The role of doctors in bioterrorism response

Victims of an attack may not connect odd symptoms to a biological agent, particularly if they coincide with another event, such as a terrorist bomb attack. These patients are more likely to go to their local doctor than turn up at hospital or seek specialist help.

Accepting the role

Physicians today are still questioning the extent of their role in responding to bioterrorism and are understandably far more concerned about naturally occurring infectious diseases, particularly a pandemic of avian influenza, which would constitute an immediate and possibly overwhelming threat. Also, no substantial event has occurred since the anthrax mail attacks in October 2001 - the perpetrator of which has still not been named. Despite a series of government initiatives to stimulate research into new vaccines and drugs, such as Project Bioshield in the US, and to train first responders in dealing with nonconventional attacks, there is a noted lack of urgency in the medical community.

Recent studies have questioned the ability of doctors in the US to recognise correctly bioterrorist-related diseases. An article published in The Lancet in January 2005, encouraged doctors to exceed their role in diagnosing and reporting cases to support the investigation of a biological event. Medical schools are also urged to incorporate more information and training into their curriculum, as well as special medical education programmes and community drills to prepare physicians for an appropriate and speedy response to an attack.

Problems of diagnosis

Probably the most difficult aspect of the physician's role is diagnosing what are often rare diseases or conditions such as plague or botulism poisoning that should arouse suspicion of a deliberate pathogen release. A person infected with smallpox, for example, would not set off traditional security sensors installed in buildings and will be infectious without showing physical signs of illness. Findings and initial tests from the 1999 outbreak of West Nile virus encephalitis in New York City were consistent with St Louis encephalitis, and several months passed before the causative agent was correctly diagnosed as West Nile virus.

A delay in diagnosis could turn a limited outbreak into an epidemic or, in the case of highly infectious diseases, a pandemic given the increase in urbanisation and global travel. In September 2005, a research team from Johns Hopkins University in the US published in the Archives of Internal Medicine the results of a survey of more than 600 US doctors' ability to correctly diagnose a bioterrorist-related disease. It found that half of the doctors surveyed misdiagnosed botulism, 84 per cent misdiagnosed plague, and chickenpox was misdiagnosed as smallpox 42 per cent of the time. On average, just 46.8 per cent of the doctors in online testing correctly diagnosed smallpox, anthrax, botulism and plague. Given the proper diagnosis, only just over a quarter of the doctors identified the appropriate management strategy for the disease concerned.

A separate study published in the journal Academic Emergency Medicine in October 2005 found that 52 emergency physicians in Washington DC, averaged 59 per cent in a test on the diagnosis and management of smallpox. The facts least known were that when dealing with a known case of smallpox, fit-tested N95 masks are not needed by treating personnel if they have been vaccinated; that the rash of smallpox begins with 24 to 48 hours of flat, red raised areas (not small swellings, or blisters of clear fluid); and that the rash of smallpox very typically begins orally.

However, educational programmes and training materials in recent years have improved the ability of medical professionals to detect such diseases. Since 2003, the American Medical Association and other organisations have conducted National Disaster Life Support courses for around 14,000 physicians and healthcare workers. The American College of Physicians regularly updates biological agent topics in its communications to members and also conduct tabletop exercises.

Doctors in the Washington study improved their diagnostic skills after they took an online training programme following the initial test. After completing the course, their correct diagnoses averaged nearly 80 per cent. Correct assessment of the diseases rose to an average of 79 per cent and proper management was over 79 per cent correct.

Dealing with biocrime

As in the case of any unusual infectious disease case, doctors would have to alert public health authorities and other government agencies - in most cases for the first time - as well as begin treating victims.

The local health authorities and law enforcement authorities require notification when certain microbes and specific diseases such as plague emerge, or about abnormal symptoms or infections that would not normally be seen at a particular time or place. Attacks may also not be ideologically based. A level of vigilance would be needed that is not common to modern practice, where many infectious diseases can be treated by antibiotics or prevented by vaccination.

Doctors are being encouraged to preserve microbial samples and other items for forensic evidence, and maintain detailed patient records that could later be used by investigating authorities. Human tissue or secretion samples and cultures taken from the throat, blood, sputum or skin lesions of a patient could be preserved for microbiological examination. Preservation of samples from anthrax victims in 2001 allowed investigators to identify the strain being used and to affirm that it was laboratory-made rather than a naturally occurring disease. Medical examiners and coroners would also be involved in notifying unusual deaths.

As an attack would involve criminal investigation, doctors would have to report any unusual findings to public health authorities and law enforcement agencies. This is new territory that may be viewed as a threat to patient confidentiality.

Medical preparedness and response

Training in diagnosis and management of bioterrorism-related diseases emphasises that such an event has similarities to a public health emergency and a traditional disaster. The pathogen is likely to be released via aerosol; victims will have no immunological response; initial symptoms will resemble other, more common diseases such as flu or may not indicate a specific illness; and assistance from specialists or other agencies may take days.

Most doctors have little or no experience of evaluating or treating patients with many of these diseases. Since there is a delay between exposure and symptoms, patients will report their symptoms at various times and to various care providers. Certain diagnostic pointers can be considered. For example, doctors should suspect inhalation anthrax - which is usually fatal unless treated immediately - in any previously healthy patient with rapidly progressive sepsis and an unexplained widened membranous partition between the lungs on a routine chest film.

An unexpected variation in incidence of specific syndromes signals epidemiological investigation. This involves doctors exchanging information and is a labour-intensive exercise. For example, while flu occurs every year, plague is not expected - but human plague does exist in some southwestern states of the US.

Trends may emerge that point to deliberate release of biological agents. These include excessive absenteeism at work or school; demand for specific over-the-counter medications; people turning up to hospital emergency departments or local clinics with similar symptoms; similar cases emerging from the same source; increased incidence of animal illnesses; illness linked to exposure to ventilation systems; and cases involving poisoning.

Laboratory testing

Diagnosis is usually confirmed by laboratory tests, as making an absolute diagnosis of a bioterrorism-related disease may not be possible in most clinical settings. But doctors would, in most cases, have to inform authorities before diagnosis was confirmed by laboratory testing - as speed is of the essence to prevent further spread and labs often take time to grow cultures.

Many viral pathogens require sophisticated testing techniques that are not widely available or may need biosafety level III or IV facilities - such as those at the Center for Disease Control and the US Army Medical Research Institute of Infectious Diseases (USAMRIID) in the US, and the Health Protection Agency (HPA) Centre for Infections and the Centre for Emergency Preparedness and Response in Britain. These laboratories also supply specialist support in diagnosis and management.

However, some pathogens can be identified in local laboratories so that empirical treatment can begin and the healthcare network alerted. Laboratories may also find pathogens or toxins transmitted through aerosol, food or water contamination or positive tests for rare or antiquated strains of pathogens.

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