Abstract
The literature relating to infectious necrotic
hepatitis is critically reviewed and discussed.
The bacteriological, parasitological and other
techniques used in this study are outlined.
Surveys on five Scottish farms are described
and the results analysed to show the correlation
between the incidence of 01.novyi type B in sheep
livers and in soil from the pastures, both with each
other, with the incidence of Pasciola hepatica in
the livers of sheep and with the incidence of
infectious necrotic hepatitis on these farms.
Infectious necrotic hepatitis was induced in
laboratory guinea-pigs, rabbits and sheep. The spores
of Cl.novyi type B were found to reach the liver within
24 hours after oral infection to guinea-pigs and sheep,
but could be detected earlier in the mesenteric lymph
glands. The Possible Pathways by which these snores
reach the liver are discussed . Death from infectious
necrotic hepatitis in guinea-pigs and rabbits occurred
4 - 6 weeks post-infection with Fasciola hepatica,
which corresponds with the critical period of maximal
parenchymal damage in the liver caused by the flukes.
In sheep the severity of the damage caused by the
flukes in the liver was assessed by assaying the
concentration of glutanic dehydrogenase (G.D.) in
the serum and the host reaction to the infection by
estimating the numbers of eosinophils in the plasma.
All the sheep which developed infectious necrotic
hepatitis died 6-8 weeks after infection with
Fasciola hepatica; all these sheep showed high serum
G.D. levels and high eosinophil counts during this
Period, which also coincides with the period of
maximal parenchymal damao in this host species.
This is believed to be the first report of the
induction of experimental infectious necrotic hepatitis
in sheep t using the natural infective agents.
The effect of putrefaction on the diagnosis of
infectious necrotic hepatitis was investigated in
experimental models and the significance of these
findings is discussed in relation to the diagnosis
of the disease in the field.
