Which type of disease can be caused by a pathogen?

Infectious diseases are specifically caused by pathogens such as bacteria, viruses, fungi, and parasites. These pathogens invade the body, multiply, and can disrupt normal bodily functions, leading to illness. The defining characteristic of infectious diseases is this direct relationship with pathogens that can be transmitted from one individual to another, or through surfaces, vectors, or other means.

While options like systematic diseases and chronic diseases can refer to broader categories of health issues and may involve pathogens, they do not specifically define diseases caused by them. Systematic disease can refer to conditions affecting multiple systems in the body without the necessity of a pathogen, and chronic diseases often develop over time due to a combination of genetic and environmental factors rather than being directly triggered by pathogens. Bloodborne diseases, though related to infections transmitted through blood, represent a subset of infectious diseases but do not encompass all infections caused by pathogens. Therefore, infectious disease is the most accurate and comprehensive term to describe illnesses originating from pathogens.