Table 2.

Detection latency and final outbreak size in four recent filovirus disease outbreaks.

Outbreak	Presumptive index case/spillover	Outbreak declared	Estimated detection latency	Cases reported at or near declaration	Final outbreak size and case fatality
Uganda, Sudan virus disease (2022)	Symptom onset retrospectively traced to approximately 8 August 2022	20 September 2022	~43 days (approx. 6 weeks)	Not systematically enumerated; retrospective review identified at least 43 early case-patients who had already sought care before recognition	164 cases (142 confirmed, 22 probable); 77 deaths (case fatality ratio 47%)
West Africa (Guinea-origin), Ebola virus disease (2013–2016)	Index case died 28 December 2013	WHO notified 23 March 2014	~85 days (approx. 12 weeks)	49 cases, 29 deaths (case fatality ratio 59%) reported at the time of WHO notification	28,616 cases; 11,310 deaths (case fatality ratio approx. 40%)
Rwanda, Marburg virus disease (2024)	Index case symptom onset retrospectively traced to approximately 8 September 2024	27 September 2024	~19 days (approx. 2.7 weeks)	Not systematically reported before declaration	66 cases; 15 deaths (case fatality ratio 23%)
Democratic Republic of the Congo (Bulape), Ebola virus disease (2025)	Index case symptom onset 10 August 2025; presentation to hospital 20 August 2025	4 September 2025	25 days (approx. 3.6 weeks)	28 suspected cases, 15 deaths (case fatality ratio 54%) reported at declaration	64 cases (53 confirmed, 11 probable); 45 deaths (case fatality ratio 70%)