Final answer:
Pathogens are specifically disease-causing bacteria that can impose a considerable disease burden on populations, including serious illnesses such as tuberculosis and pneumonia.
Step-by-step explanation:
Pathogens are most specifically disease-causing bacteria. These organisms can have a harmful effect on their human hosts by causing diseases. While many bacteria are harmless or even beneficial, pathogenic bacteria can cause a significant disease burden on human populations. This burden includes the impact of a disease represented by financial cost, mortality, morbidity, and other indicators. Examples of diseases caused by pathogenic bacteria are tuberculosis, pneumonia, and cholera, among others.
It's important to note that pathogenic bacteria can also contribute to the spread of antibiotic resistance, resulting in the development of "superbugs" that are resistant to standard treatments. The relationship between humans and many pathogenic prokaryotes is often parasitic, as these bacteria invade the body and can produce toxic substances or infectious diseases.