Development of a clinical syndrome resembling haemorrhagic septicaemia in the buffalo following intravenous inoculation of Pasteurella multocida serotype B:2 endotoxin and the role of tumour necrosis factor-alpha.
Clinical changes and acute phase responses, including tumour necrosis factor-alpha (tnfalpha), in six buffalo calves were examined following intravenous inoculation of a bolus of endotoxin (1 microg kg(-1) bodyweight in 10 ml of phosphate-buffered saline [ pbs ]) extracted from Pasteurella multocida serotype B:2, the bacterium responsible for haemorrhagic septicaemia (hs) in Asia. Endotoxin injection caused a rapid onset of clinical signs characterised by dullness, sternal recumbency, elevated rectal temperatures, excessive salivation and dyspnoea that lasted for up to 12 hours post-inoculation (p.i.). Serum concentrations of tnfalpha rose within 1 hour p.i. to reach peak values ranging between 8 and 140 ng ml(-1) at 1-2 hours p.i. and then declined rapidly to baseline levels 3-5 hours p.i. Endotoxin injection induced other acute phase changes, including a rapid leucopenia and reductions in the serum concentrations of iron and zinc and a delayed but prolonged increase in haptoglobin from 12 hours p.i. that reached a plateau from about 60 hours p.i. Three control calves injected with 10 ml pbs showed no clinical or blood compositional changes. By reproducing key signs of hs the work confirms a pivotal role of endotoxin in the pathogenesis of hs and emphasises the exquisite sensitivity of the buffalo to P multocida endotoxin.
Horadagoda
N U
NU
Department of Veterinary Paraclinical Studies, Faculty of Veterinary Medicine and Animal Science, University of Peradeniya, Peradeniya, Sri Lanka. p.d.eckersall@vet.gla.ac.uk
Hodgson
J C
JC
Moon
G M
GM
Wijewardana
T G
TG
Eckersall
P D
PD
D000818:Animals; D002020:Buffaloes; D004731:Endotoxins / Q000097:blood / Q000633:toxicity*; D005260:Female; D006242:Haptoglobins / Q000378:metabolism; D006483:Hemorrhagic Septicemia / Q000662:veterinary*; D007501:Iron / Q000097:blood; D008070:Lipopolysaccharides / Q000633:toxicity; D008297:Male; D010326:Pasteurella Infections / Q000662:veterinary*; D016979:Pasteurella multocida / Q000472:pathogenicity*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism / Q000502:physiology*; D015032:Zinc / Q000097:blood
D004731:Endotoxins; D006242:Haptoglobins; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D007501:Iron; D015032:Zinc