Shedding of Salmonella Typhimurium in vaccinated and unvaccinated hens during early lay in field conditions: A randomised controlled trial

Sharma, P, Caraguel, C, Sexton, M, McWhorter, A, Underwood, G, Holden, K and Chousalkar, K 2018, 'Shedding of Salmonella Typhimurium in vaccinated and unvaccinated hens during early lay in field conditions: A randomised controlled trial', BMC Microbiology, vol. 18, no. 1, pp. 1-9.


Document type: Journal Article
Collection: Journal Articles

Title Shedding of Salmonella Typhimurium in vaccinated and unvaccinated hens during early lay in field conditions: A randomised controlled trial
Author(s) Sharma, P
Caraguel, C
Sexton, M
McWhorter, A
Underwood, G
Holden, K
Chousalkar, K
Year 2018
Journal name BMC Microbiology
Volume number 18
Issue number 1
Start page 1
End page 9
Total pages 9
Publisher BioMed Central
Abstract Background: Salmonella vaccination is one of the control measure that farmers can use to reduce bacterial shedding in their flocks. This study aimed to examine the efficacy of the Vaxsafe® ST (Strain STM-1) attenuated live vaccine administered as ocular and oral doses followed by an intramuscular (IM) dose in rearing, in reducing contamination by Salmonellae of both eggs and the environment in the commercial multi-age cage layer sheds. A randomised controlled trial was conducted up to 26 weeks post last vaccine on two different multi-age caged egg farms. Results: No clinical symptoms were observed following IM administration of STM-1 during rearing. Following the first two STM-1 doses, both vaccinated and unvaccinated birds exhibited antibody titres below the positive cut-off value, however after IM administration of STM-1, antibody titres in the vaccinated group were above the cut-off value. Wild type Salmonella Typhimurium was not detected during the rearing of pullets. During production, the antibody titres were significantly higher in the vaccinated group at all sampling points during this trial. There was no significant difference in the prevalence of Salmonella (detected by culture and PCR method) between the vaccinated and unvaccinated groups on the egg belt and faeces in early lay. Wild-type Salmonella spp. were consistently found in dust samples. Quantitative PCR (qPCR) assay was able to differentiate between the live vaccine strain and wild type Salmonella. The load of wild-type Salmonella in shed environment was relatively low (1.3 log10 ± 0.48 CFU/m2 of surface area). Conclusion: Given that Salmonella Typhimurium and other serovars are able to survive/persist in the shed environment (such as in dust), regular cleaning and or removal of dust from shed is important. Use of the Vaxsafe® ST vaccine in multi-age flocks is "not an ultimate intervention" for reduction of Salmonella Typhimurium because of the complexities involved in achieving control, such as t
Subject Microbiology not elsewhere classified
Keyword(s) Early lay
Layer hens
Randomized controlled trial
Salmonella typhimurium
Vaccine
DOI - identifier 10.1186/s12866-018-1201-0
Copyright notice © The Author(s). 2018 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/)
ISSN 1471-2180
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