Impact of Salmonella Control Programmes in Poultry on Human Salmonellosis Burden in Greece

Myrsini Tzani,Joana Gomes Dias,Georgia Mandilara,Theologia Sideroglou,Kassiani Mellou,Anthi Chrysostomou

doi:10.3390/antibiotics10020121

Abstract

Since 2008, veterinary authorities in Greece have implemented national control programmes (NSCPs) targeting S. Enteritidis (SE) and S. Typhimurium (ST) in poultry. We assessed the effect of the programs on the reported number of human isolates. Using monthly data for 2006–2017, we defined two groups (SE, ST) and one control group with serotypes unrelated to poultry or eggs. For SE we also analysed data for 2006–2015 due to a multi-county SE outbreak in 2016. We performed an interrupted time series analysis and used a negative binominal regression model. For both SE and ST, there was no significant trend of the isolation rate before or after NSCPs’ introduction. After the NSCPs’ introduction there was an increasing rate (IRR: 1.005, 95% CI: 1.001–1.008) for control serotypes and a decreasing one for SE (IRR: 0.990, 95% CI: 0.986–0.995) (for 2009 to 2015 analysis). From 2006 to 2017, NSCPs had a statistically significant impact on the number of SE isolates that decreased by 49% (IRR:0.511, 95% CI: 0.353–0.739). No impact was shown on the number of ST (p-value = 0.741) and control isolates (p = 0.069). As a conclusion, NSCP’s implementation was associated with decreased SE isolates and overall burden of salmonellosis; however further measures aiming at human salmonellosis due to ST, should be considered.

Highlights

Non-typhoidal salmonellosis is caused by bacteria of genus Salmonella spp. which is one of the most frequently isolated foodborne pathogens, accounting for 93.8 million foodborne illnesses and 155,000 deaths per year [1]
The introduction of the National Salmonella Control Programmes (NSCPs) resulted in a statistically significant decrease by 47% (IRR: 0.526, 95% CI: 0.384–0.720) of the total number of S
Typhi-murium isolates according to the model used, Greece, 2006–2017; (d) Number of observed and predicted human isolates attributed to “Control Salmonella serotypes” according to the model used, Greece, 2006–2017. This is the first study in Greece evaluating the impact of NSCPs in poultry breeding on human salmonellosis reported number of cases

Summary

Introduction

Non-typhoidal salmonellosis is caused by bacteria of genus Salmonella spp. which is one of the most frequently isolated foodborne pathogens, accounting for 93.8 million foodborne illnesses and 155,000 deaths per year [1]. Over 2600 Salmonella serotypes have been identified and more than half of them belong to Salmonella enterica subsp. In the EU, over 90,000 salmonellosis cases are recorded every year making salmonellosis the second most frequently reported zoonotic disease after Campylobacter spp. infection [3]. It has been estimated that the overall annual economic burden of human salmonellosis in Europe is as high as three billion euros [3]. The three most commonly reported Salmonella serotypes, belonging to Salmonella enterica subsp. Enterica, are Enteritidis, Typhimurium and the monophasic variant of Typhimurium with the antigenic formula.

Objectives

Methods

Results

Conclusion