Some fungal infections prey on immunocompromised individuals

This patient sample, seen under the microscope, shows pulmonary aspergillosis, where the fungus infects the lung cells. — Wikimedia Commons

In your last column, we talked about simple and dangerous fungal infections. I have heard about Aspergillus somewhere before, but cannot remember what it causes.

Like many other fungi, Aspergillus rarely causes infections in people who have healthy immune systems.

In fact, Aspergillus is usually found outdoors, such as in dead leaves, soil and plants.

You can also sometimes find it indoors if the environment is too moist, such as in a bathroom that is always wet.

Oh? Is it called black mould then? I remember my contractor telling me that black mould is very dangerous.

Aspergillus isn’t black mould.

Black mould is the fungus Stachybotrys chartarum, which can be as problematic as Aspergillus.

Most of us can breathe in Aspergillus spores every day without getting infected.

But for some people with low immune systems, it can cause many types of diseases in a syndrome called aspergillosis.

What is aspergillosis?

Aspergillosis comes in several forms:

• The allergic form

  Allergic pulmonary (lung) aspergillosis is our body’s allergic reaction to the fungus.

  You would already have had some existing lung problem, such as asthma or cystic fibrosis.

• The ball form

  An aspergilloma is a fungus ball or growth that develops in an area of previous lung disease or a lung scar, such as old tuberculosis or an old lung abscess.

• The infective form

  Pulmonary aspergillosis is a serious type of pneumonia that can spread to other parts of the body, especially when the patients who usually get this type of pneumonia already have a weakened immune system from whatever cause, e.g. AIDS (Acquired Immunodeficiency Syndrome), chemotherapy or organ transplant drugs.

I read that global warming will cause fungi to multiply and become more dangerous. Is this true?

It is estimated that 1.5 million people die each year from a fungal infection.

Although that does not seem like much, it is probably underreported because many immunocompromised people are reported to die of other causes like AIDS or cancer, but the actual cause of death is the fungal infection.

It is indeed possible that more fungal strains, which did not usually cause disease in the past, are becoming known because they now cause disease.

This can be attributed to global warming, or even overuse of antifungal drugs, which can cause the fungi to develop resistance to them, like antibiotic resistance.

After all, there are not that many antifungal drugs in the world.

In 2009, a “new” fungus was found in the ear canal of an elderly Japanese woman in Tokyo, Japan.

It was named Candida auris.

It infects people with weakened immune systems and is so deadly that their chances of living is only 50%.

Within a few years, C. auris appeared in patients all around the world – in Africa, Asia and the Middle East.

C. auris is now on the World Health Organization’s (WHO’s) critical list of deadly fungi.

It seems to be resistant to many of the current antifungal drugs.

If any hospital detects C. auris in a patient, it has to close down the whole ward.

A class of peptides that have shown promising effects against the Botrytis cinerea fungus has been named after Reeves, seen here in a scene from John Wick: Chapter 4. — Lionsgate

That sounds scary. Are there other new fungi that have appeared?

Coccidiodes is becoming more common.

It is found in the United States, Mexico and South America.

If you breathe in its spores, it can cause an illness resembling the flu.

They call this “Valley Fever”.

One in 10 patients will have lung disease. If it spreads to your brain, it can kill you.

If you think you have never heard of this, well, it apparently infects 150,000 people in the US a year.

Valley fever has actually increased in the past couple of decades, with the reason being attributed to global warming.

Yet another fungal strain that emerged recently are the mucormycetes, which are a group of moulds that cause mucormycosis, or black fungus syndrome.

These cases increased as a result of people weakened by Covid-19.

The infection is rare, but very dangerous.

The moulds infect the body’s tissues and cause them to die and turn black.

They infect your sinuses first, then spread to your eyes and brain.

Your face can turn black, and you may have blurring of vision and altered consciousness.

Are scientists developing any new antifungal drugs?

There is a new antifungal drug that was recently approved called oteseonazole.

It is used for chronic vaginal yeast infection.

There are only three different classes of antifungal drugs in the world.

They are polyenes, azoles and echinocandins.

Polyenes are the oldest, and include the commonly-used amphotericin B.

But it has plenty of side effects that can be life-threatening.

Then came the azoles in the 1980s.

They are available in oral form, and include itraconazole and fluconazole.

One side effect, however, is liver toxicity.

Then came the echinocandins, which have to be administered once a day in a hour-long infusion.

The benefit is that they have very few side effects.

But it is inconvenient to go to hospital every day, especially since some fungal infections last for months.

New agents are being developed, especially against the fungi that affect our food crops.

One such very effective antifungal that has been developed is called keanumycin, named after the American actor Keanu Reeves.

It may potentially also be used in humans.

Dr YLM graduated as a medical doctor, and has been writing for many years on various subjects such as medicine, health, computers and entertainment. For further information, email [e-mail]. The information provided is for educational and communication purposes only, and it should not be construed as personal medical advice. Neither The Star nor the author gives any warranty on accuracy, completeness, functionality, usefulness or other assurances as to such information. The Star and the author disclaim all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.