

When to suspect and how properly early detect and treat patients with endemic mycoses

Endemic mycoses are caused by dimorphic fungi and eventually molds, as the case of implantation mycoses. In general, these diseases are acquired through trauma or inhalation of fungal elements in the environment, and less frequently by zoonotic acquisition or transmitted during organ transplantation. The target population for endemic mycoses is usually represented by normal hosts with low-income and intensive outdoor activities. Awareness of these diseases remains limited, even in regions with high prevalence, resulting in delayed diagnosis, and affecting the quality of life and outcomes of patients who suffer from these entities. In this review, we summarized relevant information about epidemiological, clinical, diagnostic, and treatment aspects of the most common endemic mycoses, including blastomycosis, coccidioidomycosis, histoplasmosis, paracoccidioidomycoses, talaromycosis, and implantation mycoses. The main goal of this review is to provide key concepts in terms of when to suspect, how early diagnose, and properly treat patients with these mycoses.

Histoplasma Endocarditis of the Native Mitral Valve in a Patient With End-Stage Renal Disease: A Diagnostic Challenge

Histoplasma is a rare cause of endocarditis. It usually occurs in immunosuppressed patients, but diagnosis can be challenging given its nonspecific clinical and laboratory findings. This report describes the case of a patient with end-stage renal disease and multiple hospitalizations who was diagnosed with blood culture-negative infective endocarditis and subsequently found to have Histoplasma endocarditis of his native mitral valve. Our patient's nonspecific symptoms posed a diagnostic challenge, which resulted in delayed diagnosis and treatment.

Pathophysiology and clinical outcomes of pancytopenia in disseminated histoplasmosis: a scoping review

PURPOSE

Pancytopenia in the setting of disseminated histoplasmosis is sparsely described in the literature. We investigated the underlying mechanisms of pancytopenia in disseminated histoplasmosis and highlighted clinical outcomes.

METHODS

We conducted a scoping review of cases and series on disseminated histoplasmosis presenting with pancytopenia published between 2001 and 2024. PubMed database was used for the search. The search terms were (disseminated histoplasmosis) AND (pancytopenia OR haemophagocytic syndrome OR lymphohistiocytosis).

RESULTS

We identified 72 cases. Forty-four (61.1%) cases were from the Americas, 18 (25.5%) from Asia, 8 (11.1%) from Europe, and 1(1.4%) each from Africa and Australia. Of the 72 cases, five cases (6.9%) were reported in children. The mean age was 41.9 ± 16.7 years with a range of 3 months to 78 years. Seven cases (9.7%) were immunocompetent, 27 (37.5%) had an underlying HIV infection and 45 (62.5%) were complicated with haemophagocytic lymphohistiocytosis syndrome. Histoplasma antigen assay (n = 29, 40.2%) was the major diagnostic method followed by bone marrow biopsy (n = 28, 38.9%). Fifty-three cases (73.6%) recovered, 15 (20.8%) died and outcomes were not stated in 4 cases (5.65%). The relationship between haemophagocytic lymphohistiocytosis and fatal outcomes was not statistically significant (P = 0.5). Likewise, HIV infection was not significantly associated with fatal outcomes (P = 0.6). Fatal outcomes were predominantly due to difficulty or delayed diagnosis of disseminated histoplasmosis and/or haemophagocytic lymphohistiocytosis (n = 5, 6.9%), multiple organ failure (n = 4, 5.6%) and late presentation (n = 2, 2.8%).

CONCLUSION

Pancytopenia in disseminated histoplasmosis is associated with poor outcomes. Such a hematologic finding should arouse the index of suspicion in the attending clinician for an invasive mycosis like disseminated histoplasmosis to avert fatal outcomes. Besides haemophagocytic lymphohistiocytosis, other factors associated with pancytopenia in disseminated histoplasmosis were the cooccurrence of viral and bacterial infections.

Fungal Pericarditis-A Systematic Review of 101 Cases

Fungal pericarditis is a rare disease but its incidence has risen in parallel with the global increase in invasive fungal infections. This systematic review analyzes data from previously reported cases of fungal pericarditis to provide an improved understanding of the etiology, clinical presentation, management, and outcomes of this rare disease. We reviewed Medline and Scopus databases from 1 January 1990 to 29 January 2024 for case reports that documented the isolation of a fungal pathogen from pericardial fluid or tissue. Of the 2330 articles screened, 101 cases met the inclusion criteria. Patients with fungal pericarditis and the involvement of at least one other organ-usually the lungs, brain, or kidney-had worse outcomes than patients with isolated pericardial disease. Immunosuppression was reported in 50% of cases and was associated with worse outcomes in adults. Patients who presented with chest pain, received adequate empiric antifungal therapy, and underwent pericardiocentesis and pericardiectomy had improved survival. The most common isolated pathogens were Candida spp., followed by Aspergillus spp. and Mucor spp., with the latter two linked to worse outcomes. Only 35% of patients received empiric antifungal medications before the causative pathogen was identified, and mortality was associated with a delay in appropriate therapy. Immunosuppression, disseminated disease, and presence of shock/multiorgan failure were additional risk factors associated with death. Fungal pericarditis carries a mortality rate of up to 50%, with nearly half of patients being immunocompromised. Clinicians frequently do not consider fungal pericarditis in the differential diagnoses, which leads to delays in treatment and poorer outcomes. Further prospective multicenter studies are urgently needed to better understand the epidemiology, improve diagnostic testing and management, and decrease unacceptably high mortality in patients with fungal pericarditis.

Coccidioidomycosis: a growing global concern

Coccidioidomycosis (CM) has been a recognized disease for about 130 years. The organisms (Coccidioides spp. fungi) inhabit desert soil in the southwestern USA, Mexico, and parts of Central and South America. Natural events such as dust storms, wildfires or outdoor activities including construction and gardening can disrupt the fungal arthroconidia, which easily become airborne and inhaled by the host. Approximately 60% of those exposed to arthroconidia are asymptomatic and do not require medical attention, but 30% show signs of pulmonary infection with symptoms ranging from a flu-like illness to pneumonia. In 5%-10% of cases serious or disseminated disease develops, which requires prompt diagnosis and management. About 1%-3% of infections disseminate to the CNS and if not appropriately treated are often fatal. There is an urgent need for improved diagnostics and treatments.

Evolving Epidemiology, Improving Diagnostic Tests and Their Importance for the Correct Diagnosis of Histoplasmosis

Histoplasmosis has traditionally been described as having discrete geographic areas of endemicity. Over the last few decades, it has become more and more clear that these areas are not accurate depictions of where histoplasmosis can occur. Our understanding of where histoplasmosis occurs has improved in recent years due to improving access to diagnostic testing and increased reporting as well as larger at-risk populations (HIV and non-HIV immune suppression) resulting in more cases. Although areas of relatively higher risk and case numbers certainly still exist, histoplasmosis has been observed in much of the world at this point. Our knowledge of the geographic distribution of histoplasmosis, though improving, remains incomplete. While diagnostic testing has traditionally been confined to visualization and/or culture in much of the world, antigen testing has emerged as an excellent tool. Unfortunately access to antigen testing has been inadequate for much of the world, but this has started to change in recent years and will likely change more dramatically in the near future, assuming ongoing positive developments in the area of lateral flow tests for antigen testing. In this review, we describe the current understanding of the geographic distribution of histoplasmosis, the current landscape of diagnostic testing, and the evolution of both areas with an eye towards the future.

Efficacy of nitrofuran derivatives against biofilms of Histoplasma capsulatum strains and their in vivo toxicity

AIM

To evaluate the efficacy of two nitrofuran derivatives against biofilms formed by two strains of Histoplasma capsulatum and to study the toxicity of these compounds in alternative models: Caenorhabditis elegans, Galleria mellonella, and zebrafish.

METHODS

The metabolic activity of biofilms was measured after treatment using the XTT reduction assay. Scanning electron microscopy (SEM) and confocal microscopy were used to observe damage to mature biofilms. Survival curves were generated for G. mellonella, while percentage survival was determined for C. elegans and zebrafish.

RESULTS

The compounds showed efficacy against early and mature biofilms at concentrations equal to or up to two times higher than those required to eliminate planktonic fungal cells (3.90 to 31.25 μg/mL). Micrographs showed a reduction in metabolic activity, biofilm thickness, and extracellular matrix. In addition, the compounds showed little or no toxicity in alternative models, even at the highest concentrations tested.

CONCLUSION

These results are promising for the development of new therapeutic alternatives, especially for species, such as H. capsulatum, which are recognized as high-priority pathogens. Few studies have investigated resistance and antifungal treatment targeting biofilms of this species, making this work a relevant contribution to future approaches.

Climate Change and Medical Mycology

This review explores how climate change influences fungal disease dynamics, focusing on emergence of new fungal pathogens, increased antifungal resistance, expanding geographic ranges of fungal pathogens, and heightened host susceptibility. Rising temperatures and altered precipitation patterns enhance fungal growth and resistance mechanisms, complicating treatment efforts. Climate-driven geographic shifts are expanding the range of diseases like Valley fever, histoplasmosis, and blastomycosis. Additionally, natural disasters exacerbated by climate change increase exposure to fungal pathogens through environmental disruptions and trauma. Many of those impacts affect primarily those already disadvantaged by social determinants of health putting them at increased risk for fungal diseases.

Histoplasmosis

This review provides an update of histoplasmosis, covering the changing epidemiology, pathogenesis, disease manifestations, diagnostic strategies, and management considerations for immunocompetent and immunocompromised populations.

Coccidioidomycosis

Coccidioidomycosis is the clinical disease caused by the dimorphic pathogenic fungi Coccidioides immitis and C posadasii. The number of clinically recognized coccidioidomycosis cases continues to increase yearly including in regions outside the traditional regions of endemicity. Following inhalation of Coccidioides spores, the course may range from asymptomatic exposure with resultant immunity, to a subacute pulmonary illness, to life-threatening disseminated infection. This review will summarize recent advances in our understanding of the infection and will include the ecology of Coccidioides, epidemiology and risk factors for infection, vaccine and novel antifungals in development, and management of immunosuppressed patients.

Blasto in the Bronx: An Unusual Case of Severe Cutaneous Blastomycosis in New York City

Urban cases of blastomycosis are extremely rare and usually involve an individual or individuals with recent travel to, and outdoor exposure in, an endemic area. We report a case of severe cutaneous blastomycosis in a New York City resident. He presented to our hospital in 2023 with multiple cavitary lung nodules and a large area of fungating lesions on his back that had been progressing for a month. Cultures and pathology from the skin lesions confirmed a diagnosis of cutaneous blastomycosis, and the patient was successfully treated with a prolonged course of oral itraconazole. Given no travel history outside of the five boroughs, we believe the patient acquired the infection endemically and is the first published case of blastomycosis acquired in New York City.

Histoplasmosis - More common than we realize

Histoplasmosis is primarily associated with immunocompromised individuals; however, its presentation in immunocompetent patients is increasingly recognized. This series of 5 cases from eastern India, a potential Histoplasmosis hotspot, describes five immunocompetent individuals with the disease. It emphasizes the diverse clinical spectrum of Histoplasmosis, often mimicking other conditions, thereby complicating diagnosis. Four patients presented with adrenal masses, emphasizing the importance of considering histoplasmosis in the differential diagnosis of adrenal enlargement. One patient developed hemophagocytic lymphohistiocytosis (HLH), underscoring the severe complications associated with disseminated histoplasmosis. Additionally, one patient exhibited localized disease, demonstrating the variable clinical presentations of this infection. Our findings emphasize the need for heightened clinical suspicion of histoplasmosis in patients with adrenal masses or unexplained fever, even in immunocompetent individuals in a relevant epidemiological setting. Early diagnosis and appropriate antifungal therapy are crucial for optimal outcomes.

Autochtonous Emergomyces pasteurianus subcutaneous infection in an Italian immunocompromised patient: a case report and review

We describe the second case of infection by Emergomyces pasteurianus that occurred in Italy. The patient presented ulcerated nodular lesions primarily in the forehead, beneath the orbital and nasal areas, but also in the neck and fingers in the early stages. Treatment involved amphotericin B, followed by long-term itraconazole, which resulted in complete clinical resolution. A review of the literature is also included.

UK guidelines for the investigation and management of eosinophilia in returning travellers and migrants

Eosinophilia is a common finding in returning travellers, migrants and other travelling groups. In this setting, it often indicates an underlying helminth infection. Infections associated with eosinophilia are frequently either asymptomatic or associated with non-specific symptoms but some can cause severe disease. Here the British Infection Association guidelines group has comprehensively reviewed and updated the UK recommendations for the investigation and management of eosinophilia in returning travellers, migrants and other relevant groups, first published in 2010.1 Literature reviews have been undertaken to update the evidence on the prevalence and causes of eosinophilia in these groups and on the treatment of relevant pathogens and clinical conditions. Diagnostic tests available to UK-based clinicians are summarised. Changes made to the guidelines include updates in the sections on the investigation and empirical treatment of asymptomatic eosinophilia and on the treatment of trichuriasis, lymphatic filariasis, onchocerciasis, hookworm, fascioliasis and taeniasis. Pathogens which are rarely encountered in UK practice have been removed from the guidelines and others added, including an expanded section on fungal infection. A section on off-license and rarely used drugs has been included.

Olorofim demonstrates in vitro activity against Coccidioides species, including isolates against which fluconazole has reduced activity

We evaluated the in vitro activity of olorofim against Coccidioides species. Olorofim demonstrated potent in vitro activity against all isolates tested with a minimum inhibitory concentration (MIC) range ≤0.008-0.06 µg/mL and geometric mean MIC of 0.010 µg/mL. This activity was also maintained against isolates with elevated fluconazole MICs (≥16 µg/mL), including strains with MICs ≥32 µg/mL (olorofim MIC range ≤0.008-0.06 µg/mL and geometric mean MICs of ≤0.009 and ≤0.013 µg/mL, respectively).

Optimizing in vitro spherulation cues in the fungal pathogen Coccidioides

Coccidioides spp. are part of a group of thermally dimorphic fungal pathogens, which grow as filamentous cells (hyphae) in the soil and transform to a different morphology upon inhalation into the host. The Coccidioides host form, the spherule, is unique and highly undercharacterized due to both technical and biocontainment challenges. Each spherule arises from an environmental spore (arthroconidium), matures, and develops hundreds of internal endospores, which are released from the spherule upon rupture. Each endospore can then go on to form another spherule in a cycle called spherulation. One of the foremost technical challenges has been reliably growing spherules in culture without the formation of contaminating hyphae and consistently inducing endospore release from spherules. Here, we present optimization of in vitro spherule growth and endospore release, by closely controlling starting cell density in the culture, using freshly harvested arthroconidia, and decreasing the concentration of multiple salts in spherulation media. We developed a minimal medium to test spherule growth on various carbon and nitrogen sources. We defined a critical role for the dispersant Tamol in both early spherule formation and prevention of the accumulation of a visible film around spherules. Finally, we examined how the conditions under which arthroconidia are generated influence their transcriptome and subsequent development into spherules, demonstrating that this is an important variable to control when designing spherulation experiments. Together, our data reveal multiple strategies to optimize in vitro spherulation growth, enabling characterization of this virulence-relevant morphology.IMPORTANCECoccidioides spp. are thermally dimorphic fungal pathogens found in the Southwest United States, Mexico, Central America, and South America. Coccidioides can infect both immunocompetent and immunocompromised people and can cause a devastating disseminated infection, including meningitis, with 30% mortality despite all currently available treatments. In this work, we tackle one of the current largest technical barriers to studying the fungus Coccidioides: reliably growing its host form in vitro. Our work is impactful because we have created a set of foundational tools for the burgeoning field of Coccidioides pathogenesis research. We have carefully optimized conditions that allow the development of Coccidioides in vitro into its pathogenic form. This work will open up many lines of investigation into the molecules that underlie Coccidioides pathogenesis.

Epidemiology of Coronavirus Disease 2019-Associated Fungal Infections in the Intensive Care Unit: A Single-Center Retrospective Study

INTRODUCTION

Invasive fungal disease (IFD) is a morbid superinfection that can arise in critically ill patients with COVID-19 infection. Studies evaluating the full spectrum of COVID-19-associated fungal infections remain limited.

METHODS

Single-center retrospective study assessing IFD in patients with COVID-19, hospitalized for ≥ 72 h in the intensive care unit (ICU) between 02/25/20 and 02/28/22 (n = 1410). IFD was assessed using consensus criteria (EORTC/MSGERC or ISHAM/ECMM criteria). T- and chi-square tests compared demographic/clinical characteristics between IFD and non-IFD patients. Cox proportional hazards regression estimated risk factors for in-hospital mortality.

RESULTS

Of 1410 patients with severe COVID-19, 70 (5%) had a diagnosis of COVID-19-associated fungal infection with invasive candidiasis occurring in 3%, and invasive aspergillosis in 2%. Other fungal infections were rare. Patients with IFD had longer ICU stays (26 vs. 13 days; p < 0.001); increased rates of mechanical ventilation (99% vs. 70%; p < 0.001); and a higher risk of in-hospital death (69% vs. 36%; p < 0.001). On multivariable analysis, COVID-associated fungal infections were associated with an increased risk of in-hospital mortality.

CONCLUSIONS

This real-world study of critically ill patients with COVID-19 demonstrated a low incidence of COVID-19-associated fungal infections with invasive candidiasis occurring most frequently. Fungal infections were associated with an increased risk of in-hospital mortality in this population.

Fungal Infections in Kidney Transplant Recipients: A Comprehensive Narrative Review

BACKGROUND

Despite kidney transplantation being a life-saving procedure, patients experience a high risk of developing fungal infections (FIs), with an increased risk of both morbidity and mortality, especially during the first year after transplant.

METHODS

We herein conducted a narrative review of the most common FIs in kidney transplant recipients (KTRs), with a focus on prevalence, risk factors, mortality, and prevention strategies.

RESULTS

The most common fungal pathogens in KTRs include Candida species (up to 70% of the overall FIs), Aspergillus species, Pneumocystis jiroveci, and Cryptococcus species. Fungal colonization, diabetes mellitus, chronic liver disease, malnutrition, and pre-existing lung conditions should all be acknowledged as possible predisposing risk factors. The mortality rate can vary from 25 to 50% and according to different settings and the types of FIs. Preventive strategies are critical for reducing the incidence of FIs in this population. These include antifungal prophylaxis, environmental precautions, and infection control measures. The use of novel tools (such as PCR-based molecular assays and NGS) for rapid and accurate diagnosis may play an important role.

CONCLUSIONS

Early recognition, the appropriate use of antifungal therapy, and preventive strategies are essential for improving graft loss and fatal outcomes in this vulnerable population. Future research is needed to optimize diagnostic tools, identify novel antifungal agents, and develop better prophylactic strategies for high-risk transplant recipients.

Hemophagocytic Lymphohistiocytosis Due to Disseminated Histoplasmosis in a Young Patient with AIDS

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening syndrome of immune dysregulation that results in multiorgan failure; HIV and histoplasmosis are known triggers of HLH. A young patient with AIDS was found to have disseminated histoplasmosis and met criteria for HLH. Despite 10 days of treatment with liposomal amphotericin B, she developed shock and acute respiratory distress syndrome and ultimately died. The few reported cases of HLH due to histoplasmosis in AIDS offer a variety of treatment approaches. There have been successful outcomes combining amphotericin with chemotherapies for HLH. Targeted therapies for HLH may be considered on a case-by-case basis in the setting of concurrent disseminated histoplasmosis and HIV/AIDS.

Evaluation of a commercial Histoplasma antigen detection enzyme immunoassay for the follow-up of histoplasmosis treatment in people living with HIV from Argentina

Histoplasmosis poses a significant risk to HIV patients, particularly in regions with limited access to antiretroviral therapy. Antigen detection assays are crucial in these settings for timely diagnosis and treatment, which can reduce mortality. While commercial antigen detection kits have performed well in diagnosing histoplasmosis, their effectiveness in monitoring treatment remains unclear. This study aimed to evaluate the correlation between urine antigen levels and clinical response using the clarus Histoplasma Galactomannan (GM) enzyme immunoassays (EIA) kit. The study followed 27 HIV patients diagnosed with histoplasmosis over 24 weeks, measuring urinary Histoplasma antigen (Ag) levels and clinical outcomes. Patients received amphotericin B as induction therapy, followed by maintenance with itraconazole. Results showed a significant decrease in Ag levels over time, with clinical scores improving in correlation with the decline in Ag levels. Four patients exhibited atypical Ag patterns due to immune reconstitution inflammatory syndrome or issues with itraconazole bioavailability. Despite these challenges, all patients showed improvement by week 24. The findings suggest that the clarus Histoplasma GM EIA kit could be a valuable tool for monitoring and evaluating the response to antifungal therapy in histoplasmosis patients.

Autochthonous Blastomyces dermatitidis, India

Blastomyces spp. fungi, the causal agent of blastomycosis, are common in North America but do occur in other areas of the world. The most prevalent pathogen in the genus is B. dermatitidis. Most B. dermatitidis isolates originate from North America, but there are sporadic reports of B. dermatitidis recovery from Africa and Asia. High-quality reports that incorporate genetic information about the fungus outside North America have been rare. Genome sequencing of 3 fungal isolates from patients in India with chronic respiratory diseases revealed that the isolates belong to a genetically differentiated lineage of B. dermatitidis. Because the patients had no history of traveling outside of Asia, blastomycosis was most likely autochthonously acquired, which suggests a local population of B. dermatitidis. Our results suggest the endemic range of B. dermatitidis is larger than previously thought, calling for a reassessment of the geographic range of different agents of endemic mycoses.

Histoplasmosis in cancer patients: a global scoping review (2001-2024)

Although classified as an AIDS-defining illness, several reports show histoplasmosis also affects patients living with cancers including haematological malignancies and solid tumours. However, reviews describing cases of histoplasmosis in malignancies are lacking in the literature. We identified a total of thirty-four cases with twenty (58.8 %) cases reported from the USA, four from Brazil (11.8 %), three from India (8.8 %), and one each from Singapore (2.9 %), France (2.9 %), Netherlands (2.9 %), Colombia (2.9 %), Canada (2.9 %), Morocco (2.9 %), and Malaysia (2.9 %). 82.4 % (n = 28) of the cases were adults. Presenting symptoms were majorly fever (61.7 %), lymphadenopathy (50.0 %) and weight loss (29.4 %). Essential haematologic findings were pancytopaenia (n = 7, 20.6 %), neutropenia (n = 2, 5.9 %) and anaemia (n = 5, 14.7 %). The associated cancers were predominantly haematological and comprised 73.5 % (n = 25) of all cases. The diagnosis of histoplasmosis was via histopathology (n = 23, 67.6%), culture (n = 13, 38.2%), Histoplasma antigen assay (n = 13, 38.2%), anti-Histoplasma antibody assay (n = 5, 14.7%), PCR and sequencing (n = 2, 5.9%), peripheral blood film/direct microscopy (n = 4, 11.8%) and cytology (n = 1, 2.9%). Of the thirty-four cases, twenty-four (70.6%) had favourable outcomes, eight (23.5%) died, one (2.9%) was lost to follow-up and in one (2.9%) case, the outcome was not stated. Histoplasmosis is not an uncommon opportunistic disease complicating malignancies but is paradoxically underdiagnosed in Africa given the huge burden of cancers in that region. Besides following chemotherapy and the use of steroids, tumour necrosis factor-α antagonists therapy, hematopoietic stem cell transplantation and environmental exposure were factors associated with Histoplasma infection in patients with malignancies. A resolution to promptly screen suspected or confirmed cases of malignancies for histoplasmosis will improve diagnosis and clinical outcomes.

Histoplasmosis Associated With Bat Guano Exposure in Cannabis Growers: 2 Cases

Histoplasma capsulatum is a pathogenic dimorphic fungus with evolving epidemiology. Initially described as endemic to the Ohio and Mississippi river valleys, the infection now regularly occurs in central and eastern United States, with cases reported across the entire country. Transmission happens via inhalation of conidia during activities that disturb fungal hyphae. Sporadic cases related to individual exposures now outnumber work-related outbreak cases in the United States. We describe 2 fatal cases of histoplasmosis in Rochester, New York, associated with exposure to bat guano as a fertilizer for cannabis cultivation, including 1 case in which it was commercially obtained.

Disseminated histoplasmosis with oral involvement and co-infection with Pneumocystis in a patient with HIV: A case report

Oral manifestations of disseminated histoplasmosis are rare but can present in immunocompromised individuals. We report a case of disseminated Histoplasmosis presenting with presumed oral involvement and Pneumocystis jirovecii pneumonia in a seropositive HIV individual. A 32-year-old male with HIV presented to the emergency department for a two-week history of abdominal pain and a tongue ulcer in the setting of significant weight loss, blood-tinged sputum, and non-adherence with antiretroviral therapy for three years. Physical exam revealed a verrucous ulcer on the lateral aspect of the tongue. CT scan of the chest revealed diffuse bilateral pulmonary nodules and ground glass opacities. At presentation, his CD4 + count was 12 cells/mm3. During his hospitalization, he developed acute hypoxic respiratory failure requiring non-invasive ventilation. His urine histoplasma antigen was positive at greater than 25 ng/mL and liposomal amphotericin was started. Shortly thereafter, Pneumocystis jirovecii PCR on bronchoalveolar lavage returned positive prompting additional therapy with trimethoprim-sulfamethoxazole. At discharge, the patient had no respiratory symptoms and near-resolution of his tongue ulcer.

High histoplasmosis incidence in kidney transplant recipients in Santa Fe city, Argentina

Histoplasmosis is endemic in the central/northeast region of Argentina. It is estimated that the incidence of this mycosis is low in solid organ transplant recipients. This work aims to describe the epidemiology, clinical forms, and evolution of kidney transplant recipients diagnosed with histoplasmosis in Santa Fe city, Argentina. A retrospective study was carried out between 2015 and 2020 on kidney transplant patients with symptoms associated with histoplasmosis in Santa Fe. Histoplasmosis diagnosis was performed through histopathology, recovery of Histoplasma spp., by culture, and/or positive nested Polimerase Chain Reaction (PCR) specific for the Histoplasma Hc100 gene. During the study period, 360 kidney transplantations were performed. Of these patients, 12 were diagnosed with histoplasmosis (3.3%). The patients' median age was 51 years, and 75% were male. Eleven patients (92%) presented the disseminated form of the disease. Thirty-three percent were diagnosed with histoplasmosis in their first year post-transplantation (mostly 6-12 months), while 42% received their diagnosis 3 years after transplantation. Laboratory diagnosis was performed by histopathology, culture, and PCR in four cases (33%), by culture and PCR in three cases (25%), and by PCR alone in three cases (25%). Thus, all 12 patients showed positive nested PCR results. All patients received amphotericin B as initial treatment. A good response was observed in 83% of patients. We found a high incidence of histoplasmosis in kidney transplant recipients (up to 10 times higher than reports from other endemic areas). Diagnosis by histopathology/culture showed 75% sensitivity, while nested PCR showed better sensitivity and diagnostic speed.

Disseminated histoplasmosis from western Mexico-rethinking our geographic distribution of endemic fungal species: a case report and review of literature

BACKGROUND

Histoplasma is a fungal pathogen found in many parts of the world. In North America, its distribution is traditionally thought to be endemic to the Ohio and Mississippi River valleys. Development of histoplasmosis after Histoplasma exposure is related to degree of inoculum exposure and susceptibility, for example, immunocompromised status. Most exposed, healthy individuals are asymptomatic and few develop pulmonary symptoms. A limited number of infectious etiologies (that is, Histoplasma, Coccidioides, and Mycobacterium tuberculosis) can cause miliary pattern on chest imaging, and thus, histoplasmosis should be considered whenever a patient presents with pulmonary symptoms and these unique radiographic findings.

CASE PRESENTATION

A previously healthy 13-year-old Hispanic male presented as a transfer from an outside hospital with fever and hypoxia in the setting of a progressive, subacute gastrointestinal illness. Given hypoxia, the concern for sepsis, and unclear etiology of his illness, broad-spectrum antimicrobial therapy and noninvasive ventilation were started. Initial evaluation demonstrated miliary pulmonary infiltrates, and travel history raised suspicion for coccidioidomycosis or tuberculosis. After a complete evaluation, lab studies confirmed a diagnosis of histoplasmosis, and the patient made a full recovery after the initiation and completion of antifungal therapy.

CONCLUSION

Herein, we present a patient who acquired histoplasmosis from an area of Mexico not currently acknowledged as endemic and review recently published data emphasizing new areas of Histoplasma endemicity in North America, particularly the southwest USA and most states of Mexico. Though limited surveillance data exist, mounting case reports/series and local epidemiologic studies illustrate the expanding worldwide endemicity of Histoplasma and underscore histoplasmosis as a growing global health concern.

Comparative genome analysis and the genome-shaping role of long terminal repeat retrotransposons in the evolutionary divergence of fungal pathogens Blastomyces dermatitidis and Blastomyces gilchristii

Blastomyces dermatitidis and Blastomyces gilchristii are cryptic species of fungi that cause blastomycosis, an often severe disease involving pulmonary infection capable of systemic dissemination. While these species appear morphologically identical, differences exist in the genetic makeup, geographical range, and possibly the clinical presentation of infection. Here, we show genetic divergence between the cryptic species through both a Blastomyces species tree constructed from orthologous protein sequences and whole genome single-nucleotide variant phylogenomic analysis. Following linked-read sequencing and de novo genome assembly, we characterized and compared the genomes of 3 B. dermatitidis and 3 B. gilchristii isolates. The B. gilchristii genomes (73.25-75.4 Mb) were ∼8 Mb larger than the B. dermatitidis genomes (64.88-66.61 Mb). Average nucleotide identity was lower between genomes of different species than genomes of the same species, yet functional classification of genes suggested similar proteomes. The most striking difference involved long terminal repeat retrotransposons. Although the same retrotransposon elements were detected in the genomes, the quantity of elements differed between the 2 species. Gypsy retrotransposon content was significantly higher in B. gilchristii (38.04-39.26 Mb) than in B. dermatitidis (30.85-32.40 Mb), accounting for the majority of genome size difference between species. Age estimation and phylogenetic analysis of the reverse transcriptase domains suggested that these retrotransposons are relatively ancient, with genome insertion predating the speciation of B. dermatitidis and B. gilchristii. We postulate that different trajectories of genome contraction led to genetic incompatibility, reproductive isolation, and speciation, highlighting the role of transposable elements in fungal evolution.

Perspectives on blastomycosis in Canada in the face of climate change

Blastomycosis is a disease of potentially varied presentations caused by thermally dimorphic fungi that appear as mold at ambient temperatures and transform to yeast at body temperature. Inhalation of aerosolized fungal spores represents the primary mode of transmission. Exposure may follow outdoor activities that disturb soil, which is warm, moist, acidic and rich in organic debris, particularly within forested areas and in proximity to waterways. Blastomycosis is endemic to several parts of Canada, but is only reportable in Ontario and Manitoba, with Northwestern Ontario being considered a hyperendemic area with average annual incidence rates of over 25 cases per 100,000 population. Delays in diagnosis and treatment are frequently observed as the symptoms and imaging findings of blastomycosis may initially be mistaken for community-acquired pneumonia, tuberculosis or malignancy, which can result in interim disease progression and worsening clinical outcomes. Risks from fungal infections such as blastomycosis are likely to increase with climate change-associated shifts in temperature and rainfall, and this may contribute to the geographic expansion of cases, a phenomenon that appears to be already underway. Further research investigating the ecological niche of Blastomyces and its climate sensitivity could help facilitate better modelling of the potential impacts of climate change on risks to Canadians and inform more effective methods of exposure prevention. Early clinical recognition and treatment of blastomycosis remain the key to minimizing morbidity and mortality.

Fungal lung disease

Fungal lung disease encompasses a wide spectrum of organisms and associated clinical conditions, presenting a significant global health challenge. The type and severity of disease are determined by underlying host immunity and infecting fungal strain. The most common group of diseases are associated with the filamentous fungus Aspergillus species and include allergic bronchopulmonary aspergillosis, sensitisation, aspergilloma and chronic and invasive pulmonary aspergillosis. Fungal lung disease remains epidemiologically heterogenous and is influenced by geography, environment and host comorbidities. Diagnostic modalities continue to evolve and now include novel molecular assays and biomarkers; however, persisting challenges include achieving rapid and accurate diagnosis, particularly in resource-limited settings, and in differentiating fungal infection from other pulmonary conditions. Treatment strategies for fungal lung diseases rely mainly on antifungal agents but the emergence of drug-resistant strains poses a substantial global threat and adds complexity to existing therapeutic challenges. Emerging antifungal agents and increasing insight into the lung mycobiome may offer fresh and personalised approaches to diagnosis and treatment. Innovative methodologies are required to mitigate drug resistance and the adverse effects of treatment. This state-of-the-art review describes the current landscape of fungal lung disease, highlighting key clinical insights, current challenges and emerging approaches for its diagnosis and treatment.

Transcriptomic atlas of the morphologic development of the fungal pathogen Coccidioides reveals key phase-enriched transcripts

Coccidioides spp. are highly understudied but significant dimorphic fungal pathogens that can infect both immunocompetent and immunocompromised people. In the environment, they grow as multicellular filaments (hyphae) that produce vegetative spores called arthroconidia. Upon inhalation by mammals, arthroconidia undergo a process called spherulation. They enlarge and undergo numerous nuclear divisions to form a spherical structure, and then internally segment until the spherule is filled with multiple cells called endospores. Mature spherules rupture and release endospores, each of which can form another spherule, in a process thought to facilitate dissemination. Spherulation is unique to Coccidioides and its molecular determinants remain largely unknown. Here, we report the first high-density transcriptomic analyses of Coccidioides development, defining morphology-dependent transcripts and those whose expression is regulated by Ryp1, a major regulator required for spherulation and virulence. Of approximately 9000 predicted transcripts, we discovered 273 transcripts with consistent spherule-associated expression, 82 of which are RYP1-dependent, a set likely to be critical for Coccidioides virulence. ChIP-Seq revealed 2 distinct regulons of Ryp1, one shared between hyphae and spherules and the other unique to spherules. Spherulation regulation was elaborate, with the majority of 227 predicted transcription factors in Coccidioides displaying spherule-enriched expression. We identified provocative targets, including 20 transcripts whose expression is endospore-enriched and 14 putative secreted effectors whose expression is spherule-enriched, of which 6 are secreted proteases. To highlight the utility of these data, we selected a cluster of RYP1-dependent, arthroconidia-associated transcripts and found that they play a role in arthroconidia cell wall biology, demonstrating the power of this resource in illuminating Coccidioides biology and virulence.

Evaluation of nikkomycin Z with frequent oral administration in an experimental model of central nervous system coccidioidomycosis

We evaluated the in vivo activity of nikkomycin Z against central nervous system coccidioidomycosis. Mice were inoculated intracranially with arthroconidia of Coccidoides immitis, and treatment with nikkomycin Z (50, 100, or 300 mg/kg orally TID) or fluconazole (25 mg/kg orally BID) began 2 days later. Each dose of nikkomycin Z and fluconazole significantly improved survival and reduced brain fungal burden compared with vehicle control. Further studies of nikkomycin Z against coccidioidomycosis are warranted.

IMPORTANCE

Coccidioides species are endemic fungi that are capable of causing disease in patients with various comorbidities, as well as in otherwise healthy individuals. Treatment options for coccidioidomycosis are suboptimal, as azole antifungals may be limited by drug interactions and adverse effects due to interactions with enzymes found in humans and other mammals. Nikkomycin Z is an investigational agent that works against a target specific to the fungal cell wall (chitin), which is not present in the cells of humans or other mammals. In this study, we show that frequent oral administration of nikkomycin Z is effective in an experimental model of central nervous system coccidioidomycosis. Further studies of nikkomycin Z against coccidioidomycosis may be warranted.

A multicentre study of amphotericin B treatment for histoplasmosis: assessing mortality rates and adverse events

BACKGROUND

Progressive disseminated histoplasmosis is a significant issue in Latin America, particularly in Brazil, contributing to high mortality rates.

OBJECTIVES

Our objectives were to comprehensively describe histoplasmosis treatment with various amphotericin B (AmB) formulations, including mortality rates, adverse effects and risk factors for mortality.

METHODS

This multicentre retrospective cohort study (January 2014-December 2019) evaluated medical records of patients with proven or probable histoplasmosis treated with at least two doses of AmB in seven tertiary medical centres in Brazil. We assessed risk factors associated with death during hospitalization using univariate and multivariate analyses.

RESULTS

The study included 215 patients, mostly male (n = 158, 73%) with HIV infection (n = 187, 87%), and a median age of 40 years. Only 11 (5%) patients initiated treatment with liposomal amphotericin B (L-AmB). Amphotericin B deoxycholate (D-AmB) was administered to 159 (74%) patients without changes in the treatment. The overall mortality during hospitalization was 23% (50/215). Variables independently associated with mortality were use of D-AmB (OR 4.93) and hospitalization in ICU (OR 9.46). There was a high incidence of anaemia (n = 19, 90%), acute kidney injury (n = 96, 59%), hypokalaemia (n = 73, 55%) and infusion reactions (n = 44, 20%) during treatment.

CONCLUSIONS

We found that D-AmB was the main formulation, which was also associated with a higher mortality rate. Lipid formulations of AmB have become more readily available in the public health system in Brazil. Further studies to evaluate the effectiveness of L-AmB will likely show improvements in the treatment outcomes for patients with disseminated histoplasmosis.

Histoplasmosis around the world: A global perspective on the presentation, virulence factors, and treatment of histoplasmosis

Histoplasmosis is a systemic infection caused by an endemic dimorphic fungus, Histoplasma capsulatum. Though prevalent in the eastern United States of America, near the Ohio and Mississippi River Valleys, the evidence underlying the global prevalence of histoplasmosis, especially in immunocompromised populations, is underappreciated. This article highlights the global epidemiology, risk factors, microbiology and pathophysiological characteristics, pulmonary and extrapulmonary manifestations, prevention measures, radiographic patterns, diagnostic techniques, and antifungal treatment approaches for Histoplasma capsulatum.

Associations between Minority Health Social Vulnerability Index Scores, Rurality, and Histoplasmosis Incidence, 8 US States

To explore associations between histoplasmosis and race and ethnicity, socioeconomic status, and rurality, we conducted an in-depth analysis of social determinants of health and histoplasmosis in 8 US states. Using the Minority Health Social Vulnerability Index (MH SVI), we analyzed county-level histoplasmosis incidence (cases/100,000 population) from the 8 states by applying generalized linear mixed hurdle models. We found that histoplasmosis incidence was higher in counties with limited healthcare infrastructure and access as measured by the MH SVI and in more rural counties. Other social determinants of health measured by the MH SVI tool either were not significantly or were inconsistently associated with histoplasmosis incidence. Increased awareness of histoplasmosis, more accessible diagnostic tests, and investment in rural health services could address histoplasmosis-related health disparities.

Exploring Histoplasma species seroprevalence and risk factors for seropositivity in The Gambia's working equid population: Baseline analysis of the Tackling Histoplasmosis project dataset

Introduction

Exposure rates to Histoplasma species, the causative agent of equine epizootic lymphangitis (EL), are unknown amongst working equids in The Gambia. The primary aims of this study were to estimate anti-Histoplasma antibody seroprevalence in the equid population in rural The Gambia and to explore risk factors for seropositivity.

Methods

A nationwide cross-sectional study was conducted (February-July 2022), representing baseline measurements of a longitudinal cohort study. Horses (n = 463) and donkeys (n = 92) without EL signs were recruited in 18 study sites. Following informed owner consent, equid clinical and management data were recorded. Blood samples were collected by jugular venepuncture, and sera were subject to the IMMY Latex Agglutination Histoplasma test (LAT). Seropositivity risk factors were explored by multi-level, multivariable logistic regression analysis. Study site and household variance were described using a latent-variable approach. Whole blood DNA extractions were subject to nested ITS-PCR to detect Histoplasma capsulatum var. farciminosum (HCF), and agreement with LAT results was measured using Cohen's kappa statistic.

Results

Anti-Histoplasma antibody seroprevalence in horses and donkeys was 79.9% [95% confidence interval (CI) 76.0-83.5%] and 46.7% (95% CI 36.3-57.4%), respectively. In horses, two multivariable models explained the maximum amount of data variability. Model 1 demonstrated increased odds of seropositivity in mares [odds ratio (OR) = 2.90 95% CI 1.70-4.95, p < 0.001] and decreased odds in horses <2.5 years (OR = 0.46 95% CI 0.22-0.95, p = 0.04; reference: ≥4.5 years). Model 2 demonstrated increased odds in horses recruited during the rainy season (OR = 2.03 95% CI 1.08-3.84, p = 0.03) and those owned by farmers reporting previous EL in their equids (OR = 1.87 95% CI 1.04-3.37, p = 0.04). Decreased odds were measured in horses <2.5 years (OR = 0.37 95% CI 0.18-0.78, p = 0.01) and horses reported to transport firewood (OR = 0.45 95% CI 0.28-0.74, p = 0.001). On multivariable analysis of donkeys, decreased odds of seropositivity were demonstrated amongst donkeys owned by households which also owned horses (OR = 0.23 95% CI 0.06-0.85, p = 0.03). HCF infection prevalence in horses and donkeys was 22.0% (n = 102/463, 95% CI 18.3-26.1%) and 5.4% (n = 5/92, 95% CI 1.8-12.2%), respectively. No significant agreement was measured between LAT and nested ITS-PCR results (κ < 0.00).

Conclusion

High Histoplasma spp. exposure was demonstrated amongst equids in The Gambia. Investigation of risk factors, including equid husbandry and management strategies, as well as geoclimatic variations, is warranted. Outcomes may inform sustainable and equitable EL control strategies in The Gambia and comparable settings worldwide.

Diagnosis of Human Endemic Mycoses Caused by Thermally Dimorphic Fungi: From Classical to Molecular Methods

Human endemic mycoses are potentially fatal diseases caused by a diverse group of fungi that can alter their morphology in response to an increase in temperature. These thermally dimorphic fungi affect both healthy and immunocompromised hosts, causing a substantial health and economic burden. Despite this, the diagnosis of endemic mycoses is still a formidable challenge for several reasons, including similar symptomatology, limited utility of classical diagnostic methods, inaccessibility to reliable molecular approaches in most endemic areas, and a lack of clinical suspicion out of these regions. This review summarizes essential knowledge on thermally dimorphic fungi and the life-threatening diseases they cause. The principle, advantages and limitations of the methods traditionally used for their diagnosis are also described, along with the application status and future directions for the development of alternative diagnostic strategies, which could help to reduce the disease burden in endemic areas.

Current and emerging technologies to develop Point-of-Care Diagnostics in medical mycology

INTRODUCTION

Advances in diagnostic technologies, particularly Point-of-Care Diagnostics (POCDs), have revolutionized clinical practice by providing rapid, user-friendly, and affordable testing at or near the patient's location. POCDs have been increasingly introduced in medical mycology and hold promise to improve patient outcomes in a variety of important human fungal diseases.

AREAS COVERED

This review focuses on validated POCDs, particularly lateral flow assays (LFAs), for various fungal diseases. Additionally, we discuss emerging innovative techniques such as body fluid analysis, imaging methods, loop-mediated isothermal amplification (LAMP), microfluidic systems, clustered regularly interspaced short palindromic repeats (CRISPR)-based diagnostics, and the emerging role of artificial intelligence.

EXPERT OPINION

Compact and user-friendly POCDs have been increasingly introduced in medical mycology, and some of these tests (e.g. Cryptococcus and Histoplasma antigen LFAs) have become mainstream diagnostics, while others, such as LFA in invasive aspergillosis show promise to become part of our routine diagnostic armamentarium. POCDs offer immense benefits such as timely and accurate diagnostic results, reduced patient discomfort, and lower healthcare costs and might contribute to antifungal stewardship. Integrated fluidics combined with microtechnology having multiplex capabilities will be pivotal in medical mycology.

Systematic Review of Prevalence of Histoplasma Antigenuria in Persons with HIV in Latin America and Africa

Histoplasmosis is a fungal disease associated with substantial mortality rates among persons with advanced HIV disease. Our systematic review synthesized data on the global prevalence of Histoplasma--caused antigenuria in persons with HIV. We searched PubMed/Medline, Embase, and Scopus databases on January 3, 2023, to identify cross-sectional and cohort studies evaluating Histoplasma antigenuria prevalence among adults with HIV infection. We calculated point estimates and 95% CIs to summarize prevalence. Of 1,294 studies screened, we included 15. We found Histoplasma antigenuria among 581/5,096 (11%; 95% CI 11%-12%) persons with HIV and 483/3,789 persons with advanced HIV disease (13%; 95% CI 12%-14%). Among persons with HIV and symptoms consistent with histoplasmosis, Histoplasma antigenuria prevalence was 14% (95% CI 13%-15%; 502/3,631 participants). We determined that persons with advanced HIV disease, inpatients, and symptomatic persons might benefit from a systematic approach to early detection of histoplasmosis using urine antigen testing.

Testing for Blastomycosis, Coccidioidomycosis, and Histoplasmosis at a Major Commercial Laboratory, United States, 2019-2024

Background

Blastomycosis, coccidioidomycosis, and histoplasmosis are environmentally acquired fungal diseases that clinically resemble bacterial and viral community-acquired pneumonia and require laboratory testing for diagnosis. Patients frequently present to primary care and experience diagnostic delays when a fungal etiology is not initially suspected. Current national-level public health surveillance for these diseases is limited and does not include laboratory data, so nationwide testing practices are unknown.

Methods

We identified laboratory tests for blastomycosis, coccidioidomycosis, and histoplasmosis ordered during 1 March 2019-29 February 2024 and performed within a major national commercial laboratory system. We analyzed test results, patient and healthcare provider features, reasons for testing, and temporal trends.

Results

Results included 5693 Blastomyces complement fixation tests (of those, 12% were positive), 71 858 immunodiffusion tests (0.1% positive), and 1186 serum enzyme immunoassay (EIA) tests (11% positive); 154 989 Coccidioides EIA immunoglobulin M results (5% positive) and 154 968 immunoglobulin G results (8% positive); and 46 346 Histoplasma complement fixation tests (30% positive), 49 062 immunodiffusion tests (1% positive), 35 506 serum EIA tests (4% positive), and 82 489 urine EIA tests (2% positive). Most histoplasmosis (58%-74%) and blastomycosis (42%-68%) tests were ordered from hospitals, whereas coccidioidomycosis tests were most frequently ordered by primary care providers (40%). A yearly average of 2727 positive tests were ordered by healthcare providers in states without public health surveillance for these diseases.

Conclusions

Blastomycosis, coccidioidomycosis, and histoplasmosis are likely underdetected in primary care settings or by public health surveillance. Increased testing by primary care providers and expanded surveillance are needed to reduce disease burden.

Metagenomic Next-Generation Sequencing as an Effective Diagnostic Tool for Talaromycosis in HIV-Negative Patients

The diagnosis of Talaromyces marneffei infection in HIV-negative patients remains challenging. There is an urgent need for rapid and convenient methods to diagnose this complicated disease. The aim of this study was to evaluate the diagnostic efficiency of metagenomic next-generation sequencing (mNGS) for talaromycosis in non-HIV-infected patients by comparing mNGS with traditional microbial culture. In total, 66 samples from 57 patients were analyzed via both mNGS and microbial culture. The ROC curve showed a sensitivity for mNGS of 97.22%, which was greater than that of microbial culture (61.11%). Samples from the respiratory tract, infectious skin lesions, and lymph nodes are recommended as routine samples for talaromycosis detection via mNGS. Furthermore, mNGS significantly reduced the diagnostic time compared to microbial culture. Overall, our study demonstrated that mNGS is a promising tool for rapid and accurate pathogenic detection in HIV-negative patients with talaromycosis.

Proceedings of the second international meeting on endemic mycoses of the Americas (IMEMA) and first international symposium on implantation mycoses (ISIM)

The second international meeting on endemic mycoses of the Americas (IMEMA) and the first international symposium on implantation mycoses (ISIM) took place in Santiago del Estero, Argentina, on September 25-27, 2023. The conference provided a platform for researchers, clinicians, and experts to discuss the latest developments in the field of endemic and implantation mycoses. Topics included epidemiology, diagnostic advances, treatment strategies, and the impact of environmental factors on the spread of these fungal diseases. IMEMA and ISIM contributed to the regional discourse on the mycoses, emphasizing the importance of international cooperation in addressing these public health challenges.