Anticipating smallpox as a bioterrorist weapon

Abstract

-The treat of bioterrorism means it is important to be able to diagnose smallpox. The responsibility for the initial recognition of cases lies with clinicians, and early diagnosis is the key to the successful control of an outbreak. Unless rapidly contained, a bioterrorist release of smallpox would constitute not just a national but a global threat to health. This brief review sets smallpox in its modern context as an infection potentially spread by bioterrorists and recommends sources of information from the twentieth century that will assist clinicians in diagnosing the disease.KEY WORDS: anti-vaccinal immunoglobulin, antivirals, cell-cultured vaccine, differential diagnosis, laboratory diagnosis, lymph vaccine, patient isolation, ring vaccination, smallpox, vaccination IntroductionSmallpox was declared globally eradicated in 1980. However, it is widely feared that the virus may have fallen into the hands of international terrorists. If so, it is important that any release into the community is recognised at the earliest possible moment lest its spread becomes uncontrollable. To ensure this, today's clinicians, few of whom have encountered smallpox, need to be aware of how it presents and what steps have to be taken to contain it.Little was written about clinical or other aspects of smallpox in the latter half of the twentieth century, but there is plenty of descriptive writing from earlier times and this should enable smallpox to be quickly recognised. The historical record also contains descriptions of outbreak control procedures and discusses the pros and cons of vaccination. It has recently been argued that the great mobility of modern populations, and uncertainty about the ways in which smallpox might be released by bioterrorists, mean that previously well-tried control strategies need to be revised, 1 but what has not changed is the importance of diagnosing and isolating first cases of smallpox at the earliest opportunity, and of searching for concurrent and subsequent cases, and for contacts. A terrorist smallpox release is unlikely to be announced by the perpetrators, and any clinician, whether in general or specialist practice, may be the first to see a case. All should therefore be able to recognise smallpox and know what action to take when they do so. General sources of informationThere are two compendia of smallpox, Dixon's Smallpox 2 and Fenner and colleagues' Smallpox and its eradication. 3 The fact that they were written 40 and 20 years ago respectively does not detract from their value. The authors deal with smallpox as the global disease that it used to be: Dixon describes the history of smallpox on every continent; Fenner et al document the inception, progress and outcome of the global eradication programme of the 1960s and 1970s. Fenner et al's publisher (WHO) has now helpfully made their entire text available electronically. 4 Clinical presentationSmallpox is a prostrating illness characterised after two to three days of fever by a rash that is at first papular and then vesicular....

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