The Ebola outbreak in the Democratic Republic of Congo has spread to a city, the World Health Organization said Thursday, fuelling concern the deadly virus may prove tougher to contain.
The fresh outbreak, publicly declared on May 8 with 23 deaths so far, had previously been confined to a very remote, rural area in Equateur Province in the northwest of the country.
But the UN's health agency confirmed that an Ebola case has been recorded in the city of Mbandaka, which lies roughly 150 kilometres (90 miles) from the Bikoro area where the outbreak originated.
"This is a concerning development," WHO Director-General Tedros Adhanom Ghebreyesus said in a statement.
Last week, a top WHO official warned that if the virus reached Mbandaka, the DRC could be confronted with yet another Ebola crisis.
The city's population has been variously estimated at between 700,000 and 1.2 million.
"If we see a town of that size infected with Ebola, then we are going to have a major urban outbreak," the WHO's head of emergency response, Peter Salama, told reporters last week.
The agency said Thursday it was deploying around 30 experts to Mbandaka "to conduct surveillance in the city," including rapid efforts to trace all contacts of the new urban case.
Forty-four cases have been reported in the outbreak so far, including three confirmed, 20 probable and 21 suspected, according to the WHO's tally.
Ebola is not only lethal but also highly contagious, which makes it difficult to contain and roll back.
Lacking an arsenal of drugs to treat or prevent the virus, doctors use classic tactics of isolating patients and tracing people who have been in contact with them.
That challenge amplifies greatly in urban environments where people move around more and have more contact with others than in the countryside.
Adding to the headache is the fact that the virus has broken out anew in one of the world's most vulnerable and volatile countries.
A country four times the size of France, the DRC has been chronically unstable and episodically racked by violence since it gained independence from Belgium in 1960.
Despite vast mineral wealth, the country remains mired in poverty, and is saddled with a reputation for corruption and poor governance. Basic infrastructure -- hospitals, roads, electricity -- is a major obstacle in remote areas.
This is the ninth time DRC has been hit with Ebola since 1976, when the deady viral disease was first identified in then-Zaire by a Belgian-led team.
The virus is widely regarded as one of the world's most terrifying as it can spread easily and kill quickly.
WHO has also confirmed that the current outbreak is the same strain of the virus that broke out in West Africa in 2013 and went on to kill more than 11,300 people, the deadliest ever Ebola epidemic.
WHO was fiercely criticised over its handling of the 2013 outbreak.
Tedros, who took charge WHO last year, has vowed that improving crisis response would be a key priority for the agency.
"We now have better tools than ever before to combat Ebola," he said Tuesday after visiting DRC at the weekend to assess the response.
Terrible infrastructure in Bikoro, especially a poor road network has created logistical complications for health workers trying to reach the area.
But WHO response this time around has been helped by a new experimental vaccine, which arrived in DRC on Wednesday and has been cleared for use by the Kinshasa government.
Tedros assured at the weekend that WHO had enough doses of the vaccine to respond, but it was not immediately clear whether the stockpiles were sufficient to handle a significant urban outbreak.