Following cool weather in May, Japan is now approaching its annual rainy season.
This means humidity will rise and mold will begin appearing in bathrooms and kitchens. We must, of course, be careful about mold growing on food, but it is also important to know that mold can enter our bodies without our being aware of it, potentially causing diseases.
Invisible to the eye, mold floats around in the air in quantities as high as around 1,000 spores per cubic meter. It is said that people inhale more than 10,000 mold spores every day.
Prof. Katsuhiko Kamei at Chiba University Medical Mycology Research Center said: “Normally people are protected by their immune system. But once they are infected by mold, it is very difficult to treat, and may even be fatal.”
Although we only refer to it with a single word — mold — there are over 300,000 varieties of mold in the world. Around 100 of them can infect people.
Kamei said by analyzing data accumulated by the Japanese Society of Pathology he found that one in 20 patients who died at hospitals in Japan had developed infectious diseases from mold. Molds that enter the lungs and cause diseases can be particularly difficult to treat.
Even healthy people can develop diseases from inhaling mold, which can cause an infection or trigger an allergy. Among them, aspergillosis and summer-type hypersensitivity pneumonitis require special caution. These can destroy cells in the lungs and make it hard to breathe. Once the disease is relatively advanced, it can be difficult to treat with medicine. The best prevention measure is to avoid creating an environment where mold can grow easily, such as by increasing ventilation in a room.
Kamei calls for caution: “Mold exists everywhere, so anybody can become ill at any time. Although the symptoms are hard to distinguish from the common cold, when you suffer from a persistent cough, phlegm or fever, it is better to consider the possibility of an infectious disease caused by mold.”
But only some molds have pathogenicity and infect humans. One that might immediately come to mind is a condition commonly referred to as athlete’s foot, which is a type of fungus known as trichophyton that attaches itself to the skin and infects the area between the toes and other parts of the feet. The fungi also infects other parts of the body, such as the crotch, and cause itchiness and pain.
Severe lung diseases
A type of fungus that exists in the air but can potentially infect the lungs when it is inhaled is aspergillus. Experts say there are over 300 different varieties of aspergillus, which originally live in soil. Koji mold, which is used for making miso, soy sauce and Japanese sake, belongs to the genus aspergillus. A small number of them are highly infectious and likely to cause diseases in the human body.
When infected with aspergillus, patients suffer from symptoms such as coughing, phlegm, continuous low fever and increased difficulty in breathing. Often blood can be seen in the phlegm. Although it is easily mistaken for pneumonia, if antibiotics do not improve the symptoms, then aspergillosis should be considered as a likely cause.
When the infection is detected at an early stage, people can expect to make a full recovery after surgical removal of the infected section of the lungs. However, eliminating the mold only with medicine is difficult.
Those with weakened immune systems due to lifestyle-related disease or old age have a higher risk of becoming infected with aspergillus, but even healthy people can become infected.
“The mold proliferates in cavities created in the lungs by diseases such as tuberculosis. The mold firmly attaches itself to the lungs and starts to multiply by destroying the lung cells,” Kamei said.
Aspergillus prefers to inhabit places with moderate humidity, such as the back of closets and drawers. Air conditioners can also be the perfect place for aspergillus to grow, as condensation forms inside them and dust tends to accumulate. In hospitals, mold is sometimes found in potted or decorative plants.
Therefore, it is important to take great caution when dealing with mold.
Carefully disinfect moldy areas
What should be done if mold appears inside the home, such as inside closets or drawers?
Tomoko Satodate, a consultant for a housing organization in Fukuoka city, advises: “Mold is lighter than air and easily floats around the room. It can cause allergies and other problems, so it is important to remove it as quickly as possible.”
Satodate says you should soak a cloth in chlorine bleach diluted with water, wring it out firmly, and gently wipe the surface of the moldy area, taking special care not to let spores scatter into the air. Wipe the surface again with a damp cloth, then with a dry cloth to let it dry properly. Finally, disinfect the surfaces using a damp cloth soaked with ethanol.
Mold can easily grow inside houses with little ventilation, particularly on vinyl wallpaper on walls and ceilings. Though mold is generally associated with the rainy season, it can often grow in the winter due to condensation.
According to Satodate, there are three important points to remember to prevent mold: humidity management, ventilation and proper storage. In particular, walk-in closets tend to be damp and stuffy, so it is recommended that you use a hygrometer to measure the level of humidity, and when the figure goes beyond 70 percent, to use a dehumidifier.
Another preventive measure is to lay or set pallets on the floor and walls in a closet so that items do not directly touch the floor or walls.
“Please dispose of items that you don’t need, and make sure that a closet is not filled up with too many items,” Satodate added.