3

inactivated by the sun's rays, thus explaining a fewer occurrences
of foot and south disease in animals during these periods of the
year, as compared to the autumn and winter months.

SOURCES OF INFECTION AND MEANS OF PROPAGATION.

The main sources of the disease are sick animals and those
that have recovered from an attack of the foot-and-mouth virus,
as well as, the products and raw materials obtained from such
animals, and the contaminated media of their environment (such
as barns, farm lands, pasture grounds, water, etc.). The carri-
ers of foot-and-mouth infection can be humans, transport, infected
house pets, wild animals and birds, which have visited a foot-and-
mouth disease center.

while studying the epizootic flare-ups of foot-and-mouth
disease in fresh farms and settlements, which had no previous
record of such epizootic areas at great distances from disease
centers (sometimes as much as hundreds of kilometers), we did
not find even one case where an animal affected by the foot-and-
mouth disease, had passed-on the disease directly. In the greater
number of cases (70%), the infection was transported by humans,
who were present in the foot-and-mouth disease center and assumed
the role of carriers of the virus to far away regions. Thus, the
foot-and-mouth virus was introduced into the VINITSKAYA region
from the foot-and-mouth center in Rastov, Kiev region, and from
the Sums'kaya region such an infection was carried to the Zhitomi-
rs'kij regions. in most cases in fact it was because timely
measures had not been undertaken in the foot-and-mouth center,
namely, veterinary, hygiene check posts had not been set upto
carry out the required checking of persons who had been present
in the region of the foot-and-mouth center, formalin-steem cham-
bers had not been set up to disinfect peronnel [personnel] and upper clothing,
special uniforms, shoes, etc. The second reason for the spread
of the foot~and-wouth infection (14%) was, according to our data,
transport vehicles, mainly of the autocar types, which were not
checked by veterinary check posts, because of non-availability of
such check posts at the time, these vehicles were not aiways
properly disinfected while leaving the farms where the foot-and-
mouth center, was located.

Very often (in 4% of the cases) the foot-and-mouth infec-
tion was caused by milk products which were not properly treated
at the dairies and were products of animals which developed foot-
and-mouth disease later. This milk wae used to feed the calves
and young pigs in farms which had remained unaffected by the virus.
The infected milk and other milk products were specially harmful
because the very young calves and young pigs generally had very
low resistance to the foot-and-mouth virus, which in such cases,
occur in a non-aphthous (septic) condition, resulting in a large
number of deaths among the young ones. That is usually the reason

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