A recently introduced Dichelobacter nodosus strain caused an outbreak of footrot in Norway

BACKGROUND: In 2008, an outbreak of ovine footrot occurred in Norway. Dichelobacter nodosus isolates collected between 2008 and 2011 have been characterised. Isolates defined as virulent by the gelatin gel test (GG-test) were only found in sheep in Rogaland County, where the severe cases of footrot were registered. The majority (96%) of the virulent isolates belonged to serogroup A. It is suspected that they represent a newly introduced strain, and the aim of the present study was to investigate whether they are genetically similar. Sixty-one virulent isolates from sheep and 116 benign isolates from sheep, cattle and goats were included. Four GG-test virulent isolates from Danish sheep were also included. All isolates were genotyped by pulsed-field gel electrophoresis (PFGE) and by PCR for pgr variant determination. RESULTS: The Norwegian virulent isolates were assigned to 8 pulsotypes (PTs), while the benign isolates were assigned to 66 PTs. Thirty-seven (68.5%) of the 54, virulent, serogroup A isolates belonged to the same PT, and included isolates from 2008 through 2011. Isolates belonging to this PT were defined as the outbreak strain. The remaining virulent serogroup A isolates belonged to 4 PTs differing by ≤3 bands from the outbreak strain. Two virulent, Danish, serogroup A isolates differed by 2 bands from the Norwegian outbreak strain. All but 3 (95%) of the virulent isolates had the pgrA variant while 85% of the benign isolates had the pgrB variant. CONCLUSION: This study provides evidence that the footrot outbreak in Norway in 2008 most likely was caused by new introduction and local spread of one virulent D. nodosus strain

Interdigital dermatitis, heel horn erosion, and digital dermatitis in 14 Norwegian dairy herds

AbstractThe aim of this study was to assess infectious foot diseases, including identification and characterization of Dichelobacter nodosus and Treponema spp., in herds having problems with interdigital dermatitis (ID) and heel horn erosion (E) and in control herds expected to have few problems. We also wanted to compare diseased and healthy cows in all herds. The study included 14 dairy herds with a total of 633 cows. Eight herds had a history of ID and E, and 6 were control herds. All cows were scored for lameness, and infectious foot diseases on the hind feet were recorded after trimming. Swabs and biopsies were taken from the skin of 10 cows in each herd for bacterial analyses. In total, samples were taken from 34 cows with ID, 11 with E, 40 with both ID and E, and 8 with digital dermatitis (DD), and from 47 cows with healthy feet. Swabs were analyzed for identification and characterization of D. nodosus by PCR, culture, virulence testing, and serotyping. Biopsies were analyzed by fluorescent in situ hybridization regarding histopathology, identification, and characterization of Treponema spp., and identification of D. nodosus. Interdigital dermatitis was the most frequent foot disease, with a prevalence of 50.4% in problem herds compared with 26.8% in control herds. Heel horn erosion was recorded in 34.8% of the cows in problem herds compared with 22.1% in control herds. Dichelobacter nodosus was detected in 97.1% of the cows with ID, in 36.4% with E, in all cows with both ID and E, in all cows with DD, and in 66.0% of cows with healthy feet. All serogroups of D. nodosus except F and M were detected, and all isolates were defined as benign by the gelatin gel test. Treponema spp. were detected in 50.0% of the cows with ID, in 9.1% with E, in 67.5% with ID and E, in all cows with DD, and in 6.4% of those with healthy feet. In total, 6 previously described phylotypes (PT) of Treponema were detected: PT1, PT3, PT6, PT13, and PT15 in cows with ID, PT1 in a cow with E, and PT1, PT2, PT3, PT6, and PT13 in cows with both ID and E. One new phylotype (PT19) was identified. The epidermal damage score was higher but the difference in inflammatory response of the dermis was minor in cows with ID versus those with healthy feet. Fisher’s exact test revealed an association between ID and D. nodosus, and between ID and Treponema spp. Logistic regression revealed an association between both ID and E and dirty claws (odds ratios=1.9 and 2.0, respectively). Our study indicates that D. nodosus, Treponema spp., and hygiene are involved in the pathogenesis of ID

Experimental infection of sheep with ovine and bovine Dichelobacter nodosus isolates

AbstractThe aim of this study was, under experimental conditions, to investigate infection of Norwegian White sheep with ovine and bovine isolates of Dichelobacter nodosus of varying virulence. In addition, the efficacy of gamithromycin as a treatment for the experimentally induced infections was examined. The study was performed as a single foot inoculation using a boot. Four groups, each with six lambs, were inoculated with four different challenge strains (Group 1: benign bovine strain; Group 2: virulent bovine strain; Group 3: benign ovine strain; Group 4: virulent ovine strain). The main criterion to determine that infection was transferred was that D. nodosus isolate was obtained by culture. After the trial all lambs were treated with gamithromycin. Clinical symptoms of footrot developed in all groups, and when removing the boots two weeks after challenge, D. nodosus was isolated from 5 of 24 experimental lambs. All lambs tested negative for D. nodosus by PCR within six weeks after treatment with gamithromycin. This study strongly indicates that D. nodosus isolates from both sheep and cattle can be transferred to sheep under experimental conditions. The study also indicates that gamithromycin may be effective against D. nodosus

2. Anbefalinger for god dyrevelferd og trygg produksjon

Produksjonen av storfekjøtt i Norge kjennetegnes bl.a. av stor variasjon med hensyn til fjøsbygg, driftssystemer, driftsrutiner og beiteforhold. Vi har besøkt 30 gårdsbruk og spurt produsentene selv om hva som er de viktigste suksessfaktorene for god produksjon og dyrevelferd i storfekjøttproduksjonen. I en serie på tre NIBIO-POPer publiseres resultater fra prosjektene «Arktisk storfekjøttproduksjon » (Hansen & Jørgensen 2016) og «Storfekjøttproduksjon i fjellregionen» (Berge m.fl. 2017). Dette er den andre, hvor vi deler bøndenes anbefalinger for god dyrevelferd og trygg produksjon. Målgruppa er storfekjøttprodusenter, spesielt de som er i etableringsfasen

Arktisk storfekjøttproduksjon

Produksjonen av storfekjøtt i Norge kjennetegnes bl.a. av stor variasjon med hensyn til fjøsbygg, driftssystemer, driftsrutiner og beiteforhold. Vi har besøkt 30 gårdsbruk og spurt produsentene selv om hva som er de viktigste suksessfaktorene for god produksjon og dyrevelferd i storfekjøttproduksjonen. I en serie på tre NIBIO-POPer publiseres resultater fra prosjektene «Arktisk storfekjøttproduksjon » (Hansen & Jørgensen 2016) og «Storfekjøttproduksjon i fjellregionen» (Berge m.fl. 2017). Dette er den andre, hvor vi deler bøndenes anbefalinger for god dyrevelferd og trygg produksjon. Målgruppa er storfekjøttprodusenter, spesielt de som er i etableringsfasen

Arktisk storfekjøttproduksjon

Produksjonen av storfekjøtt i Norge kjennetegnes bl.a. av stor variasjon med hensyn til fjøsbygg, driftssystemer, driftsrutiner og beiteforhold. Vi har besøkt 30 gårdsbruk og spurt produsentene selv om hva de mener er de viktigste suksessfaktorene for god produksjon og dyrevelferd i storfekjøttproduksjonen. I en serie på tre NIBIO-POPer publiseres resultater fra prosjektene «Arktisk storfekjøttproduksjon» (Hansen & Jørgensen 2016) og «Storfekjøttproduksjon i fjellregionen» (Berge m.fl. 2017). Dette er den første, hvor vi deler bøndenes anbefalinger for gode driftsløsninger og bygninger som de selv har erfart fungerer. Målgruppa er storfekjøttprodusenter, spesielt de som er i etableringsfasen

1. Anbefalinger for driftsløsninger og bygninger

Produksjonen av storfekjøtt i Norge kjennetegnes bl.a. av stor variasjon med hensyn til fjøsbygg, driftssystemer, driftsrutiner og beiteforhold. Vi har besøkt 30 gårdsbruk og spurt produsentene selv om hva de mener er de viktigste suksessfaktorene for god produksjon og dyrevelferd i storfekjøttproduksjonen. I en serie på tre NIBIO-POPer publiseres resultater fra prosjektene «Arktisk storfekjøttproduksjon» (Hansen & Jørgensen 2016) og «Storfekjøttproduksjon i fjellregionen» (Berge m.fl. 2017). Dette er den første, hvor vi deler bøndenes anbefalinger for gode driftsløsninger og bygninger som de selv har erfart fungerer. Målgruppa er storfekjøttprodusenter, spesielt de som er i etableringsfasen