measures. The measured duration of the incuba- tion period, and its variation, imply that the advice to follow case contacts for 21 days1 is appropriate. To curtail transmission in the com- munity, the period from symptom onset to hos- pitalization (a mean of 5 days but a maximum of >40 days) clearly needs to be reduced. Surpris- ingly, the mean was not shorter among health care workers, who are at risk both of acquiring and transmitting the infection to others. The average length of hospital stay of about 1 week (6.4 days) means that the number of beds re- quired to treat EVD patients is roughly equal to the rising weekly case incidence. Even without allowing for underreporting, 995 patients with confirmed, probable, or suspected infection were known to need clinical care in the week of Sep- tember 8 through 14 alone, which far exceeds the present bed capacity in Guinea, Liberia, and Sierra Leone (approximately 610 beds in total).
The data used in these analyses were collect- ed in the field by various field teams across Guinea, Liberia, Nigeria, and Sierra Leone. Al- though they provide an excellent opportunity to better understand the current EVD epidemic in Africa, they understate the magnitude of the