What term describes a microorganism that causes disease?

The term that describes a microorganism responsible for causing disease is "pathogen." Pathogens are biological agents, including bacteria, viruses, fungi, and parasites, that can lead to infections and illnesses in hosts. They have the ability to disrupt normal physiological functions and trigger immune responses, thereby causing disease.

Understanding pathogens is crucial in the context of wastewater management and on-site sewage facilities, as proper treatment and disposal of sewage can prevent the spread of these harmful microorganisms into the environment. By effectively managing pathogens in sewage, the risk of waterborne diseases can be significantly reduced, protecting community health.

Antigens are substances that trigger an immune response, but they are not synonymous with microorganisms. A vector refers to an organism that transmits pathogens to other hosts, such as mosquitoes in the case of malaria. Lastly, while a bacterium is a type of microorganism, not all bacteria are harmful; many are beneficial and play essential roles in various ecosystems. Therefore, the characterization of a pathogen is more encompassing and accurately reflects those microorganisms that cause disease.