Seven strains of mice as potential models of bovine pasteurellosis following intranasal challenge with a bovine pneumonic strain of Pasteurella multocida A:3; comparisons of disease and pathological outcomes.

The gram-negative bacterium Pasteurella multocida causes pneumonic and systemic pasteurellosis in bovids for which vaccines are either unavailable or inadequate. The work assessed whether an intranasal P. multocida challenge in mice might provide a model of infection for future vaccine development work. Clinical, pathological and biochemical responses were compared in seven strains of mice challenged with a virulent bovine pneumonic isolate of P. multocida A:3. Six mouse strains (Porton, CD-1, BALB/c, VM, C57BL/10 and C57BL/6) developed clinical signs of pneumonic disease and variable pneumonic lesions 41-70 h post-infection. In contrast, mouse strain RIII became septicaemic within 36 h post-infection. Concentrations of plasma acute phase proteins and serum lipopolysaccharide increased in all mice after infection, and the main or interaction effect of mouse strain and infection status was statistically significant (P<0.05). Responses in C57BL/10 mice showed close similarity to bovine pneumonic and in RIII mice to bovine systemic pasteurellosis.

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.

Role of endotoxin in the pathogenesis of haemorrhagic septicaemia in the buffalo.

The pathogenesis of haemorrhagic septicaemia in buffalo infected with Pasteurella multocida is poorly understood. However, the characteristic of sudden onset leading to the rapid death of infected animals is similar to that seen in other clinical conditions known to involve endotoxic shock. The objectives of the work were to assess the contribution of endotoxaemia to the disease's pathogenesis and to characterize the pathophysiological reaction, including the acute phase response, of buffalo to experimental infection with P. multocida serotype B:2, the bacterium responsible for the disease in Asia. After intranasal infection of eight buffaloes with a culture of a field isolate of P. multocida serotype B:2, three animals succumbed to the disease at 26-30 h post-infection (p.i.) and five survived. Rectal temperatures of infected animals rose to a peak at about 10 h p.i. and surviving animals showed a second peak in rectal temperature at 36 h p.i. Endotoxin was present only in serum of non-surviving animals 3-5 h before death or killing during which time concentrations increased rapidly, correlating with the development of overt clinical signs and reductions in rectal temperature, concentrations of white blood cells, serum thyroxine, iron, copper and zinc, an increase in serum haptoglobin and cortisol and the detection of a low-grade bacteraemia. A strong acute phase response was maintained in surviving animals with a progressive rise in serum haptoglobin over 96 h p.ia slow rise in the serum copper concentration from 24 h p.i. and an increase, from about 65 h p.iin serum alpha(1)-acid glycoprotein. The findings demonstrate that a progressive endotoxaemia and associated sequelae correlates with the development of overt haemorrhagic septicaemia disease and sudden death in buffalo.

Prophylactic use of human endotoxin-core hyperimmune gammaglobulin to prevent endotoxaemia in colostrum-deprived, gnotobiotic lambs challenged orally with Escherichia coli.

The efficacy of human IgG polyclonal antibody to endotoxin-core in preventing endotoxaemia and subsequent disease was studied in colostrum-deprived gnotobiotic lambs challenged orally at about 5 h old with 10(9) cfu Escherichia coli. Human endotoxin-core hyperimmune gammaglobulin was given intravenously to 5 lambs at 1.9 g IgG/kg bodyweight prior to challenge. Human albumin was given intravenously to 3 control lambs. Bacteraemia was observed in all lambs, but the incidence was lower (P < 0.01) and the onset later (P < 0.05) in gammaglobulin pre-treated lambs. These lambs showed no signs of disease, whereas clinical endotoxaemia, manifesting as watery mouth disease, was diagnosed in 2 of the 3 control lambs which were killed between 18 and 22 h after challenge. Thus, prophylactic treatment of colostrum-deprived lambs with human IgG enriched in endotoxin-core antibodies was effective in reducing the degree of bacteraemia and preventing endotoxaemia, leukopenia and clinical disease following oral challenge with E. coli.

Immediate responses in serum TNF alpha and acute phase protein concentrations to infection with Pasteurella haemolytica A1 in calves.

The concentrations of tumour necrosis factor-alpha (TNF alpha), serum amyloid A (SAA) and haptoglobin were determined in serum samples taken from four calves in the 10 hours after their intra-tracheal inoculation with Pasteurella haemolytica serotype A1. The concentration of haptoglobin did not increase but the concentration of SAA rose progressively from within two hours of inoculation. The concentration of TNF alpha reached a peak in all the animals two hours after inoculation but had returned to undetectable levels after a further four hours. TNF alpha is likely to be an important mediator of the acute phase response in cattle and SAA is a more rapid bovine acute phase protein than haptoglobin in its response to infection with P haemolytica.

Specialism in nursing: the case of nursing care for elderly people.

Is elderly care nursing a specialty? This paper reports results from an interview-based study which aims to uncover the distinctive elements of nursing work with elderly people. Within the context of sociological literature on specialism it is concluded that a case for seeing elderly care nursing as a specialty area can be made. However, that case has implications for the continued marginalization of elderly people in society.