Smallpox and Bioterrorism

Article excerpt

Abstract Smallpox was declared to be eradicated on 8 May 1980, during the Thirty-third World Health Assembly. However, concerns about the possible use of the virus as a weapon of bioterrorism have increased in recent years. Governments have responded by initiating selective vaccination programmes and other public health measures. This review uses historical data from 20th century outbreaks to assess the risks to current populations (which have declininq immunity) from a deliberate release of virus. The data presented supports the conclusion of a previous reviewer (Mack) that "smallpox cannot be said to live up to its reputation. Far from being a quick-footed menace, it has appeared as a plodding nuisance with more bark than bite." Its R value (the average number of secondary cases infected by a primary case) is lower than that for measles, human parvovirus, chickenpox, mumps, rubella, and poliomyelitis; only the value for severe acute respiratory syndrome (SARS) is lower. Like SARS, close person-to-person contact is required for effective spread of the disease, and exposure to the virus in hospitals has played an important role in transmission for both viruses. In the present paper the dangers of mass vaccination are emphasized, along with the importance of case isolation, contact tracing, and quarantine of close contacts for outbreak control. The need for rapid diagnosis and the continued importance of maintaining a network of electron microscopes for this purpose are also highlighted.

Keywords Smallpox/diagnosis/epidemiology; Disease outbreaks/history/prevention and control; Bioterrorism/prevention and control; Mass immunization/adverse effects; Infection control/methods (source: MeSH, NLM).

Mots cles Variole/diagnostic/epidemiologie; Epidemie/histoire/prevention et controle; Terrorisme biologique/prevention et controle; Immunisation de masse/effets indesirables; Lutte contre infection/methodes (source: MESH, INSERM).

Palabras clave Viruela/diagnostico/epidemiologia; Brotes de enfermedades/historia/prevencion y control; Bioterrorismo/prevencion y control; Inmunizacion masiva/efectos adversos; Control de infecciones/metodos (fuente: DeCS, BIREME).

Bulletin of the World Health Organization 2003;81:762-767

Resume

Variole et bioterrorisme

La variole a ete declaree eradiquee le 8 mai 1980 pendant la Trente-Troisieme Assemblee mondiale de la Sante. Ces dernieres annees, cependant, la crainte de voir le virus utilise comme arme par des terroristes s'est amplifiee. Dans cette perspective, des gouvernements ont mis en place des programmes de vaccination selectifs et adopte d'autres mesures de sante publique. Sur la base des donnees relatives aux flambees enregistrees au X[X.sup.e] siecle, le present article evalue les risques auxquels seraient aujourd'hui exposees les populations (dont I'immunite est en baisse) en cas de propagation deliberee d'un virus. Les donnees presentees corroborent les conclusions d'une precedente etude (Mack) selon lesquelles << La variole a une reputation usurpee. De meme que pour un chien qui aboie mais ne mord pas, il semble qu'on lui ait prete une capacite de nuisance demesuree. >> Dans le cas de la variole, R (nombre moyen de cas secondaires contamines par un cas primaire) est moins eleve que pour la rougeole, le parvovirus humain, la varicelle, les oreillons, la rubeole et la poliomyelite ; seul le syndrome respiratoire aigu severe (SRAS) a un taux inferieur. Comme pour le SRAS, la cotamination n'intervient qu'entre des personnes ayant eu des contacts rapproches et l'exposition en milieu hospitalier a joue un role important dans la transmission de ces deux virus. L'article insiste sur les risques associes a la vaccination de masse et sur la necessite, pour endiguer les flambees, d'isoler les cas, de rechercher les contacts et d'isoler les contacts proches. La necessite de poser un diagnostic rapide et de continuer d'entretenir un reseau de microscopes electroniques a cet effet est egalement soulignee. …