If you mean an infectious disease, like those due to bacteria, viruses and fungi, then no. However, many plants can cause allergies, or contain poisonous or irritating chemicals.

A follow up to my original reply. The genus Prototheca has been found in a few cases of mastitis and ulcerative infections. Since this is a non-photosynthesizing alga it is a 'plant' infection only in the very broadest sense of the phrase.

Interesting question. Although it is not very specific as you must define disease.

I am unaware of any direct diseases caused by limited exposure to plants. Illnesses and negative reactions certainly do occur. the book Into the Wild comes to mind where Chris McCandells dies from possibly eating a plant which looks very similar to wild peas (or potatoes).

You can also argue that prolonged exposure to certain plants (outside of their natural state) would cause disease, albeit chronic diseases. I.e. tobacco.

An example of extreme reaction to plant matter would be someone who is highly allergic to a plant such as poison ivy.

Honestly I dont think there are any actual diseases that developed with plants that were directly transferrable to people or animals. The biological structure is just so dissimilar between the organisms that the disease would never be able to mutate fast enough to survive our effecient immune systems and live within our bodies.

Fish in aquariums can get algae on their skin as a disease.

Sorry I doubled the answer. Can I delete the second one? If so, how?

Several types of alga are on record as causing human infection. Both superficial and more deep seated infections are known, and are documented in reputable journals. A search on Google will reveal them.

David Meadows.

Yeovil.

Somerset.