The difference between biological warfare and bioterrorism: Australia finally makes a start towards real preparedness for bioterrorism

There are key differences between biological warfare (BW) and bioterrorism (BT) and the responses required for each are therefore different. In BW, the primary target is generally a military one (such as an army), which consists of a reasonably homogeneous population of otherwise fit, healthy soldiers who have possibly undergone appropriate pre-attack vaccin­ation. The time and place of the BW exposure is likely to be known, which allows a planned response that is based on the BW agent used, its known mode of spread and incubation time prior to onset of clinical disease. The primary objective with BW is massive destruction, or at least disruption, of enemy forces. In comparison, the purpose of BT is not necessarily to cause mass casualties, but instead to generate social paralysis through mass terror, confusion and community disruption. The target is frequently a heterogeneous civilian population which includes the young, elderly, immunocompromised and healthy. For most BT agents, pre-attack vaccination of the population is either impossible or is complex and potentially associated with unacceptable complications (as with smallpox). Instead, vaccination against BT agents is likely to be implemented primarily as a therapeutic or public health measure to exposed individuals following an attack, as part of a containment response. Identification of the site and timing of a BT attack may not be obvious until sufficient casualties have presented to health-care facilities to indicate that a BT attack has taken place. By this time, depending on the agent used, massive secondary spread may have already occurred. For instance, smallpox is thought to be associated with a 10-fold multiplier effect, so that for every case that presents with clinical smallpox, there are already another 10 case contacts incubating (and potentially spreading) virus.1 Given that clinical cases are likely to first present to health-care facilities, the potential for smallpox to selectively disrupt the entire health-care sector within 1−2 weeks of the first case is very real. Large numbers of casualties are not necessary for a BT attack to be considered highly successful. For instance, the anthrax attacks in the USA in 2001 were associated with only five deaths (roughly equivalent to the number of gunshot homicides that occur every 2.5 h in the USA),2 yet the social disruption and diversion of health and policing resources was massive.3 Similarly, the subsequent ‘white powder attacks’ in Australia, where no anthrax was ever identified, resulted in major public hysteria and public health gridlock.4 For health-care workers, the threat of BT must be taken very seriously and the response planned carefully. However, despite the hype and obvious danger that BT may pose, this issue has been presented to the Australian health-care community in a manner that has lacked the scientific content that usually accompanies a critical public health initiative. Planning for most infectious outbreaks in Australia has occurred in the setting of knowledge about the disease, its likelihood, epidemiology, treatment and prevention. For some diseases, this has included information regarding likely vectors (e.g. mosquito numbers with arbovirus encephalitis) and potential epicentres. For BT, however, much of this information has either not been presented or is not known and health-care workers are instead being asked to accept the risk of BT as a simple fact. Nevertheless, it is clear that the risk of BT − particularly anthrax (given recent attacks in the USA) and smallpox (given the likelihood that some of the previous Russian stocks are missing,3,5,6) − is real. The seriousness of the situation is further illustrated by the fact that the US Congress recently approved a massive $US1.72 billion increase in funding for BT medical research and preparedness.7 Despite a number of public health statements regarding Australia's purported preparedness for a BT attack, such preparations appear to have been largely made at a government public health level, with only limited education of clinicians to date.4,8,9 Yet, as the anthrax attacks in the USA so clearly demonstrated, it was the astute, well-informed clinician who promptly considered the possibility of a BT-related disease that led to the rapid implementation of the public health response that limited the mortality impact of the attack(s).3 It is in this setting that the article by Cherry et al.10 in this edition of the Journal is such a welcome and well-presented contribution to what is likely to be an intense educational period for most Australian clinicians. The need for a rapid ‘catch-up’ in knowledge about BT by Australian clinicians has recently been recognized by the Commonwealth Department of Health and Ageing which is presently preparing appropriate clinical BT management guidelines for Australia. Some of the BT responses that are currently being considered may in themselves pose a significant challenge. For instance, as the current smallpox vaccination programmes in the USA and Israel are demonstrating, complications from vaccinia can be problematic.11−13 The results of recent modelling suggest that mass smallpox vaccination are unlikely to be worthwhile unless there is a massive attack.14 But even targeted vaccination of volunteer health-care workers will require careful planning and initiation to avoid the emergence of secondary vaccinia among patient contacts or the need for extended health-care worker absenteeism following vaccination.1,15,16 The education of clinicians regarding BT agents and their clinical presentation must be considered a national priority if we are to limit the potential health and terror impact of a BT attack and avoid substantial undermining of our current health-care gains.