SEPTEMBER, 1948]
JOHN
B.
POLDING
153
In buffaloes the position is entirely different, for, sometimes during primary epidemics of abortion
in these animals, but 5-10 per cent dubious reactors can be found and it seems possible that some
factor other than Brucellosis is at work. The aspect of specificity is discussed on (p. 188); here,
it is important only to note that, if these primary epidemics amongst buffalo are indeed
due to Brucellosis, then the agglutination test is wholly inadequate for their diagnosis.
Tests of buffaloes, co-habiting with endemically infected cows, and themselves aborting spordical-
ly, show that 25 per cent of buffaloes as opposed to 38 per cent of cows are Brucella positive. In
one flare-up of an endemic amongst co-habiting cows and buffaloes, 12 per cent of each population
aborted within a few months and, whereas 70 per cent of aborting cows were strongly positive but
48 per cent of buffaloes were weak reactors, and some 30 per cent were doubtful.
In a herd of buffaloes suffering from a major Brucella epidemic (20 per cent abortions per annum),
during the third year of the outbreak, at a time when some 60-70 animals had aborted, 25 per cent
of the whole 215 animals were positive, while, three months later, a further 23 out of 152 previously
negative animals had become so. In the fourth and fifth year of the endemic, about 50 per cent
positive reactors were found. The highest positive incidence yet encountered in buffalo is 63 per
cent of aborting animals in the fifth year of a fairly severe exacerbation of the disease. Finally,
in the ordinary minor endemics of military farms, i.e., in cases where a trickle of abortion has been
going on for years, the incidence of reactors is alike in cows and buffaloes (Table XXXII).
TABLE XXXII
The incidence of Brucella reactors in aborting cows and buffaloes in minor endemics on military establish-
ments
—
Cows . . . . . . . .
Buffaloe . . . . . . . .
15 farms observed.
Actual
Per cent
Actual
Per cent
Abortions
117
100
67
100
Positive
51
43
28
42
Doubtful
8
7
5
7
Negative
58
49
34
50
The sum of the evidence, therefore, tends to show that once an outbreak of Brucellosis has become
well established the Brucella agglutination test is about equally reliable in buffaloes and cows. On
the other hand, in primary outbreaks of clinical abortion amongst cows, the incidence of Brucella
reactors has up to the present been more than high enough to allow no doubt as to the specificity of
the disease ; but, in buffaloes, the incidence of reactors is either negligible, if the buffaloes are not
n contact with cows, or if co-habiting, it is considerably less than in cows. This anomally can only
be explained by supposing that either Brucella strains require adaptation to buffaloes, before they
will provoke an agglutinin response, or, that certain primary epidemics of abortion in buffaloes are
wholly or in part not due to Brucella infection.
SECTION VI. BRUCELLOSIS AND PUBLIC-HEALTH
In certain fairly well defined areas of the world, where the natural hosts the sheep and goat
abound, melitensis fever is a serious disease of man. The main endemic region is the Mediterranean
basin whence, it is supposed, infection has spread radially wherever communications are sufficient,
and the environment is propitious. As will be shown later, it is also possible that infection can be
carried by sea-routes, with man as the vector. An excellent example of the spread of this discas
can be seen in its penetration into metropolitan France, where Brucellosis excited little interest until
well after the turn of the century. In Sicily and southern Italy, on the other hand, it was described