Abstract
Background. Cholera epidemics devastated 19th century European cities in multiple outbreaks during 1830-1900. Most Danish cities experienced only a single epidemic in 1853 and detailed data are available. This uniquely allows study of unmitigated epidemic cholera in a fully susceptible population. These insights can be used for empirical parameterization of mathematical models of cholera transmission. Here we describe the Danish cholera experience and provide a detailed examination of the transmission and impact of cholera outbreaks in three cities including Copenhagen.
Methods: We accessed cholera surveillance data and contemporary descriptions by physicians of the outbreaks from Danish archives. We also accessed census data and annual mortality time series data available by cause and age, and used statistical modeling to attribute age-specific cholera mortality burden. The intrinsic transmission coefficient, R0, was estimated from the early epidemic weeks using an exponential growth and maximum likelihood method. Narratives of individual case clusters were used to estimate the serial interval.
Results: The outbreaks typically occurred in late summer months of 1853. Physicians recorded only patients with severe cholera (rice water diarrhea and severe dehydration). The case fatality ratio (CFR) was 54%-68% and the overall mortality impact ranged from 3.4% to 7.7% of the population. Seniors aged 70+ years in Copenhagen had the highest mortality rates (16% died) whereas only 2.7% of children under 5 died. We derived point estimates for R0 at 1.5-2.2. Narratives of index patients and their contacts were used to compute the generation interval to be 3.1 days (1.9 - 4.5).
Discussion: Unique data of cholera outbreaks in Danish historic pre-sanitation cities allowed assessment of key epidemiological parameters needed to parameterize dynamic disease models used to gage the likely effect of interventions in contemporary disaster settings. This low-income pre-sanitation historic setting may serve as a proxy for populations in contemporary resource poor urban settings.
Methods: We accessed cholera surveillance data and contemporary descriptions by physicians of the outbreaks from Danish archives. We also accessed census data and annual mortality time series data available by cause and age, and used statistical modeling to attribute age-specific cholera mortality burden. The intrinsic transmission coefficient, R0, was estimated from the early epidemic weeks using an exponential growth and maximum likelihood method. Narratives of individual case clusters were used to estimate the serial interval.
Results: The outbreaks typically occurred in late summer months of 1853. Physicians recorded only patients with severe cholera (rice water diarrhea and severe dehydration). The case fatality ratio (CFR) was 54%-68% and the overall mortality impact ranged from 3.4% to 7.7% of the population. Seniors aged 70+ years in Copenhagen had the highest mortality rates (16% died) whereas only 2.7% of children under 5 died. We derived point estimates for R0 at 1.5-2.2. Narratives of index patients and their contacts were used to compute the generation interval to be 3.1 days (1.9 - 4.5).
Discussion: Unique data of cholera outbreaks in Danish historic pre-sanitation cities allowed assessment of key epidemiological parameters needed to parameterize dynamic disease models used to gage the likely effect of interventions in contemporary disaster settings. This low-income pre-sanitation historic setting may serve as a proxy for populations in contemporary resource poor urban settings.
| Original language | English |
|---|---|
| Publication date | Nov 2016 |
| Number of pages | 1 |
| Publication status | Published - Nov 2016 |
| Event | American Society of Tropical Medicine and Hygiene Annual Meeting - Atlanta, Atlanta, United States Duration: 13 Nov 2016 → 17 Nov 2016 Conference number: 65 |
Conference
| Conference | American Society of Tropical Medicine and Hygiene Annual Meeting |
|---|---|
| Number | 65 |
| Location | Atlanta |
| Country/Territory | United States |
| City | Atlanta |
| Period | 13/11/2016 → 17/11/2016 |
