Title: Default for Step 1.15 Calculating a serial interval - Quiz

Q: Assume that in Ebola the infectious period starts a minimum of one day after the onset of fever. What is the minimum serial interval for Ebola? (Hint: the minimum incubation period is two days.)
- 1 day (If the primary case develops a fever on day 0 and transmits the infection on day 1, the shortest time until the secondary case develops fever (i.e. the minimum incubation period) is 2 days. What would the minimum time be from the onset of fever in the primary case to the onset of fever in the secondary case? You may find 1.14 Epidemic curves and the spread of Ebola useful.)
- 2 days (If the primary case develops a fever on day 0 and transmits the infection on day 1, the shortest time until the secondary case develops fever (i.e. the minimum incubation period) is 2 days. What would the minimum time be from the onset of fever in the primary case to the onset of fever in the secondary case? You may find 1.14 Epidemic curves and the spread of Ebola useful.)
- 3 days (If the primary case develops a fever on day 0 and transmits the infection on day 1, the shortest time until the secondary case develops fever (i.e. the minimum incubation period) is 2 days. Thus the minimum serial interval is 3 days.)
- 4 days (If the primary case develops a fever on day 0 and transmits the infection on day 1, the shortest time until the secondary case develops fever (i.e. the minimum incubation period) is 2 days. What would the minimum time be from the onset of fever in the primary case to the onset of fever in the secondary case? You may find 1.14 Epidemic curves and the spread of Ebola useful.)
A: 3 days

Q: What is the approximate maximum serial interval for Ebola?

Remember that the maximum incubation period for Ebola is 21 days and that men who survive Ebola may continue to have the virus in their semen for up to 3 months after their symptoms have ended.
- Approximately 2 months (To calculate the maximum serial interval, think how long after the fever onset the first case can transmit, and how late after that the second case can get ill. You may find 1.14 Epidemic curves and the spread of Ebola useful.)
- Approximately 3 months (To calculate the maximum serial interval, think how long after the fever onset the first case can transmit, and how late after that the second case can get ill. You may find 1.14 Epidemic curves and the spread of Ebola useful.)
- Approximately 4 months (If we assume that the first case transmits as late as possible (3 months after symptoms have ended), and that the second case has the maximum incubation period of 21 days, then the maximum time between the onset of fever in successive cases is approximately 4 months. This is worked out as below: Maximum duration of illness in the first case (about 2 weeks) + 3 months (maximum of transmission in semen) before transmission to the second person (total so far: 3 and a half months). Then another 21 days (maximum incubation period) before the second case becomes ill - so slightly over 4 months.)
- Approximately 6 months (To calculate the maximum serial interval, think about how long after the fever onset the first case can transmit, and how late after that the second case can get ill. You may find 1.14 Epidemic curves and the spread of Ebola useful.)
A: Approximately 4 months