In the US, the Centers for diseases Control (CDC) have raised the alert level 2 of Ebola, which still implies a probability 'very low arrival of the virus, but which provides more' medical checks on travelers. This was announced by an official of the agency during a news conference. "The probability 'that the disease spreads outside of West Africa and' very low - explained Stephan Monroe, head of zoonoses CDC - but we must also be prepared to this remote possibility ''. The alert requires that physicians identify patients who may have recently traveled to the affected area, and to study the symptoms of the disease and to provide immediate treatment. The agency also warned those traveling in affected countries, currently Liberia, Guinea and Sierra Leone with a case 'imported' in Nigeria, to avoid contact with body fluids and blood of strangers. In Nigeria meanwhile the hospital where 'dead man coming from Liberia a few days ago and' quarantined. Health personnel, have announced the authorities' Nigerian, showed no signs of illness at the time, which can 'incubate up to 21 days but that and' contagious only when symptoms appear, while the airline with which he traveled the man has not yet provided a full list of passengers.