LONDON In A.D. 166, a smallpox epidemic struck Rome. Galen, who had already acquired a reputation for his dissections, fled the city. In 1382, Venice passed a law forbidding physicians to flee in times of plague, and other European cities followed suit. When the plague hit London in 1665, many of the city's physicians - the great Thomas Sydenham included - abandoned their patients to escape the outbreak. In 2003, there were nurses and physicians who refused to care for SARS-infected patients
Whether wise or cowardly, all these health care workers were aware of a simple fact: Those treating patients are often among the first victims of virulent epidemics. In 2005, with the impending arrival of bird flu on our shores, the question arises: Do health care professionals have a duty to treat bird flu patients?
Aware of the likely shortage in case of a pandemic, some forward-thinking physicians are already keeping stocks of the antiviral Tamiflu to treat their relatives. "As a husband, a father and a friend, do I think the idea of personally stockpiling is something you should be considering? Absolutely," one public health physician said on a Canadian news channel.
Whatever one's ethical stance on this practice, it raises an important point: A physician is not just a physician, but also a parent, spouse, son or daughter. Each of these roles brings accompanying duties and obligations that in a time of epidemic may clash with his or her role as a physician.
If bird flu proves to be dangerously infectious and some health care workers refuse to treat afflicted patients on the grounds of excessive risk, what should hospitals do? More than self-preservation, many doctors with partners, elderly parents or small children at home may be reluctant to expose their loved ones to the disease. In such situations, which duty should prevail - the duty to patients, to children, to oneself? Which carries more moral weight? How can this tension between professional and personal duties be reconciled, if at all?
In the medical and academic literature, little has been written on the limits of a physician's duty of care. It is a neglected issue, perhaps because only recently have physicians in the West been exposed to serious occupational risks from new, highly infectious diseases. Illustrating the complacent optimism of the second half of the 20th century, the U.S. surgeon general William Stewart confidently announced to Congress in 1969, "It is time to close the book on infectious diseases."
In the last 30 years, major Western hospitals have treated patients with HIV/AIDS, Ebola hemorrhagic fever, Lassa fever, West Nile virus, SARS and a range of other lethal pathogens from Africa and Asia. The popularity and speed of air travel has opened up the possibility of transferring hitherto local diseases into all parts of the world. Whereas it took a year to travel around the world in 1850, it takes little more than 24 hours in 2005.
As hospitals and governments discuss emergency responses to the bird flu pandemic, they must address the acute ethical dilemmas of health care workers' duty of care. Physicians and nurses are indispensible to any emergency response. I suspect the limits of the duty of care are not absolute, but determined by a combination of factors, like workers' specialties - an infectious disease specialist should undergo more risk than a rheumatologist - their competing obligations as wearers of multiple hats and the normal risk level of their working environment.
In any case, the limits of the duty of care need to be discussed and specified before the arrival of the bird flu pandemic. If the experts are correct, time is short.
(Daniel K. Sokol, a medical ethicist at the Imperial College Faculty of Medicine, London, is a co-author of ''Medical Ethics and Law.'')