What are the main types and species of mould?


Scientists agree that there are more than one and a half million species of moulds, of which about one hundred thousand have been precisely identified. Only an identification by laboratory analysis can determine exactly what type of mould you are dealing with.
Nevertheless, moulds can be grouped into three main categories: allergenic, pathogenic and toxic.

Allergenic moulds

For people who are prone to allergies or affected by asthma these moulds are at best irritating but they can also lead to complications that can be more serious.
Young children are the most sensitive to it.

Pathogenic moulds

These are moulds that can cause diseases and infections and are therefore particularly dangerous for people with weak immune systems.
It is this type of mould that triggers chronic inflammation of the respiratory system.

Toxic moulds

Toxic moulds are toxic moulds when mycotoxins are present on the surface of the mould spores.
Anyone can be potentially contaminated by this type of mould that enters the body through inhalation, ingestion, or simple skin contact.

Among indoor moulds, Cladosporium, Penicillium, Aspergillus and Alternaria are the most common.
The toxic Stachbotrys Chartarum are fortunately less common but not rare.

Main species of moulds identified

Among indoor moulds, Cladosporium, Penicillium, Aspergillus and Alternaria are the most common.
The toxic Stachbotrys Chartarum are fortunately less common but not rare.

  •     Alternaria

These moulds are often found in the pots of houseplants.
They cause respiratory allergic reactions due to their presence in the respiratory tract.
There is a vaccination against its effects.

There are currently about 300 species.

  •      Aspergillus

Very common, they are found all over the world, in dust, on the ground, in plants, fruits, air.
 It is estimated that each person swallows about 20 spores per day.

This type of mould is widely used by the food industry and the pharmaceutical industry, particularly for fermentation or for antimicrobials, but some species are pathogenic such as Aflatoxins.

Aflatoxins are found in hot and humid regions in Africa and Asia, on cereal (corn, rice) or oilseed (groundnut, sunflower) seeds, spices (chilli, curry, ginger), nuts (almonds, pistachios), figs, dates, cocoa, coffee or cassava but also in the milk of animals fed with contaminated grain.
Regular ingestion of aflatoxin-contaminated products will initially cause diarrhoea, vomiting and weight loss, but over time, if the diet remains the same, it can cause liver cancer.
There are four types of aflatoxins (B1, B2, G1, G2), B1 being the most common and most toxic with genotoxic and carcinogenic properties.

To date, there are about 200 species of aflatoxins.

  •     Cladosporium

They are mainly found outdoors, but sometimes in a favourable (humid) indoor environment they can grow on wood or textiles, for example.
Although they are the cause of many allergies, they are generally not pathogenic or toxic to humans.
They exhale malodorous volatile organic compounds and are often the cause of symptoms such as hay fever or asthma attacks.
If concentrations are too high, asthmatics and people with airways problems will suffer from their presence. Over time, prolonged exposure can weaken the immune system.

There are currently about 50 species of asthma.

  • Penicillium

This mould has a rather good reputation among the general public between penicillin and Roquefort cheese but the downside is that some species produce mycotoxins which can be fatal to humans.
They are found on the soil, in food, decomposing organic matter, compost, seeds, cereals.
In the home they are also found on wallpaper, carpets and in fibreglass pipes.

There are currently about 250 species.

  • Stachybotrys Chartarum

It is the famous "black moulds" that are among those we should fear the most.
They are common in dwellings and their spores, which are mycotoxins, can cause skin rashes, breathing difficulties and pulmonary complications by spreading through the air.

What is much less known is that these forms of mould are associated with behavioural disorders such as feeling listless, weepy, anxious, sleep disturbances, irritability, headaches...
And as a rule, these are not symptoms that can be linked to mould, which may mean that the cause of the problem will not be treated for a long time if it ever is.

Positive points they are usually visible, via a large black spot, and require a large amount of free water to grow. A support with a high cellulose content favours their development.

There are currently about a hundred species.

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