JOHN
FRANCIS
39
TABLE I
—
Incubation period .
Infectivity . .
Symptoms . .
Action of neosalvarsan
Mortality . .
Contagious
pneumonia
Long, up to 40 days
Low, only by direct
contact. Spread is
irregular and the
duration of an out-
break in a group of
horses is much longer
than with the other
diseases.
Primary fever with
regular temperature
curve may pass almost
unnoticed. Pneumo-
nia may then develop,
accompanied by a
secondary rise of
temperature. A
yellow discharge from
the nose is said to be
pathogomonic.
Effective . . .
Higher than in the
other
Influenza
Short . . .
High, by direct and
indirect contact. May
assume very severe
epidemic proportions.
Primary fever with
larger diurnal varia-
tions of temperature
marked depression,
cardiac and muscular
weakness. Reddening
of mucous membranes
and swelling of sub-
cutaneous
tissues.
Severe intestinal, or
less often respiratory
involvement
may
follow.
Not effective . .
Usually low . .
Infectious
respiratory
catarrh
Short . . .
High, by direct and
indirect contact.
Fever, purulent
rhinitis, coughing and
occasionally swelling
of the submaxillary
lymphnodes. Pneumo-
nia may occur under
adverse conditions.
Not effective . .
Low
.
.
.
.
Strangles
Short.
High, by direct and
indirect contact.
Fever, early rhinitis
followed by marked
swelling and often
abscess formation
of the sub-maxillary
lymphnodes. Pneu-
monia may occur
under adverse con-
ditions.
Presumably
effective
Usually low.
It would appear that infectious pneumonia can be differentiated from the other diseases by
its longer incubat on period and lower infectivity ; the clinical observation that there is no cross-
immumity between infectious pneumonia and influenza supports this view. Bemelmans [ 1932 ]
wrote a long review comparing human influenza brustseuche and canine distemper. Many of
his views can no longer be accepted, but the review is valuable in that there are 345 references
to the older literature. Luhrs [ 1933 ] commented on Bemelmans' article. They both agreed
that brustseuche and influenza were distinct diseases, but it is probable that Bemelmans [ 1933 ]
described infectious catarrh as ' abortive brustseuche, ' and other writers have stated that out-
breaks of catarrh predispose to brustseuche. Luhrs [ 1933 ], however, is quite definite that they
are separate diseases : the whole course of an outbreak of infectious catarrh is much shorter and
neosalvarsan exerts no therapeuric action.
Discussing strangles, Percival [ 1834 ] said : ' I now begin to doubt, whether any tumour or
abscess at all is absolutely necessary
I believe most horses to have sooner or later in life,
strangles fever ; but I doubt that everyone that has that fever has it demonstrated or accompanied
by local tumour or abscess
Of the many young three to four year-old horses which have
in the course of years passed under my medical superintendance, 1 should say that not have
above one in four of them had undergone regular strangles , though very many of them at one
time or the other had sickened . Let other veterinarians turn their attention to these interes-
ting points : we shall then probably, ere many years pass over our heads, elicit some curious if
not valuable addition to our present stock of knowledge on the subject, Pillers and others [1934]