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

Clinical mastitis in ewes; bacteriology, epidemiology and clinical features

<p>Abstract</p> <p>Background</p> <p>Clinical mastitis is an important disease in sheep. The objective of this work was to identify causal bacteria and study certain epidemiological and clinical features of clinical mastitis in ewes kept for meat and wool production.</p> <p>Methods</p> <p>The study included 509 ewes with clinical mastitis from 353 flocks located in 14 of the 19 counties in Norway. Clinical examination and collection of udder secretions were carried out by veterinarians. Pulsed-field gel electrophoresis (PFGE) was performed on 92 <it>Staphylococcus aureus </it>isolates from 64 ewes.</p> <p>Results and conclusion</p> <p><it>S. aureus </it>was recovered from 65.3% of 547 clinically affected mammary glands, coagulase-negative staphylococci from 2.9%, enterobacteria, mainly <it>Escherichia coli</it>, from 7.3%, <it>Streptococcus </it>spp. from 4.6%, <it>Mannheimia haemolytica </it>from 1.8% and various other bacteria from 4.9%, while no bacteria were cultured from 13.2% of the samples. Forty percent of the ewes with unilateral clinical <it>S. aureus </it>mastitis also had a subclinical <it>S. aureus </it>infection in the other mammary gland. Twenty-four of 28 (86%) pairs of <it>S. aureus </it>isolates obtained from clinically and subclinically affected mammary glands of the same ewe were indistinguishable by PFGE. The number of identical pairs was significantly greater than expected, based on the distribution of different <it>S. aureus </it>types within the flocks. One-third of the cases occurred during the first week after lambing, while a second peak was observed in the third week of lactation. Gangrene was present in 8.8% of the clinically affected glands; <it>S. aureus </it>was recovered from 72.9%, <it>Clostridium perfringens </it>from 6.3% and <it>E. coli </it>from 6.3% of the secretions from such glands. This study shows that <it>S. aureus </it>predominates as a cause of clinical ovine mastitis in Norway, also in very severe cases. Results also indicate that <it>S. aureus </it>is frequently spread between udder halves of infected ewes.</p

Distribution of 318 cases of clinical mastitis in relation to weeks of lactation

<p><b>Copyright information:</b></p><p>Taken from "Clinical mastitis in ewes; bacteriology, epidemiology and clinical features"</p><p>http://www.actavetscand.com/content/49/1/23</p><p>Acta Veterinaria Scandinavica 2007;49(1):23-23.</p><p>Published online 24 Sep 2007</p><p>PMCID:PMC2048968.</p><p></p