Salmonella control in poultry flocks and its public health impact

Abstract

An increase in confirmed human salmonellosis cases in the EU after 2014 triggered investigation of contributory factors and control options in poultry production. Reconsideration of the five current target serovars for breeding hens showed that there is justification for retaining Salmonella Enteritidis, Salmonella Typhimurium (including monophasic variants) and Salmonella Infantis, while Salmonella Virchow and Salmonella Hadar could be replaced by Salmonella Kentucky and either Salmonella Heidelberg, Salmonella Thompson or a variable serovar in national prevalence targets. However, a target that incorporates all serovars is expected to be more effective as the most relevant serovars in breeding flocks vary between Member State (MS) and over time. Achievement of a 1% target for the current target serovars in laying hen flocks is estimated to be reduced by 254,400 CrI 95 [98,540; 602,700] compared to the situation in 2016. This translates to a reduction of 53.4% CrI 95 [39.1; 65.7] considering the layer-associated human salmonellosis true cases and 6.2% considering the overall human salmonellosis true cases in the 23 MSs included in attribution modelling. A review of risk factors for Salmonella in laying hens revealed that overall evidence points to a lower occurrence in non-cage compared to cage systems. A conclusion on the effect of outdoor access or impact of the shift from conventional to enriched cages could not be reached. A similar review for broiler chickens concluded that the evidence that outdoor access affects the occurrence of Salmonella is inconclusive. There is conclusive evidence that an increased stocking density, larger farms and stress result in increased occurrence, persistence and spread of Salmonella in laying hen flocks. Based on scientific evidence, an impact of Salmonella control programmes, apart from general hygiene procedures, on the prevalence of Campylobacter in broiler flocks at the holding and on broiler meat at the end of the slaughter process is not expected.

The European Union One Health 2018 Zoonoses Report

“…Although the prevalence of Salmonella is lower in egg than in meat matrices, 'egg and egg products' are more frequently associated with Salmonella outbreaks than any other food matrix for a variety of reasons. First, due to vertical transmission of the pathogen, eggs can be internally contaminated; secondly, eggs are commonly used as raw products to prepared different food specialities; and, finally, there is the risk of temperature abuse of such products (EFSA, 2014a;EFSA BIOHAZ Panel, 2019). The importance of eggs as source of human Salmonella infections has been already mentioned in relation to the large European multicountry salmonellosis outbreak (with 838 confirmed and 371 probable cases) occurring during the last 3 years (2016-2018) and originating from a large agricultural business consortium in Poland (Pijnacker et al, 2019).…”

An Optimized Bacteriophage Cocktail Can Effectively Control Salmonella in vitro and in Galleria mellonella

“…Salmonella infection arising from eating contaminated food products remains a major concern to human health with greater percent of cases resulting in mild to severe intestinal gastroenteritis and fatality in others ( Sockett and Roberts, 1991 ; Majowicz et al, 2010 ). As a result, a number of trade restrictions are introduced in cases where there is contamination with prevalent serotypes of S. Enteritidis and S. Typhimurium leading to major loss of income to farmers and producers due to rejection of substandard contaminated animal products ( Majowicz et al, 2010 ; Kirk et al, 2015 ; EFSA Panel on Biological Hazards et al, 2019 ). Although antibiotics are useful in controlling the infection in both humans and animals, many of the bacterial strains are becoming resistant to routinely used antibiotics leading to treatment failure and disease outbreaks ( O’Neil, 2014 ; Fong et al, 2020 ).…”

Heritable Gut Microbiome Associated with Salmonella enterica Serovar Pullorum Infection in Chickens

“…Pullorum) ( 1 , 2 ). Since the early 20th century, pullorum disease has caused substantial economic losses in the poultry industry ( 3 , 4 ). This disease has a higher mortality rate in 2- to 3-week-old chicks.…”