Dataset Information

The influenza pandemic of 1918-1919 in Sri Lanka: its demographic cost, timing, and propagation.

ABSTRACT:

Background

As an island and a former British colony, Sri Lanka is a case of special interest for the study of 1918-1919 influenza pandemic because of its potential for isolation from as well as integration into the world epidemiologic system.

Objectives

To estimate population loss attributable to the influenza pandemic and weekly district-level excess mortality from the pandemic to analyze its spread across the island.

Methods

To measure population loss, we estimated a population growth model using a panel of 100 district-level observations on population for five consecutive censuses from 1891 to 1931, allowing for a one-time drop in population in 1918-1919. To estimate weekly excess mortality from the pandemic, we estimated a seasonally adjusted weekly time series of district-specific mortality estimates from vital registration records, ranked them, and plotted the ranks on weekly maps to create a picture of the geographic pattern of propagation across Sri Lanka.

Results

Total loss of population from the influenza pandemic was 307 000 or approximately 6·7% of the population. The pandemic peaked in two discrete (northern and southern) regions in early October of 1918 and in a third (central) region in early March 1919.

Conclusions

The population loss estimate is significantly higher than earlier estimates of mortality from the pandemic in Sri Lanka, suggesting underreporting of influenza-attributable deaths and a role for influenza-related fertility declines. The spatial pattern of peak mortality indicates the presence of two distinct entry points and three distinct epidemiologic regions, defined by population density and ethnicity, in colonial Sri Lanka.

SUBMITTER: Chandra S

PROVIDER: S-EPMC4181474 | biostudies-literature | 2014 May

REPOSITORIES: biostudies-literature

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Publications

The influenza pandemic of 1918-1919 in Sri Lanka: its demographic cost, timing, and propagation.

Chandra Siddharth S Sarathchandra Dilshani D

Influenza and other respiratory viruses 20140224 3

<h4>Background</h4>As an island and a former British colony, Sri Lanka is a case of special interest for the study of 1918-1919 influenza pandemic because of its potential for isolation from as well as integration into the world epidemiologic system.<h4>Objectives</h4>To estimate population loss attributable to the influenza pandemic and weekly district-level excess mortality from the pandemic to analyze its spread across the island.<h4>Methods</h4>To measure population loss, we estimated a popu ...[more]

PMID: 24612961

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Project description:BACKGROUND: The impact of socio-demographic factors and baseline health on the mortality burden of seasonal and pandemic influenza remains debated. Here we analyzed the spatial-temporal mortality patterns of the 1918 influenza pandemic in Spain, one of the countries of Europe that experienced the highest mortality burden. METHODS: We analyzed monthly death rates from respiratory diseases and all-causes across 49 provinces of Spain, including the Canary and Balearic Islands, during the period January-1915 to June-1919. We estimated the influenza-related excess death rates and risk of death relative to baseline mortality by pandemic wave and province. We then explored the association between pandemic excess mortality rates and health and socio-demographic factors, which included population size and age structure, population density, infant mortality rates, baseline death rates, and urbanization. RESULTS: Our analysis revealed high geographic heterogeneity in pandemic mortality impact. We identified 3 pandemic waves of varying timing and intensity covering the period from Jan-1918 to Jun-1919, with the highest pandemic-related excess mortality rates occurring during the months of October-November 1918 across all Spanish provinces. Cumulative excess mortality rates followed a south-north gradient after controlling for demographic factors, with the North experiencing highest excess mortality rates. A model that included latitude, population density, and the proportion of children living in provinces explained about 40% of the geographic variability in cumulative excess death rates during 1918-19, but different factors explained mortality variation in each wave. CONCLUSIONS: A substantial fraction of the variability in excess mortality rates across Spanish provinces remained unexplained, which suggests that other unidentified factors such as comorbidities, climate and background immunity may have affected the 1918-19 pandemic mortality rates. Further archeo-epidemiological research should concentrate on identifying settings with combined availability of local historical mortality records and information on the prevalence of underlying risk factors, or patient-level clinical data, to further clarify the drivers of 1918 pandemic influenza mortality.

Dataset Information

The influenza pandemic of 1918-1919 in Sri Lanka: its demographic cost, timing, and propagation.

Background

Objectives

Methods

Results

Conclusions

Publications

The influenza pandemic of 1918-1919 in Sri Lanka: its demographic cost, timing, and propagation.

Similar Datasets

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