It’s too bad that many of the people debating the Ebola quarantine issue don’t know anything about virology. So far, the focus on New York’s reversal of its Ebola quarantine rule has centered on a single repeated claim: “The nurse tested NEGATIVE for Ebola!” Therefore she should be released, the logic goes.
Unfortunately, Ebola doesn’t work that way. A person who is carrying Ebola and replicating Ebola inside their own blood will test negative for Ebola for up to six weeks. The test won’t show a positive result until the virus has replicated to a sufficient quantity to be detectable.
This is the whole point behind the current 21-day observations periods and self-quarantine measures. If a person’s Ebola status could be instantly determined by one test administered at any time, then everyone could be either diagnosed or cleared on day one and there would be no reason to observe anyone for 21 days (or 42 days) in the first place.