Table 1.
Ebola Virus Disease Incubation Period, Latent Period, and Time to Onset of Wet Symptoms
| Author | Incubation Period |
||||||
|---|---|---|---|---|---|---|---|
| Reference | Outbreak Location | Year | Species | Exposure Type | Value ± SD or (Range), Days | N | |
| Incubation period, percutaneous transmission | |||||||
| Breman et al; International Commission | [9, 13] | Zaire | 1976 | Zaire ebolavirus | Contaminated needle injection | 6.3 ± N/A (range 1–15) | 57 |
| Emond et al | [14] | Porton Down, England | 1976 | Not specified (Zaire ebolavirus or Sudan ebolavirus inferred) | Needlestick | 6 ± N/A | 1 |
| Heymann et al | [15] | Tandala, Zaire | 1977–1978 | Zaire ebolavirus | Laceration | 12 ± N/A | 1 |
| Khan et al | [16] | Kikwit, DRC | 1995 | Zaire ebolavirus | Contaminated needle injection | 3 ± N/A (range 1–6) | 11 |
| Mean incubation period (percutaneous route)a | 5.86 ± 1.42 | 70 | |||||
| Incubation period, person-to-person transmission | |||||||
| Breman et al; International Commission | [9, 13] | Zaire | 1976 | Zaire ebolavirus | Single contact | 2 ± N/A | 1 |
| Bwaka et al | [17] | Kikwit, DRC | 1995 | Zaire ebolavirus | Direct HCW contact | 6.2 ± N/A (range 5–8) | 5 |
| Bitekyerezo et al | [18] | Mbarara, Uganda | 2000 | Sudan ebolavirus | Crowded accommodation contact | 7 ± N/A | 1 |
| Leroy et al | [19] | Ndongo, DRC | 2007 | Zaire ebolavirus | Washed corpse | 8 ± N/A | 1 |
| Incubation period, animal-to-person transmission | |||||||
| Baize et al | [20] | Mayibout, Gabon | 1996 | Zaire ebolavirus | Consumed chimpanzee (decedents) | 7.8 ± 0.9 | 12 |
| Baize et al | [20] | Mayibout, Gabon | 1996 | Zaire ebolavirus | Consumed chimpanzee (survivors) | 8.4 ± 1.3 | 5 |
| Mean incubation period (non-percutaneous route)a | 7.34 ± 1.35 | 25 | |||||
| Incubation period, unknown route of transmission | |||||||
| Richards et al | [21] | Gabon/Johannesburg, RSA | 1996 | Zaire ebolavirus (inferred) | Assisted in CVC placement | 3 ± N/A | 1 |
| Mean incubation period (all routes of transmission)a | 6.22 ± 1.57 | 96 | |||||
| Latent Period |
|||||||||
|---|---|---|---|---|---|---|---|---|---|
| Reference | Outbreak Location | Year | Species | Exposure Type | Initial Symptom(s) | Initial wet Symptom(s) | Value ± SD, days | N | |
| Emond et al | [14] | Porton Down, England | 1976 | Not specified (Zaire ebolavirus or Sudan ebolavirus inferred) | Needlestick | Fever, central abdominal pain, nausea | Diarrhea, vomiting | 9.5 ± N/A | 1 |
| Richards et al | [21] | Gabon/Johannesburg, RSA | 1996 | Zaire ebolavirus (inferred) | Assisted in CVC placement | Fever | Hematemesis, melena | 14 ± N/A | 1 |
| Mean latent perioda | 11.75 | 2 | |||||||
| Time to Onset of Dry to Wet Symptoms |
||||||||
|---|---|---|---|---|---|---|---|---|
| Reference | Outbreak Location | Year | Species | Initial Symptom(s) | Initial wet Symptom(s) | Value ± SD, days | N | |
| International Commission; Isaacson et al; Sureau et al | [13, 22, 23] | Zaire | 1976 | Zaire ebolavirus | Fever, headache | Hematemesis | 6 ± N/A | 1 |
| Sureau et al | [23] | Zaire | 1976 | Zaire ebolavirus (inferred) | Fever, generalized pain, vomiting | Vomiting | 0 ± N/A | 1 |
| Sureau et al | [23] | Zaire | 1976 | Zaire ebolavirus (inferred) | Fever, lumbar pain, vomiting | Vomiting | 0 ± N/A | 1 |
| Emond et al | [14] | Porton Down, England | 1976 | Not specified (Zaire ebolavirus or Sudan ebolavirus inferred) | Fever, central abdominal pain, nausea | Diarrhea, vomiting | 3.5 ± N/A | 1 |
| WHO/International Study Team | [24] | Southern Sudan | 1976 | Not specified | Fever, headache, chest pain | Epistaxis, bloody diarrhea | 4 ± N/A | 1 |
| Richards et al | [21] | Gabon/Johannesburg, RSA | 1996 | Zaire ebolavirus (inferred) | Fever | Hematemesis, melena | 11 ± N/A | 1 |
| Shoemaker et al | [25] | Uganda | 2011 | Sudan ebolavirus | Mild headache | Vomiting | 4 ± N/A | 1 |
| Kreuels et al | [26] | Sierra Leone | 2014 | Zaire ebolavirus | Malaise, headache, myalgia, arthralgias | Vomiting, nonbloody diarrhea | 6 ± N/A | 1 |
| Lyon et al | [27] | Monrovia, Liberia | 2014 | Zaire ebolavirus | Fever, fatigue, nausea | Diarrhea, melena | 5 ± N/A | 1 |
| Lyon et al | [27] | Monrovia, Liberia | 2014 | Zaire ebolavirus | Fever, fatigue, malaise | Diarrhea | 8 ± N/A | 1 |
| Wolf et al | [28] | Sierra Leone | 2014 | Zaire ebolavirus | Fever, diarrhea | Diarrhea | 0 ± N/A | 1 |
| Lopaz et al | [29] | Spain | 2014 | Zaire ebolavirus | Fever, malaise | Vomiting, diarrhea | 7 ± N/A | 1 |
| Mean time to onset of dry to wet symptomsa | 6.05 ± 2.38 | 12 | ||||||
Abbreviations: CVC, central venous catheter; DRC, Democratic Republic of the Congo; HCW, healthcare worker; N/A, not applicable; RSA, Republic of South Africa; SD, standard deviation; WHO, World Health Organization.
a Combined parameter values were fitted to the normal distribution and weighted by observation frequency.