Greg Cochran argues that quarantine is the most effective strategy when dealing with serious infectious diseases. It works first time and every time.
So, why don’t the health authorities implement quarantine? I think the key issue is the management of blame.
If the authorities stop some-one coming directly from an infected area to an uninfected area without a period of observation in quarantine, they will be held responsible for having inconvenienced a large number of uninfected travelers. Identifying a few infected persons will seem almost redundant because the authorities assume that, being responsible and truthful citizens, infected persons would have handed themselves in to the health authorities the moment they started having symptoms. Hence, no need for quarantine.
The authorities also assume that people tell the truth on travel forms, and will tell the truth when interviewed at borders, and are bright enough to work out whether they are a possible vector.
So, the powers-that-be have a fall-back position: they assume that people are honest and, if not, they imagine can deal with the problem later. For example, the US authorities do not want to be seen treating an African from Milan the same as an African from Liberia, because that would prove they had identified the person as an African and were applying a blanket racial precaution. Of course, if the US authorities prevent a Liberian from flying direct to the US, then they need a procedure to prevent him flying in from a stop-over somewhere else. It would be almost as bad as profiling Chinese people for SARS.
The US health authorities also assume that tracing 100 possibly infected persons in the USA is less onerous than applying quarantine restrictions in the first place. However, if their failure to trace and contain possibly infected persons is only 1 in a 100, they will have doubled the Ebola risk for US citizens. They will be dealing with their US Patient Zero and an unknown US Patient One.
Perhaps, without being explicit about it, the authorities believe that once the virus takes a good hold then the outbreak will not be anyone's fault, because it will be seen as a fact of nature. They would have been blamed for having restricted tourists from Africa, but they cannot be blamed for an Act of God.
Those against quarantine for infectious diseases should recall the IRA's warning when they blew up the Brighton conference hotel where Mrs Thatcher and her Cabinet were sleeping but failed to assassinate her: "Today we were unlucky, but remember, we have only to be lucky once. You will have to be lucky always."