Pediatric Plague Clinical Presentation

Updated: Jan 18, 2016
  • Author: Vinod K Dhawan, MD, FACP, FRCPC, FIDSA; Chief Editor: Russell W Steele, MD  more...
  • Print


The incubation period of plague is 3-4 days (range, hours to 10 d). Sore throat may be the only complaint of patients with plague pharyngitis.

Bubonic plague

Bubonic plague, resulting from the bite of an infected flea, accounts for approximately 80%–85% of cases.

Patients complain of fever with abrupt onset and other constitutional symptoms. These symptoms usually manifest 3-6 days after contracting the organism but may appear in the first day or be delayed for longer than a week. Clinical manifestations of plague are the same for children and adults.

Fever with chills is virtually universal. Temperatures typically range from 38.5-40ºC.

Headache, malaise, and weakness are all very common.

An area of focal painful lymphadenopathy (bubo) develops and progresses during the first few days of illness (see the image below).

Inguinal bubo on upper thigh of a person with bubo Inguinal bubo on upper thigh of a person with bubonic plague. Image courtesy of the Centers for Disease Control and Prevention (CDC).

This bubo rapidly becomes very tender and can measure up to 10 cm. Over time, fluctuance develops, and the buboes often suppurate and drain. The most common site affected is the groin, followed by the axillary and cervical lymph nodes. Intra-abdominal buboes may present as an acute abdomen.

Nausea, vomiting, diarrhea, and abdominal pain are common. These, as well as the constitutional symptoms of headache and malaise, are thought to result from the gram-negative septicemia caused by Y pestis.

Patients with plague may complain of sleep disturbance, vertigo, and loss of memory. Weakness, delirium, stupor, ataxia, and speech disorders may also occur. These manifestations are due to the effects of endotoxin on the brain. Meningitis may develop. Children younger than 15 years appear to be more susceptible to meningitis.

Septicemic plague

Constitutional symptoms are similar to bubonic plague. Absence of palpable buboes differentiates the 2 forms.

Meningitis is 4 times more common in this form of the disease than with bubonic plaque. Additionally, pneumonic plaque occurs twice as often in septicemic plaque than in the bubonic form.

Patients with septicemia are often older than 60 years. They are usually less febrile, but mortality is higher.

Bacteremia may be so great that organisms can be visualized on peripheral smears.

Pneumonic plague

Primary pneumonic plague is a fulminant infection, occurring in approximately 3% of plague patients. It results from inhalation of infectious droplets. Secondary pneumonic plague results from the spread of Y. pestis to the lungs in patients with bubonic or septicemic infection.

Patients primarily manifest fever and respiratory symptoms, including cough, hemoptysis, and chest pain. Tachypnea and dyspnea are also common.

Thin, watery, blood-tinged sputum becomes frankly bloody and mucopurulent as the disease rapidly progresses.

Plague bacillus can be cultured from sputum, and disease transmission is thought to occur up to 2 meters from a patient who may be coughing.



Generally, patients with any form of plague are toxic in appearance. Apprehension and tachycardia are also common.

All patients are febrile with chills.

A large bubo is palpable in the groin, axilla, or neck of patients with bubonic plague. The mass is fixed, edematous, exquisitely tender, and often surrounded by an area of erythema.

Intra-abdominal buboes may be accompanied by tenderness, guarding, and other peritoneal signs. Hepatomegaly can be present.

Septicemic patients present with tachycardia, tachypnea, and hypotension. Systolic blood pressures are usually less than 100 mm Hg. Differentiation of patients with septicemic plague from patients with other types of gram-negative sepsis is often difficult due to the similarity of signs and symptoms.

Patients with pneumonic plague manifest cough productive of bloody sputum, tachypnea, and dyspnea.

Fever and meningismus accompany plague meningitis.

Patients with plague pharyngitis resemble those with any other form of bacterial pharyngitis or tonsillitis. Large anterior cervical adenopathy may be appreciated.




The causative bacterium (Y pestis) was discovered by Yersin in 1894. It is a nonmotile, pleomorphic, gram-negative coccobacillus that belongs to the family Enterobacteriaceae. Bipolar staining (giving the appearance of a closed safety pin) can be observed with Giemsa, Wayson, or Wright stains (see the images below).

Wright stain peripheral blood smear of patient wit Wright stain peripheral blood smear of patient with septicemic plague demonstrating bipolar, safety pin staining of Yersinia pestis. Although Wright stain often demonstrates this characteristic appearance, Giemsa and Wayson stains most consistently highlight this pattern. Courtesy of Jack Poland, PhD, Centers for Disease Control and Prevention (CDC), Fort Collins, CO.

It grows at a wide range of temperatures (4-40ºC) but demonstrates optimal growth at room temperature.

Both an endotoxin and an exotoxin are produced, adding to the organism's pathogenicity.


Human infection is usually acquired through the bites of infected rodent fleas. X cheopis, the Oriental rat flea, is the classic vector, but many other species of flea are also capable of transmitting plague. Typically, this form of transmission is common in crowded urban areas.

Plague can also be contracted from handling infected animals, especially rodents, lagomorphs (eg, rabbits or hares), and domestic cats, or through close contact with patients with pneumonic plague.

A recent study suggests that lice might play a role in transmission of Y pestis and that preventing and controlling louse infestations might help limit the extension of plague epidemics in louse-infested populations. [16]

Another potential cause of plague transmission in humans is contact with an infected dog. In 2014, the Colorado Department of Public Health and Environment (CDPHE) laboratory isolated Y pestis in a blood specimen from a hospitalized man with pneumonia. Further investigation found that the man’s dog had recently died with hemoptysis and that 3 other persons who came into contact with the dog had respiratory symptoms and fever. Specimens from the dog and the other three persons showed evidence of acute Y pestis infection. One of the transmissions may have been human to human, which would be the first such reported US case since 1924. [17]

Person-to-person transmission is extremely rare. Person-to-person transmission occurs primarily through droplet exposure from a patient with the pneumonic form of the disease, although direct contact with body fluids can also be infectious.