Plague


– A zoonosis caused by the Gram-negative bacillus Yersinia pestis that mainly affects wild and domestic rodents.
– Plague is transmitted to man by the bite of an infected flea vector or through a break in the skin by contact with a rodent. Human-to-human transmission occurs through the bites of human fleas, or, in the case of pneumonic plague, by inhaling infected droplets expelled by coughing.
– Vast foci of infection remain in Asia, Africa, Madagascar, and in North and South America1 .

Clinical features and progress

There are 3 main clinical forms:

 Bubonic plague is the most common form: high fever, chills, headache, associated with one (or more) very painful lymph node, usually inguinal (bubo). Frequent gastrointestinal signs: abdominal pain, vomiting, diarrhoea, etc. The mortality rate in untreated patients is approximately 50% as a result of septicaemia.

– Septicaemic plague is a complication of untreated bubonic plague and is a fulminant illness.

– Pneumonic plague is a very contagious form: high fever, chills, headache, myalgia associated with paroxysmal coughing, blood stained sputum and respiratory distress. This form progresses rapidly, and is fatal unless treated. It occurs either as a complication of bubonic plague or as the result of a primary infection.

Occasionally, the disease can take the form of meningitic plague.

Laboratory

– Isolation of Y. pestis (direct examination and culture) from lymph node aspirate, blood, sputum, cerebrospinal fluid, depending on the form involved.
– Serodiagnosis: ELISA reads positive soon after the onset of the illness.
– Transportation of the samples requires a cold chain (failing that, the temperature must be kept below 30 °C).

Management and treatment

– When plague is suspected: take samples for cultures and antibiotic sensitivity testing and then treat immediately without waiting for the diagnosis to be confirmed. Inform the health authorities as soon as the diagnosis has been confirmed.

– Isolation:
• Patients suffering from bubonic plague do not have to be isolated. Treat the patient and his/her bedding and clothing with an insecticide (e.g. permethrin 0.5% powder; see Pediculosis, Chapter 4). Observe standard precautions (handwashing, gowns, gloves, etc.).
• Patients with primary or secondary pneumonic plague must be strictly isolated. Their bedding, clothing, sputum and excreta must be disinfected with a chlorinated solution. Observe standard precautions (handwashing, gowns, gloves, etc.) and both the patient and carers should wear facemasks for 48 hours after beginning appropriate antibiotherapy .

Treatment of suspected or confirmed cases

If treatment is begun early, recovery is rapid and complete. Penicillins, cephalosporins and macrolides should not be used.
Aminoglycosides, tetracyclines, chloramphenicol and sulphonamides are effective. Follow national recommendations. For information:

streptomycin IM for 10 days
Children: 15 mg/kg every 12 hours (max. 2 g daily)
Adults: 1 g every 12 hours

gentamicin IM or IV for 10 days
Children: 2.5 mg/kg every 8 hours
Adults: 5 mg/kg once daily

doxycycline PO for 10 days
Children over 8 years: 2 mg/kg 2 times daily (max. 200 mg daily)
Adults: 100 mg 2 times daily or 200 mg once daily

chloramphenicol PO or IV for 10 days
Children 1 year to < 13 years: 25 mg/kg every 8 hours
Children ≥ 13 years and adults: 1 g every 8 hours

Indications

First choice

Alternative

Bubonic plague

doxycycline

chloramphenicol or streptomycin

Pneumonic plague

streptomycin

Septicaemic plague

streptomycin

chloramphenicol

Meningitic plague

chloramphenicol

Pregnant or breast-feeding women

gentamicin

Chemoprophylaxis of contacts

In the event of contact with a pneumonic plague patient or direct contact with infected body fluids or tissues and within one week after the end of exposure:
doxycycline PO for 7 days
Children over 8 years: 2 mg/kg 2 times daily (max. 200 mg daily)
Adults: 100 mg 2 times daily or 200 mg once daily
or
ciprofloxacin PO for 7 days
Children : 20 mg/kg 2 times daily (max. 1 g daily)
Adults: 500 mg 2 times daily 

Prevention

– Flea vector control is essential to controlling an epidemic.
– Long-term prevention: environmental sanitation and control of rodent reservoir.
– Vaccination against plague is indicated for laboratory technicians handling rodents and is not as a method for controlling an epidemic.



Footnotes
Ref Notes
1 For more information on distribution of natural foci : http://www.who.int/csr/disease/plague/Plague-map-2016.pdf