Coccidioidomycosis and COVID-19 Infection. An Analysis from a Single Medical Center Within the Coccidioidal Endemic Area

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.

Developing a Coccidioides posadasii and SARS-CoV-2 Co-infection Model in the K18-hACE2 Transgenic Mouse

BACKGROUND

Early reports showed that patients with COVID-19 had recrudescence of previously resolved coccidioidomycosis (Valley fever, VF), and there were indications that coinfection had more severe outcomes. We therefore investigated serial infection of Coccidioides posadasii and SARS-CoV-2 in a K18-hACE2 mouse model to assess disease outcomes.

METHODS

In our model, we challenged K18-hACE2 mice sequentially with a sub-lethal dose of SARS-CoV-2 and 24 hours later with low virulence strain of Coccidioides posadasii, and vice versa, compared to mice that only received a single infection challenge. We performed survival and pathogenesis mouse studies as well as looked at the systemic immune response differences between treatment groups.

RESULTS

Here we show that co-infected groups have a more severe disease progression as well as a decrease in survival. Importantly, results differ depending on the SARS-CoV-2 variant (WA-1, Delta, or Omicron) and infection timing (SARS-CoV-2 first, C. posadasii second or vice versa). We find that groups that are infected with the virus first had a decrease in survival, increased morbidity and weight loss, increased fungal and viral burdens, differences in immune responses, and the amount and size of fungal spherules. We also find that groups coinfected with C. posadasii first have a decrease fungal burden and inflammatory responses.

CONCLUSIONS

This is the first in vivo model investigation of a coinfection of SARS-CoV-2 and Coccidioides. Because of the potential for increased severity of disease in a coinfection, we suggest populations that live in areas of high coccidioidomycosis endemicity may experience higher incidence of complicated disease progression with COVID-19.

Factors Associated with Older People's Anxiety Symptom Positioning after COVID-19: Cross-Sectional Findings from a Canadian Sample

This study sheds light on the personal characteristics of older Canadians self-identifying as severely anxious and the coping strategies that they gravitated to mitigate their anxiety. Our studied sample consisted of 606 Canadians aged 60 and above who took part in an e-survey across all 10 of Canada's provinces, launched in July 2022, when social distancing was lifted across the country. Participants completed a personal characteristics questionnaire, the Geriatric Anxiety Scale or GAS-10, and a checklist of everyday coping strategies for mitigating anxiety. A seemingly greater number of severely anxious Canadians were born female, self-identified as a cisgender woman, and were in their 60s and in poor to fair health. A univariate logistic regression analysis revealed that all such personal characteristics were associated with statistically significantly greater odds of experiencing severe anxiety. In our multivariate logistic regression analysis, no significant differences were observed between the sexes (AOR = 0.590, p = 0.404), and non-binary and cisgender men (AOR = 0.689, p = 0.441) and women (AOR = 0.657, p = 0.397). Nor were there statistically significant differences in the odds of experiencing severe anxiety for those living with versus without a life partner and chronic illnesses. Older Canadians experiencing severe anxiety were far more likely to normalize their fear and anxiety (AOR = 4.76, p < 0.001), challenge their worries (AOR = 5.21, p < 0.001), and to relax or meditate (AOR = 2.36, p = < 0.001). They were less inclined to decrease other sources of stress in their lives, to stay active, and to get enough sleep. We offer anticipatory guidance for mental health program planners and practitioners, and fruitful avenues of inquiry for researchers.

Fungal pathogens and COVID-19

COVID-19 pandemic highlighted the complications of secondary fungal infections that occurred globally in severe cases of coronavirus disease managed in the intensive care units. Furthermore, varied underlying host factors, such as preexisting immunosuppression, the use of immunomodulatory agents, and invasive procedures predisposing lung tissues to fungal colonization and proliferation, caused increased susceptibility to fungal infections in COVID-19 patient populations. These invasive fungal infections directly impact the overall length of hospitalization and mortality. The most commonly reported fungal infections in patients with COVID-19 include aspergillosis, invasive candidiasis, and mucormycosis. An overall worldwide increase in the prevalence of candidiasis and aspergillosis was observed in COVID-19 patients , whereas outbreaks of mucormycosis were mainly recorded from India. Diagnostic challenges and limited antifungal treatment options make secondary fungal infections among COVID-19 patients more burdensome, which results in improper management and increased mortality.

Genetic and Other Determinants for the Severity of Coccidioidomycosis: A Clinician's Perspective

The endemic fungal infection, coccidioidomycosis, occurs after inhalation of one or very few Coccidioides spp. spores. Infections produce diverse clinical manifestations, ranging from insignificant to extremely destructive, even fatal. Approaches to understanding this range of consequences have traditionally categorized patients into a small number of groups (asymptomatic, uncomplicated self-limited, fibro-cavitary, and extra-thoracic disseminated) and then looked for immunologic differences among them. Recently, variants within genes of innate pathways have been found to account, in part, for infections that result in disseminated disease. This discovery raises the very attractive theory that, in patients without severe immunosuppression, much of the disease spectrum can be accounted for by various combinations of such deleterious variants in innate pathways. In this review, we summarize what is known about genetic determinants that are responsible for the severity of coccidioidal infections and how complex innate genetic differences among different people might account for the spectrum of disease observed clinically.

Clinical Challenges of Emerging and Re-Emerging Yeast Infections in the Context of the COVID-19 Pandemic

During the geological eras, some fungi, through adaptation and/or environmental/ecological pressure, interacted directly and indirectly with humans, through occasionally harmful interaction interdependent on the individual's immunological condition. Infections caused by yeasts are underreported, subjugated, and underdiagnosed, and treatment is restricted to a few drugs, even after the significant progress of medicine and pharmacology. In the last centuries, antagonistically, there has been an exponential increase of immunocompromised individuals due to the use of immunosuppressive drugs such as corticosteroids, increased cases of transplants, chemotherapeutics, autoimmune diseases, neoplasms, and, more recently, coronavirus disease 2019 (COVID-19). This review aims to survey emerging and re-emerging yeast infections in the current clinical context. Currently, there is an immense clinical challenge for the rapid and correct diagnosis and treatment of systemic mycoses caused by yeasts due to the terrible increase in cases in the current context of COVID-19.

Reactivation of Coccidioidomycosis in a Mouse Model of Asymptomatic Controlled Disease

The majority of human coccidioidomycosis infections are asymptomatic or self-limited but may have sequestered spherules in highly structured granulomas. Under immunosuppression, reactivation of fungal growth can result in severe disease. B6D2F1 mice asymptomatically infected with C. posadasii strain 1038 were immunosuppressed with dexamethasone (DXM) in drinking water. Treated mice died 16−25 days later, while untreated mice survived (p < 0.001). Flow cytometry of lung granulomas on days 5, 10, 15, and 20 of DXM treatment showed immune cell populations decreased 0.5−1 log compared with untreated mice though neutrophils and CD19+IgD−IgM− cells rebounded by day 20. Histopathology demonstrated loss of granuloma structure by day 5 and increasing spherules through day 20. On day 20, T-cells were nearly absent and disorganized pyogranulomatous lesions included sheets of plasma cells and innumerable spherules. Mice given DXM for 14 days then stopped (DXM stop) survived 6 weeks (9/10). Lung fungal burdens were significantly lower (p = 0.0447) than mice that continued treatment (DXM cont) but higher than untreated mice. Histopathologically, DXM stop mice did not redevelop controlled granulomas by sacrifice, though T-cells were densely scattered throughout the lesions. This demonstrates a mouse model suitable for further study to understand the immunologic components responsible for maintenance control of coccidioidomycosis.