The comparative pathogenicity of four serovars of Actinobacillus (Haemophilus) pleuropneumoniae.
Aust Vet J
; 67(1): 9-12, 1990 Jan.
Article
em En
| MEDLINE
| ID: mdl-2334378
ABSTRACT
The pathogenicity of 2 isolates of each of serovars 7, 3, 1 and 2 of Actinobacillus pleuropneumoniae was tested by intranasal inoculation into 60, 6-week-old large white pigs. Four dose rates varying from 0.27 to 560 x 10(6) organisms per pig with 10-fold serial dilutions were used. Surviving pigs were necropsied 7 days after inoculation. The proportion of pigs dying and developing gross lesions following infection was significantly greater for pigs given serotype 1 than for each of the other 3 serotypes, which did not differ significantly from each other. Twelve of 16 pigs given either of the 2 isolates of serovar 1 died after acute illness and 1 of 44 pigs given either of the 2 isolates each of serovars 7, 3 and 2 died. Pigs given serovar 1 showed high temperatures, severe respiratory distress, frothy haemorrhagic nasal discharge and weight loss. Lung lesions were produced in all 16 pigs given serovar 1, in 7 of 14 pigs given serovar 7, 7 of 14 pigs receiving serovar 3 and in 5 of 16 pigs given serovar 2. The lethal infections were characterised by a severe acute fibrinohaemorrhagic necrotising pleuropneumonia, whereas non-lethal cases had lung lesions ranging from necrotising purulent pleuropneumonia to abscessation. Significant differences between isolates in proportions of tissues culture positive for A. pleuropneumoniae for serovars 7 and 2, but not for serovars 3 and 1 suggested that isolates may vary in virulence within serovars, but more detailed studies are needed to clarify this point.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Pleuropneumonia Contagiosa
/
Doenças dos Suínos
/
Actinobacillus
/
Haemophilus
/
Infecções por Mycoplasma
Limite:
Animals
Idioma:
En
Revista:
Aust Vet J
Ano de publicação:
1990
Tipo de documento:
Article