Cholera Epidemics of the Past Offer New Insights Into an Old Enemy. (20th November 2017)

• Record Type: Journal Article
• Authors: Phelps, Matthew; Perner, Mads Linnet; Pitzer, Virginia E; Andreasen, Viggo; Jensen, Peter K M; Simonsen, Lone
• Is Part Of: Journal of infectious diseases. Volume 217:Number 4(2018)
• Page Start: 641
• Page End: 649
• Publication Date: 2017-11-20
• Subjects: cholera -- epidemiology -- historical -- epidemics -- R0 -- transmission patterns; Communicable diseases -- Periodicals; Diseases -- Causes and theories of causation -- Periodicals; Medicine -- Periodicals; Communicable Diseases -- Periodicals; Electronic journals; 616.9
• DOI: 10.1093/infdis/jix602
• Languages: English
• ISSNs: 0022-1899

Abstract

Abstract : We investigate cholera transmission using data from historical cholera epidemics. The results suggest short-cycle (household/institution level) transmission was important in early secondary transmission. This study of historical outbreaks can inform investigations in current cholera epidemic settings. Abstract: 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 (R0 ). 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 (R0 ) 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 R0 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.