Endemic human blastomycosis in Quebec, Canada, 1988-2011

Acute Dyspnea With an Infiltrative Tracheal Mass

CASE PRESENTATION

A 48-year-old woman presented to the ED with a nonproductive cough, shortness of breath, and stridor. She was otherwise healthy and had never used tobacco. The patient was mildly tachycardic but otherwise hemodynamically stable, afebrile, and saturating well on room air. She did not display any signs of increased work of breathing at rest. Although auscultation of her thorax indicated good air entry bilaterally without any adventitious sounds, stridor was elicited with forced expiration.

Osteoarticular Mycoses

Osteoarticular mycoses are chronic debilitating infections that require extended courses of antifungal therapy and may warrant expert surgical intervention. As there has been no comprehensive review of these diseases, the International Consortium for Osteoarticular Mycoses prepared a definitive treatise for this important class of infections. Among the etiologies of osteoarticular mycoses are Candida spp., Aspergillus spp., Mucorales, dematiaceous fungi, non-Aspergillus hyaline molds, and endemic mycoses, including those caused by Histoplasma capsulatum, Blastomyces dermatitidis, and Coccidioides species. This review analyzes the history, epidemiology, pathogenesis, clinical manifestations, diagnostic approaches, inflammatory biomarkers, diagnostic imaging modalities, treatments, and outcomes of osteomyelitis and septic arthritis caused by these organisms. Candida osteomyelitis and Candida arthritis are associated with greater events of hematogenous dissemination than those of most other osteoarticular mycoses. Traumatic inoculation is more commonly associated with osteoarticular mycoses caused by Aspergillus and non-Aspergillus molds. Synovial fluid cultures are highly sensitive in the detection of Candida and Aspergillus arthritis. Relapsed infection, particularly in Candida arthritis, may develop in relation to an inadequate duration of therapy. Overall mortality reflects survival from disseminated infection and underlying host factors.

Let's talk about Sex Characteristics - as a Risk Factor for Invasive Fungal Diseases

Biological sex, which comprises differences in host sex hormone homeostasis and immune responses, can have a substantial impact on the epidemiology of infectious diseases. Comprehensive data on sex distributions in invasive fungal diseases (IFDs) is lacking. In this review we performed a literature search of in vitro/animal studies, clinical studies, systematic reviews, and meta-analyses of invasive fungal infections. Females represented 51.2% of invasive candidiasis cases, mostly matching the proportions of females among the general population in the United States and Europe (>51%). In contrast, other IFDs were overrepresented in males, including invasive aspergillosis (51% males), mucormycosis (60%), cryptococcosis (74%), coccidioidomycosis (70%), histoplasmosis (61%), and blastomycosis (66%). Behavioral variations, as well as differences related to biological sex, may only in part explain these findings. Further investigations concerning the association between biological sex/gender and the pathogenesis of IFDs is warranted.

Changing Patterns of Disease Severity in Blastomyces dermatitidis Infection, Quebec, Canada

The increase in severe cases might be related to an increased number of immunosuppressed patients; climate change might also play a role.

This retrospective multicenter cohort study assessed temporal changes in the severity and mortality rate of blastomycosis in Quebec, Canada, and identified risk factors for death in patients with blastomycosis in 1988–2016. The primary outcome was 90-day all-cause deaths. Among 185 patients, 122 (66%) needed hospitalization and 30 (16%) died. We noted increases in the proportion of severe cases, in age at diagnosis and in the proportion of diabetic and immunocompromised patients over time. Independent risk factors for death were age (adjusted odds ratio [aOR] 1.04, 95% CI 1.00–1.07), immunosuppression (aOR 4.2, 95% CI 1.5–11.6), and involvement of >2 lung lobes (aOR 5.3, 95% CI 1.9–14.3). There was no association between the Blastomyces genotype group and all-cause mortality. The proportion of severe cases of blastomycosis has increased in Quebec over the past 30 years, partially explained by the higher number of immunosuppressed patients.

A case of tracheal and pulmonary blastomycosis presenting as asymptomatic pulmonary nodules

Blastomyces is an endemic fungal pathogen found in regions of North America. It is endemic in the Ohio and Mississippi river valleys, New York, Wisconsin, Colorado, Texas, Kansas, Nebraska, and other regions of the United States. It is common in Canada, mainly Ontario and Manitoba. Here, we report a case of tracheal and pulmonary blastomycosis. Interestingly, this case presented as an unexpected diagnosis as part of a malignancy workup. To our knowledge, this is only the second case of tracheal blastomycosis reported in the literature.

Blastomycosis in Minnesota, USA, 1999-2018

Blastomycosis is a systemic disease caused by Blastomyces spp. fungi. To determine its epidemiology in blastomycosis-endemic Minnesota, USA, we evaluated all cases reported to public health officials during 1999-2018. We focused on time to diagnosis, exposure activities, and exposure location. A total of 671 cases and a median of 34 cases/year were reported. Median time to diagnosis was 31 days; 61% of patients were not tested for blastomycosis until they were hospitalized. The case-fatality rate was 10%, and patients who died were 5.3 times more likely to have a concurrent medical condition. Outdoor activities and soil exposure were reported by many patients, but no specific activity or exposure was common to most. Almost one third of patients were probably exposed in geographic areas other than their home county. Providers should consider alternative etiologies for patients with pneumonia not responding to antibacterial treatment, and public health officials should increase awareness in blastomycosis-endemic areas.

Mortality associated with Blastomyces dermatitidis infection: A systematic review of the literature and meta-analysis

Published case fatality in blastomycosis patients ranges between 4% and 78%. This study aimed to assess mortality associated with blastomycosis and identify its associated risk factors. We conducted a systematic review of publications related to Blastomyces dermatitidis available in PubMed and Scopus databases. Studies that reported data on blastomycosis mortality and that were published from inception through February 2018 were assessed and included in the analysis. Using the R meta package, a random-effect model meta-analysis was used to calculate pooled and stratified estimates of case-fatality proportions and risk ratios. Of 1553 publications, we included 20 studies reporting on a total of 2820 cases of blastomycosis between 1970 and 2014 and three case series reports with 10, 21, and 36 patients. The mean or median ages ranged from 28 to 59 years. Mortality was defined as attributable mortality caused by blastomycosis in 13 studies. Among 14 studies with a standard error ≤0.05, the overall pooled mortality was 6.6% (95% confidence interval [CI], 4.9-8.2) with 57% heterogeneity. The mortality rate was 37% (95% CI, 23-51) in immunocompromised patients and 75% (95% CI, 53-96) in patients who developed an acute respiratory distress syndrome (ARDS) (n = 3 studies each). ARDS was the only identified risk factor in general patients (risk ratio = 10.2). The overall mortality was significantly higher in studies involving immunocompromised patients and ARDS patients. Our analysis showed considerable heterogeneity among studies. Inconsistent mortality definitions may have contributed to the observed heterogeneity. Further research is needed to assess potential risk factors for mortality.

A case of disseminated blastomycosis with pulmonary, genitourinary, and osteoarticular involvement in southern Saskatchewan

Although southern Saskatchewan is not known to be a region endemic to blastomycosis, we present a case of disseminated blastomycosis in a 39-year-old man with pulmonary, genitourinary, and osteoarticular involvement. The patient presented with persistent fevers despite recent antibiotic therapy, arthritis in his left foot, and urinary obstruction. A computed tomography (CT) scan of the chest revealed a diffuse miliary pattern. A transbronchial biopsy only showed granulomatous changes, and washings were negative for fungal culture. Magnetic resonance imaging (MRI) of the left foot revealed signs of septic arthritis. Pathology from the joint aspiration and debridement revealed budding yeast in keeping with blastomycosis. Urine culture also grew blastomycosis, confirming urinary involvement. He was initiated on itraconazole, with complete resolution of his symptoms within 2 weeks. This case illustrates the challenges in diagnosing disseminated blastomycosis, and further establishes the endemicity of blastomycosis in southern Saskatchewan.

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.

Blastomyces helicus, a New Dimorphic Fungus Causing Fatal Pulmonary and Systemic Disease in Humans and Animals in Western Canada and the United States

Background

Blastomyces helicus (formerly Emmonsia helica) is a dimorphic fungus first isolated from a man with fungal encephalitis in Alberta, Canada. The geographic range, epidemiology, and clinical features of disease are unknown.

Methods

We reviewed human and veterinary isolates of B. helicus identified among Blastomyces and Emmonsia isolates at the University of Alberta Microfungus Collection and Herbarium, University of Texas Health San Antonio’s Fungus Testing Laboratory, and Associated Regional and University Pathologists Laboratories. Isolates were selected based on low Blastomyces dermatitidis DNA probe values and/or atypical morphology. Species identification was confirmed for most isolates by DNA sequence analysis of the internal transcribed spacer with or without D1/D2 ribosomal RNA regions. Epidemiological and clinical data were analyzed.

Results

We identified isolates from 10 human and 5 veterinary cases of B. helicus infection; all were referred from western regions of Canada and the United States. Isolates remained sterile in culture, producing neither conidia nor sexual spores in the mycelial phase, but often producing coiled hyphae. Isolates were most frequently cultured from blood and bronchoalveolar lavage in humans and lungs in animals. Most infected persons were immunocompromised. Histopathological findings included pleomorphic, small or variably sized yeast-like cells, with single or multiple budding, sometimes proliferating to form short, branching, hyphal-like elements. Disease carried a high case-fatality rate.

Conclusions

Blastomyces helicus causes fatal pulmonary and systemic disease in humans and companion animals. It differs from B. dermatitidis in morphological presentation in culture and in histopathology, by primarily affecting immunocompromised persons, and in a geographic range that includes western regions of North America.

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.

Blastomycosis in Southern Saskatchewan 2000-2015: Unique presentations and disease characteristics

In the literature, cases of blastomycosis in Canada have been documented in provinces bordering the Great Lakes, including Ontario and Quebec, as well as Manitoba. This is the first study to our knowledge reporting cases of mycosis seen in southern Saskatchewan suggesting a broader area of endemicity. We searched the Regina Qu'Appelle Health Region (RQHR) Microbiology Laboratory for all culture-confirmed cases of Blastomyces from January 2000 to December 2015 and identified 15 cases. Thirteen cases were reviewed, identifying common presenting symptoms, misdiagnosis, comorbidities, travel history, time from presentation to diagnosis, diagnostic specimen, treatment, and clinical outcome. Nine patients had no travel to areas known to be endemic to environmental blastomycosis. Eight patients presented with respiratory symptoms, four with skin lesions, four with constitutional symptoms, and one presented with chest pain after a fall. Initial misdiagnosis occurred in nine (69%) of the 13 cases, and all six patients that died of the disease were misdiagnosed. These six patients (46%) were acutely ill with refractory disseminated disease, leading to respiratory failure. It is probable that Blastomyces is present as an endemic fungus in the soil of southern Saskatchewan. Possibly due to a lack of awareness of this pathogen in the area, initial misdiagnoses were common and likely contributed to significant morbidity and mortality.

Blastomycosis in Children: An Analysis of Clinical, Epidemiologic, and Genetic Features

BACKGROUND

Blastomyces spp. are endemic in regions of the United States and result in blastomycosis, a serious and potentially fatal infection. Little is known about the presentation, clinic course, epidemiology, and genetics of blastomycosis in children.

METHODS

A retrospective review of children with blastomycosis confirmed by culture or cytopathology between 1999 and 2014 was completed. Blastomyces sp. isolates were genotyped by using microsatellite typing, and species were typed by sequencing of internal transcribed spacer 2 (its2).

RESULTS

Of the 114 children with blastomycosis identified, 79% had isolated pulmonary involvement and 21% had extrapulmonary disease. There were more systemic findings, including fever (P = .01), poor intake (P = .01), elevated white blood cell count (P < .01), and elevated C-reactive protein level (P < .01), in children with isolated pulmonary disease than in children with extrapulmonary disease. Children with extrapulmonary disease had more surgeries (P = .01) and delays in diagnosis (P < .01) than those with isolated pulmonary infection. Of 52 samples genotyped, 48 (92%) were Blastomyces gilchristii and 4 (8%) were Blastomyces dermatitidis.

CONCLUSION

This is the first large-scale study of the clinical, epidemiologic, and genetic features of blastomycosis in children. The majority of the children had isolated pulmonary disease with systemic findings. Patients with extrapulmonary disease were less likely to have systemic symptoms or additional laboratory evidence of infection, which made delays in diagnosis more common. More than 90% of the pediatric cases were caused by B gilchristii.

Serious fungal infections in Canada

There are currently no nationwide epidemiological data on fungal infections in Canada. We estimated the burden of serious fungal diseases using literature review and modeling, as per a methodology previously described by the LIFE program ( http://www.LIFE-worldwide.org ). Among the population of Canada (35.5 million in 2014), it was estimated that approximately 1.8% are affected by a serious fungal infection. Recurrent vulvovaginal candidiasis, severe asthma with fungal sensitization, and allergic bronchopulmonary aspergillosis are the most frequent infections, with population prevalences of 498,688 (1403/100,000), 73,344 (206/100,000), and 61,854 (174/100,000) cases, respectively. Over 3000 invasive fungal infections are estimated to occur annually, with incidences of 2068 cases (5.8/100,000) of invasive candidiasis, 566 cases (1.6/100,000) of invasive aspergillosis, 252 cases (0.71/100,000) of Pneumocystis pneumonia, 99 cases (0.28/100,000) of endemic mycoses, and 63 cases (0.18/100,000) of cryptococcosis. These estimates warrant validation through more formal epidemiological studies in Canada.

Red Fox as Sentinel for Blastomyces dermatitidis, Ontario, Canada

Blastomyces dermatitidis, a fungus that can cause fatal infection in humans and other mammals, is not readily recoverable from soil, its environmental reservoir. Because of the red fox’s widespread distribution, susceptibility to B. dermatitidis, close association with soil, and well-defined home ranges, this animal has potential utility as a sentinel for this fungus.

Blastomycosis in Indiana: Clinical and Epidemiologic Patterns of Disease Gleaned from a Multicenter Retrospective Study

BACKGROUND

To better understand clinical and epidemiologic patterns of blastomycosis, we report on a large series of blastomycosis in Indiana.

METHODS

All microbiologically and histopathologically confirmed cases of blastomycosis from four hospitals serving Central Indiana from 1985 to 2014 were identified. Available data were collected. Data on population estimates, annual precipitation, and construction in Indiana were evaluated for correlations with incidence rates of blastomycosis.

RESULTS

A total of 114 patients were identified. The mean age was 44.4 years; 27% had diabetes mellitus, and 16% were immunosuppressed. Most presented with pneumonia (90%); 48% had extrapulmonary disease (CNS involvement in 9%), and 15% developed ARDS. Cultures, cytopathology, and histopathology were positive in 86%, 27%, and 85% of the sample, respectively, and fungal antigen was positive in 76%. Amphotericin B was administered in 49%, and 87% received an azole. Total mortality was 12%. Immunosuppression (OR = 3.0), diabetes mellitus (OR = 2.9), and multilobar pneumonia (OR = 2.9) were associated with increased likelihood of ICU admission. There was a significant increase in incidence over time in Marion County. There was no correlation with amount of precipitation, but the rise in incidence coincided with a 2005 state initiative to expand Indiana's highway infrastructure.

CONCLUSIONS

The incidence of blastomycosis in Central Indiana may be on the rise. Physicians in endemic areas should be aware of the potentially fulminant consequences of the disease.

Blastomyces Antigen Detection for Diagnosis and Management of Blastomycosis

Blastomyces spp. antigen testing was evaluated over a 10-year period in an area where blastomycosis is endemic. Antigen testing was less sensitive than previously reported, but serial urine testing was useful in monitoring disease resolution or progression. Culture and cytopathology remain the gold standard for diagnosis and exclusion of this infection.