Forms of plague
Bubonic plague: symptoms, bubo (swollen lymph node) and treatment
Quick answer
- Bubonic plague is the most common form of plague (about 80–85% of cases). It happens when the bacterium Yersinia pestis enters through the skin, usually via the bite of an infected flea.
- The hallmark sign is a painful swollen lymph node (the bubo), most often in the groin, armpit or neck, together with high fever and chills.
- Incubation is usually 2 to 6 days. Untreated, the case fatality rate is 30–60%; with early antibiotics it falls sharply.
- Bubonic plague generally does not spread from person to person.
What bubonic plague is
Bubonic plague is the most common clinical form of plague, a disease caused by the bacterium Yersinia pestis. It is named after the bubo — the swollen, intensely painful lymph node that forms near the site where the bacteria entered the body.
In most cases the entry point is the skin, after the bite of an infected flea carried by rodents. The bacteria travel through the lymphatic system to the nearest lymph node, which becomes inflamed and enlarged. From there they may spread to the blood (septicemic form) or, in a minority of cases, to the lungs (secondary pneumonic form).
Symptoms of bubonic plague
- Sudden high fever and chills.
- Headache, severe fatigue and general malaise.
- Muscle aches.
- A painful, warm, firm swollen lymph node (bubo), usually in the groin, armpit or neck.
- Nausea, vomiting and sometimes abdominal pain.
The abrupt onset of fever together with an extremely painful swelling is what usually draws attention. Unlike many causes of enlarged nodes, the plague bubo is intensely painful and may reach several centimetres.
The bubo: how to recognise it
| Feature | Description |
|---|---|
| Most common site | Groin (femoral nodes), then armpit and neck |
| Pain | Severe, even at rest |
| Appearance | Enlarged, firm, warm; surrounding skin may redden |
| Evolution | May suppurate in later stages |
| Time to appear | 2 to 6 days after exposure (range 1 to 7 days) |
Warning
A painful swollen node with fever, after contact with rodents, fleas or travel to an area where plague circulates, is a medical emergency. Seek care immediately and report the possible exposure.
How you get bubonic plague
Bubonic plague is transmitted mainly by the bite of infected fleas, especially the rat flea (Xenopsylla cheopis). The natural cycle involves rodents and their fleas; when this cycle comes close to people, the risk of human infection rises.
- Bite of an infected flea — the main route.
- Contact with tissues or fluids of an infected animal, such as skinning or handling carcasses.
- Scratches or bites from sick cats, which can carry the bacterium.
- Rarely, handling contaminated material in a laboratory.
Importantly, bubonic plague generally does not pass from person to person. Human-to-human transmission occurs in the pneumonic form, through respiratory droplets in close, prolonged contact.
Incubation period
The incubation period for bubonic plague is usually 2 to 6 days after the flea bite, and may range from 1 to 7 days. Because it is short, exposed people are monitored for several days and treatment should not wait for laboratory confirmation when suspicion is strong.
Is bubonic plague curable? Treatment
Yes. Bubonic plague is treatable with antibiotics, and the earlier treatment starts, the better the outcome. Untreated, the case fatality rate can reach 30–60%; with prompt appropriate antibiotics it drops substantially.
| Aspect | Information |
|---|---|
| Main class | Aminoglycosides (streptomycin, gentamicin) |
| Alternatives | Doxycycline, ciprofloxacin, levofloxacin; chloramphenicol in specific situations |
| Typical duration | About 10 to 14 days, depending on clinical course |
| When to start | As early as possible, on clinical and epidemiological suspicion |
Do not self-medicate
Plague is a medical emergency. No antibiotic should be started on your own. Seek medical care immediately.
When to seek care
Seek care immediately if you have fever and a painful swelling, especially with any exposure in the previous weeks: contact with rodents, fleas or wildlife; travel to areas where plague is endemic among animals; handling carcasses or hunting; close contact with a suspected pneumonic plague patient; or laboratory work with the bacterium.
Frequently asked questions
Is bubonic plague contagious between people?
Generally not. Bubonic plague is usually transmitted by infected fleas and contact with sick animals. Person-to-person spread occurs in the pneumonic form, through respiratory droplets in close, prolonged contact.
Is bubonic plague curable?
Yes. It is a bacterial disease treatable with antibiotics, with good response when treatment starts early. Untreated, the fatality rate is high (about 30–60%).
How long after a flea bite do symptoms appear?
The incubation period is typically 2 to 6 days, ranging from 1 to 7 days.
Does bubonic plague require isolation?
The bubonic form does not require respiratory isolation, because it does not spread between people by air. The pneumonic form requires droplet precautions until 48 hours of effective antibiotics.
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.