An Australian nutritionist began experiencing symptoms of fatigue and dementia after moving to a new house and was later diagnosed with a form of Alzheimer’s disease. Eventually, it was discovered that her symptoms were linked to severe mold growth caused by water leaks in the house. This case was reported by Australian media in 2022.

Household mold may act as a potential trigger for Alzheimer’s disease, though this claim remains a topic of debate among experts. Some microbiology researchers suggest that untreated mold infections in their early stages could impair brain function.

On the program “Health 1+1,” professor Shao-Hung Wang, chairman of the Department of Microbiology, Immunology, and Biopharmaceuticals at National Chiayi University in Taiwan, discussed the dangers of household mold, methods for checking indoor humidity and preventing mold, and important considerations when using disinfectants.

A Potential Trigger for Alzheimer’s Disease

Early-onset Alzheimer’s disease is marked by the accumulation of beta-amyloid plaques, while late-onset Alzheimer’s is characterized by neurofibrillary tangles and neuronal death, Wang said. Infections from viruses, bacteria, or fungi in the brain can trigger inflammation, leading to gradual brain atrophy and potentially resulting in Alzheimer’s disease.

One study identified several fungal species in the brains of Alzheimer’s patients. Researchers believe that inhalation through the olfactory system is the most likely route of exposure.

Mold is a general term for certain filamentous fungi. If mold exposure is not addressed promptly, molds can lead to significant brain damage and may even severely affect the cerebral cortex, Wang noted. The cerebral cortex is crucial for functions such as memory, cognition, thinking, and language.

A study found that inhalation of mold can disrupt cognitive processing in different ways, and exposure to both toxic and nontoxic mold in mice can lead to various cognitive and emotional issues.

Neurological Effects of Mold

Cryptococcus is a type of fungus that can infect the brain. Cryptococcus infections can manifest in two ways, according to Wang:

• Cryptococcal meningitis: Cryptococcus can infect the membranes surrounding the brain, potentially leading to permanent, irreversible damage to brain tissue. If detected early, partial brain function may be restored through medication or surgical removal of the affected areas.


• Asymptomatic infection: Some strains of Cryptococcus may not cause noticeable symptoms in the early stages. However, the infection can reactivate when the immune system is weakened, and chronic brain inflammation may develop, potentially leading to brain damage that is difficult to treat by the time it is detected.

Symptoms of Mold Exposure

Common molds do not have much of an effect on people with normal immune function, Wang noted. The most typical response to mold exposure is an allergic reaction, with symptoms such as sneezing, runny nose, and nasal congestion. However, in individuals with weakened immune systems, even spores from less toxic fungi can cause severe infections.

Mold infections can be classified into three types:

1. Superficial infections: These include skin conditions such as ringworm (tinea corporis) and athlete’s foot (tinea pedis). These infections can be treated with medication and typically do not pose serious problems.


2. Systemic infections: When the immune system is weakened or prolonged use of antibiotics has disrupted the balance of beneficial bacteria, fungi such as Candida, which are normally present on the skin or within the body, can proliferate and enter the bloodstream, leading to systemic infections.


3. Exogenous infections: Fungi from the environment, such as certain strains of Cryptococcus, can infect humans, often through contact with bird droppings. These infections are particularly harmful to individuals with weakened immune systems, newborns, or the elderly.

If you come into contact with bird droppings outdoors, it is important to handle them carefully, Wang advised. Use disinfecting wipes or ordinary paper towels soaked in alcohol or disinfectant to cover and remove the droppings.

Afterward, spray the area with alcohol for initial disinfection, soak any contaminated clothing in bleach, and then wash the clothing thoroughly in a washing machine. For those who keep birds at home, wearing goggles and a mask while cleaning the birdcage is recommended to protect yourself from potential exposure.

How can you identify a fungal infection that requires medical attention? Ringworm may cause itching and appear as a whitish, radiating rash centered around a spot, Wang said. In such cases, it is best to consult a dermatologist. If you do not have this rash but are experiencing persistent fever or cough, consider your travel and exposure history and consult a family medicine doctor.

Measuring Indoor Humidity

A warm and humid environment is ideal for mold growth. Wang suggests the following methods to assess whether the humidity in your surroundings is too high:

• Install a hygrometer in a well-ventilated area. A reading exceeding 80 percent indicates high humidity.


• Examine silicone sealants in damp, poorly ventilated areas. The presence of black spots likely signals excessive humidity.


• Check the surface of wooden or veneered furniture. Black spots or fungal growth on rough areas are signs of high humidity.


• Check textiles such as leather, cotton, and yarn. These are prone to fungal growth. A moldy odor when opening your closet is a clear sign of high humidity.

If you discover black, white, or other colored fungal growth beneath the carpet or on the underside of a mattress that has not been moved for years, it suggests that your home environment is too humid, Wang noted.

Mold Prevention Methods

Using an air conditioning does not always reduce humidity. For those living in humid subtropical areas, Wang advised using a dehumidifier at home. He also outlined three key methods for mold prevention:

• Place fans or air circulators in well-ventilated areas to keep the air flowing.


• Use a dehumidifier to keep indoor humidity between 40 percent and 60 percent, which helps prevent mold growth.


• Regularly open closet doors and use moisture absorbers, such as dehumidifying sheets or boxes, to reduce humidity.

A house that has been unoccupied for an extended period may develop a musty odor. Wang recommends ventilating the space by opening the windows and using an exhaust fan in the kitchen. He also suggests keeping the windows in both the kitchen and bathroom open, along with other doors and windows, to ensure proper air circulation and help expel moisture.

Tips When Using Disinfectants

If you find mold in your home, you can use disinfectants or diluted bleach to clean it, but complete removal can be challenging. While baking soda creates an alkaline environment that inhibits mold growth, it does not eliminate the mold entirely. The most important step is to keep the humidity below 60 percent, as this effectively prevents widespread mold growth, Wang said.

It is essential to exercise caution when using disinfectants, as they can pose adverse effects to the respiratory system. Wang provided two key tips to consider:

• Ensure disinfectant safety. Choose disinfectants carefully, ensuring they are approved by local agencies and come with product liability insurance.


• Use in a well-ventilated area. Open windows while using disinfectants and continue to ventilate the area afterward, as these chemicals can linger in the environment.