Stachybotrys, aspergillis, and penicillium are three moulds that can grow on water damaged building materials, especially plaster board. They are found world wide.

Their spores can secrete neurotoxins, such as trichothecines, aflatoxins, and tremorgenic compounds that can be very harmful. One site that documents the effect these moulds have on our home and offices is run by the State of California

Even though these spores are everywhere, it is only in poorly ventilated or especially damp buildings that they can be found in concentrations high enough to be harmful to human health.

One population that is at especially high risk are infants. A group of Paediatricians at The Cleveland Clinic have posted a site that documents the harm that can be caused in these youngest patients.

Common complaints in older children and adults are coughing, headaches, feeling as though in a mental fog, bloody noses - especially soon after entering the contaminated space, numbness and tingling of extremities, and mood and personality changes.

There are some physicians who feel that this is a serious problem, and others who feel otherwise.

The only thing to do if you have had water leaks from any source that have kept an area wet enough to get really mouldy is to leave. Remember - if you can see mould on your side of the wall - imagine what it may look like between the walls - and this air circulates to some degree. The damage can be cleaned - but in severe cases this has meant removing whole walls and washing down large areas with bleach - the only thing that does a good job of killing it.

Unfortunately this is not really a DIY project, but for further information there's a site called Indoor Air that addresses this issue.

The latest research seems to show that antioxident supplements such as vitamins A,C, and E are very helpful in reversing some of the damage caused by these toxins.