What term refers to organisms such as bacteria and viruses that can cause diseases in humans?

The term that specifically refers to organisms capable of causing diseases in humans is "pathogens." Pathogens include a wide variety of disease-causing agents such as bacteria, viruses, fungi, and parasites. These organisms are significant in the field of public health and wastewater treatment as they require specific management processes to prevent them from contaminating water sources and posing health risks to humans and the environment.

While the term "infectious agents" also applies to pathogens, it encompasses a broader range of entities that include not only biological organisms but also the infectious particles they produce, such as prions. "Toxins" specifically refer to poisonous substances that can be produced by living organisms, but they do not necessarily denote the organisms themselves. "Microorganisms" is a more general term that includes all types of tiny organisms, both harmful (like pathogens) and beneficial (like those used in wastewater treatment processes). Therefore, "pathogens" is the most precise term for what the question describes.