TY - JOUR
T1 - Cholera epidemics of the past offer new insights into an old enemy
AU - Phelps, Matthew
AU - Perner, Mads Linnet
AU - Pitzer, Virginia E
AU - Andreasen, Viggo
AU - Jensen, Peter K M
AU - Simonsen, Lone
PY - 2018/2/15
Y1 - 2018/2/15
N2 - Background. Although cholera is considered the quintessential long-cycle waterborne disease, studies have emphasized the existence of short-cycle (food, household) transmission. We investigated singular Danish cholera epidemics (in 1853) to elucidate epidemiological parameters and modes of spread. Methods. Using time series data from cities with different water systems, we estimated the intrinsic transmissibility (R 0 ). Accessing cause-specific mortality data, we studied clinical severity and age-specific impact. From physicians' narratives we established transmission chains and estimated serial intervals. Results. Epidemics were seeded by travelers from cholera-affected cities; initial transmission chains involving household members and caretakers ensued. Cholera killed 3.4%-8.9% of the populations, with highest mortality among seniors (16%) and lowest in children (2.7%). Transmissibility (R 0 ) was 1.7-2.6 and the serial interval was estimated at 3.7 days (95% confidence interval, 2.9-4.7 days). The case fatality ratio (CFR) was high (54%-68%); using R 0 we computed an adjusted CFR of 4%-5%. Conclusions. Short-cycle transmission was likely critical to early secondary transmission in historic Danish towns. The outbreaks resembled the contemporary Haiti outbreak with respect to transmissibility, age patterns, and CFR, suggesting a role for broader hygiene/sanitation interventions to control contemporary outbreaks.
AB - Background. Although cholera is considered the quintessential long-cycle waterborne disease, studies have emphasized the existence of short-cycle (food, household) transmission. We investigated singular Danish cholera epidemics (in 1853) to elucidate epidemiological parameters and modes of spread. Methods. Using time series data from cities with different water systems, we estimated the intrinsic transmissibility (R 0 ). Accessing cause-specific mortality data, we studied clinical severity and age-specific impact. From physicians' narratives we established transmission chains and estimated serial intervals. Results. Epidemics were seeded by travelers from cholera-affected cities; initial transmission chains involving household members and caretakers ensued. Cholera killed 3.4%-8.9% of the populations, with highest mortality among seniors (16%) and lowest in children (2.7%). Transmissibility (R 0 ) was 1.7-2.6 and the serial interval was estimated at 3.7 days (95% confidence interval, 2.9-4.7 days). The case fatality ratio (CFR) was high (54%-68%); using R 0 we computed an adjusted CFR of 4%-5%. Conclusions. Short-cycle transmission was likely critical to early secondary transmission in historic Danish towns. The outbreaks resembled the contemporary Haiti outbreak with respect to transmissibility, age patterns, and CFR, suggesting a role for broader hygiene/sanitation interventions to control contemporary outbreaks.
U2 - 10.1093/infdis/jix602
DO - 10.1093/infdis/jix602
M3 - Journal article
C2 - 29165706
SN - 0022-1899
VL - 217
SP - 641
EP - 649
JO - The Journal of Infectious Diseases
JF - The Journal of Infectious Diseases
IS - 4
ER -
