Pneumonic Plague Diagnosis, DRC | CDC EID

EID Journal Home > Volume 17, Number 5–May 2011

Volume 17, Number 5–May 2011
Synopsis
Lessons Learned about Pneumonic Plague Diagnosis from 2 Outbreaks, Democratic Republic of the Congo

Eric Bertherat, Philippe Thullier, Jean Christophe Shako, Kathleen England, Mamadou-Lamine Koné, Lorraine Arntzen, Herbert Tomaso, Louis Koyange, Pierre Formenty, Florent Ekwanzala, Rosa Crestani, Isa Ciglenecki, and Lila Rahalison

Author affiliations: World Health Organization, Geneva, Switzerland (E. Bertherat, P. Formenty); Centre de Recherche du Service de Santé des Armées, Grenoble, France (P. Thullier); Plague Reference Laboratory, Bunia, Democratic Republic of the Congo (J.C. Shako); National Institutes of Health, Bethesda, Maryland, USA (K. England); World Health Organization, Brazzaville, Republic of Congo (M.-L. Koné); National Health Laboratory Service, Johannesburg, South Africa (L. Arntzen); Bundeswehr Institute of Microbiology, Munich, Germany (H. Tomaso); Institut National de la Recherche Biomédicale, Kinshasa, Democratic Republic of the Congo (L. Koyange); World Health Organization, Kinshasa (F. Ekwanzala); Médecins Sans Frontière, Bruxelles, Belgium (R. Crestani); Médecins sans Frontières, Geneva (I. Ciglenecki); and Institut Pasteur, Antananarivo, Madagascar (L. Rahalison)

Suggested citation for this article

Abstract

Pneumonic plague is a highly transmissible infectious disease for which fatality rates can be high if untreated; it is considered extremely lethal. Without prompt diagnosis and treatment, disease management can be problematic. In the Democratic Republic of the Congo, 2 outbreaks of pneumonic plague occurred during 2005 and 2006. In 2005, because of limitations in laboratory capabilities, etiology was confirmed only through retrospective serologic studies. This prompted modifications in diagnostic strategies, resulting in isolation of Yersinia pestis during the second outbreak. Results from these outbreaks demonstrate the utility of a rapid diagnostic test detecting F1 antigen for initial diagnosis and public health management, as well as the need for specialized sampling kits and trained personnel for quality specimen collection and appropriate specimen handling and preservation for plague confirmation and Y. pestis isolation. Efficient frontline management and a streamlined diagnostic strategy are essential for confirming plague, especially in remote areas.


Plague is a zoonotic disease caused by the bacterium Yersinia pestis, an agent circulating among small mammals and fleas (1–3). Human infection is usually transmitted by the bite of an infected flea, and bubonic plague is the most common form of the disease. The illness can progress into advanced clinical forms of septicemic and pneumonic plague. Pneumonic plague is of serious concern because of the potential for human-to-human transmission from aerosolized bacteria spread through coughing. Pneumonic plague can lead to localized outbreaks, or even devastating epidemics, because the infectious dose by inhalation can be as low as 100–500 organisms (4). Untreated, pneumonic plague usually leads to death within 2–4 days after respiratory exposure; in some instances, death occurs as rapidly as 24 hours after exposure (1,3,5,6). The rapid onset and high lethality are its only distinguishable clinical features as the disease otherwise manifests itself as a severe respiratory infection that could be caused by various pathogens.

In regions where clinicians are unfamiliar with plague, risk of misdiagnosis is high, and specific diagnostic tools are often not readily accessible in remote areas. Identification of the causal agent is critical for implementing immediate public health measures in the community. Furthermore, in previously plague-free areas, confirmation of the diagnosis may lead to the identification of the emergence of a new natural focus that requires a revised public health strategy.

Rapid diagnostic tests (RDTs) are available and can be effective for helping manage such situations; however, they do not replace bacterial isolation, which remains the most accurate method and enables crucial antimicrobial drug susceptibility testing. In the absence of bacterial isolation, plague confirmation requires serologic detection of a 4-fold rise in plague-specific antibodies, or, in plague-endemic regions, a positive RDT (7). Whichever technique is used, plague confirmation depends on appropriate sample collection, effective sample preservation measures, and direct transportation of samples to diagnostic laboratory facilities, as illustrated in the 2 pneumonic plague outbreaks we discuss. We highlight important lessons on frontline sample collection methods and transport and provide an awareness of the challenges faced in regard to diagnostic strategies in remote, war-torn regions of the world.

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Pneumonic Plague Diagnosis, DRC | CDC EID


Suggested Citation for this Article
Bertherat E, Thullier P, Shako JC, England K, Koné M-L, Arntzen L, et al. Lessons learned about pneumonic plague diagnosis from 2 outbreaks, Democratic Republic of the Congo. Emerg Infect Dis [serial on the Internet]. 2011 May [date cited].
http://www.cdc.gov/EID/content/17/5/778.htm


DOI: 10.3201/eid1705.100029


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Eric Bertherat, WHO – HSE/GAR, 20 Av Appia, Geneva 1211, Switzerland; email: bertherate@who.int