Answer:
Pathogen
Step-by-step explanation:
We call pathogens, organisms that are capable of causing disease in a host. Some bacteria, for example, can cause disease in humans, which is therefore a pathogen. Besides bacteria, we can mention as pathogens: fungi, protozoa and viruses. In addition to causing disease, pathogens are difficult to detect because they are undetectable by sight, smell or taste.
The ability of a pathogen to cause changes in infected host organisms is called pathogenicity. There are organisms with great pathogenicity, that is, that produce symptoms in practically all infected. However, there are organisms with low pathogenicity, that is, that cause severe symptoms in a few infected.