Smallpox: A Disease of the Past or a Weapon of Tomorrow?

Can this once eradicated killer return as a weapon of mass destruction?

Information published in this month's International Journal of Infectious Diseases discusses the potential return of smallpox - one of the deadliest viruses known to man - and whether we would be equipped to deal with a bioterrorist outbreak.

It has been almost 25 years since the World Health Organization (WHO) declared the global eradication of smallpox - the first and only disease ever to be eradicated and a key achievement in public health. In the 1950s, approximately 50 million new cases of this highly contagious disease were diagnosed each year; following the WHO eradication programme, the last naturally-occurring case arose in 1977.

Smallpox now represents a bigger threat than ever, according to a 2002 US Intelligence Review indicating potential interest of Al Qaeda in the virus. This fear has been endorsed by reports from Russian defectors concerning illegal production of virulent strains of the virus after all strains were supposedly destroyed.

Historically, smallpox is associated with mortality rates of 20-50%; however, with suspected cultivation of more virulent strains, this rate may increase. In addition, global immunity to smallpox has waned to almost nothing following cessation of mass vaccination in the 1970s. Due to increased mobility of the world's populations and the crowded nature of modern cities, the disease could spread rapidly causing immeasurable devastation.

Smallpox has never been used as a large-scale bioweapon so it is incredibly difficult to predict the extent of the danger - the only way to counter this threat is to be prepared for it. Since 2000, the world has experienced outbreaks of three infectious diseases (anthrax, influenza, SARS) that have threatened public health security. In response to these episodes, the WHO has updated its guidelines and governments worldwide have pushed bioterrorism preparedness to the tops of their political agendas.

Smallpox preparedness means having policies and plans in place to deal with bioterrorism. Smallpox is one of the few potential bioterrorist agents for which a vaccine is available, meaning that nations have been able to stockpile smallpox vaccine as a countermeasure.

With global investment in surveillance and response mechanisms, such as the Global Outbreak Alert and Response Network, governments are starting to plan for potential bioterrorist outbreaks. However, the threat of bioterrorism is very unpredictable and capable of severely endangering public health, and with each bioterrorist threat the need for governments to invest further in healthcare infrastructures is increased. This is the only way in which we will avoid the potential devastation of a smallpox outbreak.

The International Journal of Infectious Diseases is an official publication of the International Society for Infectious Diseases. The IJID publishes peer reviewed original articles and incisive reviews dealing with all aspects on infection, on the global stage. The Journal focuses on novel clinical and epidemiological findings of importance to the wider international healthcare community.