Reference
Plague glossary: medical terms explained in plain language
Quick answer
- This glossary gathers, in plain language, the medical and epidemiological terms used when discussing plague.
- It includes clinical terms (bubo, septicemia), epidemiological terms (vector, reservoir, fatality) and laboratory terms (PCR, F1 antigen, BSL-3).
- It is reference material for reading the guides and news about the topic.
Clinical terms
| Term | Meaning |
|---|---|
| Bubo | An enlarged, firm and painful lymph node, typical of bubonic plague |
| Bubonic | The form of plague that affects the lymph nodes |
| Pneumonic | The form of plague that affects the lungs and can spread between people |
| Septicemic | The form of plague in which the bacterium circulates in the blood |
| Sepsis | A severe inflammatory response to infection, with risk of organ failure |
| Haemoptysis | Coughing up blood |
| Cyanosis | Bluish discolouration of the skin from lack of oxygen |
| Prostration | A state of extreme weakness and exhaustion |
Epidemiological terms
| Term | Meaning |
|---|---|
| Vector | An organism that transmits an infectious agent; in plague, the flea |
| Reservoir | An animal population where the agent naturally circulates; in plague, rodents |
| Zoonosis | A disease that can be transmitted between animals and people |
| Incubation | The time between exposure and the onset of symptoms |
| Fatality rate | The proportion of ill people who die from the disease |
| Endemic | The constant presence of a disease in a region |
| Epidemic | An increase in cases above what is expected in a region and period |
| Pandemic | An epidemic that affects several countries or continents |
| Contact tracing | Identifying and monitoring people who had contact with a case |
| Notifiable disease | A legal obligation to report cases to health authorities |
Laboratory and treatment terms
| Term | Meaning |
|---|---|
| Yersinia pestis | The bacterium that causes plague |
| Culture | Growing the bacterium in a laboratory to confirm infection |
| PCR | A test that detects the agent's genetic material |
| F1 antigen | A capsule protein of the bacterium used in diagnostic tests |
| Serology | A test that measures antibodies in the blood |
| Prophylaxis | A measure to prevent disease, such as antibiotics after exposure |
| Antibiotic therapy | Treatment with antibiotics |
| BSL-3 | A biosafety level for handling agents with respiratory risk |
| Aerosol | A suspension of microscopic particles in the air |
How to use this glossary
When reading news about plague, these terms are often mixed together. Distinguishing “form of the disease” (bubonic, pneumonic, septicemic) from “mode of transmission” (flea, contact, droplets) helps interpret what is being said — and avoids confusing reports with confirmed risks.
Frequently asked questions
What is a bubo?
It is the enlarged, firm and very painful lymph node that characterises bubonic plague, usually in the groin, armpit or neck.
What is a fatality rate?
It is the proportion of ill people who die from the disease. It should not be confused with mortality, which refers to the total population.
What is prophylaxis?
It is any measure to prevent a disease — for example, using antibiotics for contacts of a pneumonic plague case before they become ill.
What does BSL-3 mean?
It is a laboratory biosafety level for handling agents that can cause severe respiratory disease, with strict containment controls.
Sources
Medical review
Review by a licensed health professional is being arranged. This educational content is based on reference sources (WHO, CDC and medical literature) and does not replace evaluation, diagnosis or treatment by a health professional.
How this content was produced
- Who
- Produced by the Equipe editorial do Peste.com.br, the editorial team responsible for gathering, verifying and classifying public information about plague (Yersinia pestis).
- How
- Information is compiled from official and scientific sources (WHO, CDC and national health authorities) and from recognised news outlets. Every statement is classified as confirmed, reported or unconfirmed, and each article lists its sources.
- Why
- To offer clear, source-based information in Portuguese about plague and to separate verified fact from rumour. This content is educational and does not replace medical advice.
- Medical review
- Review by a licensed health professional is being arranged; no credential is claimed until a real professional is credited.
- Last review
See our sources and methodology and the editorial team.A revisão por profissional de saúde habilitado está em processo de credenciamento. Assim que concluída, o nome e o registro serão informados nesta página e nos dados estruturados.