Why does the CDC want us to think about mushrooms?

When people think of infectious microbes, they usually think of bacteria and viruses. There is, however, another huge group of organisms that can affect our health: fungi.

It is estimated that there are 5.1 million species of fungi on the Earth, fungi that we eat at the microscopic fungi that can infect us. Most fungi are present in the environment – soil, trees, air and water – and they surround us all. Only a small subset of 5.1 million, or about 300 species, poses a health threat and is capable of causing serious life-threatening infections. What makes these pathogenic species so special? How do these fungi affect our health?

The Centers for Disease Control and Prevention have designated the week of September 23-27 as "Fungal Disease Awareness Week" to help the public better understand how this microscopic organism can make humans sick. CDCs treat between three and five outbreaks of fungi per year. This number was between one and two in the 1990s. This increase in the total number of outbreaks is alarming.

How do fungi infect us?

Mushrooms are all around us and people are infected when they inhale microscopic fungi, fungal spores or direct contact.

Sometimes exposure to mushrooms is done through contaminated products. This occurred during the 2012 outbreak, when more than 13,534 people were exposed to methylprednisolone (an anti-inflammatory drug), which was contaminated by a fungus called Exserohilum rostratum which usually infects plants but not humans. In this outbreak, 753 cases of fungal infections related to contaminated products were reported and 61 people died.

Fungal outbreaks caused by poorly studied species are particularly difficult because diagnostic tools and treatment options are insufficient.

The mushrooms are neglected

I am a microbiologist and I am interested in mushrooms because fungal infections are becoming more common and are neglected in the past.

I'm studying a species of mushroom called Cryptococcus neoformans, and aim to unveil its molecular and cellular biology to better understand how it causes infections. It is one of the most devastating fungi of HIV / AIDS, especially at the time of the AIDS epidemic in the 1980s and 1990s in the United States.

People whose immune systems are weakened or affected by diseases such as cancer, HIV / AIDS and organ transplants are the most vulnerable populations to fungal infections in general.

the cryptococcal Infection occurs as a lung disease with non-specific flu-like symptoms such as fever, cough, and chest pain. cryptococcal can travel from the lungs to the brain and can cause Cryptococcal meningitis, and can be fatal if it is not treated. cryptococcal is in the environment and people are often infected by inhalation of fungi and fungal spores. In fact, the majority of the urban population is already infected with the virus. cryptococcal.

With the development of therapies to combat HIV, the number of fungal infections related to AIDS has decreased. But cryptococcal is still a threat to organ transplant recipients and other vulnerable groups, and early diagnosis saves lives. Not to mention that there are 36.9 million people living with HIV in the world and that cryptococcal meningitis is still one of the leading causes of death among HIV / AIDS patients in sub-Saharan Africa .

The number of outbreaks of mushrooms is increasing

In 2017, there was an unexpected outbreak of blastomycosis in the metropolitan area surrounding Albany, in the state of New York, caused by the fungus. Blastomyces. While the infection rate was 0.2 per 100,000 in 2016, the infection rate rose to 2.2 per 100,000 in 2017. Blastomyces are present in the environment and thrive in moist soils and decomposing organic matter. Although blastomycosis often manifests as pneumonia, pneumonia is often asymptomatic. Between 1990 and 2010, in the United States alone, 1216 people died of blastomycosis.

Far away in another part of the country, in the southwestern United States, another fungal infection, coccidioidomycosis, also called valley fever and caused by the fungus Coccidioides, was threatening people and has now spread to Washington state. People can get fever from the valley when spores are inhaled or exposed to contaminated soil.

Blastomycosis and coccidioidomycosis are both difficult to diagnose, as they manifest as flu-like symptoms that are not specific enough, making it difficult to identify the cause and provide effective treatment in time. timely. If left untreated, fungal infections that manifest as a lung infection can spread to other organs and even to the brain, resulting in lethal scenarios.

Sudden onset of patients infected with multiple drugs Candida auris in American hospitals. In this case, the symptoms of fungal infection may be less noticeable because the infection occurs mainly in already hospitalized patients with already existing symptoms. Patients often have fever and chills during Candida auris blood infection. This mushroom was first isolated in Japan and then spread to four other continents. There is strong evidence that global warming plays a role in the sudden emergence of Candida auris as a threat.

Global warming causes fungal infections

Most fungi often grow between 12 and 30 degrees Celsius (53.6 and 86 degrees Fahrenheit). During infection, fungi experience a sudden increase in temperature – about 37 ° C (about 98.6 ° F) – as fungi enter the human body; therefore, only fungi that can survive body temperature and bypass the immune system can cause an infection.

It is crucial to understand how fungi need to change to survive at high temperatures. This is because only species capable of surviving 37 degrees Celsius or more can infect humans.

It is expected that more fungal species will adapt to survive high temperatures due to global warming. The impact of this adaptation on human health is largely uncertain, but the hypothesis is that the geographical distribution of infectious fungi could expand and that more fungal species could potentially become infectious.

Strong and clear: 'Think Fungus'

Fungal infections can be devastating and continue to appear faster than ever before. This is partly due to the growing number of people with weakened immune systems, environmental changes and drug resistance issues. Fungal infections are difficult to diagnose, making them difficult to treat.

It is important that we all "think of mushrooms", especially in case of unresolved antibiotic infections. More people should know that fungi are a common – and growing – source of infection.

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