ORIGINAL ARTICLES
LTIPLICATION OF B. ANTHRACIS, CL. CHAUVOEI AND PASTEURELLA
N ANIMAL CARCASES WITH A NOTE ON THE RATE OF COOLING OF
CARCASES
By F. C. MINETT, Imperial Veterinary Research Institute, Mukteswar
(Received for publication on 27 October 1944)
(With two text-figures)
PROBLEM of importance in epizootiology,
cially in hot countries, is the degree and
tion of the infectivity of carcases of animals
of disease. This is particularly so with such
monly occurring and acute diseases as anthrax,
xquarter, haemorrhagic septicaemia where
organisms are both numerous and widely
ibuted in the body of the animal at the time
eath. In such cases not only has contamina-
of the immediate surroundings by body
charges to be considered, but there is also the
widespread distribution of infective material
arrion feeders. At the same time, there are
mber of questions which should be answered
ar knowledge is to be precise. We should
some idea not only of the extent of infectivity
ie body at the time of death but also whether
ogenic bacteria, such as those of the diseases
ioned, actually multiply within the body
death particularly during the first few hours;
to what extent, and what is the influence of
ronmental conditions such as atmospheric
perature. The effect of air temperature on
of heat loss from bodies after death may be
prtant in this connection and a note on this
ter is included. With an organism producing
γ and sudden death in a highly susceptible
oal, such as happens with a virulent strain
pasteurella in a rabbit, cessation of multiplica-
of the organism would not be expected to
cide with the moment of death. With anthrax,
same may be true, unless the bacilli appear
the circulating blood mainly as a result of
tiplication in internal organs. In the case of
kquarter, where at least some of the bacteria
folate in the living animal, it is commonly
eved that young vegetative organisms continue
multiply for some little time after death especial-
n the liver, and so further increase the number
ores available for infecting pasture land and
er supplies.
To throw more precise light on such questions
as these, some experiments were carried out with
Past. septica in rabbits, B. anthracis in mice,
guinea-pigs and goats, and Cl. chauvoei in guinea-
pigs and sheep. In practice, it may be somewhat
arduous to obtain the desired information, since
it involves being present at the moment of death,
which is frequently at night, in order to remove
tissues for immediate use or for transfer to ice
until they can be dealt with.
Methods
Cultural
Bone-marrow was usually employed for estimat
ing the variations in bacterial count which might
occur in the carcases of animals dead of pasteurel-
losis, anthrax and blackquarter, since this tissue
is easily obtained and can be made into a tolerably
smooth suspension. Moreover, the marrow re
mains for a long time free from contaminating
organisms. A femur was removed and the bone
cautiously cracked with a hammer. With sheep
and goats, the red marrow at the proximal end of
the cavity was selected, 2 or 3 gm. being removed
to a sterile tube for accurate weighing, In order
to reduce the sampling error, approximately the
same amount was taken in consecutive tests
on the same animal. With rabbits and guinea-
pigs, at first a similar technique was followed and
as much marrow as possible (about 0.9 to 0.4
gm.) removed for weighing; latterly with guinea-
pigs, weighing was dispensed with, as much marrow
as possible being first removed and the remainder
then collected by thorough washing with saline.
After weighing, sterile sand was added, the
mixture thoroughly ground and diluent gradually
added with continued grinding up to a definite
weight volume. From this, serial ten-fold dilutions
were prepared by transferring 2.0 c.c. amounts
to 18.0 c.c. diluent. In the case of pasteurellosis
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