Mad Cow Disease....... New person here, can't see how to answer question, so will just edit: Listeria comes to mind as well.
There are several: BSE (Bovine Spongiform Encephalopathy), Brucellosis (Undulant Fever), Anthrax, Vesicular Stomatitis there are several others.
Ignorance
Ticks are often harmful to humans. For instance, the sheep tick could cause Lyme disease in humans.
Einsteinium is extremely radioactive and dangerous.
No, amoeba is not harmful to humans. The only amoeba that is harmful is Naegleria fowleri, however, it is extremely rare.
Yes, plankton is harmful to humans because they carry salmonella disease. Other than that, they are not harmless at all.
it is harmful because the Plasmodium is carrying a malaria disease then it can get to a mosquito to humanss
Yes, it is extremely toxic to both humans and animals.
It is unlikely, but in theory any animal might carry a disease that could be harmful to humans.
Bees don't carry any diseases that are harmful to humans but they can carry diseases that are harmful to other bees.
The Tasmanian Devil Facial Tumour Disease (DFTD) poses no risk at all to humans or animals of any other species.
The word pathogenic means disease causing. So they can be harmful...but some pathogenic bacteria only are harmful to plants or dogs or cats, etc.
Prion