Updated

Ebola centres in Sierra Leone overflowed on Wednesday as health workers combed the streets of the capital Freetown for patients, after the government launched a major operation to contain the epidemic in West Africa's worst-hit country.

President Ernest Bai Koroma said on national television that travel between all parts of the country had been restricted as part of "Operation Western Area Surge", and public gatherings would be strictly controlled in the run-up to Christmas.

In the Devil Hole neighbourhood just outside Freetown, Ebola surveillance officers questioned Ibrahim Kamara as he sat in a discarded vehicle tyre, his eyes glassy and his breath coming in gasps.

"Is the body weak?" a surveillance officer shouted. Kamara, 31, nodded despondently while onlookers gathered round.

"Vomiting?" the officer asked. Kamara nodded again.

Kamara's wife, Adama, said a neighbour had died on Saturday from Ebola-like symptoms. When they had tried to take a taxi to hospital, the driver made them get out when he discovered her husband was ill.

The surveillance officers wrote down the Kamaras' address and the names of five family members in their household, before calling an ambulance.

Such street-by-street searches form a key part of a month-long push by the government, a British task force and international groups in the populous west of Sierra Leone, where the epidemic is raging. Their aim is to score a breakthrough against the disease within four to six weeks.

Sierra Leone, neighbouring Guinea and Liberia are at the heart of the world's worst recorded outbreak of Ebola. Rates of infection are rising fastest in Sierra Leone, which now accounts for more than half of the 18,603 confirmed cases of the virus.

The death toll from the epidemic has risen to 6,915 as of Dec. 14, the World Health Organization said on Wednesday, adding that the increase cases in Sierra Leone appeared to have slowed, although 327 new cases were confirmed there in the past week.

Shortages of resources, strikes by unpaid healthcare workers and logistical challenges have dogged the fight against Ebola in Sierra Leone.

The ambulance meant to collect Kamara took three hours to arrive in Devil Hole, where he had already been waiting for six hours on the street. A nurse in the ambulance said some holding centres were already full as a result of the surge.

When the ambulance drove away, Kamara left behind a red blanket. It was immediately sprayed with disinfectant by the Ebola response team while his wife watched expressionless.

NEW MEASURES

At the King Tom Cemetery in Freetown, weary grave diggers clothed head to foot in protective waterproof yellow clothing said that they had buried 51 people on Wednesday alone.

With the cemetery already full, burial teams have expanded the site to a former rubbish dump, angering some bereaved families. Syringes and rusting iron lay in empty graves, while the burial teams had to throw stones at pigs roaming among the rubbish to keep them away from the dead.

Health officials are alarmed by the widespread transmission in Freetown, similar to an eruption of Ebola in the Liberian capital Monrovia in August which is only now being brought under control.

According to the government plan, health workers will seek victims and anyone with whom they have had contact, transporting the infected to new British-built treatment centres.

"Given the efforts we have undertaken we would expect to see a significant decrease in cases within several weeks," Tom Frieden, director of the U.S.-based Centers for Disease Control and Prevention, told Reuters during a visit to Freetown.

The programme showed some early signs of progress. Russell Macleod, a British military consultant with the surveillance team in the Western command and control centre in Freetown, told Reuters they received a record number of alerts that morning.

By lunchtime, they exceeded Tuesday's total by 50 percent with 140 alerts on the Ebola hotline. In response, the live case management team dispatched teams to 52 suspected cases, he said.

As part of the efforts, Koroma said worshippers on Christmas Day must return home after services and other festivities are banned. New Year's Eve services must stop by 5 p.m. local time (12.00 noon ET), while New Year's Day festivities are prohibited.

The government also banned Sunday trading and halted Saturday shopping at noon, Koroma said.

"This is the festive season where Sierra Leoneans often celebrate with families in a flamboyant and joyous manner but all must be reminded that our country is at war with a vicious enemy," he said.