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Cladosporium: A Common Allergenic Indoor Mould

Cladosporium is a leaf mould and one of the most common in outdoor and indoor air worldwide. It is a very common household mould in bathrooms, around tubs, shower stalls, or window frames and even bathroom walls and ceilings.  Like every other mould, it requires free water for growth.  Around the edge of the tub there is water from splashing or water running down the wall from the shower.  The water just sits around the edge of the tub and may evaporate very slowly.  On walls and ceilings  the steamy air results in condensate, especially on colder, outer walls.  The spores are ubiquitous and will germinate in this available water and  very quickly little dark brown colonies start to grow.  Eventually there will be an olive-brown to blackish brown growth of Cladosporium around the tub.

Some species of Cladosporium cause serious diseases to plants. The mold is commonly isolated from air, soil, foodstuffs, stored fruits, cereal grains, groundnuts, paint, and textiles. Cladosporium is a well known allergenic mould. The most common Cladosporium species in outdoor air are Cladosporium cladosporioides and Cladosporium herbarum. During summer there can be very high concentrations of airborne spores of Cladosporium cladosporioides and Cladosporium herbarum, and both contain allergenic proteins in their spores. Cladosporium cladosporioides and Cladosporium hebarum may be found colonizing painted metal surfaces of covering panels and vents of heating, air conditioning and ventilation systems.Cladosporium sp.

Cladosporium sphaerospermum is the most predominant species growing in buildings. Studies have shown it can outgrow Penicillium chrysogenum because of its ability to re-initiate growth from the hyphal tips much faster than Penicillium species. Cladosporium sphaerospermum and occasionally Cladosporium herbarum is frequently isolated from indoor surfaces such as in bathrooms, windowsills and damp painted surfaces. It is also commonly found colonizing wood.

Species of Cladosporium are not known to produce any serious mycotoxins.

Do you have a mould question? Send it to My Question.

Mould in Your Home Or Office: What You Should Know

As you read this article there could be some mould growing silently somewhere in your house or in the office where you work. This thought may not have bothered you if you had not heard in the media phrases like “toxic mould” or “black mould”! These phrases create fear, panic and confusion. The objective of this article is to provide the reader with some basic facts about mould and the associated health effects.

Should One Be Concerned About Indoor Mould Growth?

Yes. Apart from mould being unsightly in a building there are 3 good reasons why people should be concerned about mould growth.

Health Risk

As mould grows indoors, it produces spores and/or chemical compounds that easily become airborne. The health effects associated with inhaling or getting into contact with these spores and chemicals may include runny nose, eye irritation, cough, congestion, aggravation of asthma and respiratory problems, headache, flu-like symptoms, fatigue, skin rash and other allergic reactions. Individuals with weak immune systems may also get infected by certain moulds as a result of exposure.

Legal Issues

Those responsible for building maintenance or health and safety of building occupants, contractors and other professionals involved in the building operations are at risk of being sued if occupants get sick from mould growth.

Material Damage and Impairment of Processes

Mould if allowed to grow, can impair the functioning of many processes from air conditioning units to electrical circuits. Surfaces of materials on which mould is growing get stained or discoloured and may disintegrate over time. Wood-rotting moulds are capable of weakening wooden structures.

Three Things You Should Know About Mould

  • Mould growth is a fact of life for almost all industrial and indoor environments. However, mould growth can be controlled by providing adequate ventilation and maintaining indoor humidity at levels below 65%. When excessive moisture or water accumulates indoors, mould growth will often occur, particularly if the moisture problem remains unnoticed or unaddressed for more than 48 hours. The key to mould control is keeping the building dry and clean, timely maintenance and prompt repairs.
  • Not all moulds are harmful but to be safe it is better to treat all moulds as potentially harmful. The colour of the mould does not determine whether it is harmful or not. Therefore, black mould is not necessarily bad mould. Mould related health effects depend on:
    • types of mould present,
    • amount of mould one is exposed to and for how long,
    • individual health status or sensitivity. Children, elderly and sick people are more vulnerable to mould.
  • It is difficult to eliminate all mould spores in the indoor environment. However, the levels can be minimised by controlling growth. Monitor mould growth by looking for water stains or discoloration on the ceiling, walls, baseboards, floors, and window sills. Pay particular attention to the basement and the attic.

What Should You Do When You Find Mould?

If you are an indoor mould consultant

  • Assess the extent of the mould problem.
  • Discuss the problem with your client and reassure them.
  • Have the dominant moulds identified preferably to species level. However, before sampling, prepare a sampling plan that details how and when samples
    would be collected, the type of samples to collect, collection requirements for each type of samples, the criteria to use to interpret results, and the benefits expected from sampling, i.e., what question(s) would be answered by the laboratory results and what actions would be taken. Share the sampling plan with the client.
  • Discuss the lab results with the client. If the client is concerned about their health, advise them to seek medical opinion from their family doctors.
  • Discuss the remediation plan (or options if any), the remediation costs and the expected results with your client.

If you Are a Property Manager or Homeowner

  • Do not panic! The presence of mould does not necessarily mean that you or the building occupants could have adverse health effects or that they have even been exposed.
  • Do not disturb the mould since this could help the mould in shedding more spores into the air.
  • If what you suspect to be mould covers more than 10 square feet, seek the advice of a qualified consultant immediately. If unsure of how to handle mould covering less than 10 square feet, seek professional advice. Avoid exposing yourself or others to mould.
  • Ask for the mould to be identified to reassure yourself or the building occupants that it is not among those that cause serious health effects.
  • Discuss the problem with your family doctor or if you are the property manager reassure the occupants and let them know the actions you are taking.
  • If you find a professional who seem to concentrate more on how the mould could or have affected you or the building occupants, seek a second opinion. A good professional should provide facts and avoid causing fear.

 

Should you have a question concerning indoor moulds, please send your question to My Question.

Airborne Mould Spores: Could They Be Dangerous To Health?

Mould spores are tiny structures produced by moulds for reproduction purposes. They are so small that we can hardly see some of them even when magnified 400 times. One cubic meter of outdoor air may contain as many as 1,000,000 spores. The volume of air we inhale at rest is estimated at 10 litres per minute. Therefore, in an hour we inhale close to 600,000 spores. The air in some working environments including mouldy buildings may contain up to 1,000,000,000 spores per cubic meter of air.

In indoor environments moulds grow on moist surfaces such as the drywall, wallpaper, carpet, baseboards, and heating, ventilation and air-conditioning systems (HVACs). As these moulds grow, a stage is reached when they produce spores. The spores become airborne after drying out or if disturbed.

Could airborne spores be dangerous to our health?
About 20% of the population is allergic to mould spores. Apart from being allergenic, spores of some mould species such as Stachybotrys contain toxic compounds called mycotoxins. Symptoms associated with mould spores may include allergy, headache and fatigue, running nose, sneezing, coughing, pneumonia and Asthma among other non-specific symptoms. Young children, the elderly and people undergoing medical treatment are particularly susceptible to mould spores.

How can we control indoor mould spores?
It is extremely difficult to get rid of spores completely. We can, however, reduce their numbers by controlling mould growth in our houses or offices. Mould growth is associated with moisture problem as a result of flooding, leaks in roofs or plumbing and condensation in case of poor ventilation or inadequate insulation. The key to controlling mould growth is keeping our houses or offices dry by maintaining low relative humidity (below 70%) thus eliminating or slowing the growth of most mould species. Any water leakage should be repaired immediately and the water dried out within 48 hours. Constant monitoring for mould growth in the kitchen, bathrooms, window frames, carpets and baseboards is recommended. The earlier the mould is discovered the cheaper and easier it is to get rid of the problem.

What should you do if you notice mould growing in your house or office?
Do not panic! Seek professional advice. Not all moulds are dangerous to health, but no mould should be allowed to grow in our dwellings. Also the health effects of indoor moulds depend on the amount of mould one has been exposed to, length of time of exposure, the types of moulds present and individual’s resistance. Therefore, presence of mould does not necessarily mean the occupants have been affected.

Which are the most dangerous moulds?
People have come to believe that black moulds are the most dangerous.
The truth is, colour does not determine whether a mould is of health concern or not. To know whether a mould is dangerous or not requires the mould to be identified by a qualified mycologist.

Should you have a question concerning moulds, please send your question to us at My Question.

Salmonella food poisoning and symptoms

Salmonella food poisoning has been a growing concern in recent news. It has frequently lead to recalls of beef, salads and organic products and, even peanut butter products. Salmonella food poisoning occurs when one eats raw or undercooked foods such meat, poultry, eggs or egg products. Properly cooked food can get contaminated with Salmonella if […]

Legionella pneumophila – Guidelines for Laboratory Interpretation

Legionella pneumophila is a Gram negative, aerobic bacteria that is characterized as an opportunistic pathogen. It is the cause of Legionnaires’ Disease, a severe form of pneumonia and, it is the cause of Pontiac fever, a non-pneumonic form of L. pneumophila infection. Legionella spp.’s mode of transmission is through aerosols or aspiration of contaminated water. The Public Health […]

The Indoor Mold Is An Early Warning Device

The mold (or mould, in the Queen’s English) has been the victim of a bad press. Mention the word and it conjures up an image of something rotting or in the process of decomposition. And yet, were it not for the mold that inspired the discovery of penicillin millions of lives would have been lost. […]