The Columbian. [volume] (Bloomsburg, Pa.) 1866-1910, 1908-12-17
THE CAUSE OF APHTHOUS FEVER


This has not been isolated but
she properties of the virus of the
disease have been studied. 1t is
known that this virus may retain
its vitality and virulence i'll a stable
or a manure pile for as long as six
months, that it will withstand
freezing, and that it may be de-
stroyed by disinfectants; dark,
camp places are most suited for the
prolongation Of its life. The virus
appears, also, to live upon or in the
bodies of recovered animals for sew
eral months, so that such animals
are a source of danger if they are
permitted to come into direct or
indirect contact with susceptible
animals. Fleming reports a case
wherein the virus of aphthous fever
retained its virulence for four
months in a feeding trough exposed
all of this time to the weather. He
cites another instance wherein the
virus persisted five months in hay
rack that had been used by diseas-
ed cattle, and the infection was car
ried in this hay rack to cattle on
another farm to which the rack
was taken.
The virus of aphthous fever
spreads more easily than that of
any other known disease Of cattle;
It is carried most readily and most
surely by affected animals, or by
animals that have come from in
fected herds or premises. 1t may
also be carried, and in numerous
authenticated instances has been
shown to have been carried, i'll hay,
straw. grain, manure, stable uteu-
sis, blankets, bags, etc, from pre-
misses where diseased animals have
been. 1t is also carried upon the
hands, boots or clothing of persons
who have been on infected premis
es. Small animals may transport
The contagion just in the way it is
carried by inanimate objects, and
so it is necessary to guard against
the spread of infection by dogs,
cats, poultry and pigeons. There
are numerous examples of the car
riage of infection long distances
wherein all means of communica-
ton excepting by birds have been
excluded. Bolz reported in 1904 a
case wherein the virus persisted in
manure pile for six months and
caused a new outbreak Nnen COWS
,ame in contact with ih1 scattered
manure. In the prcscut outbreak
n Pennsylvania some cows became
infested while walking across a rail-
road unloading platform over
which some exposed cattle that lat
.r developed foot and mouth di-
,ease had passed some hours before;
hese cows were later placed among
ther cattle and have infected
ierds.
Calf buyers and cattle dealers
Who go frcm farm to farm and
rom herd to herd have often car
led infection, presumably upon
heir boots or clothing. Such per-
,ons unknowingly come into con-
act with the disease i'll its earlier
,tages or i'll its later stages and may
all to recognize that the animal is
ick and that they are exposed,
md then may carry the seeds CT di-
ease to other premises. During
outbreaks of foot and mouth di-
ease, visits of perambulating cattle
ealers, of castrators and of careless
ow doctors are particularly dan
,erous. There is, however, no
anger from the visits of veterinar-
ans who observe certain WELL
;nown precautions. Cattle hides,
'af and sheep skins, wool, milk
nd the carcasses of unslaughtered
,iseased or exposed animals may
.'so convey contagion.
The virus may be taken by eX-
osed animals through the digestive
r respiratory tract, or infection
lay result from inoculation upon
he skin or into the blood stream.
The period of incubation, or the