1
|
Heinemann L, Methner U, Klassen A, Donat K, Moog U. [Influence of breed and herd size on the intra-herd prevalence of Salmonella enterica subspecies diarizonae serovar 61: k: 1, 5, (7) in sheep]. Tierarztl Prax Ausg G Grosstiere Nutztiere 2023; 51:367-375. [PMID: 37722598 DOI: 10.1055/a-2121-2635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/20/2023]
Abstract
SUBJECT AND AIM At present, only little information is available on the within-flock prevalence of Salmonella enterica subspecies diarizonae serovar 61: k: 1, 5, (7) (SASd) in sheep flocks in Germany as well as their possible influencing factors. The aim of the study was to investigate relationships between flock size, breed and within-flock prevalence. MATERIAL AND METHODS A total of 1610 clinically healthy ewes from 14 sheep flocks of 9 different breeds aged 2 to 12 years were microbiologically tested for SASd by nasal swab and fecal samples. Linear multivariable models were used to analyse the associations between within-flock prevalence and farm factors (flock size, breed) or detection frequencies in fecal or nasal swabs. RESULTS SASd was detected in all sheep flocks examined, with 75% of adults having at least one positive nasal or fecal result. In comparison to the 11 flocks in which commercial breeds were kept, the 3 flocks of landraces had a lower apparent within-flock prevalence (p=0.01). No association with herd size was evident. With respect to the age of the ewes, there was a negative relationship (p=0.05) with the frequency of detection of SASd in the nasal swab but not in the fecal swab. The health status and fertility performance of the flocks were in line with a normal range for commercial sheep flocks, with lambing losses of 5% to 10% and lambing scores of 130% to 158%. CONCLUSIONS Despite the high prevalence of SASd infections particularly within commercial breeds, there was no evidence of a relevant risk to sheep health. Compared with commercial breed flocks, a lower spread of SASd within flocks keeping landraces was evident. CLINICAL RELEVANCE Despite a high prevalence, infections with SASd are very unlikely to lead to clinical symptoms or disease. Regulation and monitoring of SASd in sheep are of low priority for animal health authorities.
Collapse
Affiliation(s)
- Lisa Heinemann
- Thüringer Landesamt für Verbraucherschutz (TLV), Bad Langensalza
| | - Ulrich Methner
- Friedrich-Loeffler Institut - Bundesforschungsinstitut für Tiergesundheit (FLI), Institut für bakterielle Infektionen und Zoonosen, Jena
| | - Anne Klassen
- Thüringer Tierseuchenkasse AdöR, Tiergesundheitsdienst, Jena
| | - Karsten Donat
- Thüringer Tierseuchenkasse AdöR, Tiergesundheitsdienst, Jena
- Klinik für Geburtshilfe, Gynäkologie und Andrologie der Groß- und Kleintiere mit Tierärztlicher Ambulanz, Justus-Liebig-Universität, Gießen
| | - Udo Moog
- Thüringer Tierseuchenkasse AdöR, Tiergesundheitsdienst, Jena
| |
Collapse
|
2
|
Heinemann L, Methner U, Donat K, Moog U. [Longitudinal study on the time of infection of sheep lambs with Salmonella enterica subspecies diarizonae serovar 61: k: 1, 5, (7)]. Tierarztl Prax Ausg G Grosstiere Nutztiere 2023; 51:135-143. [PMID: 37567192 DOI: 10.1055/a-2097-7085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/13/2023]
Abstract
OBJECTIVE Infections with Salmonella enterica subspecies diarizonae serovar 61: k: 1, 5, (7) (SASd) are widespread in sheep. SASd is considered as host associated with low virulence. The aim of the study was to determine the time of infection of lambs after birth with consideration of the Salmonella status of the mother. MATERIAL AND METHODS Fecal and nasal swabs from 88 ewes of a flock with known SASd status but unknown intraherd prevalence were examined for SASd in the period of 6 weeks before the beginning of the lambing period. Fecal and nasal swabs from one female lamb from each of these ewes were also examined for SASd at 4-6 time points between the 4th and 50th day of life and at 7, 30 and 40 months of age. RESULTS In the first two weeks after birth, significantly more lambs were positive in the nasal swab than in the fecal swab. SASd positive nasal swabs were mainly found in lambs originating from ewes also positive in nasal swabs. 43 lambs remained SASd-negative until day 50 of age. There was no correlation between the SASd status of ewes and their off-spring. At 7 months of age, the number of animals with a positive detection of SASd increased significantly. 32% of the nasal swabs and 62% of the fecal samples were positive for SASd. CONCLUSIONS There is no rapid and intensive transmission of SASd from ewes to their offspring. Most likely, the infection begins by colonising the nasal mucosa of the lambs and does not cause any clinical symptoms. CLINICAL RELEVANCE Even with a high intraherd prevalence, infections with SASd are very unlikely to cause clinical symptoms.
Collapse
Affiliation(s)
- Lisa Heinemann
- Thüringer Landesamt für Verbraucherschutz, Bad Langensalza
| | - Ulrich Methner
- Friedrich-Loeffler Institut - Bundesforschungsinstitut für Tiergesundheit (FLI), Institut für bakterielle Infektionen und Zoonosen, Jena
| | - Karsten Donat
- Thüringer Tierseuchenkasse AdöR, Tiergesundheitsdienst, Jena
- Klinik für Geburtshilfe, Gynäkologie und Andrologie der Groß- und Kleintiere mit Tierärztlicher Ambulanz, Justus-Liebig-Universität Gießen
| | - Udo Moog
- Thüringer Tierseuchenkasse AdöR, Tiergesundheitsdienst, Jena
| |
Collapse
|
3
|
Weber M, Zanolari P, Ardüser F, Stucki D, Akarsu H, Overesch G. Prevalence and antimicrobial resistance of Salmonella enterica subsp. diarizonae serovar 61:k:1,5,(7) in Swiss sheep flocks. Prev Vet Med 2022; 206:105697. [DOI: 10.1016/j.prevetmed.2022.105697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 06/14/2022] [Accepted: 06/16/2022] [Indexed: 11/28/2022]
|
4
|
Uelze L, Borowiak M, Deneke C, Fischer J, Flieger A, Simon S, Szabó I, Tausch SH, Malorny B. Comparative genomics of Salmonella enterica subsp. diarizonae serovar 61:k:1,5,(7) reveals lineage-specific host adaptation of ST432. Microb Genom 2021; 7. [PMID: 34338625 PMCID: PMC8549363 DOI: 10.1099/mgen.0.000604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Unlike most Salmonella enterica subsp. diarizonae, which are predominantly associated with cold-blooded animals such as reptiles, the serovar IIIb 61:k:1,5,(7) (termed SASd) is regarded as host-adapted to sheep. The bacterium is rarely associated with disease in humans but, nevertheless, SASd isolates are sporadically obtained from human clinical samples. It is unclear whether these transmissions are directly linked to sheep or whether transmissions may, for example, occur through other domestic animals also carrying SASd. For this reason, we utilized whole-genome sequencing to investigate a set of 119 diverse SASd isolates, including sheep-associated and human-associated isolates, as well as isolates obtained from other matrices. We discovered that serovar IIIb 61:k:1,5,(7) is composed of two distinct lineages defined by their sequence types ST432 and ST439. These two lineages are distinguished by a number of genetic features, as well as their prevalence and reservoir. ST432 appears to be the more prevalent sequence type, with the majority of isolates investigated in this study belonging to ST432. In contrast, only a small number of isolates were attributed to ST439. While ST432 isolates were of sheep, human or other origin, all ST439 isolates with source information available, were obtained from human clinical samples. Regarding their genetic features, lineage ST432 shows increased pseudogenization, harbours a virB/D4 plasmid that encodes a type IV secretion system (T4SS) and does not possess the iro gene cluster, which encodes a salmochelin siderophore for iron acquisition. These characteristics likely contribute to the ability of ST432 to persistently colonize the intestines of sheep. Furthermore, we found isolates of the lineage ST432 to be highly clonal, with little variation over the sampling period of almost 20 years. We conclude from the genomic comparisons that SASd underlies a microevolutionary process and that it is specifically lineage ST432 that should be considered as host-adapted to sheep.
Collapse
Affiliation(s)
- Laura Uelze
- Department of Biological Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Straße 8-10, 10589 Berlin, Germany
| | - Maria Borowiak
- Department of Biological Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Straße 8-10, 10589 Berlin, Germany
| | - Carlus Deneke
- Department of Biological Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Straße 8-10, 10589 Berlin, Germany
| | - Jennie Fischer
- Department of Biological Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Straße 8-10, 10589 Berlin, Germany
| | - Antje Flieger
- Unit for Enteropathogenic Bacteria and Legionella (FG11)/National Reference Centre for Salmonella and Other Bacterial Enteric Pathogens, Robert Koch Institute (RKI), Burgstraße 37, 38855 Wernigerode, Germany
| | - Sandra Simon
- Unit for Enteropathogenic Bacteria and Legionella (FG11)/National Reference Centre for Salmonella and Other Bacterial Enteric Pathogens, Robert Koch Institute (RKI), Burgstraße 37, 38855 Wernigerode, Germany
| | - István Szabó
- Department of Biological Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Straße 8-10, 10589 Berlin, Germany
| | - Simon H Tausch
- Department of Biological Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Straße 8-10, 10589 Berlin, Germany
| | - Burkhard Malorny
- Department of Biological Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Straße 8-10, 10589 Berlin, Germany
| |
Collapse
|
5
|
López‐Tamayo S, Rubira I, De las Heras M, Castells E, Lacasta D. Use of thermography for the diagnosis of chronic proliferative rhinitis in sheep and its application in the differential diagnosis of the first case affecting the dorsal turbinate. VETERINARY RECORD CASE REPORTS 2020. [DOI: 10.1136/vetreccr-2020-001070] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Silvia López‐Tamayo
- Animal Pathology DepartmentVeterinary FacultyUniversity of ZaragozaZaragozaSpain
| | - Ines Rubira
- Gabinete Técnico Veterinario S.LZaragozaSpain
| | - Marcelo De las Heras
- Animal Pathology DepartmentVeterinary FacultyUniversity of ZaragozaZaragozaSpain
| | | | - Delia Lacasta
- Animal Pathology DepartmentVeterinary FacultyUniversity of ZaragozaZaragozaSpain
| |
Collapse
|
6
|
|
7
|
Uelze L, Borowiak M, Deneke C, Jacobs C, Szabó I, Tausch SH, Malorny B. First complete genome sequence and comparative analysis of Salmonella enterica subsp. diarizonae serovar 61:k:1,5,(7) indicates host adaptation traits to sheep. Gut Pathog 2019; 11:48. [PMID: 31636715 PMCID: PMC6791114 DOI: 10.1186/s13099-019-0330-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 09/27/2019] [Indexed: 11/10/2022] Open
Abstract
Background The Salmonella enterica subsp. diarizonae serovar 61:k:1,5,(7) (SASd) has been found to be host-adapted to sheep, with a high prevalence in sheep herds worldwide. Infections are usually sub-clinical, however the serovar has the potential to cause diarrhea, abortions and chronic proliferative rhinitis. Although occurrence and significance of SASd infections in sheep have been extensively studied, the genetic mechanism underlying this unusual host-adaptation have remained unknown, due to a lack of (a) available high-quality genome sequence(s). Results We utilized Nanopore and Illumina sequencing technologies to generate a de novo assembly of the 4.88-Mbp complete genome sequence of the SASd strain 16-SA00356, isolated from the organs of a deceased sheep in 2016. We annotated and analyzed the genome sequence with the aim to gain a deeper understanding of the genome characteristics associated with its pathogenicity and host adaptation to sheep. Overall, we found a number of interesting genomic features such as several prophage regions, a VirB4/D4 plasmid and novel genomic islands. By comparing the genome of 16-SA00356 to other S. enterica serovars we found that SASd features an increased number of pseudogenes as well as a high level of genomic rearrangements, both known indicators of host-adaptation. Conclusions With this sequence, we provide the first complete and closed genome sequence of a SASd strain. With this study, we provide an important basis for an understanding of the genetic mechanism that underlie pathogenicity and host adaptation of SASd to sheep.
Collapse
Affiliation(s)
- Laura Uelze
- 1Bundesinstitut für Risikobewertung (BfR), Max-Dohrn-Str. 8-10, 10589 Berlin, Germany
| | - Maria Borowiak
- 1Bundesinstitut für Risikobewertung (BfR), Max-Dohrn-Str. 8-10, 10589 Berlin, Germany
| | - Carlus Deneke
- 1Bundesinstitut für Risikobewertung (BfR), Max-Dohrn-Str. 8-10, 10589 Berlin, Germany
| | - Cécile Jacobs
- Landeslabor Schleswig-Holstein, Max-Eyth-Straße 5, 24537 Neumünster, Germany
| | - István Szabó
- 1Bundesinstitut für Risikobewertung (BfR), Max-Dohrn-Str. 8-10, 10589 Berlin, Germany
| | - Simon H Tausch
- 1Bundesinstitut für Risikobewertung (BfR), Max-Dohrn-Str. 8-10, 10589 Berlin, Germany
| | - Burkhard Malorny
- 1Bundesinstitut für Risikobewertung (BfR), Max-Dohrn-Str. 8-10, 10589 Berlin, Germany
| |
Collapse
|
8
|
Rubira I, Figueras L, De las Heras M, Bueso J, Castells E, Climent M, Lacasta D. Chronic proliferative rhinitis in sheep: An update. Small Rumin Res 2019. [DOI: 10.1016/j.smallrumres.2019.09.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
9
|
Methner U, Moog U. Occurrence and characterisation of Salmonella enterica subspecies diarizonae serovar 61: k: 1, 5, (7) in sheep in the federal state of Thuringia, Germany. BMC Vet Res 2018; 14:401. [PMID: 30558604 PMCID: PMC6296128 DOI: 10.1186/s12917-018-1741-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 12/07/2018] [Indexed: 11/28/2022] Open
Abstract
Background The occurrence of Salmonella enterica subspecies diarizonae serovar 61: k: 1, 5, (7) (SASd) and other Salmonella organisms in sheep in the German federal state of Thuringia was examined for the first time. Pooled faecal samples from 90 flocks located in this state were monitored. Results Only SASd was detected in 74 (82.2%) out of the 90 sheep herds, other Salmonella serovars were not identified. A positive correlation was found between the flock size and the detection probability of SASd. Despite the agent’s high prevalence, clinical symptoms of a disease exclusively due to SASd have not been observed. The SASd strains were characterised by macrorestriction analysis, antimicrobial testing and the biochemical profile. All strains were sensitive to 13 out of 14 antimicrobial substances and resistant to only sulfamethoxazole. The high number of macrorestriction groups of SASd strains indicated a low clonality of the serovar. Conclusions Data from sheep derived foods and public health data in Germany strongly suggest that the significance of SASd for public health is considerably lower than that of serovars belonging to Salmonella enterica subspecies enterica. For this reason and because of the low disease-causing potential of SASd in sheep, it is worthwile to consider a reduction in ongoing activities from combating to monitoring serovar 61: k: 1, 5, (7) in the sheep population.
Collapse
Affiliation(s)
- Ulrich Methner
- Institute of Bacterial Infections and Zoonoses at the Friedrich-Loeffler-Institute, Federal Research Institute for Animal Health, Naumburger Str. 96a, 07743, Jena, Germany.
| | - Udo Moog
- Thuringian Animal Diseases Fund, Victor-Goerttler-Str. 4, 07745, Jena, Germany
| |
Collapse
|
10
|
Schnydrig P, Overesch G, Regli W, Bee A, Rodriguez-Campos S. Salmonella enterica subspecies diarizonae serovar 61:(k):1,5,(7) as cause of caprine abortion. Small Rumin Res 2018. [DOI: 10.1016/j.smallrumres.2018.07.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
11
|
Lamas A, Miranda JM, Regal P, Vázquez B, Franco CM, Cepeda A. A comprehensive review of non-enterica subspecies of Salmonella enterica. Microbiol Res 2018; 206:60-73. [DOI: 10.1016/j.micres.2017.09.010] [Citation(s) in RCA: 109] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 09/22/2017] [Accepted: 09/26/2017] [Indexed: 12/11/2022]
|
12
|
Salmonella enterica subsp . diarizonae serotype 61:k:1,5,(7) associated with chronic proliferative rhinitis and high nasal colonization rates in a flock of Texel sheep in Switzerland. Prev Vet Med 2017; 145:78-82. [DOI: 10.1016/j.prevetmed.2017.07.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 06/19/2017] [Accepted: 07/02/2017] [Indexed: 11/22/2022]
|
13
|
Lacasta D, Figueras L, Bueso J, De las Heras M, Ramos J, Ferrer L, González J, Ruíz de Arcaute M, Ortín A, Marteles D, Navarro T, Fernández A. Experimental infection with Salmonella enterica subsp. diarizonae serotype 61:k:1,5,(7) in sheep: Study of cell mediated immune response. Small Rumin Res 2017. [DOI: 10.1016/j.smallrumres.2017.01.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
14
|
Benavides J, González L, Dagleish M, Pérez V. Diagnostic pathology in microbial diseases of sheep or goats. Vet Microbiol 2015; 181:15-26. [PMID: 26275854 DOI: 10.1016/j.vetmic.2015.07.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Post-mortem examination is a key step in the diagnostic process of infectious diseases in sheep and goats. Diagnostic pathology deals with identification and study of lesions, at the same time providing also significant clues regarding pathogenesis of the diseases. This article reviews the salient pathological findings associated with the most significant infectious diseases of sheep and goats present in countries where small ruminants are a relevant agricultural industry. Lesions are reviewed according to the different organ systems where they occur. Emphasis has been given in the description of the salient lesional patterns than can be identified in each organ and which can be of help in the differential diagnosis of the lesions caused by bacteria, viruses, fungi or prions. Finally, a review of the usefulness of ancillary tests that may be used on various tissue samples for performing an aetiological diagnosis, is included; the application of various techniques, from immunohistochemistry to molecular biology-based tests, is described.
Collapse
Affiliation(s)
- J Benavides
- Departamento de Sanidad Animal, Instituto de Ganadería de Montaña (CSIC-ULE), Facultad de Veterinaria, Universidad de León, Campus de Vegazana s/n, 24071 León, Spain
| | - L González
- Animal Health and Veterinary Laboratories Agency (AHVLA), Pentlands Science Park, Bush Loan, Midlothian EH26 0PZ, Scotland, UK
| | - M Dagleish
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Midlothian EH26 0PZ, Scotland, UK
| | - V Pérez
- Departamento de Sanidad Animal, Instituto de Ganadería de Montaña (CSIC-ULE), Facultad de Veterinaria, Universidad de León, Campus de Vegazana s/n, 24071 León, Spain.
| |
Collapse
|
15
|
Capucchio M, Mignacca S, Vitale M, Tasca D, Spuria L, Amato B, Fiasconaro M, Di Marco Lo Presti V. Polypoid nasal neoformations in sheep: Pathological investigations. Small Rumin Res 2015. [DOI: 10.1016/j.smallrumres.2015.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
16
|
Sörén K, Lindblad M, Jernberg C, Eriksson E, Melin L, Wahlström H, Lundh M. Changes in the risk management of Salmonella enterica subspecies diarizonae serovar 61:(k):1, 5, (7) in Swedish sheep herds and sheep meat due to the results of a prevalence study 2012. Acta Vet Scand 2015; 57:6. [PMID: 25644506 PMCID: PMC4324828 DOI: 10.1186/s13028-015-0096-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 01/15/2015] [Indexed: 11/16/2022] Open
Abstract
Background The prevalence of Salmonella in food producing animals is very low in Sweden due to rigorous control programmes. However, no active surveillance is in place in sheep. The authorities decided to perform a prevalence study in sheep herds because findings at slaughter indicated that sheep associated S. diarizonae (S. enterica subspecies diarizonae serovar 61:(k):1, 5, (7)) might be common in sheep. Sampling was stratified by herd size in two groups, small herds with ≤ 30 animals and large herds with > 30 animals. In each stratum, 237 herds were selected at random. Faecal samples received from 244 out of the 474 randomly selected herds were analysed. Results A total of 40 of 100 (40%) of large herds and 17 of 144 (12%) of small herds were positive. The overall adjusted prevalence was 17.6% (95% CI, 12.9-22.2). Sheep associated S. diarizonae was detected in all counties (n = 21). Scientific opinions and an evaluation of on-farm control measures performed concluded that the impact of sheep associated S. diarizonae on human health is very low, and that risk management measures applied in response to findings of sheep associated S. diarizonae in sheep or sheep meat can be expected to have very little impact on reducing risks to human health. As a result, Swedish authorities decided to make an exemption for sheep associated Salmonella diarizonae in sheep and sheep meat in the current Salmonella control measures. Conclusions Sheep associated S. diarizonae is endemic in Swedish sheep herds. It is more common in large herds and not limited to certain parts of the country. The responsible authorities concluded that current risk management actions regarding sheep associated S. diarizonae in sheep and sheep meat are not proportional to the risk. This is the first time in the history of the Swedish Salmonella control programme that an exemption from the legislation has been made for a specific serovar. If there is any future indication of an increasing risk, due to e.g. change in the pathogenicity or development of antimicrobial resistance, the risk assessment will be re-evaluated and control measures reinforced if needed.
Collapse
|