Conway McLean, DPM

Viral infections are big news, with the COVID-19 virus being a current topic of discussion. The latest iteration of a corona virus infestation has gone beyond epidemic proportions, resulting in our current global pandemic. Concerns about bacterial organisms and all the myriad problems they can produce have never left the news, with new, more resistant strains discovered almost daily.

Unmentioned in the headlines is another potentially deadly microbe, although this one serves many critical functions and, in fact, is essential to the cycle of life, death and renewal. Without the presence of this group of organisms in our world, life would grind slowly to a halt. Yet many members of this class cause chronic, debilitating, even deadly disease world-wide. What could be so important to the biology of our world but also creating significant morbidity (sickness)?

There is a fungus among us! Fungal organisms are plentiful, as pervasive as bacteria, and can be found throughout our world. For many years, scientists considered them plants, although we know now this is not the case. Fungi show a closer relationship to animals, yet are a unique, distinct life form, different from bacteria, separate from plants, and obviously not animals. The kingdom of fungi are multicellular organisms that cannot make their own food, like humans. But the similarities don’t stop there. Like mammals, they are eukaryotes, meaning we both have a true cell nucleus (what might be considered the headquarters of a cell). Fungi have critically important roles in the recycling of nutrients in our environment. 

Humans have used yeasts and mushrooms since prehistoric times, but we understood little about their biology. That is, until the mid-20th century, when scientist’s investigations revealed some of the important differences between fungi and plants, and some similarities. Like plants, fungi are mostly stationary, seemingly rooted in place. Again, like plants, they possess a stem-like structure, as well as having a root system.

Fungal organisms act as the decomposers in most ecosystems, feeding on dead organic matter such as leaf litter, dung, wood and dead animals. They recycle 85 percent of the carbon from dead organic matter and release the locked-up nutrients so they can be used by other organisms. One class of fungus is essential for the growth of many plants. As a food source, mushrooms play a vital role in human nutrition. Other types are necessary for fermentation, used in the production of bread, cheeses, alcoholic beverages, and more.

When the word fungi is mentioned, certain things typically come to mind, such as mushrooms, athlete’s feet, even mold. These are innocuous things, mild, unpleasant at worst. But these microscopic organisms can be fatal, leading to an estimated 1.5 million deaths annually around the world. This is more than the number of people who die from malaria. Unbelievably, there are over 1 and a half million different species of fungi. And we interact with them every day. Three hundred are known to make people sick, and again, some of these can be fatal.

Superficial fungal infections, things like athlete’s foot, fungal nail infections, aren’t killing anyone, but they afflict billions. Nail fungus is classified as epidemic by the CDC. Like many fungal problems, these infections are generally chronic, enduring, often lasting for years. Certainly onychomycosis, the ubiquitous nail fungus infection, is often with someone for life, at least without appropriate, continued treatment.

Many people attempt some type of therapy, most of these efforts wholly ineffective. Hearsay and internet postings are hardly the stuff of science and medicine. This is a complex situation and it’s a challenging condition, resistant to many agents and therapies. The success is also dependent on the ancillary techniques, like treating your shoes, continuing medication for sufficient duration, and many other facets of treatment. Because the nail plate provides such an excellent barrier to medications, reducing the thickness of that barrier is also beneficial.

Fungal infections of the skin are a less resistant problem, partially because of the absence of any real barrier to a topical medicine. Some formulations penetrate the outer layers of the skin better than others but there are multiple factors to consider when creating an effective treatment plan. Still, cutaneous fungal infections are significantly easier to cure. Athlete’s foot is a typical example of this general class of infection, which is termed tinea.

The real problem is recurrence. Tinea infections are infamous for redeveloping, time and again. This is often not a new infection, but simply the previous one which never actually resolved. Most people stop use of the antifungal cream when it looks all better. Unfortunately, many fungal organisms form spores, which is sort of a state of hibernation. These spores can endure harsh conditions or deprivation but still result in a full blown infection.

These are opportunistic infections, meaning they will occur anywhere they get the right opportunity, as in a moist environment that receives minimal air and light exposure. Some areas of the human body are especially prone to recurrent fungal infections because of the setting: dark and moist, like the foot inside a shoe. A part of this topic is the effectiveness of one’s immune system, but also important is your level of hygiene.

Although not often recognized as being a deadly menace, certain kinds of fungal infections invade our blood, lungs and other organs. Sometimes these are infections that can never be cured. Others resolve on their own. There has been a steady increase in the frequency of invasive fungal infections over the last two decades, largely because of the increasing number of immunosuppressed patients and those with bone marrow transplants.

Although serious consequences of fungal infections are not common, many suffer from chronic fungal skin contagions. These can have serious ramifications, but typically this occurs in those with an impaired immune system (like diabetics, or seniors!). The blisters which form may allow bacterial invasion so it is a problem worth treating, even for the average citizen. On the other hand, Hollywood will continue to find abundant low brow humor on the topic. Fungal organisms are a critical part of the ecosystem, and as such, are necessary for life. Thus fungi should be considered, like so many things these days, both dangerous and extremely important.

Editor’s note: Dr. Conway McLean is a physician practicing foot and ankle medicine in the Upper Peninsula, with a move of his Marquette office to the downtown area. McLean has lectured internationally on wound care and surgery, being double board certified in surgery, and also in wound care. He has a sub-specialty in foot-ankle orthotics. Dr. McLean welcomes questions or comments atdrcmclean@outlook.com.