Transfer
Patients with plague who are critically ill and require transfer to another facility should be transported under strict isolation precautions.
Deterrence/Prevention
Prophylactic antibiotic therapy
The CDC recommends short-term prophylactic antibiotic therapy in people who have been bitten by potentially infected rodent fleas during a plague outbreak.
Prophylactic antibiotic therapy is recommended in persons who have handled an animal known to be infected with the plague bacterium.
Choice of agent should be based on established recommendations and usually utilize doxycycline or ciprofloxacin.
Prophylactic antibiotic therapy is recommended in persons who have had close exposure to a person or an animal thought to have pneumonic plague. Sulfadoxine prophylaxis has been effective in outbreaks of pneumonic plague. [40] The infection rate in contacts was 8.4% with this strategy. Recent studies have shown that doxycycline can be used as an alternative for sulfadoxine. [39]
Preferred antibiotics for prophylaxis against plague include doxycycline 100 mg PO q12h for 14-21 days (for patients >8 y) or full-dose ciprofloxacin for 7 days. [41] Chloramphenicol may be used as an alternative. To be effective, chemoprophylaxis must be initiated within 7 days of exposure.
Plague vaccine
A recent review by Sun and Singh provides an excellent review of current efforts to produce safe and effective anti-plague vaccines. [42] The hope of vaccination strategies is to provide long-term prevention against the acquisition of the disease.
Historically, plague vaccination is of limited use [43] and has not been mandatory for entry into any country. The vaccine is not effective against the pneumonic form of plague. Plague vaccine is recommended for field workers in endemic areas and for scientists and laboratory personnel who routinely work with the plague bacterium. The vaccine is composed of killed whole cells. It needs to be taken as 2 injections 1-3 months apart followed by the booster every 6 months until the patient is no longer considered to be at risk. [24] Live vaccines are in development. [44]
Animal studies have conclusively established that certain antibodies are protective against plague. [45] Murine antibodies to fraction (FI) protein and/or fraction V antigen have been shown to be protective against bubonic and pneumonic plague in murine models. [46]
The F1-V (fusion protein) vaccine protected mice for a year against an inhalation challenge and is now being tested in primates. [41]
An oral vaccine with an attenuated strain of Y pseudotuberculosis named VTNF1 has been reported to provide highly efficient and long-lasting protection against both bubonic and pneumonic plague after a single oral vaccine dose. It confers full protection against the two forms of plague. This may offer an option for mass vaccination in tropical endemic areas, as well as for populations exposed to bioterrorism. [47]
Multiple other vaccine constructs are being tested, but so far none are ready for routine use in humans or are licensed in the western world. [42]
Environmental sanitation
Efforts to control the animal reservoir and flea population may be effective in reducing transmission of plague bacteria.
Remove food sources used by rodents.
Rodent-proof homes, buildings, and warehouses.
Trained professionals should apply chemicals to kill fleas and rodents.
Trained professionals should fumigate cargo areas of ships and docks.
Complications
Potential complications of plague include the following:
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Chronic lymphedema from lymphatic scarring
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DIC
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Superinfections of the buboes by Staphylococcus and Pseudomonas species
Prognosis
Untreated plague carries a mortality rate of approximately 50%; however, with appropriate therapy, the mortality rate drops dramatically. [48]
Patient Education
Report sick or dead animals to the local health department or law enforcement officials and wear gloves when handling potentially infected animals.
Eliminate food sources and nesting places for rodents around homes, workplaces, and recreation areas and make homes rodent-proof.
Personal protective measures include wearing protective clothing and applying insect repellents to clothing and skin to prevent flea bites.
Restrain pet dogs and cats in areas endemic to plague and regularly treat pets to control fleas.
Spraying of appropriate chemicals by health authorities may be necessary to kill fleas at selected sites during animal plague outbreaks.
For patient education information, see Plague Disease (Black Death). For additional information, visit the Centers for Disease Control and Prevention Web page on Plague.
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1998 world distribution of plague. Image courtesy of the Centers for Disease Control and Prevention (CDC), Atlanta, GA.
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The prairie dog is a burrowing rodent of the genus Cynomys. It can harbor fleas infected with Yersinia pestis, the plague bacillus. Image courtesy of the Centers for Disease Control and Prevention (CDC), Atlanta, Ga.
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Oriental rat flea (Xenopsylla cheopis), the primary vector of plague, engorged with blood. Image courtesy of Centers for Disease Control and Prevention (CDC), Atlanta, Ga.
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Ulcerated flea bite caused by Yersinia pestis bacteria. Image courtesy of Centers for Disease Control and Prevention (CDC), Atlanta, Ga.
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Swollen lymph glands, termed buboes, are a hallmark finding in bubonic plague. Image courtesy of Centers for Disease Control and Prevention (CDC), Atlanta, Ga.
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Wayson stain showing the characteristic "safety pin" appearance of Yersinia pestis, the plague bacillus. Image courtesy of Centers for Disease Control and Prevention (CDC), Atlanta, Ga.
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Fluorescence antibody positivity is observed as bright, intense green staining around the cell wall of Yersinia pestis, the plague bacillus. Image courtesy of Centers for Disease Control and Prevention (CDC), Atlanta, Ga.
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Histopathology of lung in fatal human plague–fibrinopurulent pneumonia. Image courtesy of Marshall Fox, MD, Centers for Disease Control and Prevention (CDC), Atlanta, Ga.
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Histopathology of lung showing pneumonia with many Yersinia pestis organisms (the plague bacillus) on a Giemsa stain. Image courtesy of Marshall Fox, MD, Centers for Disease Control and Prevention (CDC), Atlanta, Ga.
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Histopathology of spleen in fatal human plague. Image courtesy of Marshall Fox, MD, Centers for Disease Control and Prevention (CDC), Atlanta, Ga.
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Histopathology of lymph node showing medullary necrosis and Yersinia pestis, the plague bacillus. Image courtesy of Marshall Fox, MD, Centers for Disease Control and Prevention (CDC), Atlanta, Ga.
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Histopathology of liver in fatal human plague. Image courtesy of Marshall Fox, MD, Centers for Disease Control and Prevention (CDC), Atlanta, Ga.
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Focal hemorrhages in islet of Langerhans in fatal human plague. Image courtesy of Marshall Fox, MD, Centers for Disease Control and Prevention (CDC), Atlanta, Ga.
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Pictured is a flea with a blocked proventriculus, which is equivalent to the gastroesophageal region in a human. In nature, this flea would develop a ravenous hunger because of its inability to digest the fibrinoid mass of blood and bacteria. If this flea were to bite a mammal, the proventriculus would be cleared, and thousands of bacteria would be regurgitated into the bite wound. Courtesy of the United States Army Environmental Hygiene Agency.
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After the femoral lymph nodes, the next most commonly involved regions in plague are the inguinal, axillary, and cervical areas. This child has an erythematous, eroded, crusting, necrotic ulcer at the presumed primary inoculation site in the left upper quadrant. This type of lesion is uncommon in patients with plague. The location of the bubo is primarily a function of the region of the body in which an infected flea inoculates plague bacilli. Courtesy of Jack Poland, PhD, Centers for Disease Control and Prevention (CDC), Fort Collins, Colo.
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Ecchymoses at the base of the neck in a girl with plague. The bandage is over the site of a prior bubo aspirate. These lesions are probably the source of the line from the children's nursery rhyme, "ring around the rosy." Courtesy of Jack Poland, PhD, Centers for Disease Control and Prevention (CDC), Fort Collins, Colo.
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Acral necrosis of the nose, the lips, and the fingers and residual ecchymoses over both forearms in a patient recovering from bubonic plague that disseminated to the blood and the lungs. At one time, the patient's entire body was ecchymotic. Reprinted from Textbook of Military Medicine. Washington, DC, US Department of the Army, Office of the Surgeon General, and Borden Institute. 1997:493. Government publication, no copyright on photos.
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Acral necrosis of the toes and residual ecchymoses over both forearms in a patient recovering from bubonic plague that disseminated to the blood and the lungs. At one time, the patient's entire body was ecchymotic. Reprinted from Textbook of Military Medicine. Washington, DC: US Department of the Army, Office of the Surgeon General, and Borden Institute. 1997:493. Government publication, no copyright on photos.
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Rock squirrel in extremis coughing blood-streaked sputum related to pneumonic plague. Courtesy of Ken Gage, PhD, Centers for Disease Control and Prevention (CDC), Fort Collins, Colo.
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CDC, Reported Cases of Human Plague - United States, 1970-2018. Image courtesy of the Centers for Disease Control and Prevention (CDC), Atlanta, GA.
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CDC, Reported Plague Cases by Country, 2013-2018. Image courtesy of the Centers for Disease Control and Prevention (CDC), Atlanta, GA.
