The most searched topic! Cleaning a moldy wardrobe can cause mold to grow in your lungs! Can you still touch moldy things?

Recently, an unexpected piece of news topped the hot search list: a Hangzhou girl unfortunately contracted fungal infection and developed pneumonia while cleaning her moldy closet.

Image source: Screenshot from Sina Weibo

Coincidentally, there was also news in 2021 that a woman went to her hometown to help harvest corn, and later went to the doctor for continuous coughing. After examination, it was found that her lungs were infected with Aspergillus flavus. What is going on? Is it so easy to be infected with Aspergillus flavus?

Let me first state the conclusion:

There are indeed many species of Aspergillus in nature that can infect human lungs, but this is often seen in occupational groups that are frequently exposed to Aspergillus, such as brewery workers, gardeners, farmers, etc. In addition, the risk of Aspergillus infection in healthy people is not high, and it is usually people with low immune function who are at risk of Aspergillus infection.

The cases of Aspergillus infection in the lungs reported so far are all sporadic cases, which means that there is no close connection between the patients in time or space, and no cases of transmission or even epidemic due to contact with patients have been found so far. Therefore, we don’t need to feel anxious or even panic about this.

So, under what circumstances can people be infected with Aspergillus in the lungs, and how can we protect ourselves? Let’s start with the culprit this time, Aspergillus flavus.

What is Aspergillus?

Aspergillus flavus is a fungus and a member of the Aspergillus family. The name of Aspergillus in Chinese is very down-to-earth, which may come from its use - it is often used as "qu" for fermentation, such as "jiu qu". In fact, in addition to wine, Aspergillus fuciformis is also used in the fermentation process of bean paste and soy sauce.

The origin of the scientific name of Aspergillus is very interesting, because the first person to discuss and name Aspergillus was the Italian botanist and clergyman Micheli. He found that Aspergillus looked a bit like a sprinkler used for sprinkling holy water (aspergillum), so the scientific name of Aspergillus became Aspergillus.

Aspergillus looks like a sprinkler under a microscope. | Image from Wikipedia

Aspergillus is saprophytic and can grow in dead plants, animal carcasses and excrement. For example, there are often a large number of Aspergillus in rotten and moldy grains. Aspergillus is widely distributed in nature, from the Antarctic to the Arctic, and can be isolated from air, grain, hay, soil, clothing, furniture and other places. Aspergillus is so widely distributed that its spores are everywhere - in fact, we may inhale Aspergillus spores every day.

Some people may be anxious after reading this. What happened to the promise that we don’t have to worry about Aspergillus? We can inhale it every day and we don’t have to worry?

It's not that easy to get infected with Aspergillus

Only when there are enough living pathogens to infect people can people get sick, and the same is true for Aspergillus. Our immune system is by no means a decoration. Even if a small number of Aspergillus spores can enter our respiratory tract, they will be stuck to the cilia and trapped in the mucus, and finally be expelled from the body through sneezes, coughs, sputum, and nasal discharge. Our immune cells can also recognize the invading spores and engulf and eliminate them. In this way, we will not be infected.

However, if we inhale too many spores and cannot handle them, they may actually enter our lungs and make their home, and we will get sick. Like the two unfortunate women mentioned at the beginning of this article, they inhaled too many spores in a short period of time because they handled moldy wardrobes and moldy corn without proper protection, and unfortunately became ill.

In addition, when a person's immune system is weakened, they are more susceptible to infection. For example, if they suffer from other diseases such as tuberculosis, AIDS, or have undergone an organ transplant and are using immunosuppressants, they may still be infected even if they inhale a small number of Aspergillus spores because their immune system cannot function properly.

If the lungs are infected with Aspergillus, symptoms such as cough, low fever, and sputum often appear. Severe cases may even lead to hemoptysis or even death. Antifungal antibiotics can be taken for treatment, and surgery may be required if necessary.

Preventing Aspergillus infection is actually very simple. For healthy people, it is no problem to avoid inhaling large amounts of Aspergillus spores. It is very simple to do this in daily life - just wear a mask in advance when we may encounter a large number of Aspergillus spores, such as cleaning up old houses covered with dust, cleaning moldy items, etc.

Planning and production

Author: Dingzhong Popular Science Creator

Reviewer: Zhang Wenjuan, deputy chief physician of the Department of Respiratory Medicine, the Fourth People's Hospital of Chenzhou City, Hunan Province

Editor: He Tong

Proofread by Xu Lai and Lin Lin