Public Health Assessment of Salmonella enterica Serovar Enteritidis Inactivated-Vaccine Treatment in Layer Flocks

Abstract

Although there have been several reports on the efficacy assessment of a Salmonella enterica serovar Enteritidis vaccine against intestinal and parenchymatous organ diseases of laying hens, no public health risk characterization of its long-term effect on eggs has been reported. In this study, we attempted to assess the public health effect of an inactivated S. enterica serovar Enteritidis vaccine against serovar Enteritidis contamination of chicken eggs. We analyzed serovar Enteritidis isolation test results from four windowless farms in which inactivated-vaccine administration was initiated based on the sanitary monitoring program of a farm. When flocks with and without S. enterica serovar Enteritidis vaccine treatments were mixed, the application of an inactivated serovar Enteritidis vaccine decreased the most probable number (MPN) of bacteria by at least 100-fold in broken (liquid) egg samples positive for serovar Enteritidis, although a statistical difference between those MPNs could not be obtained. The isolation frequency after the vaccine application was less than 1/10 (P < 0.01). No S. enterica serovar Enteritidis bacteria were isolated approximately 1 year after all of the chickens had received the inactivated serovar Enteritidis vaccine. It was suggested that an adequate administration of an inactivated serovar Enteritidis vaccine reduced the contamination risk of eggs (the number of isolated serovar Enteritidis cells and detection frequency) compared to the contamination risk of eggs laid by nonvaccinated hens.The microorganism risk of food and food materials has been studied in order to be characterized

Emergence and clonal dissemination of Salmonella enterica serovar Enteritidis causing salmonellosis in Mauritius

“…Control strategies could include the use of Salmonellafree parent flocks and Salmonella-free chicken feeds, regular cleaning and disinfection of poultry houses, with empty resting periods between flocks, measures to prevent domestic and wild animals, including wild birds, from gaining access to the premises, vaccination of breeder and layer flocks [19,20], and intensive flock-level testing with destruction of infected flocks [21]. However, apparently expensive measures could eventually be cost-effective as reduction of Salmonella in food animals would most likely lower the burden of human infections and reduce the cost associated with such illnesses.…”

Effect of Salmonella Vaccination of Breeder Chickens on Contamination of Broiler Chicken Carcasses in Integrated Poultry Operations

“…Vaccination works by reducing the prevalence of Salmonella in breeder hens and their progeny (19,23,25) or by increasing the passive immunity of meat birds and blocking the horizontal transmission of Salmonella to broiler chickens (22,25,35). However, there have been few studies focusing on whether the vaccines are effective in reducing Salmonella on a commercial scale (13,14,16,17,34,39).…”

Salmonella serovars in laying hen flocks and commercial table eggs from a region of São Paulo state, Brazil

“…Hygiene and biosecurity in addition to the administration of an appropriate form of oil emulsion bacterium against S. Enteritidis in flocks of farms A, B, C and D could be some of the factors that contributed to the absence of this serovar. In a study conducted in Japan, S. Enteritidis was isolated in several samples of faeces, eggs and the environment from farms containing vaccinated and unvaccinated flocks and the percentage of isolation was lower in flocks where the oil-emulsion bacterin against S. Enteritidis was administered (Toyota-Hanatani et al, 2009). Freitas Neto et al (2008) also reported reductions in shedding of S. Enteritidis and egg contamination in laying hens experimentally vaccinated with bacterin.…”