What term is used for organisms that can cause diseases such as cholera and typhoid fever?

The term "pathogens" refers specifically to microorganisms, such as bacteria, viruses, fungi, and parasites, that can cause diseases in other organisms. In the context of diseases like cholera and typhoid fever, the causative agents are typically bacteria: Vibrio cholerae for cholera and Salmonella typhi for typhoid fever.

Pathogens are responsible for initiating infections and leading to disease symptoms in hosts, including humans. Understanding pathogens is critical in wastewater treatment as their presence can indicate potential health risks and necessitate specific treatment processes to ensure that water is safe for discharge or reuse. This characterization helps in developing effective treatment methods that can eliminate or reduce these harmful organisms in treated wastewater.

The other terms, while related to disease processes, do not specifically refer to the disease-causing organisms themselves. Toxins are poisonous substances produced by pathogens or other organisms; parasites are organisms that live on or in a host causing harm; and infections refer to the invasion of the body by pathogens, causing disease but not limited to one type of organism. Hence, "pathogens" is the most accurate term for organisms responsible for diseases like cholera and typhoid fever.