National case definition: Plague

Plague

Date of last revision/review: May 2008

National notification

Only confirmed cases of disease should be notified.

Type of surveillance

Routine case-by-case notification to the federal level

Case classification

Confirmed case

Clinical evidence of illness with laboratory confirmation of infection:

• isolation of Yersinia pestis from body fluids

or

• a significant (i.e. fourfold or greater) rise in serum antibody titre to Y. pestis fraction 1 (F1) antigen by EIA or passive hemagglutination/inhibition titre

Probable case

Clinical evidence of illness with any of the following laboratory evidence:

• demonstration of elevated serum antibody titre(s) to Y. pestis F1 antigen (without documented significant [i.e. fourfold or greater] change) in a patient with no history of plague immunization

or

• demonstration of Y. pestis F1 antigen by immunofluorescence

or

• detection of Y. pestis nucleic acid

or

• > 1:10 passive hemagglutination/inhibition titre in a single serum sample in a patient with no history of vaccination or previous infection

or

• detection of Y. pestis antibody by EIA

Laboratory comments

Serologic confirmation is done by demonstration of a significant (i.e. fourfold or greater) rise in serum antibody titre to Y. pestis F1 antigen by EIA or passive hemagglutination/inhibition titre.

Clinical evidence

Plague is characterized by fever, chills, headache, malaise, prostration and leukocytosis, and is manifest in one or more of the following principal forms:

• Bubonic plague: regional lymphadenitis
• Septicemic plague: septicemia with or without an evident bubo
• Primary pneumonic plague: inhalation of infectious droplets
• Secondary pneumonic plague: pneumonia, resulting from hematogenous spread in bubonic or septicemic cases
• Pharyngeal plague: pharyngitis and cervical lymphadenitis resulting from exposure to larger infectious droplets or ingestion of infected tissues

ICD code(s)

• ICD-10 code(s): A20.2
• ICD-9 code(s): 020.5

Type of international reporting

Under Article 6 of the International Health Regulations (IHR) (2005), each State Party shall notify the World Health Organization (WHO) by way of the IHR National Focal Point,^{Footnote 1} and within 24 hours of assessment of public health information, of all events which may constitute a public health emergency of international concern within its territory in accordance with the decision instrument (Annex 2 of the IHR^{Footnote 2}), as well as any health measure implemented in response to those events.

• An event involving pneumonic plague shall always lead to the utilization of the algorithm in Annex 2 of the IHR, because it has demonstrated the ability to cause serious public health impact and to spread rapidly internationally. The need to notify any event involving plague to the WHO will depend upon the outcome of the assessment using the Annex 2 decision instrument.

Note: If event does not meet the criteria for notification under Article 6 of the IHR, then other IHR-related reporting requirements may still apply with WHO and/or other States Parties, including those under Art. 7 (information-sharing during unexpected or unusual public health events), Art. 8 (consultation with WHO on public health events), Art. 9 (any public health risk that may cause international disease spread), Art. 10 (requests for verification from WHO), and Art. 44 (collaboration and assistance).

Elimination or eradication efforts should be reported.

Comments

Probable case definitions are provided as guidelines to assist with case finding and public health management, and are not for national notification purposes.

References

• Case definitions for diseases under national surveillance. CCDR 2000;26(S3). Retrieved May 2008, from http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/00vol26/26s3/index.html
• Centers for Disease Control and Prevention. Case definitions for infectious conditions under public health surveillance. MMWR 1997; 46(No. RR-10):25-6.
• World Health Organization. Department of Communicable Disease Surveillance and Response (October 1999). WHO Recommended Surveillance Standards. 2nd ed. WHO/CDS/CSR/ISR/99.2. Retrieved May 29, 2007, from www.who.int/csr/resources/publications/surveillance/whocdscsrisr992.pdf
• Dennis DT, Gage KL, Gratz N et al. Plague Manual. Epidemiology, Distribution, Surveillance and Control. WHO/CDS/CSR/EDC/99.2. Geneva: World Health Organization, 1999.
• Prentice MB, Rahalison L. Plague. Lancet 2007;369:1196-207.
• World Health Organization. International Health Regulations (2005). 3rd ed. Geneva, 2016, from http://www.who.int/ihr/publications/9789241580496/en/