Is Aspergillus clavatus an unicellular organism? I could not find the piece of information form Burton Human Parasitology -book and not by Google. Yeast is divided to two phylums: one of them is Ascomycota. Aspergillus clavatus belong to the given phylum. Yeast is unicellular. So it is possible that Aspergillus clavatus is unicellular. **Can you tell whether the Aspergillus clavatus is an unicellular orgarism or not from the following picture?** !enter image description here I need to find unicellular parasites that cause damage of brain. The fungus causes patulin so hemorrhaging of brain, but should still be unicellular to meet the criteria.

You're right in saying that yeast is single celled.

However, moulds are described to be filamentous fungi that are multicellular. The filaments of the mould give colonies _"a woolly, fluffy, or velvety appearance, sometimes punctuated with a granular or powdery aspect that is produced by the formation of asexual reproductive structures"_ (1).

Aspergillus is such a species. The filaments are called _hyphae_. In Aspergillus, hyphae have divisions or walls which separate it into multiple cells. This is called septate hyphae.

1. McPherson, et al. _Henry's Clinical Diagnosis and Management by Laboratory Methods._ 22nd ed. 2011. Saunders.