Appropriate responses to bioterrorist threats

The health services will play a vital role in protection against covert releases

Although the threat of bioterrorism in the United Kingdom is still considered to be low, concern has heightened in the wake of the terrorist outrages in the United States on 11 September and subsequent covert releases of anthrax. 1 2 Potential events can be considered in three groups: deliberate release of a “weaponised” biological agents such as anthrax; use of a common pathogen such as salmonella; and hoaxes or false alarms. Release could occur covertly, or a warning may be given, or a suspect device discovered.

Experience of such incidents is limited. The use of a common pathogen is illustrated by deliberate contamination of salad bars in restaurants with Salmonella typhimurium by the religious sect led by Rajneesh in Oregon, United States, in 1984, causing illness in over 700 people.3 In 1995 the Aum Shinrikyo sect used sarin in the Tokyo underground.4 Subsequent investigations found that the sect was experimenting with Bacillus anthracis and Clostridium botulinumtoxin, and the incident prompted a wave of planning to deal with release of chemical and biological agents. Subsequently the UK Department of Health issued confidential guidance on the management of this type of incident to directors of public health and NHS trust chief executives in March 2000.5

When a device or suspect package is discovered, or a warning is given, management of the incident is led by the police, as is customary in all terrorist incidents. Arrangements to provide public health advice to the police in chemical or biological incidents are based on the guidance from the Department of Health.5 This requires local planning and formation of a joint health advisory cell. Exercises involving multiple agencies have been carried out in most health regions to work out practical details. Examination of suspect material from a device or package (for example, a powder) is carried out for the police by specialist laboratories. This is not a job for the local hospital laboratory—not only may the substance not be recognisable in a routine clinical laboratory, it can pose a threat to inexperienced staff, and also the forensic investigation of a possible attack is clearly of enormous importance.

The health services have an especially crucial role in covert releases. In the unlikely event of these occurring in the United Kingdom, patients will present to the healthcare system and may be investigated before the attack is recognised. Mitigating its effects requires early recognition, confirmation, and prompt activation of an effective multi-agency response. The United Kingdom has a good public health infrastructure, well rehearsed in surveillance and in dealing with outbreaks of communicable disease, such as meningococcal disease. A threat involving a common pathogen, particularly if small scale or botched, may be recognised only by routine surveillance after the event.4 However, an attack involving a weaponised biological agent would produce disease not normally seen in this country, such as anthrax, plague, or botulism, and would have the most serious consequences. Early recognition will save lives and there is an imperative need to raise awareness among clinical staff both of the diseases and what must be done when such diagnoses are suspected (see box). The Public Health Laboratory Service, working with the Centre for Applied Microbiology and Research, the Department of Health, clinicians, and other public health doctors, has drawn up protocols and formalised a system for providing clinical and public health advice and confirmation by a reference laboratory. Interim guidance is available through the Public Health Laboratory Service website (www.phls.co.uk/facts/deliberate_releases.htm).

The broader public health response focuses on defining who has been exposed; logistic aspects such as delivering testing, treatment, or prophylaxis for large numbers of people; and providing appropriate timely advice to the health community and general public. The difficulty of these tasks, given the number of people who may be affected, cannot be overstated. Antibiotics remain our first line of defence for the bacterial agents and can be protective if given early in the incubation period. For example, in the anthrax cases in Florida, early appreciation of one man developing severe overwhelming respiratory disease allowed for deployed stocks of antibiotics to be rapidly delivered and administered to people thought to have been exposed on the same day as the diagnosis was made. There is no role for widespread use of antibiotics where no deliberate release has occurred or is suspected.

The disadvantage of raising awareness is the inevitable rise in false alarms and hoaxes. Suspect packages are a matter for the police, and must be dealt with in the same way as a bomb threat. If an opened package contains a suspicious powder (or a note threatening anthrax) it should be left alone. But the person who opened it should remain in the room and shut the door to avoid spreading possible contamination. The air conditioning should be switched off and help summoned via the local police. If the powder is found to contain anthrax, prophylactic antibiotics need to be started within a few hours, but this does allow time to make a proper assessment.6

The initial public health response to the current anthrax incidents in Florida and New York city has been exemplary. The initial Florida patient became ill one weekend; a diagnosis of pulmonary anthrax was made on the day he died. Once the diagnosis was made, the response was almost instantaneous, with the central state authorities and Centers for Disease Control in Atlanta immediately starting intensive case finding. This was because after 11 September the Centers for Disease Control and state public health departments had put most emergency rooms and hospitals on high alert through electronic alerting systems. Fortunately anthrax is not transmitted person to person, and to date in the Florida release only two cases of disease have been found.

The United Kingdom has been preparing to deal with the deliberate use of chemical or biological agents since the Toyko incident. No system will be able to mitigate the effects of a release completely, but our excellent public health systems and infrastructure give us a good start.