Geographic distribution of endemic fungal infections among older persons, United States

The WHO fungal priority pathogens list: a crucial reappraisal to review the prioritisation

In October, 2022, WHO published the first fungal priority pathogen list, which categorised 19 fungal entities into three priority groups (critical, high, and medium), for prioritisation of research efforts. The final ranking was determined via multiple criteria decision analysis, considering both research and development needs and perceived public health importance. In this Personal View, we discuss the positioning of the fungal pathogens, namely, Mucorales, Candida spp, Histoplasma spp, Coccidioides and Paracoccidioides spp, Fusarium spp, eumycetoma causative agents, Talaromyces marneffei, and Pneumocystis jirovecii, while expressing concerns about potential disparities between the WHO fungal priority pathogen list ranking and the actual disease burden associated with these pathogens. Finally, we propose a revised prioritisation list that also considers the regional disparities in the burden of fungal diseases.

Genotypic diversity, virulence, and molecular genetic tools in Histoplasma

SUMMARYHistoplasmosis is arguably the most common fungal respiratory infection worldwide, with hundreds of thousands of new infections occurring annually in the United States alone. The infection can progress in the lung or disseminate to visceral organs and can be difficult to treat with antifungal drugs. Histoplasma, the causative agent of the disease, is a pathogenic fungus that causes life-threatening lung infections and is globally distributed. The fungus has the ability to germinate from conidia into either hyphal (mold) or yeast form, depending on the environmental temperature. This transition also regulates virulence. Histoplasma and histoplasmosis have been classified as being of emergent importance, and in 2022, the World Health Organization included Histoplasma as 1 of the 19 most concerning human fungal pathogens. In this review, we synthesize the current understanding of the ecological niche, evolutionary history, and virulence strategies of Histoplasma. We also describe general patterns of the symptomatology and epidemiology of histoplasmosis. We underscore areas where research is sorely needed and highlight research avenues that have been productive.

Overcoming barriers to lung cancer screening using a systemwide approach with additional focus on the non-screened

BACKGROUND

The lung cancer screening program at St Elizabeth Healthcare (Kentucky, USA) began in 2013. Over 33,000 low-dose computed tomography lung cancer screens have been performed. From 2015 through 2021, 2595 lung cancers were diagnosed systemwide. A Screening Program with Impactful Results from Early Detection, reviews that experience; 342 (13.2%) were diagnosed by screening and 2253 (86.8%) were non-screened. As a secondary objective, the non-screened cohort was queried to determine how many additional individuals could have been screened, identifying barriers and failures to meet eligibility.

METHODS

Our QlikSense database extracted the lung cancer patients from the Cancer Patient Data and Management System, and identified and categorized them separately as screened or non-screened populations. Stage distribution was compared in screened and non-screened groups. Those meeting age criteria, with any smoking history, were further queried for screening eligibility, accessing the electronic medical record smoking history and audit trail, and determining if enough information was available to substantiate screening eligibility. The same methodology was applied to CMS 2015 and USPSTF 2021 criteria.

RESULTS

The screened and non-screened patients were accounted for in a stage migration chart demonstrating clear shift to early stage among screened lung cancer patients. Additionally, analysis of non-screened individuals is presented.

CONCLUSION

Of the St Elizabeth Healthcare eligible patients attributed to primary care providers, 49.6% were screened in 2021. Despite this level of success, this study highlighted a sizeable pool of additional individuals that could have been screened. We are shifting focus to the non-screened pool of patients that meet eligibility, further enhancing the impact on our community.

Background incidence rates of health outcomes in populations at risk for Lyme disease using US administrative claims data

BACKGROUND

Background incidence rates (IRs) of health outcomes in Lyme disease endemic regions are useful to contextualize events reported during Lyme disease vaccine clinical trials or post-marketing. The objective of this study was to estimate and compare IRs of health outcomes in Lyme disease endemic versus non-endemic regions in the US during pre-COVID and COVID era timeframes.

METHODS

IQVIA PharMetrics® Plus commercial claims database was used to estimate IRs of 64 outcomes relevant to vaccine safety monitoring in the US during January 1, 2017-December 31, 2019 and January 1, 2020-December 31, 2021. Analyses included all individuals aged ≥ 2 years with ≥ 1 year of continuous enrollment. Outcomes were defined by International Classification of Diseases Clinical Modification, 10th Revision (ICD-10-CM) diagnosis codes. IRs and 95 % confidence intervals (CIs) were calculated for each outcome and compared between endemic vs. non-endemic regions, and pre-COVID vs. COVID era using IR ratios (IRR).

RESULTS

The study population included 8.7 million (M) in endemic and 27.8 M in non-endemic regions. Mean age and sex were similar in endemic and non-endemic regions. In both study periods, the IRs were statistically higher in endemic regions for anaphylaxis, meningoencephalitis, myocarditis/pericarditis, and rash (including erythema migrans) as compared with non-endemic regions. Conversely, significantly lower IRs were observed in endemic regions for acute kidney injury, disseminated intravascular coagulation, heart failure, myelitis, myopathies, and systemic lupus erythematosus in both study periods. Most outcomes were statistically less frequent during the COVID-era.

CONCLUSION

This study identified potential differences between Lyme endemic and non-endemic regions of the US in background IRs of health conditions during pre-COVID and COVID era timeframes to inform Lyme disease vaccine safety monitoring. These regional and temporal differences in background IRs should be considered when contextualizing possible safety signals in clinical trials and post-marketing of a vaccine targeted at Lyme disease prevention.

Histoplasmosis in Solid Organ Transplantation

Histoplasma capsulatum, the etiological agent for histoplasmosis, is a dimorphic fungus that grows as a mold in the environment and as a yeast in human tissues. It has a broad global distribution with shifting epidemiology during recent decades. While in immunocompetent individuals infection is usually self-resolving, solid organ transplant recipients are at increased risk of symptomatic disease with dissemination to extrapulmonary tissue. Diagnosis of histoplasmosis relies on direct observation of the pathogen (histopathology, cytopathology, and culture) or detection of antigens, antibodies, or nucleic acids. All transplant recipients with histoplasmosis warrant therapy, though the agent of choice and duration of therapy depends on the severity of disease. In the present article, we describe the pathogenesis, epidemiology, clinical manifestations and management of histoplasmosis in solid organ transplant recipients.

Progressive disseminated histoplasmosis: The experience in one non-endemic medical center

Histoplasmosis, the most common endemic mycosis in North America, presents in a myriad of ways, spanning the spectrum from self-limiting pneumonia to progressive disseminated histoplasmosis (PDH). Toward better describing contemporary histoplasmosis syndromes, risks, and outcomes, this single-center retrospective cohort study was performed (2009-2019). The population who developed PDH was similar to that with other forms of histoplasmosis (OFH) except for higher rates of preexisting immunocompromising conditions (91.3% vs. 40%, P < .001) and a trend toward receiving more chronic immunosuppression (65.2% vs. 33.3%, P = .054) compared to those with OFH. Diagnosis was most frequently achieved by urinary or serum antigen positivity. People with PDH more frequently tested positive compared to those with OFH, but negative tests did not rule out histoplasmosis. Median time to diagnosis was prolonged among people with both PDH and OFH (32 vs. 31 days, respectively). Following diagnosis, people with PDH received more liposomal amphotericin (78.3% vs. 20%, P < .001). Subsequent survival at 90 and 365 days and treatment response were similar in both groups. Patients with PDH were more often hospitalized (95.7% vs. 60%, P = .006); however, once admitted, there were no differences in hospital length of stay or intensive care unit admission rate. The challenges of diagnosing histoplasmosis based on clinical presentation alone highlight the need for heightened awareness of these entities especially given the recent reports on expanded endemicity and delays in diagnosis.

Fungal Pathogens as Causes of Acute Respiratory Illness in Hospitalized Veterans: Frequency of Fungal Positive Test Results Using Rapid Immunodiagnostic Assays

Fungal respiratory illnesses caused by endemic mycoses can be nonspecific and are often mistaken for viral or bacterial infections. We performed fungal testing on serum specimens from patients hospitalized with acute respiratory illness (ARI) to assess the possible role of endemic fungi as etiologic agents. Patients hospitalized with ARI at a Veterans Affairs hospital in Houston, Texas, during November 2016-August 2017 were enrolled. Epidemiologic and clinical data, nasopharyngeal and oropharyngeal samples for viral testing (PCR), and serum specimens were collected at admission. We retrospectively tested remnant sera from a subset of patients with negative initial viral testing using immunoassays for the detection of Coccidioides and Histoplasma antibodies (Ab) and Cryptococcus, Aspergillus, and Histoplasma antigens (Ag). Of 224 patient serum specimens tested, 49 (22%) had positive results for fungal pathogens, including 30 (13%) by Coccidioides immunodiagnostic assays, 19 (8%) by Histoplasma immunodiagnostic assays, 2 (1%) by Aspergillus Ag, and none by Cryptococcus Ag testing. A high proportion of veterans hospitalized with ARI had positive serological results for fungal pathogens, primarily endemic mycoses, which cause fungal pneumonia. The high proportion of Coccidioides positivity is unexpected as this fungus is not thought to be common in southeastern Texas or metropolitan Houston, though is known to be endemic in southwestern Texas. Although serological testing suffers from low specificity, these results suggest that these fungi may be more common causes of ARI in southeast Texas than commonly appreciated and more increased clinical evaluation may be warranted.

Pulmonary Infections in Intestinal Transplant Recipients With Preexisting Pulmonary Nodules

BACKGROUND

Pulmonary nodules in asymptomatic patients could represent latent pulmonary infections. Intestinal transplant (ITx) recipients with preexisting lung nodules might be at higher risk for pulmonary infections. However, data is scarce.

METHODS

This retrospective study included adult patients who underwent ITx from May 2016 to May 2020. Chest computed tomography scans performed within 12 months before ITx were obtained to evaluate for preexisting pulmonary nodules. Screening for endemic mycoses, Aspergillus, Cryptococcus, and latent tuberculosis infection performed within 12 months before ITx was obtained. We assessed for worsening pulmonary nodules, and fungal and mycobacterial infections during the first year post-transplant. Survival and graft loss at 1-year post-transplant was also assessed.

RESULTS

Forty-four patients underwent ITx. Thirty-one had preexisting lung nodules. No invasive fungi were recorded in the pretransplant period and one individual had latent tuberculosis infection. In the post-transplant period, one individual developed probable invasive aspergillosis and had worsening nodular opacities, whereas one had disseminated histoplasmosis with stable lung nodules in chest computed tomography. No mycobacterial infections were documented. The cohort survival was 84% at 12 months after transplant.

CONCLUSION

Preexisting pulmonary nodules were common in the cohort (71%), yet latent and active pulmonary infections were rare. Appearance of new or worsening pulmonary nodules does not appear to directly correlate with pulmonary infections in the post-transplant period. Routine chest computed tomography is not recommended in the pretransplant period, but follow-up is favored in patients with confirmed nodular opacities. Clinical monitoring is essential.

Pulmonary Histoplasmosis: A Clinical Update

Histoplasma capsulatum, the etiological agent for histoplasmosis, is a dimorphic fungus that grows as a mold in the environment and as a yeast in human tissues. The areas of highest endemicity lie within the Mississippi and Ohio River Valleys of North America and parts of Central and South America. The most common clinical presentations include pulmonary histoplasmosis, which can resemble community-acquired pneumonia, tuberculosis, sarcoidosis, or malignancy; however, certain patients can develop mediastinal involvement or progression to disseminated disease. Understanding the epidemiology, pathology, clinical presentation, and diagnostic testing performance is pivotal for a successful diagnosis. While most immunocompetent patients with mild acute or subacute pulmonary histoplasmosis should receive therapy, all immunocompromised patients and those with chronic pulmonary disease or progressive disseminated disease should also receive therapy. Liposomal amphotericin B is the agent of choice for severe or disseminated disease, and itraconazole is recommended in milder cases or as "step-down" therapy after initial improvement with amphotericin B. In this review, we discuss the current epidemiology, pathology, diagnosis, clinical presentations, and management of pulmonary histoplasmosis.

Isolated Colonic Histoplasmosis in Patients Undergoing Immunomodulator Therapy: A Systematic Review

Gastrointestinal histoplasmosis remains an inconspicuous clinicopathologic entity. It is predominantly considered a protean manifestation of disseminated disease. We hereby delineate a unique case of biopsy-proven isolated colonic histoplasmosis in a patient undergoing methotrexate therapy. Furthermore, we present the first systematic review of the MEDLINE, Google Scholar, Embase, and Scopus databases regarding isolated colonic histoplasmosis in adult patients receiving immunomodulator therapy (IMT). A total of 13 case reports (level of clinical evidence: IV) were identified. The mean age was 55.6 ± 11.1 years, with 9 (69.2%) cases reported in women. Patients with subclinical disease (5, 38.5%) were often incidentally diagnosed by screening colonoscopy. Symptomatic individuals predominantly presented with diarrhea (4, 30.8%), weight loss (3, 23.1%), and/or abdominal pain (3, 23.1%). IMT was mainly administered for liver transplant (4, 30.8%), renal transplant (4, 30.8%), and ulcerative colitis (2, 15.4%). Common colonoscopy features included colonic ulcerations (7, 53.8%), polyps or pseudopolyps (3, 23.1%), and/or mass-like lesions (3, 23.1%). Diagnosis was made by histology of colonic biopsy in 11 (84.6%) and resected specimens in 2 (15.4%) patients. Treatment consisted of a combination of amphotericin B with oral itraconazole in 6 (46.2%), oral itraconazole alone in 5 (38.5%), and amphotericin B alone in 2 (15.4%) patients. Complete clinical recovery was achieved in all patients. This article illustrates that isolated colonic involvement can be the only clinical presentation of histoplasmosis. It may masquerade as other bowel disorders, presenting diagnostic and therapeutic conundrums. Gastroenterologists should rule out colonic histoplasmosis in IMT recipients who develop unexplained colitis symptoms.

Comparison of Indirect Fungal Diagnostic Tests in Patients With Proven Histoplasmosis

BACKGROUND

Histoplasmosis is a common cause of invasive fungal infection in endemic regions and accurate diagnosis is difficult without direct tissue culture or pathology. Indirect fungal antigen testing for various fungal pathogens are typically performed to assist with diagnostic workup, though cross-reaction can lead to difficulty in interpreting results. We aimed to compare indirect fungal diagnostic tests and evaluate prevalence of positive antigen testing for non-Histoplasma fungal pathogens in patients with proven histoplasmosis.

METHODS

We performed a single-center retrospective review of adult patients with proven histoplasmosis diagnosed by fungal culture and/or cytology from January 2010 to March 2018. Patient demographics, clinical characteristics, and results of fungal antigen testing for Histoplasma, Blastomyces, Aspergillus, Cryptococcus, and (1→3)-β-D-glucan were evaluated. Two different urine Histoplasma antigen assays were used during the study period.

RESULTS

Fifty-seven of 182 (31.3%) patients reviewed had proven histoplasmosis and presented with acute pulmonary (n = 10), chronic pulmonary (n = 7), and disseminated (n = 40) disease. Forty-one (72%) of these patients were immunosuppressed. Urine Blastomyces antigen (93%) and serum (1→3)-β-D-glucan (88%) were commonly positive in patients with histoplasmosis, whereas Aspergillus antigen was detected in 50% of patients and Cryptococcus antigenemia was rare (5%). In patients with disseminated disease, the MiraVista urine Histoplasma antigen assay had higher sensitivity than the Viracor urine Histoplasma antigen assay (86% vs 50%, respectively; P = .019).

CONCLUSIONS

Noninvasive fungal antigen assays are helpful diagnostic tools; however, given their low specificity, clinicians must be aware of the various clinical presentations of invasive fungal infections and be aware of the limitations of these tests.

Increasing Alkaline Phosphatase as the Primary Manifestation of Disseminated Histoplasmosis in an AIDS Patient Without Pulmonary Disease

Histoplasmosis is an infection caused by the dimorphic fungi Histoplasma. Hepatic involvement in the setting of disseminated histoplasmosis from a pulmonary source is well documented. Hepatic involvement as the primary manifestation in the absence of pulmonary disease is rare. We present a patient with acquired immune deficiency syndrome found to have disseminated histoplasmosis with worsening alkaline phosphatase as the primary manifestation of disease, which has not been reported in a review of the literature. After diagnosis, the patient was started on appropriate therapy with alkaline phosphatase return to baseline.

Hepatic Histoplasmosis: An Update

Histoplasma capsulatum is the most common cause of endemic mycosis in developing countries. It is a self-limited and asymptomatic disease in immunocompetent individuals but remains a frequent cause of opportunistic infection in patients with compromised immune status. Liver involvement as a part of disseminated histoplasmosis is well known. However, liver infection as a primary manifestation of histoplasmosis without evidence of primary lung involvement is rare. In conclusion, clinicians should be aware of isolated histoplasmosis affecting the hepatobiliary system, and careful evaluation is warranted to confirm the diagnosis. Given the appropriate clinical context, histoplasmosis should be considered in both immunocompetent and immunocompromised patients, regardless of pulmonary symptoms, in non endemic as well as endemic areas.

Blastomycosis-Some Progress but Still Much to Learn

Blastomycosis, caused by Blastomyces spp., is an endemic mycosis capable of causing significant disease throughout the body. Higher rates of infection are seen in the Mississippi and Ohio River valleys, the Great Lakes region of the United States and Canada, much of Africa, and, to a lesser extent, in India and the Middle East. Limited reporting inhibits our true understanding of the geographic distribution of blastomycosis. An estimated 50% of those infected remain asymptomatic. Of those who present with symptomatic disease, pulmonary involvement is most common, while the most common extrapulmonary sites are the skin, bones, genitourinary system, and central nervous system. Itraconazole is the standard therapy for mild-moderate disease. Data for other azoles are limited. Amphotericin is used for severe disease, and corticosteroids are occasionally used in severe disease, but evidence for this practice is limited. Despite increasing incidence and geographic reach in recent years, there are still significant knowledge gaps in our understanding of blastomycosis. Here, we provide an updated review of the epidemiology, clinical presentations, and diagnostic and therapeutic approaches for this infection. We also discuss areas needing further research.

Disseminated Histoplasmosis with Underlying Sarcoidosis-Rheumatoid Arthritis Overlap Syndrome: An Example of Diagnostic Test Threshold of Detection Affecting Test Results and Patient Care

Histoplasmosis is common in many parts of the world but with areas of hyperendemicity. Disseminated histoplasmosis is the deadliest form of histoplasmosis and is most common among immunocompromised patients. Timely diagnosis is crucial to improve outcomes. We describe a patient on azathioprine and rituximab with disseminated histoplasmosis in which diagnosis was delayed in part because of negative early Histoplasma antigen testing, which was positive later in the course. This case serves as an example of the concept of “threshold of detection” in which a certain concentration of a microbe must be present for it to be detected by a diagnostic test that focuses on detection of a microbe or its components. This concept applies to many tests used to diagnose infectious diseases.

Management of Histoplasmosis by Infectious Disease Physicians

Background

The Infectious Diseases Society of America (IDSA) guidelines for the management of histoplasmosis were last revised 15 years ago. Since those guidelines were compiled, new antifungal treatment options have been developed. Furthermore, the ongoing development of immunomodulatory therapies has increased the population at increased risk to develop histoplasmosis.

Methods

An electronic survey about the management practices of histoplasmosis was distributed to the adult infectious disease (ID) physician members of the IDSA's Emerging Infections Network.

Results

The survey response rate was 37% (551/1477). Only 46% (253/551) of respondents reported seeing patients with histoplasmosis. Regions considered endemic had 82% (158/193) of physicians report seeing patients with histoplasmosis compared to 27% (95/358) of physicians in regions not classically considered endemic (P < 0.001). Most ID physicians follow IDSA treatment guidelines recommending itraconazole for acute pulmonary (189/253 [75%]), mild-moderate disseminated (189/253 [75%]), and as step-down therapy for severe disseminated histoplasmosis with (232/253 [92%]) and without (145/253 [57%]) central nervous system involvement. There were no consensus recommendations observed for survey questions regarding immunocompromised patients.

Conclusions

Though there are increased reports of histoplasmosis diagnoses outside regions classically considered endemic, a majority of ID physicians reported not seeing patients with histoplasmosis. Most respondents reported adherence to IDSA guidelines recommending itraconazole in each clinical situation. New histoplasmosis guidelines need to reflect the growing need for updated general guidance, particularly for immunocompromised populations.

Disseminated histoplasmosis in an immunocompetent patient with COVID-19 pneumonia

Disseminated histoplasmosis is usually associated with immunosuppressive conditions like AIDS. People with respiratory distress syndrome secondary to SARS-CoV-2 pneumonia are vulnerable to bacterial infections. Additionally, coinfection with fungal pathogens should be considered as a differential diagnosis even in immunocompetent patients who remain on mechanical ventilation secondary to COVID-19. The case presents a 61-year-old immunocompetent man, admitted to the medical ward due to COVID-19 pneumonia. Despite appropriate therapy, the patient required transfer to the intensive care unit for invasive mechanical ventilation. He remained critically ill with worsening respiratory failure. Two weeks later, coinfection by disseminated histoplasmosis was detected. After immediate treatment with amphotericin B and itraconazole, the patient tolerated weaning from mechanical ventilation until extubation. Awareness of this possible fungal coinfection in immunocompetent patients is essential to reduce delays in diagnosis and treatment, and prevent severe illness and death.

An Indian lineage of Histoplasma with strong signatures of differentiation and selection

Histoplasma, a genus of dimorphic fungi, is the etiological agent of histoplasmosis, a pulmonary disease widespread across the globe. Whole genome sequencing has revealed that the genus harbors a previously unrecognized diversity of cryptic species. To date, studies have focused on Histoplasma isolates collected in the Americas with little knowledge of the genomic variation from other localities. In this report, we report the existence of a well-differentiated lineage of Histoplasma occurring in the Indian subcontinent. The group is differentiated enough to satisfy the requirements of a phylogenetic species, as it shows extensive genetic differentiation along the whole genome and has little evidence of gene exchange with other Histoplasma species. Next, we leverage this genetic differentiation to identify genetic changes that are unique to this group and that have putatively evolved through rapid positive selection. We found that none of the previously known virulence factors have evolved rapidly in the Indian lineage but find evidence of strong signatures of selection on other alleles potentially involved in clinically-important phenotypes. Our work serves as an example of the importance of correctly identifying species boundaries to understand the extent of selection in the evolution of pathogenic lineages. IMPORTANCE: Whole genome sequencing has revolutionized our understanding of microbial diversity, including human pathogens. In the case of fungal pathogens, a limiting factor in understanding the extent of their genetic diversity has been the lack of systematic sampling. In this piece, we show the results of a collection in the Indian subcontinent of the pathogenic fungus Histoplasma, the causal agent of a systemic mycosis. We find that Indian samples of Histoplasma form a distinct clade which is highly differentiated from other Histoplasma species. We also show that the genome of this lineage shows unique signals of natural selection. This work exemplifies how the combination of a robust sampling along with population genetics, and phylogenetics can reveal the precise genetic changes that differentiate lineages of fungal pathogens.

Multipotentiality of Luliconazole against Various Fungal Strains: Novel Topical Formulations and Patent Review

BACKGROUND

Luliconazole is a broad-spectrum antifungal agent with impactful fungicidal and fungistatic activity. It has shown exceptional potency against miscellaneous fungal strains like Candida, Aspergillus, Malassezia, Fusarium species and various dermatophytes.

OBJECTIVE

Luliconazole belongs to class Ⅱ of the Biopharmaceutical Classification System with low aqueous solubility. Although it is available conventionally as 1% w/v topical cream, it has limitations of lower skin permeation and shorter skin retention. Therefore, nanoformulations based on various polymers and nanostructure carriers can be employed to overcome the impediments regarding topical delivery and efficacy of luliconazole.

METHODS

In this review, we have tried to provide insight into the literature gathered from authentic web resources and research articles regarding recent research conducted on the subject of formulation development, patents, and future research requisites of luliconazole.

RESULTS

Nanoformulations can play a fundamental role in improving topical delivery by escalating dermal localization and skin penetration. Fabricating luliconazole into nanoformulations can overcome the drawbacks and can efficiently enhance its antimycotic activity.

CONCLUSION

It has been concluded that luliconazole has exceptional potential in the treatment of various fungal infections, and therefore, it should be exploited to its maximum for its innovative application in the field of mycology.

Endemic mycoses: Expansion of traditional geographic ranges and pitfalls in management

The endemic mycoses are a diverse group of environmental fungi that share several characteristics. Pitfalls in the recognition and management of endemic fungal infections are common. A general understanding of common presenting manifestations and their lingering effects is of paramount importance to the treating physician. We review the unmet needs of recently published guidelines and outline future areas of research.

Treatment and Prevention of Histoplasmosis in Adults Living with HIV

Histoplasmosis causes life-threatening disseminated infection in adult patients living with untreated HIV. Although disease incidence has declined dramatically in countries with access to antiretroviral therapy, histoplasmosis remains prevalent in many resource-limited regions. A high index of suspicion for histoplasmosis should be maintained in the setting of a febrile multisystem illness in severely immunosuppressed patients, particularly in persons with hemophagocytic lymphohistiocytosis. Preferred treatment regimens for initial therapy include liposomal amphotericin B for severe disease, or itraconazole for mild to moderate disease. Subsequently, itraconazole maintenance therapy should be administered for at least one year and then discontinued if CD4 count increases to ≥150 cells/µL. Antiretroviral therapy, which improves outcome when administered together with an antifungal agent, should be instituted immediately, as the risk of triggering Immune Reconstitution Syndrome is low. The major risk factor for relapsed infection is nonadherence. Itraconazole prophylaxis reduces risk for histoplasmosis in patients with CD4 counts <100/µL but is not associated with survival benefit and is primarily reserved for use in outbreaks. Although most patients with histoplasmosis have not had recognized high-risk exposures, avoidance of contact with bird or bat guano or inhalation of aerosolized soil in endemic regions may reduce risk. Adherence to effective antiretroviral therapy is the most important strategy for reducing the incidence of life-threatening histoplasmosis.

Long-Term Mortality after Histoplasma Infection in People with HIV

Histoplasmosis is a common opportunistic infection in people with HIV (PWH); however, no study has looked at factors associated with the long-term mortality of histoplasmosis in PWH. We conducted a single-center retrospective study on the long-term mortality of PWH diagnosed with histoplasmosis between 2002 and 2017. Patients were categorized into three groups based on length of survival after diagnosis: early mortality (death < 90 days), late mortality (death ≥ 90 days), and long-term survivors. Patients diagnosed during or after 2008 were considered part of the modern antiretroviral therapy (ART) era. Insurance type (private vs. public) was a surrogate indicator of socioeconomic status. Out of 54 PWH infected with histoplasmosis, overall mortality was 37%; 14.8% early mortality and 22.2% late mortality. There was no statistically significant difference in survival based on the availability of modern ART (p = 0.60). Insurance status reached statistical significance with 38% of survivors having private insurance versus only 8% having private insurance in the late mortality group (p = 0.05). High mortality persists despite the advent of modern ART, implicating a contribution from social determinants of health, such as private insurance. Larger studies are needed to elucidate the role of these factors in the mortality of PWH.

The Consequences of Our Changing Environment on Life Threatening and Debilitating Fungal Diseases in Humans

Human activities have significantly impacted the environment and are changing our climate in ways that will have major consequences for ourselves, and endanger animal, plant and microbial life on Earth. Rising global temperatures and pollution have been highlighted as potential drivers for increases in infectious diseases. Although infrequently highlighted, fungi are amongst the leading causes of infectious disease mortality, resulting in more than 1.5 million deaths every year. In this review we evaluate the evidence linking anthropomorphic impacts with changing epidemiology of fungal disease. We highlight how the geographic footprint of endemic mycosis has expanded, how populations susceptible to fungal infection and fungal allergy may increase and how climate change may select for pathogenic traits and indirectly contribute to the emergence of drug resistance.

Epidemiology and Clinical Characteristics of Presumed Ocular Histoplasmosis in Olmsted County, Minnesota

Purpose: To describe the incidence, prevalence, and clinical characteristics of presumed ocular histoplasmosis syndrome (POHS) in a Histoplasma endemic region.Methods: The International Classification of Diseases, 9^th and 10^th Revision codes were used to search the Rochester Epidemiology Project, a record-linkage system for medical care provided in Olmsted County, MN. Medical records were reviewed to confirm POHS diagnoses in county residents from January 1, 2006, to December 31, 2015. Age- and sex-adjusted incidence rates were calculated and adjusted to the 2010 U.S. White population.Results: There were 18 incident cases (30 eyes) and 87 prevalent cases (131 eyes). The incidence rate was 1.35 per 100,000 per year. The mid-study prevalence rate was 0.064%. Choroidal neovascularization (CNV) occurred in 17.4% of the affected eyes. At the last follow-up, 16.8% of the affected eyes had POHS-related decreased visual acuity (<20/40).Conclusion: This study assesses the epidemiology and clinical features of POHS in a Midwestern U.S. county.ABBREVIATIONS/ACRONYMS; POHS = Presumed ocular histoplasmosis syndrome; ICD = International Classification of Diseases; CI = Confidence interval; VA = Visual acuity; Anti-VEGF = Anti-vascular endothelial growth factor; REP = Rochester Epidemiology Project, CNV = Choroidal neovascularization.

Flip flop fungus sign: an FDG PET sign of benign pulmonary nodules

A 71-year-old man was referred to pulmonary clinic for incidental findings of hypermetabolic lung nodule and mediastinal adenopathy on CT FDG PET performed for evaluation of cough. The patient underwent bronchoscopy with endobronchial ultrasound that was non-diagnostic. The patient was subsequently sent for video-assisted thoracoscopic lymph node biopsy notable for confluent caseating granulomas due to chronic infection by Histoplasma capsulatum Review of previous PDG PET was notable for the flip flop fungus sign-a PDG PET finding that could have altered the patients' clinical course by potentially avoiding the need for invasive surgical tissue diagnosis.

Biodiverse Histoplasma Species Elicit Distinct Patterns of Pulmonary Inflammation following Sublethal Infection

Acute pulmonary histoplasmosis in healthy individuals comprises most of the disease burden caused by the fungal pathogen Histoplasma. Fungal pneumonia is frequently delayed in diagnosis and treatment due to a prolonged period of quiescence early during infection. In this study, we used a murine respiratory model of histoplasmosis to investigate how different Histoplasma species modulate lung inflammation throughout the complete course of infection. We propose that a relatively low, sublethal inoculum is ideal to model acute pulmonary histoplasmosis in humans, primarily due to the quiescent stage of fungal growth that occurs in the lungs of mice prior to the initiation of inflammation. Our results reveal the unique course of lung immunity associated with divergent species of Histoplasma and imply that the progression of clinical disease is considerably more heterogeneous than previously recognized.

Histoplasma is an endemic dimorphic fungus that can cause disease in healthy and immunocompromised individuals after the transition of inhaled spores into the facultative intracellular yeast form. There is substantial diversity among Histoplasma species, but it is not clear how this heterogeneity impacts the progression of pathology and cellular immune responses during acute respiratory infection, which represents the vast majority of histoplasmosis disease burden. After inoculating mice intranasally with a sublethal inoculum, we characterized the immune response to Histoplasma capsulatum (strain G186A) and Histoplasma ohiense (strain G217B) using comprehensive flow cytometric and single-cell analyses. Within 8 days after inoculation, H. ohiense induced a significantly higher infiltration of neutrophils and inflammatory monocytes into the lung compared to H. capsulatum. Microscopic analysis of infected lung tissue revealed that although the total number of fungi was similar within inflamed lung lesions, we observed different species-dependent intracellular yeast distribution patterns. Inoculation with gfp-expressing strains indicated that H. ohiense, but not H. capsulatum, was associated primarily with alveolar macrophages early after infection. Interestingly, we observed a significant reduction in the total number of alveolar macrophages 12 to 16 days after H. ohiense, but not H. capsulatum infection, despite similar intracellular growth dynamics within AMJ2-C11 alveolar macrophages in vitro. Together, our data suggest that H. ohiense, but not H. capsulatum, preferentially interacts with alveolar macrophages early after infection, which may lead to a different course of inflammation and resolution despite similar rates of fungal clearance.

IMPORTANCE Acute pulmonary histoplasmosis in healthy individuals comprises most of the disease burden caused by the fungal pathogen Histoplasma. Fungal pneumonia is frequently delayed in diagnosis and treatment due to a prolonged period of quiescence early during infection. In this study, we used a murine respiratory model of histoplasmosis to investigate how different Histoplasma species modulate lung inflammation throughout the complete course of infection. We propose that a relatively low, sublethal inoculum is ideal to model acute pulmonary histoplasmosis in humans, primarily due to the quiescent stage of fungal growth that occurs in the lungs of mice prior to the initiation of inflammation. Our results reveal the unique course of lung immunity associated with divergent species of Histoplasma and imply that the progression of clinical disease is considerably more heterogeneous than previously recognized.

Endemic mycoses: epidemiology and diagnostic strategies

INTRODUCTION

The global frequency of endemic mycoses has considerably increased, mainly due to environmental changes, population growth in endemic areas, and the increase in HIV-related immunosuppressed status. Among the most frequent endemic mycoses are coccidioidomycosis in semi-desert climates, and paracoccidioidomycosis, and histoplasmosis in tropical climates. The inoculum can enter the host through the airway or directly through the skin. Lymphatic and hematogenous spread may involve the skin.

AREAS COVERED

In this article, we provide up-to-date epidemiological and diagnostic data on major (histoplasmosis, paracoccidioidomycosis, coccidioidomycosis, blastomycosis) and minor (talaromycosis, adiaspiromycosis, emergomycosis) endemic mycoses.

EXPERT OPINION

Endemic mycoses include diseases with a localized endemic area, and a few of them converge. These mycoses all have in common the airway involvement and can cause pulmonary symptoms following initial asymptomatic infection. Among the risk groups to acquire these mycoses are travelers from endemic areas, archeologists, speleologists, and immigrants. Promising and useful diagnostic tools have been developed in endemic mycoses; however, most of them are not standardized or available in low-income countries.

Close encounters of three kinds: Case-based report of endemic mycoses in the environs of New York city

The term "endemic mycoses" refers to a group of fungi that maintains a baseline rate of infection only in certain geographical regions due to the hospitable enviormental conditions these regions offer. In the United States, Histoplasma capsulatum, Coccidioides spp, and Blastomyces dermatitidis are the three most prevalent endemic human fungal infections. The traditional endemic regions for these pathogens are defined based on data acquired many decades ago, and case detection is subject to diagnostic delays even in classically endemic areas, a problem that is likely to be magnified in areas less familiar with these fungal infections. The present series includes an example of each of these infections diagnosed in a medical center situated in the suburbs of New York City, a location not considered endemic for any of them. Likely routes of acquisition for the three patients are considered, and the history of encounters with these pathogens in New York State is briefly recounted. Altogether, this report is intended to serve as a reminder to clinicians that traditional distribution maps for the endemic mycoses are bound to be outdated in the face of modern trends in globalization, population dynamics, and ecological change.

Cholestasis and disseminated histoplasmosis in a psoriatic patient on infliximab: case report and review of literature

Background

Histoplasma capsulatum is the most common endemic mycosis in the United States and frequently presents as an opportunistic infection in immunocompromised hosts. Though liver involvement is common in disseminated histoplasmosis, primary gastrointestinal histoplasmosis of the liver in absence of lung involvement is rare. Similarly, cholestatic granulomatous hepatitis in liver histoplasmosis is rarely seen.

Case presentation

We present a rare case of primary gastrointestinal histoplasmosis manifesting with acute granulomatous hepatitis and cholestasis in a 48-year-old female with psoriatic arthritis, receiving methotrexate and infliximab. The epidemiology, risk factors, clinical presentation, diagnosis, and treatment of histoplasmosis is discussed. Furthermore, we review the published cases of biopsy-proven disseminated histoplasmosis with cholestatic jaundice to highlight histoplasmosis involvement in the liver.

Conclusion

Histoplasmosis should be considered in immunosuppressed patients with fever, chills, abdominal pain and cholestasis with progressive jaundice, particularly in subjects without evidence of biliary obstruction. Future studies are needed to accurately assess the risk of this fungal infection, specifically in patients on immunomodulatory therapy for autoimmune disease.

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.

Opportunistic Infections Are More Prevalent in Crohn's Disease and Ulcerative Colitis: A Large Population-Based Study

BACKGROUND

Opportunistic infections (OIs) are more common in patients with inflammatory bowel disease (IBD); however, there have been limited large-scale studies of OIs in IBD. We investigated the epidemiological characteristics of OI in Crohn's disease (CD) and ulcerative colitis (UC) using a large population-based database.

METHODS

Data were collected from a commercial database (Explorys Inc., Cleveland, OH, USA) that provided electronic health records from 26 major integrated US health care systems from 1999 to March 2018. In this data set, we identified all CD and UC patients, based on Systemized Nomenclature of Medicine-Clinical Terms. Within these cohorts, we identified a variety of OIs and compared the prevalence rate of OI in individuals with IBD with that of controls (patients in the database between March 2013 and March 2018 without the diagnosis of IBD).

RESULTS

Explorys included 153,290 patients with CD and 128,540 patients with UC between March 2013 and March 2018. The prevalence of OIs was 17.8% in CD, 19.2% in UC, and 7% in non-IBD controls. When compared with non-IBD controls, all OIs were more common in CD (prevalence ratio [PR], 2.54; 95% confidence interval [CI], 2.51-2.57) and UC (PR, 2.74; 95% CI, 2.71-2.77). Overall, viral infections were numerically more common, whereas bacterial infections had the highest PRs in CD and UC when compared with controls without IBD.

CONCLUSIONS

We found significantly higher rates of OI in IBD. Our study suggests the need for close follow-up of IBD patients to diagnose and provide vaccinations where applicable for prevention of infections.

Novel canine anti-Coccidioides immunoglobulin G enzyme immunoassay aids in diagnosis of coccidioidomycosis in dogs

The diagnosis of coccidioidomycosis (CM) in dogs is typically based on clinical presentation, serology, and (less frequently) spherule identification. Agar gel immunodiffusion (AGID) is the most commonly employed serological method, but AGID is slow (requiring up to a week for titer). A Coccidioides antigen enzyme immunoassay (EIA) is also available; however, sensitivity is low in CM dogs. An antibody EIA was developed to detect canine immunoglobulin G (IgG) reacting to Coccidioides antigens. Serum was evaluated from dogs with pathology proven CM and/or AGID positive CM, as well as dogs with histoplasmosis, blastomycosis, non-fungal infections, or healthy dogs. A standard curve was used to convert optical density (OD) values into EIA units (EU). Serum and urine samples from CM dogs were also tested in the antigen EIA. Sensitivity and specificity for IgG were 89.2% and 97.2%, respectively, upon evaluation of dogs with proven or probable CM and control dogs. Cross-reactivity was observed in 7.7% and in 6.4% of dogs with histoplasmosis or blastomycosis, respectively. The antigen EIA alone was insensitive (33.8%). Combined IgG and antigen testing increased sensitivity to 93.2%, as three dogs were IgG-negative but had detectable serum or urine antigen. In 22 dogs with proven CM, sensitivity was statistically similar for antibody EIA and AGID (86% and 73%; P = .487). The MiraVista® canine Coccidioides antibody IgG EIA may aid in the diagnosis of CM by improving turnaround time with comparable sensitivity to AGID. Serial or concurrent testing by antibody and antigen EIAs may be beneficial when screening dogs for CM.

Histoplasma capsulatum presenting as generalized lymphadenopathy after renal transplantation

Histoplasma capsulatum is typically an indolent disease among immunocompetent patients. However, immunocompromised patients, such as solid organ transplant recipients, are at risk of developing severe histoplasmosis. Yet post-transplant histoplasmosis is a rare pathology, representing less than five percent of invasive fungal infections among transplant recipients. Furthermore, patients tend to present with nonspecific clinical symptoms, complicating timely diagnosis and delaying treatment. Disease features that may be more representative of H. capsulatum infection, such as anemia, leukopenia and pulmonary involvement are often not present until late in the disease course, when the patient is at greater risk of decompensation. Unlike H. capsulatum infections among immunocompetent hosts, extrapulmonary infection among immunocompromised hosts is more the rule than the exception. Treatment with liposomal amphotericin B followed by oral itraconazole is the standard therapy, but special considerations must be made for patients with hepatic and/or renal insufficiency, underlying cardiac abnormalities or malabsorptive pathologies and doses of immunosuppressants will need to be adjusted for drug interactions. Herein we present a case of H. capsulatum infection presenting with generalized lymphadenopathy post-renal transplant.

Impact of IVIG therapy on serologic testing for infectious diseases

Intravenous immunoglobulin (IVIG) is used to treat an increasing number of conditions. The anti-inflammatory and immunomodulatory effects of IVIG can be life-saving; however, recent administration may complicate evaluation for infection. To assess the impact of IVIG therapy on a variety of common viral, bacterial, fungal, and parasitic serologies we prospectively evaluated serologic changes pre- and post-IVIG infusion in 7 participants. The number of new antibody detections ranging from 2 to 5. New detections included positivity for Epstein-Barr virus early D antigen, herpes simplex virus, West Nile virus, cytomegalovirus, and the endemic mycoses Histoplasma and Coccidioides. The greatest number of newly positive serologies was observed in subjects receiving cumulative doses of IVIG in excess of 100 g. Our results illustrate the difficulty in serologic interpretation following IVIG therapy and suggest a dose-response to new positive results. These findings may be a helpful resource to clinicians facing similar circumstances.

Chronic Meningitis

PURPOSE OF REVIEW

This article describes the clinical presentation, diagnostic approach (including the use of novel diagnostic platforms), and treatment of select infectious and noninfectious etiologies of chronic meningitis.

RECENT FINDINGS

Identification of the etiology of chronic meningitis remains challenging, with no cause identified in at least one-third of cases. Often, several serologic, CSF, and neuroimaging studies are indicated, although novel diagnostic platforms including metagenomic deep sequencing may hold promise for identifying organisms. Infectious etiologies are more common in those at risk for disseminated disease, specifically those who are immunocompromised because of human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS), transplantation, or immunosuppressant medications. An important step in identifying the etiology of chronic meningitis is assembling a multidisciplinary team of individuals, including those with specialized expertise in ophthalmology, dermatology, rheumatology, and infectious diseases, to provide guidance regarding diagnostic procedures.

SUMMARY

Chronic meningitis is defined as inflammation involving the meninges that lasts at least 4 weeks and is associated with a CSF pleocytosis. Chronic meningitis has numerous possible infectious and noninfectious etiologies, making it challenging to definitively diagnose patients. Therefore, a multifaceted approach that combines history, physical examination, neuroimaging, and laboratory analysis, including novel diagnostic platforms, is needed. This article focuses on key aspects of the evaluation of and approach to patients with chronic meningitis. Specific infectious etiologies and differential diagnoses of subacute and chronic meningitis, including noninfectious etiologies, are addressed.

Computed Tomography Scanning for Early Detection of Lung Cancer

Parallel and often unrelated developments in health care and technology have all been necessary to bring about early detection of lung cancer and the opportunity to decrease mortality from lung cancer through early detection of the disease by computed tomography. Lung cancer screening programs provide education for patients and clinicians, support smoking cessation as primary prevention for lung cancer, and facilitate health care for tobacco-associated diseases, including cardiovascular and chronic lung diseases. Guidelines for lung cancer screening will need to continue to evolve as additional risk factors and screening tests are developed. Data collection from lung cancer screening programs is vital to the further development of fiscally responsible guidelines to increase detection of lung cancer, which may include small groups with elevated risk for reasons other than tobacco exposure.

Performance of community-based lung cancer screening program in a Histoplasma endemic region

OBJECTIVES

Lung cancer screening with low dose computed-tomography (LDCT) is currently recommended for high-risk populations based on mortality benefit shown in the National Lung Screening Trial (NLST). This study evaluated performance of a community-based lung cancer screening program in a Histoplasma endemic region.

MATERIALS AND METHODS

Demographic and clinical information was collected through retrospective review of patients in the Lung Cancer Screening program of a Kentucky (Histoplasma endemic region) health system from 2016 and 2017. A positive LDCT screen is defined as Lung-RADS version 1.0 assessment categories 3 or 4. Patients characteristics, initial screening results and follow up were analyzed and compared to NLST results.

RESULTS

A total of 4500 LDCT screens were performed in 2016 (39%) and 2017 (61%) with 43% adherence rate to repeat annual screen in 2017. Mean age of patients was 64 years, with majority being females (54%) and current smokers (69%) with average 52-pack year smoking history. The rate of positive LDCT was 13.3% (600) varying based on baseline (14.6%) and annual (9.5%) screen. A total of 70 lung cancers were diagnosed among all positive LDCT screens (11.7%) with a false positive rate of 12%.

CONCLUSIONS

Baseline positive screens in our study are similar to NLST data with Lung-RADS criteria implementation (14.6% vs 13.6%, p = 0.15) despite being a Histoplasma endemic region. Our study shows a successful performance of a community-based lung cancer screening program in a Histoplasma endemic region.

An unusual infection in an immunocompetent male from a non-endemic area: Lessons from a vacation

Primary pulmonary histoplasmosis is found worldwide, and is particularly endemic in some areas of North America, usually those surrounding the Ohio and Mississippi river valleys. It is not common in the East Coast of the United States, and is in fact reportable in Pennsylvania. It has been rarely described in immunocompetent individuals residing in a non-endemic region. We present a case of a previously healthy middle-aged male, a Pennsylvania resident, who presented with mid-sternal chest discomfort, fatigue, chills and mild shortness of breath, and was diagnosed with primary pulmonary histoplasmosis.

An unusual presentation of disseminated histoplasmosis in a non-HIV patient from Vietnam

BACKGROUND

Histoplasmosis is a systemic infection caused by the dimorphic fungus Histoplasma capsulatum, naturally found in nitrogen-rich soil, whose main transmission route is the inhalation of conidia. Up to 95% of histoplasmosis cases are asymptomatic or transient, and the remaining 5% of cases have pathological manifestations in the lungs, bone marrow, liver, spleen, intestine, mucous membranes, and rarely on the skin. This mycosis has been reported from many endemic areas, mainly in immunosuppressed patients, such as HIV-positive patients, and its disseminated form is rarely reported.

CASE REPORT

Histoplama capsulatum was isolated and identified by means of microscopy, culture characteristics and nested PCR from the cutaneous lesions of a non-HIV patient from Vietnam. The patient improved significantly with systemic itraconazole treatment.

CONCLUSIONS

Disseminated histoplasmosis with cutaneous involvement in non-HIV patients is an extremely unusual presentation.

Mediastinal Lymphadenopathy in Children With Histoplasmosis

BACKGROUND

Mediastinal lymphadenopathy (ML) in children can arise from malignancy, infection, or rheumatic illness among others, and may be found incidentally on imaging or during workup for a variety of symptoms. Our aim was to describe the clinical presentation and natural history of histoplasmosis in children who present to a tertiary care center with ML in an endemic area of the country.

METHODS

After institutional review board approval, a retrospective study of all children (aged < 21 y) presenting with proven (positive serologies) or suspected histoplasmosis (negative serologies, negative tuberculosis testing, and benign outcomes in follow-up) over a 5-y period was done. Seventy-four patients were tested; those with another diagnosis (n = 6) or without ML (n = 26) were excluded, for a total cohort of 44 patients. Demographics, clinical presentation, symptoms, laboratory data, treatment course, radiography studies, and inpatient and outpatient visits were examined.

RESULTS

Of the 44 patients with ML, 27 had proven histoplasmosis, and 19 had suspected histoplasmosis. The median follow-up by imaging or clinical examination was 6.9 mo (0.3-73.2 mo). Sixteen patients received antifungal therapy with itraconazole, and 15 patients received at least one course of steroids, nearly all for respiratory symptoms; 11 patients (24%) received both. There was no difference in readmission rate (n = 5 versus 2, P = 0.7) or recurrence of symptoms (n = 2 versus 5, P = 0.4) between patients who received an antifungal and those that did not. Receiving steroid therapy was associated with airway narrowing and a higher readmission rate (n =6 versus 2 who were not treated with steroids, P = 0.04), but not with symptom recurrence. Nine lymph node or mass biopsies were performed; however, the pathology only confirmed nonspecific infection in three and was nondiagnostic in the remaining six patients. Twenty-seven patients had at least one confirmatory laboratory test positive for histoplasmosis. Thirty-nine of the 44 patients (84%) with a diagnosis of histoplasmosis (proven or suspected) were asymptomatic by 1-2 mo follow up, with the remainder having intermittent chest pain or reactive airway disease.

CONCLUSIONS

ML because of proven or suspected histoplasmosis is usually a self-limiting disease that can be managed with treatment of the child's symptoms. Antifungals and steroids are of unclear benefit and may not alter the natural course of the disease. Biopsies are rarely diagnostic in the setting of ML, and invasive procedures should be avoided.

The HIF-1α/LC3-II Axis Impacts Fungal Immunity in Human Macrophages

The fungal pathogen Histoplasma capsulatum causes a spectrum of disease, ranging from local pulmonary infection to disseminated disease. The organism seeks residence in macrophages, which are permissive for its survival. Hypoxia-inducible factor 1α (HIF-1α), a principal regulator of innate immunity to pathogens, is necessary for macrophage-mediated immunity to H. capsulatum in mice. In the present study, we analyzed the effect of HIF-1α in human macrophages infected with this fungus. HIF-1α stabilization was detected in peripheral blood monocyte-derived macrophages at 2 to 24 h after infection with viable yeast cells. Further, host mitochondrial respiration and glycolysis were enhanced. In contrast, heat-killed yeasts induced early, but not later, stabilization of HIF-1α. Since the absence of HIF-1α is detrimental to host control of infection, we asked if large amounts of HIF-1α protein, exceeding those induced by H. capsulatum, altered macrophage responses to this pathogen. Exposure of infected macrophages to an HIF-1α stabilizer significantly reduced recovery of H. capsulatum from macrophages and produced a decrement in mitochondrial respiration and glycolysis compared to those of controls. We observed recruitment of the autophagy-related protein LC3-II to the phagosome, whereas enhancing HIF-1α reduced phagosomal decoration. This finding suggested that H. capsulatum exploited an autophagic process to survive. In support of this assertion, inhibition of autophagy activated macrophages to limit intracellular growth of H. capsulatum Thus, enhancement of HIF-1α creates a hostile environment for yeast cells in human macrophages by interrupting the ability of the pathogen to provoke host cell autophagy.

Mapping Histoplasma capsulatum Exposure, United States

Maps of Histoplasma capsulatum infection prevalence were created 50 years ago; since then, the environment, climate, and anthropogenic land use have changed drastically. Recent outbreaks of acute disease in Montana and Nebraska, USA, suggest shifts in geographic distribution, necessitating updated prevalence maps. To create a weighted overlay geographic suitability model for Histoplasma, we used a geographic information system to combine satellite imagery integrating land cover use (70%), distance to water (20%), and soil pH (10%). We used logistic regression modeling to compare our map with state-level histoplasmosis incidence data from a 5% sample from the Centers for Medicare and Medicaid Services. When compared with the state-based Centers data, the predictive accuracy of the suitability score–predicted states with high and mid-to-high histoplasmosis incidence was moderate. Preferred soil environments for Histoplasma have migrated into the upper Missouri River basin. Suitability score mapping may be applicable to other geographically specific infectious vectors.

Epidemiology and Geographic Distribution of Blastomycosis, Histoplasmosis, and Coccidioidomycosis, Ontario, Canada, 1990-2015

Elevated incidence of blastomycosis in Ontario calls for diagnostic vigilance.

Endemic mycoses represent a growing public health challenge in North America. We describe the epidemiology of 1,392 microbiology laboratory–confirmed cases of blastomycosis, histoplasmosis, and coccidioidomycosis in Ontario during 1990–2015. Blastomycosis was the most common infection (1,092 cases; incidence of 0.41 cases/100,000 population), followed by histoplasmosis (211 cases) and coccidioidomycosis (89 cases). Incidence of blastomycosis increased from 1995 to 2001 and has remained elevated, especially in the northwest region, incorporating several localized hotspots where disease incidence (10.9 cases/100,000 population) is 12.6 times greater than in any other region of the province. This retrospective study substantially increases the number of known endemic fungal infections reported in Canada, confirms Ontario as an important region of endemicity for blastomycosis and histoplasmosis, and provides an epidemiologic baseline for future disease surveillance. Clinicians should include blastomycosis and histoplasmosis in the differential diagnosis of antibiotic-refractory pneumonia in patients traveling to or residing in Ontario.

Histoplasmosis Following Systemic Immunomodulatory Therapy for Ocular Inflammation

PURPOSE

Histoplasmosis is a known complication of systemic immunosuppressive therapy, particularly among patients who are receiving tumor necrosis factor α inhibitors. There are limited data on the development of disseminated or pulmonary histoplasmosis among patients who are receiving systemic immunosuppressive medication for noninfectious ocular inflammation.

DESIGN

Retrospective case series.

METHODS

We reviewed all patients with uveitis or scleritis who subsequently developed pulmonary or disseminated histoplasmosis at the Mayo Clinic in Rochester, Minnesota between September 1, 1994 and July 1, 2017, with a 3:1 age- and sex-matched control cohort who did not develop histoplasmosis. This was a single institutional study examining patients that developed histoplasmosis after the initiation of systemic immunomodulatory therapy (IMT). Patients had to develop either disseminated or pulmonary histoplasmosis while receiving systemic immunosuppressive therapy and have an ophthalmic examination at Mayo Clinic Rochester. The control group was comprised of patients who received systemic IMT for ocular inflammation but did not develop histoplasmosis.

RESULTS

Nine cases of histoplasmosis were identified: 2 disseminated and 7 pulmonary. Both patients with disseminated histoplasmosis were taking tumor necrosis factor α inhibitors. Seven of the 9 patients received systemic antifungal medication, including both disseminated cases. Over a median follow-up of 4.4 years, none of the patients died, and there were no recurrences of histoplasmosis. When compared to the control cohort, there was no correlation between length of time on IMT and the risk of histoplasmosis.

CONCLUSIONS

Ocular inflammation patients on systemic immunomodulatory therapy may develop pulmonary or disseminated histoplasmosis. Most cases require treatment with systemic antifungal medication, but it might not be necessary to stop systemic immunomodulatory medication for ocular inflammation. Ophthalmologists should be aware that patients receiving systemic immunomodulatory therapy have a higher risk of developing Histoplasma infections. Prompt diagnosis and treatment using the expertise of an infectious diseases specialist may ensure low mortality for these patients.