The Foreign Office said that because of the narrowing commercial options for flights and the impact on medical facilities, it advised against all but essential travel there, except for those involved in the direct response to the outbreak.
British citizens in the affected countries are advised to stay in contact with their employer or host organisation about the support they could provide for them while they were in the country or in the event of them wishing to leave.
The advice added: "You should be aware that the narrowing range of commercial flight options and growing restrictions on travel in the region may make it difficult to leave, particularly at short notice, and consider your own plans in this context."
It came as the World Health Organisation said the outbreak could eventually exceed 20,000 cases.
Latest figures revealed 1,552 people have now died from the virus.