How Ebola spread

4 In October and November 2014, the virus goes from Guinea to Mali

3 June 2014: type B travels back into Guinea, where it spreads rapidly

2 Virus A mutates into type B and is exported to Sierra Leone and Liberia at end of May 2014

1 Virus A emerges in Guinea between December 2013 and February 2014. It spreads locally and nearly dies out around July 2014

Tonkolili

Kissidougou,

Gueckedou,

Macenta

Sierra

Leone

Outbreak centre

Mali

Guinea

Liberia

Cote

d’Ivoire

4 In October and November 2014, the virus goes from Guinea to Mali

3 June 2014: type B travels back into Guinea, where it spreads rapidly

2 Virus A mutates into type B and is exported to Sierra Leone and Liberia at end of May 2014

1 Virus A emerges in Guinea between December 2013 and February 2014. It spreads locally and nearly dies out around July 2014

Tonkolili

Kissidougou,

Gueckedou,

Macenta

Sierra

Leone

Outbreak centre

Mali

Guinea

Liberia

4 In October and November 2014, the virus goes from Guinea to Mali

3 June 2014: type B travels back into Guinea, where it spreads rapidly

2 Virus A mutates into type B and is exported to Sierra Leone and Liberia at end of May 2014

1 Virus A emerges in Guinea between December 2013 and February 2014. It spreads locally and nearly dies out around July 2014

Tonkolili

Kissidougou,

Gueckedou,

Macenta

Sierra

Leone

Outbreak centre

Mali

Guinea

Cote

d’Ivoire

Liberia

Cote

d’Ivoire

4 In October and November 2014, the virus goes from Guinea to Mali

3 June 2014: type B travels back into Guinea, where it spreads rapidly

2 Virus A mutates into type B and is exported to Sierra Leone and Liberia at end of May 2014

1 Virus A emerges in Guinea between December 2013 and February 2014. It spreads locally and nearly dies out around July 2014

Tonkolili

Kissidougou,

Gueckedou,

Macenta

Sierra

Leone

Outbreak centre

Mali

Guinea

Liberia