R. L. KAURA 371
in the living bird based on exposure and examination of the sciatic nerve for
macroscopic changes. The nerves running from the backbone (just in front
of the ovary) to the gizzard and proventriculus are often enlarged and should
be examined before the viscera are removed. These nerves may be very much
enlarged whilst those supplying the legs or wings are but slightly abnormal.
A nerve lying between the rectum and oviduct may be enlarged when
all the nerves are normal and it is usually involved when the large
intestine (rectum) just preceding the cloaca is ballooned. The small
intestines particularly the duodenum may show inflammation with
yellowish brown discolouration. In the case of leukaemia, the liver, spleen
and kidneys are usually enlarged, soft, and easily ruptured. The liver is
usually spotted with brownish or grey areas. Tumours may be present in all
parts of the body but the ovary, kidneys, heart, lungs, spleen and digestive
tract are usually affected. For definite diagnosis histopathological examina-
tion of the suspected nerves and tissues is necessary in order to
demonstrate the infiltration by lymphocyte-like cells, as in certain acute cases
no naked eye lesions may be observed except perhaps some inflammation of
the digestive tract and the nerves may appear to be normal.
Control.—There is no treatment of proved value. There are two ways of
dealing with infected farms. In the case of a severe outbreak the best plan
is to dispose of all birds which may be used for table purposes provided they
are in good condition, thoroughly disinfect the premises and all equipment and
leave the farm un-occupied for several months. Fresh re-stocking should
be done with chicks from healthy hens from farms which are known to be
free of the disease. Another plan, where it is not necessary to carry out whole-
sale slaughter, is to cull all weak or affected birds and examine the remaining
flock regularly and remove all suspected cases. Birds showing symptoms of
fowl paralysis should never be kept alive, for though improvement may take
place, in many cases the symptoms recur. It is inadvisable to breed from the
survivors of a strain in which the disease has appeared. It is also inadvisable
to breed from stock with grey, pearl-like eyes as their progeny has a greater
tendency to this disease. All such birds should be eliminated no matter how
good their laying powers. The best plan is to breed from families
which have shown little or no loss from the disease on the farm and hatch chicks
from hen eggs only and not from pullet eggs. Birds from flocks supposed to be
free of the disease should not be introduced into a farm where the disease is
known to exist on account of their higher susceptibility. Measures should be
taken to control intestinal parasites, regulate feeding and management and
allow a plentiful supply of green food to the young growing stock in order to
reduce the incidence of this disease to a minimum. Fritzsche [1937] tried a
formalinized vaccine but it did not produce immunity. He considered it un-
likely that an effective curative or preventive agent will be found.
The spread of the disease from infected farms and areas to clean places
can be checked by prohibiting the introduction of birds from the former into
the latter. It is also necessary to avoid the secondary factors which have been
mentioned above under etiology and which play a very significant role in the
causation of this disease,