Now that two nurses treating Ebola victim Thomas Eric Duncan have themselves been cleared of the disease, it is time to ask: Do nurses and other healthcare professionals have a duty to treat patients? What of the unsung healthcare "workers" -- hazmat teams, EMTs, transporters who wheel stretchers, lab techs who test urine and blood, or the valet who escorts a vomiting person to the ER door?

It feels irreverent to ask this while across West Africa altruistic people are risking death each day to provide care. Sheik Umar Khan, Sierra Leone's top Ebola doctor, died this July at age 39 after treating over 100 patients. He joins a growing number of physicians, nurses, and workers who have given their lives since the first outbreak in 1976.

The "duty" question dates back many years ago. In 1982 and 1983, when no one knew much about a "gay plague" other than that it was deadly, the right professional specialists stepped up to treat patients. Infectious disease specialists, including my colleague Dr. Roy Steigbigel, Professor of Infectious Disease at Stony Brook Hospital, affirmed their duty and worked on the AIDS ward, together with well-trained volunteer nurses. When in early 1984 the anxiety subsided, AIDS patients came to be treated by all professionals as needed.

Even earlier, during the Civil War, the Sisters of Mercy were the ones who stepped forward to provide comfort to those stricken with Yellow Fever, not the doctors. Later, in the Yellow Fever epidemics of the 1890s, Army physician Walter Reed braved the contagion in Cuba during the Spanish American War and proved the "mosquito hypothesis," which led to the disease's eradication. Yellow Fever virus, a viral hemorrhagic fever as is Ebola, was isolated in 1927. Vaccines were developed in the 1930s.

There is always risk in serving patients, just as there is a general duty for all doctors and nurses to treat born from three dimensions of the professional ethics: First, countries around the world invest significant resources in medical education and can, therefore, justifiably make demands on beneficiaries. Second, a general beneficence, including some risk to self, is fitting for those "called" into medicine and can reasonably be expected. And third, a duty to treat is one aspect of justice within the profession. It is necessary for the just distribution of physician and nursing burdens.

But specific epidemics differ in both degree of risk and the extent to which treatments can make any substantive difference in patient outcomes. When the risks are very high and the treatment benefits low, a duty to treat is less than categorical.

In fact, the risks of Ebola are very high. After 10 months in West Africa, 348 of 2000 (or 17.4 percent) of those fighting the disease contracted it, at least half of whom have died. Most infections occur when removing protective gear (masks, gowns, gloves or full "hazmat" suits), even though removal should be monitored and include being sprayed with disinfectant (generally followed by a mild disinfectant shower). The CDC is likely to require these steps after the failures in Dallas. But all it takes to become infected is to touch the outside of a gown or goggles and then touch one's eyes, nose, mouth, or scratch.

Equally significant, CDC authorities are asking if procedures like intubation and dialysis make sense given the added risks to those who implement them and unlikely benefits. In West Africa, such treatments are not used with Ebola patients. The American tendency to over treat the dying will not serve us well.

What will be beneficial are well trained and experienced professionals with expertise in infectious disease, who dutifully follow stringent procedure and apply their craft, such as those at Emory University Hospital who treated two American volunteers infected in West Africa, and another at the University of Nebraska. Risks were well controlled and benefits to patients significant. With great care good things happen.

So do professionals have a duty to treat Ebola patients? I say yes for physicians and nurses who are infectious disease specialists so long as they have ample experience. They accepted their duty when they chose their specialty. Intensive care specialists should also treat Ebola patients, but high tech dying makes no sense. Emergency medicine staff have certain duties. Hematologists have a duty to treat because of the hemorrhagic nature of Ebola. But this duty is not generalizable across medicine or nursing.

Caring for Ebola patients is strictly a matter for experienced personnel, and not for the young Dallas graduate of a nursing program who now has tested positive for the disease. Perhaps she might have stepped forward on a volunteer basis, but she should have had a great deal of training and monitoring first. Of course, it is difficult to spot Ebola until it is highly symptomatic. Thus, inexperienced people will encounter Ebola patients without choice when it is only mildly symptomatic - like unwitting travelers on the flight from Cleveland to Dallas.

What of healthcare "workers"? Society can hope that with proper preparation to better handle lab specimens, body fluids and waste on surfaces, they might also be counted on. We could call for volunteers, train well, and triple salaries. Nevertheless, they swore no oath.

The world is a small place now. Rarely have developed nations done less when they should have been doing more. Let's hope for a vaccine because the ethical questions are too complex and a cure is unlikely. But in the meanwhile, we cannot neglect the question of who has a duty to treat.