A trend analysis of Vibrio vulnificus Mortality, Using the Cholera and Other Vibrio Illness Surveillance System Public

Caton, Mikala (Spring 2018)

Permanent URL: https://etd.library.emory.edu/concern/etds/hh63sv915?locale=fr
Published

Abstract

Background: Vibrio vulnificus (Vv.) is an opportunistic gram-negative bacterium commonly found in warm coastal waters. As a rare and severe infection, Vv. cases are reported and monitored through the Cholera and other Vibrio Illness Surveillance (COVIS) System. While the case fatality ratio was reported to be around 50%, recent COVIS data shows a decrease in the mortality of Vv. infections over the past 25 years (from as high as 41% to as low as 18%). Though Vv. became nationally notifiable in 2007, it is unlikely this change in surveillance is entirely responsible for the downward trend in mortality. This study aims to determine which factors may be facilitating the downward trend in Vv. mortality and develop corresponding models to determine the risk for Vv. mortality before and after the implementation of the 2007 policy change. 

Methods: Vv. cases reported to COVIS between 1988 and 2015 were selected and divided into the pre-policy (1988-2007) and post-policy period (2008-2015). The following variables were analyzed for their association with mortality and potential changes over time: patient characteristics, clinical outcomes, severity, and mode of transmission. Logistic models were created to assess changes in the relationship between each variable and mortality across the pre- and post-policy periods. Predictive margin risk ratios were used to calculate the risk of death per exposure variable over time. 

Results: Among all the variables considered, only region and mode of transmission were found to be changing over time. Compared to the Gulf Coast, the Pacific and Atlantic Coasts were increasingly protective against mortality from Vv. Compared to non-foodborne infections, cases with foodborne and unknown origins of transmission were at an increased risk for mortality from Vv. 

Conclusions: The study results demonstrate there is a significant downward trend in Vv. mortality partially due to a shift in where cases are reported and how cases are becoming infected. Future interventions surrounding safe-food education are needed across the Gulf Coast and Non-Coastal states to decrease the risk of mortality among raw seafood consumers. Research evaluating the impact of current interventions and environmental factors are needed to understand Vv. trends across the regions. 

Table of Contents

Table of Contents 

 

Chapter I: Background and Literature Review........................................................................1 

Transmission Modes and Clinical Outcomes...................................................................................2 

Severity....................................................................................................................................................3 

Patient Characteristics..........................................................................................................................4 

 

Chapter II: Manuscript..................................................................................................................7 

Introduction...........................................................................................................................................7 

Methods..................................................................................................................................................9 

Results...................................................................................................................................................12 

Discussion............................................................................................................................................14 

Tables and Figures…….....................................................................................................................19 

 

Chapter III: Public Health Implications………………………………………….........28 

References............................................................................................................................................30 

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