What a heartbreaking disappointment this is for the people of Liberia, with a reported new case of EVD in a 44-year old woman who showed signs of disease 15th March and tested positive for Ebola virus on Friday 20th in Monrovia, Liberia.[2,7,8] after more then 3-weeks (28 days or more) with zero new cases and no ongoing, known, transmission of Ebola virus in any county in the country. The previous final case in Liberia tested negative around the 3rd of March (about 17-days ago), when the 42-day clock was started.
Now it has been stopped.
Starting it again will await this new case returning a negative test as well as all their contacts (who will be monitored for 21-days) being declared infection- (actually disease-, but I say infection intentionally) free.
And thus we enter the next phase – that of a different type of frustration and heartbreak as countries within the tri-nation hotzone come tantalisingly close to being declared free of known cases of Ebola virus disease (EVD; see how those seemingly pedantic words  have added meaning now?) or virus transmission, or in fact succeed only to have a random case pop up from somewhere unexpected or travel across a border causing disappointment for the people of the country, the aid workers and the family and friends of the new case.
A random case will also trigger all new contact tracing efforts to try and find the source and lock down further spread as quickly as possible.
There is noise on twitter (see Tweet below) and in the media quoting authorities  noting that the case may have been from a sexual contact with a previously infected male. Infectious virus has been found in semen in the past in which it can linger for more than a month [3,4], but this has not been a factor in the timing of release of convalescent males in the recent epidemic. If this is the route of acquisition, then the ensuing costs, scope of the response, risk to a country that had nearly cleared the virus and to the stamina of an Ebola-ravaged country may serve to justify additional testing the future.
#Liberia Min of Info says 'initial suspicions' are that country's 1st #Ebola victim in 28 days could have had sex w/ ebola survivorThe route of acquisition in this latest case remains totally unconfirmed at writing. I'll update this post as I find more details.
— Katerina Vittozzi (@kvittozzi) March 20, 2015
My thoughts are with you Liberians – stay strong – it’s a setback to be sure, but you were very close this time and will get there.