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Plague is a bacterial disease, caused by Yersinia pestis, that primarily affects wild rodents. It spreads from one rodent to another by fleas. Humans bitten by an infected flea usually develop a bubonic form of plague, which is characterized by a bubo, i.e. a swelling of the lymph node near the flea bite site.

Plague is a disease that triggers the use of the decision instrument for the assessment and notification of events that might constitute a Public Health Emergency for International Concern under the International Health Regulations 2005 (IHR 2005). On 14 June 2009, plague was reported in the Libyan Arab Jamahiriya in the Tobruk area, a known focus of this disease. Accordingly, the Government of the Libyan Arab Jamahiriya conducted a preliminary assessment and notified WHO about the occurrence of plague cases.

Immediate measures were taken by the local authorities including collaboration with relevant sectors, spraying of the infected areas, strengthening surveillance activities, broadcasting educational messages to the public and treating all cases.

A senior expert from WHO, together with the Libyan authorities, is currently in the field to initiate a wide-scale investigation and assessment and assist in setting up an effective response system to contain this outbreak quickly. According to IHR 2005, WHO will provide further public health information once received from the field.


Rapid diagnosis and treatment is essential to reduce complications. Effective treatment methods enable almost all plague patients to be cured if diagnosed in time. These methods include the administration of antibiotics and supportive therapy.


The objective of preventive measures is to inform people to be aware of the areas where zoonotic plague is active and to take precautions against flea bites and handling of carcasses while in plague-endemic areas. People should avoid direct contact with infective tissues and exposure to patients with pneumonic plague.


Plague vaccines were widely used at one time but have not proven to be an effective approach to timely prevention of plague. Vaccines are not recommended for immediate protection in outbreak situations. Vaccination is only recommended as a prophylactic measure for high-risk groups (e.g. laboratory personnel who are constantly exposed to the risk of contamination).