Plague: Bubonic, Pneumonic, and Septicemic

Plague, often associated with medieval times, remains a significant public health concern in certain parts of the world. This infectious disease, caused by the bacterium Yersinia pestis, manifests in three primary forms: bubonic, pneumonic, and septicemic. The plague is an infectious disease that affects both humans and animals. Historically known as the Black Death, this disease, which ravaged populations centuries ago, still persists today and remains a significant threat.

Fortunately, advancements in our understanding of infectious diseases have equipped us with effective strategies for managing the plague. Prompt treatment can now lead to a successful cure, offering hope in combating this ancient yet still dangerous disease.

Causes and transmission

It is caused by a bacterium called Yersinia pestis. Typically, the plague is transmitted through fleas. These insects acquire the bacteria when they bite infected animals such as rats, mice, or squirrels, and subsequently transmit it to other animals or humans they bite. Additionally, direct transmission from infected animals or individuals is possible.

Forms of Plague

This infectious disease manifests in three primary forms:

Bubonic Plague:

Typically transmitted through a flea bite, bubonic plague prompts lymph node swelling within 2 to 8 days due to bacterial accumulation. These swollen glands, known as “buboes,” are characteristic of this type.

Septicemic Plague:

Septicemic plague can result from a flea bite or direct contact with an infected animal. It may also develop from untreated bubonic plague when the bacteria infiltrate the bloodstream. Onset of symptoms can occur within days, with manifestations including bleeding under the skin or from mucous membranes, blackened skin, abdominal pain, diarrhea, vomiting, and shock.

Pneumonic Plague:

Considered the most severe type, pneumonic plague is the only form capable of person-to-person transmission. Infection can occur through inhalation of droplets expelled during sneezing or coughing by an infected individual. It can also develop from bubonic or septicemic plague if the bacteria spread to the lungs. Symptoms typically appear within 1 to 3 days and may include chest pain, coughing (potentially with blood), difficulty breathing, nausea, and vomiting.

Brief history of plague

Archaeological evidence indicates the presence of plague DNA in Bronze Age skeletons dating back nearly 3,800 years. The first recorded pandemic, known as the Justinian plague, occurred during the years 541 and 542. Subsequent waves of plague swept through Europe and Asia during the 6th to 8th centuries.

The second pandemic, famously referred to as the Black Death, emerged in Italy in 1347. Believed to have originated in Central Asia, it spread rapidly across Europe via trading ships infested with fleas and rats. Within five years, approximately one-third of Europe’s population succumbed to the disease.

Although the second pandemic waned around 1400, Europe continued to experience deadly outbreaks over the next four centuries. Notable instances include the mid-1600s plague in Italy, which claimed two-thirds of Naples and Genoa’s population, and London losing roughly a quarter of its inhabitants. Moreover, an outbreak in Moscow in 1770 resulted in approximately 100,000 deaths.

The third plague pandemic commenced in southwest China in 1855, claiming around 70,000 lives in Canton before spreading globally. It reached Japan, Australia, and North and South America in the early 1900s. Experts estimate that the plague claimed 12 million lives in India during the late 1800s and early 1900s.

Prevalence

While historically associated with pandemics that ravaged Europe in the Middle Ages, plague still exists today, albeit in much smaller outbreaks. Regions of Africa, Asia, and the Americas continue to report cases of this infectious disease,, particularly in rural and less developed areas.

Symptoms

Bubonic Plague:

• Painful, swollen lymph nodes, called buboes, usually in the groin, armpit, or neck.
• Fever, chills, and overall feeling of illness.
• Headaches, muscle aches, and fatigue.

Pneumonic Plague:

• Fever, cough, and difficulty breathing.
• Chest pain, coughing up blood-tinged sputum.
• Rapid onset of symptoms after exposure.

Septicemic Plague:

• Fever, chills, extreme weakness.
• Abdominal pain, vomiting, diarrhea.
• Shock
• Bleeding under the skin or from orifices and other tissues.

Risk Factors

Individuals at higher risk of contracting this infectious disease, include those living in or traveling to regions where the disease is endemic, handling infected animals or their fleas, and having compromised immune systems.

Diagnosis

Diagnosing this infectious disease, typically involves several steps, especially if an individual exhibits symptoms suggestive of the disease and resides in an area known for plague prevalence or has recently visited such a location.

Initial Assessment:

Your doctor may suspect plague infection based on specific symptoms and your geographic location.

Sample Collection:

To confirm the diagnosis, your doctor will collect samples from your body. These samples may include blood or tissue extracted from swollen lymph nodes. These samples are then sent to a laboratory for testing to detect the presence of the plague-causing bacteria.

Advancements in Testing:

In recent years, researchers have developed a rapid test capable of identifying indications of this infectious disease bacteria within 15 minutes. This test examines fluid obtained from infected lymph nodes or coughed-up material. While not yet widely utilized, this rapid test could serve as a valuable initial diagnostic tool, particularly in regions where accessing laboratory testing facilities is challenging.

Treatments

Seeking medical attention promptly is crucial if you’ve been in an area with this infectious disease, and are experiencing symptoms, as time is of the essence. Even hours can make a significant difference in treatment outcomes.

If you’ve been in close contact with someone who has this infectious disease, your doctor may initiate treatment preemptively, even if you haven’t exhibited symptoms yet. In such cases, wearing tight-fitting disposable surgical masks can help prevent inhalation of plague bacteria.

Hospital Admission:

If diagnosed with this infectious disease, hospital admission is necessary. Treatment primarily involves administering antibiotics, such as Ciprofloxacin (Cipro), Doxycycline (Vibramycin), Gentamicin (Garamycin), or Levofloxacin (Levaquin). Antibiotic therapy is highly effective, with most individuals experiencing improvement within a week or two. However, without treatment, the prognosis is poor, as the majority of untreated cases result in death.

Home Care Tip

While medical treatment is indispensable for managing this infectious disease, individuals can reduce their risk of exposure by avoiding contact with wild rodents, using insect repellent in plague-endemic areas, and practicing good hygiene.

Prevention

Currently, there’s no vaccine available for this infectious disease in the United States. Therefore, adopting preventive measures is essential if you anticipate potential exposure to plague-causing bacteria.

• Before traveling to regions like Africa, Asia, or South America, check for traveler advisories regarding plague outbreaks on the CDC website. Whenever possible, avoid areas known for plague prevalence and refrain from close contact with sick or dead animals during your visit.
• For individuals residing in plague-endemic areas or areas with recent plague cases:
• Seal holes and gaps in your home to prevent rodents like mice, rats, and squirrels from entering. Maintain a tidy yard by removing debris like piles of leaves, wood, and rocks that may serve as habitats for animals.
• Use insect repellents containing DEET to safeguard against flea bites during outdoor activities like hiking or camping. If handling wild animals, whether alive or deceased, wear gloves to minimize the risk of exposure.
• Implement flea control measures for your pets, such as using flea control sprays or treatments. Avoid allowing outdoor pets like cats or dogs to sleep in your bed.

When to See a Doctor

Seek medical attention immediately if you develop symptoms suggestive of this infectious disease, especially if you’ve been in an area where the disease is known to occur or have had contact with rodents.

Outlook/Prognosis

With early diagnosis and appropriate treatment, most cases of plague can be successfully treated. However, delays in seeking medical care or inadequate treatment can lead to severe complications and even death.

In conclusion, plague, in its bubonic, pneumonic, and septicemic forms, remains a serious infectious disease with potentially grave consequences. Vigilance, prompt medical attention, and preventive measures are crucial in combating this ancient scourge.

Sources

• Centers for Disease Control and Prevention (CDC)
• World Health Organization (WHO)
• Mayo Clinic
• National Institute of Allergy and Infectious Diseases (NIAID)
• UpToDate: “Epidemiology, microbiology and pathogenesis of plague (Yersinia pestis infection),” “Clinical manifestations, diagnosis, and treatment of plague (Yersinia pestis infection).”
• American Journal of Medicine
• Cochrane Database of Systematic Reviews