| 1. |
- Eriksson, Helena, et al.
(författare)
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Characterization of Erysipelothrix rhusiopathiae isolates from laying hens and poultry red mites (Dermanyssus gallinae) from an outbreak of erysipelas
- 2010
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Ingår i: Avian Pathology. - : Informa UK Limited. - 0307-9457 .- 1465-3338. ; 39, s. 505-509
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Tidskriftsartikel (refereegranskat)abstract
- Infection with the zoonotic bacterium Erysipelothrix rhusiopathiae causes severe disease outbreaks (erysipelas) in poultry flocks. As this bacterium has been isolated from the poultry red mite (Dermanyssus gallinae), this parasite has been suggested as a possible means of transmission of E. rhusiopathiae on and between poultry farms. To further elucidate the capacity of the mite as a reservoir, we analysed and compared 56 bacterial isolates from laying hens and nine isolates from mites by pulsed-field gel electrophoresis (PFGE), using the restriction enzyme SmaI. The isolates originated from one outbreak in a laying hen flock housed in an indoor litter-based aviary system. Except for two isolates, a homogeneous banding pattern was obtained from all isolates analysed, suggesting that a single strain was the cause of the outbreak. Another finding was that isolates from individual hens could exhibit slightly different PFGE patterns. Mites collected from the same house at the end of the production period of the following flock were negative for the presence of E. rhusiopathiae. An increasing number of erysipelas outbreaks as well as escalating problems with D. gallinae are expected in other European countries related to the forthcoming changes in housing systems for laying hens. Consequently, further studies are needed to investigate the importance of erysipelas in poultry and the importance of D. gallinae in the transmission of E. rhusiopathiae.
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| 2. |
- Eriksson, Helena, et al.
(författare)
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Erysipelothrix rhusiopathiae contamination in the poultry house environment during erysipelas outbreaks in organic laying hen flocks
- 2014
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Ingår i: Avian Pathology. - : Informa UK Limited. - 0307-9457 .- 1465-3338. ; 43, s. 231-237
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated organic laying hen farms for the presence of Erysipelothrix rhusiopathiae in the house environment and from potential carriers (i.e. insects and mice) during ongoing erysipelas outbreaks, and compared the obtained isolates with those from laying hens. The samples were investigated by selective culture followed by species-specific polymerase chain reaction on cultures. E. rhusiopathiae was isolated from the spleen, jejunal contents, manure, dust and swabs from water nipples. Three more samples from the house environment tested positive by polymerase chain reaction compared with selective culture alone. Selected isolates were investigated by pulsed-field gel electrophoresis (PFGE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). One farm was represented by isolates from laying hens only, and one of these isolates differed in one PFGE band from the others. Different banding patterns were observed for isolates from laying hens and manure on one farm. On the remaining two farms, the isolates from the house environment and laying hens were identical but differed between farms. Outbreaks reoccurred in the next flock on two of the farms, and different PFGE types were isolated from consecutive flocks. Our results suggest an external source of infection, which would explain the previously reported increased risk of outbreaks in free-range flocks. Contaminated manure and dust may represent sources of transmission. For the isolates, MALDI-TOF MS and biochemical typing results were in agreement but, since the type strain of Erysipelothrix tonsillarum was typed as E. rhusiopathiae using MALDI-TOF MS, further studies into this method are needed.
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| 3. |
- Jansson, Desirée, et al.
(författare)
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Antimicrobial susceptibility of Brachyspira spp. isolated from commercial laying hens and free-living wild mallards (Anas platyrhynchos)
- 2011
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Ingår i: Avian Pathology. - : Informa UK Limited. - 0307-9457 .- 1465-3338. ; 40, s. 387-393
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Tidskriftsartikel (refereegranskat)abstract
- In vitro antimicrobial susceptibility to tylosin, valnemulin, tiamulin, doxycycline, lincomycin and ampicillin was investigated by broth dilution in 48 Brachyspira spp. isolates from commercial laying hens (n = 30) and free-living wild mallards (Anas platyrhynchos) (n = 18). Presumed pathogens (Brachyspira alvinipulli, Brachyspira intermedia, Brachyspira pilosicoli), commensals (Brachyspira murdochii, Brachyspira innocens, "Brachyspira pulli''), and isolates of undetermined species affiliation were included. The laying hens had not been exposed to therapeutic levels of antimicrobials for at least 50 weeks before sampling, and low levels of environmental antimicrobial exposure were presumed in mallards. No isolates with decreased susceptibility to tylosin, valnemulin, tiamulin or doxycycline were found. Decreased susceptibility to lincomycin (minimum inhibitory concentration 16 mu g/ml) was detected in two isolates (Brachyspira sp.) from laying hens. Five isolates showed decreased susceptibility to ampicillin (minimum inhibitory concentration 16 to >32 mu g/ml), including two "B. pulli'' and one B. alvinipulli from laying hens, and isolates of B. pilosicoli and "B. pulli'' from mallards. Decreased susceptibility to ampicillin was associated with beta-lactamase activity in four isolates. A new variant of a class D beta-lactamase gene designated bla(oxa-192) was identified in a B. pilosicoli isolate of mallard origin. This is the first time the genetic basis for antimicrobial resistance is described in Brachyspira spp. from a free-living wild bird. Isolates displaying decreased susceptibility to ampicillin were accompanied by fully susceptible isolates of the same species or other genotypes within three laying hen flocks. This underlines the need for performing antimicrobial susceptibility tests on single clones/genotypes, and to analyse multiple isolates from the same flock.
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| 4. |
- Jansson, Desirée, et al.
(författare)
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Ascarid infections in laying hens kept in different housing systems
- 2010
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Ingår i: Avian Pathology. - : Informa UK Limited. - 0307-9457 .- 1465-3338. ; 39, s. 525-532
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Tidskriftsartikel (refereegranskat)abstract
- The present study was undertaken to investigate the prevalence of ascarid infections in Swedish commercial laying hens in 2004 and 2008 following a recent nationwide change to alternative housing systems but before anthelmintics became available. Also, the influence on prevalence of farm and flock characteristics and management was studied in 2004. The results showed that the overall prevalence was significantly higher in 2008 (38%; n = 64/169) compared with 2004 (24%; n = 44/186) (P = 0.001). Ascarid infections were rare in caged flocks, including furnished (enriched) cages, both years (2.4 to 4.3%), and were significantly more common in non-cage systems in both years (16.7 to 48.6% in 2004, and 28.6 to 77.1% in 2008 depending on the housing system). There was no significant difference in prevalence between hens kept on litter indoors and free-range/organic hens. The absence of a hygiene barrier at the entrance of the house or unit increased the risk of infection (P 0.001), which suggests that parasite eggs were introduced horizontally to the farms. The risk of infection also increased with the age of equipment used in the barn; for example, the risk increased with an odds ratio of 7.5 (95% confidence interval = 2.3 to 25) when comparing equipment 1 year old with equipment epsilon 7 years old. The results of this study show that ascarid infections may re-emerge following a change to alternative housing. With the impending ban on conventional battery cages in the member states of the European Union, ascarid infections are likely to increase in importance and efficient control options such as hygiene barriers should be implemented on all farms.
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| 5. |
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| 6. |
- Lindgren, Ylva Maria, et al.
(författare)
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Gizzard erosions in broiler chickens in Sweden caused by fowl adenovirus serotype 1 (FAdV-1): investigation of outbreaks, including whole-genome sequencing of an isolate
- 2022
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Ingår i: Avian Pathology. - : Informa UK Limited. - 0307-9457 .- 1465-3338. ; 51, s. 257-266
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Tidskriftsartikel (refereegranskat)abstract
- The present paper describes the investigation of the first outbreaks of adenoviral gizzard erosions (AGE) in Sweden, in five broiler flocks. The investigation included whole viral genome sequencing and investigation of genomic organization and sequence relationships with other adenoviruses. All five flocks had a history of decreased growth and uneven size of birds since 9-10 days of age. Macroscopically, lesions consistent with AGE (detached koilin layers, discolouration, bleeding, erosions) were identified in gizzards in all five flocks. In four flocks histology was performed, and degeneration and inflammation of the koilin layer and gizzard mucosa were identified in all four. In one flock, intranuclear inclusion bodies typical for fowl adenovirus (FAdV) were detected in trapped epithelial cells in the koilin layer. In four flocks in situ hybridization was performed, and cells positive for FAdV serotype 1 (FAdV-1) were demonstrated in the koilin layer and gizzard mucosa. FAdV species A (FAdV-A) was detected in gizzard, liver, caecal tonsils and bursa of Fabricius by polymerase chain reaction (PCR) and sequencing. Ten out of ten examined parent flocks of the affected chickens were seropositive for FAdV, indicating former or on-going infection. However, FAdV was not detected in embryos from seropositive parent flocks and thus vertical transmission was not demonstrated. The entire nucleotide sequence of one sample was determined and found to be 43,856 base pairs (bp) in length. The genome sequence and organization were found to be similar to that of the reference apathogenic avian adenovirus "chicken embryo lethal orphan" (CELO).
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