Health workers will fan out in Guinea's capital of Conakry to try to identify people who may have been exposed to the deadly Ebola virus, the World Health Organisation (WHO) said on Thursday.
Tracing people in a city of around 2 million who may have had physical contact with infected people is harder than in the epicenter of the outbreak, Guinea Forestiere some 900 km from the capital, the United Nations agency says.
Seventy people have begun intensive training on contact tracing in Conakry, the WHO said in a statement. "They will go into the communities to follow up on specific persons who had close contacts with patients with a confirmed Ebola infection."
Infection control measures in Donka national hospital and health facilities are also being stepped up to halt spread of the disease, which can kill up to 9 out of 10 patients, it said. The virus can be transmitted by touching victims or their vomit or body fluids.
To date, 157 possible cases of Ebola have been identified in Guinea, 66 of whom have been confirmed as having the virus, the WHO said. They include 101 deaths.
Liberia has 21 suspected and confirmed cases including 10 deaths, but experts fear the virus could spread to other countries in the West Africa region. Samples tested in Mali, Ghana and Sierra Leone have been negative so far.
The WHO said on Tuesday it could take two to four months to contain the "challenging" outbreak, the first in the region.
Keiji Fukuda, the WHO's assistant director-general, told reporters the virus tends to transmit more easily in cities, which is complicating control measures.
"Once you get into populations which are dense and people are interacting with each other in a close way in a way that you do in cities, it can it make easier for the infection to transmit," he said.
"It can also make it more difficult to actually identify contacts. Because everyone you have contact with is not necessarily people that you are going to know.
"So these things tend to be a little bit easier when we are in a rural setting and we have a less dense population."