Your comment about HIV and Ebola transmission, and the need for hazmat suits, is not consistent with the many medical workers who were infected in Africa, as well as three infected in Spain and the US. HIV was not responsible for such a common occurrence of infections in medical workers.

The reason why there are over 1000 people being monitored or in isolation in the US is that there is evidence that Ebola survives on surfaces for up to 6 days. Body fluids in which Ebola virus has been found include sweat. As far as we know, Ebola can be transmitted by shaking a sweaty hand (with an abrasion on your hand [abrasions are quite common} or later touching your face). Or by touching an arm rest that was previously touched. This is quite different from HIV. Moreover, (1) an infected Ebola patient profusely bleeds, vomits and has diarrhea due to the action of the disease, and (2) the density of Ebola virus in body fluids has been measured to be orders of magnitude higher than that of HIV, which means that how contact results in infection is quite different.

More generally, speculation about whether we are safe or are not is just that, the amount of knowledge is limited. Until this outbreak Ebola was confined to villages in remote rural areas of a few countries in Africa. There is not much research and not much experience with it. Without data we just don't know. So ultimately we may find it is not very contagious, or we may find it is contagious enough to overwhelm the tracing methods used now. The difference is only a few cases. If current knowledge is right we may have no new cases in the US, or we may have 10 new cases. With 10 cases the tracing of individual contacts becomes remarkably difficult, with a few more it becomes essentially impossible. An outbreak in Africa might be contained if we send thousands of workers there to control it. If it becomes uncontrolled here, who is able to stop it?

Anticipating risks and responding to uncertainty is critical to survival, not just hindsight if things happen to work out for the best.

As an additional point: It is my understanding that the approach which precludes quarantines is responsible for the problem that we have today. If there were boundaries enforced at earlier times during the epidemic within the countries affected it would not have spread within those countries as much as it has. It would have been confined to smaller regions. Note that Senegal successfully avoided transmission by closing its border as of March!

I see the reluctance to use travel restrictions as a failure of basic understanding of how contagions must be controlled in general. The problem arises because the public health officials are trained to think in terms of individual care rather than community vulnerability. They are focused on treating the individual who is sick, and presents him or her self to the hospital. The public is an aggregate of individuals without structure of its own. This is the standard medical model today. It works for many problems. The addition of contact tracing is effective also for a limited number of types of diseases, including TB which is the epidemiological background of CDC Director Frieden. It works for TB because there is a latent population whose number changes only very slowly that is the source of infective individuals. Detecting the latent individuals and treating them reduces the number of infective individuals. There is no exponential growth of the population affected as there is in Ebola. An exponential growing outbreak requires direct attention to the transmission not just the specific care that is needed for individuals. Stopping the transmission cuts off the number of cases that then need care. This is the key to controlling outbreaks --- i.e. prevention of new cases.

That is a very important point, Delise.