1st Ebola relapse recorded in Congo outbreak, WHO says

Health officials in eastern Congohave documented the first relapse in the current Ebola epidemic,the World Health Organization said on Friday.

The Ebola outbreak in Congo has sofar infected more than 3,300 people and killed more than 2,200 since the middle of last year, making it the second-worst onrecord.

In early December, Congolese health authorities reportedthat a survivor in Mabalako, North Kivu province, had fallen illwith the virus again.

Preliminary tests have since classified it as a relapse, theWHO said in a weekly report.

"Rare cases of relapse in which a person who has recoveredfrom EVD [Ebola]gets disease symptoms again have beendocumented during past outbreaks, but this is the first relapsedocumented in this outbreak," it said.

Eleven new Ebola cases were confirmed in the past week, allof whom are believed to have caught the virus from the personwho relapsed, according to the WHO. Overall the case was apotential source of infection for 28 people, it said.

"It is a single transmission chain but it is worrying," saidMike Ryan, head of the WHO's emergencies program, on Thursday.

He said the situation in Mabalako was worrying partly due toits proximity to the town of Butembo, a populous trading hub andone-time epicentre of the outbreak.

Virus goes underground+

"We had a massive problem [in Butembo] only sixmonths ago, sothere is real concern that any continued transmission inMabalako may potentially re-infect Butembo."