Blastomycosis, coccidioidomycosis (valley fever) and histoplasmosis are the most common endemic fungal diseases (mycosis) in North America. Authors of an opinion piece in Annals of Internal Medicine argue that we need to improve the diagnosis and reporting of these infections to better serve patients and understand the magnitude of the problem.
Traditionally, these infections have known endemicity regions, allowing for targeted education of clinicians and community members. Unfortunately, the borders of these regions seem to be changing due to climate change.
Lead author George R. Thompson III, MD, professor of medicine at the University of California, Davis, said Medscape Medical News in an email, “These mycoses are increasingly recognized outside of traditional endemic regions. The regions where they occur are expanding.”
Underdiagnosed and underreported
Because these environmentally acquired yeast infections present as community-acquired pneumonia (CAP) or with other nonspecific symptoms such as night sweats, fever, chills, cough, or fatigue, providers often mistakenly treat patients for a bacterial or viral disease, without suspecting a fungal pathogen. . Neglecting yeast infection leads to delayed treatment, multiple courses of unnecessary and potentially harmful antibiotics, not to mention excessive health care expenditures and health care utilization.
Even in areas where yeast infections are known to be endemic, fungal diseases can often be overlooked, says Fariba Donovan, MD, PhD, assistant professor of medicine at the University of Arizona’s Valley Fever Center for Excellence (VFCE). , in Tucson. (Donovan was not involved in the Annals article.) Tucson is in an area considered hyperendemic for Valley fever. In hyperendemic areas of Arizona and California, Valley fever is thought to be the causative agent in about 20% of CAP cases.
Even with this increased regional awareness, Donovan’s research showed that 43% of patients with Valley fever at Banner University Medical Center in Tucson had diagnostic delays of more than a month, and the median delay was 23 days. “The most important aspect of early diagnosis of Valley fever is raising awareness in the medical communities,” she said. Medscape Medical News. The VFCE provides regular training on Valley fever to medical staff and community members.
In addition to the general lack of awareness, Annals the authors point out that endemic mycoses are not included in common laboratory diagnostic panels used for patients with pneumonia. Serum antibody and urine antigen tests for endemic mycoses are usually only available in certain laboratories, so providers must be trained to order them.
Nor are endemic mycoses specifically addressed in the professional guidelines physicians should follow regarding CAP. For example, the 2019 joint guideline on community-acquired pneumonia from the American Thoracic Society and the Infectious Diseases Society of America does not directly address the issue of when to suspect endemic mycoses.
The epidemiology of endemic mycoses
The temperature and precipitation of a region are important for the ecology of mycoses, so changes in climate can lead to geographic shifts in endemicity. Forest fires may also play a role in the spread of some of these organisms. For the sake of human and non-human patients, the authors argue that current maps need to be redrawn.
In recent years, researchers have found Valley fever among non-travellers in Nebraska, much further east than the historic hotspots of Arizona and California. Similarly, researchers and clinicians are discovering histoplasmosis and Blastomyces infections in areas well outside of what were previously thought to be their endemic areas.
If county, state, and federal public health authorities do not specifically require that a certain pathogen be reported to them, epidemiological data will not be routinely collected from providers and diagnostic laboratories. Lack of data means lack of awareness among providers who may not consider fungal infections in a differential diagnosis.
These endemic mycoses often also infect non-human animals, so the authors recommend increased surveillance and reporting of veterinary infections, arguing that this could help determine the current boundaries of endemicity maps. “The much higher number of animals and their higher environmental exposure put them at greater risk of encountering these infections,” Thompson explained.
Five suggestions to help improve diagnosis and reporting
The authors have five suggestions for improving the rates of diagnosis and notification of endemic mycoses:
1. National surveillance and notification of endemic mycoses in human and veterinary patients
2. Education for Providers and Patients
3. Inclusion of endemic mycoses in future CAP guidelines
4. Development of point-of-care diagnostics to reduce the time from patient presentation to diagnosis and receipt of effective treatment
5. Exploration of a pan-endemic fungal vaccine to prevent infection
Thompson recommends, “In areas where these fungal diseases flourish, physicians should consider diagnosis and screening for mycoses in all patients with suggestive disease.”
Ann Intern Med. Published online November 22, 2022. Summary. doi:10.7326/M22-2371.
This research received financial support from the National Institutes of Health (5U19AI166798-02) and the UC-Davis Burden Family Gift Fund for Research on Coccidioidomycosis. Thompson and Donovan report no relevant financial relationship.
Erin Archer, RN, BSN, CIC is a registered nurse, freelance writer, and infection preventionist in Tucson, Arizona.
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