J. B. POLDING
163
Nevertheless, it is of deep interest why a disease, so prevalent in man on the goat-populated
Mediterranean littoral, should be apparently so rare in man in India, where in certain parts at least
sheep and goats are abundant. At one time the simple explanation of the almost universal Indian
custom of the boiling of milk was stressed as the explanation, but in France Taylor, Lisbonne, Vidal
and Hazemann [1938] have clearly shown that at least among breeders of goats and sheep, and possibly
also amongst all who come in close contact with these animals—such as small-holders, house—
wives and butchers—some 40-60 per cent of infection is transmitted to man by contact. For a
considerable section of the Indian public, therefore, the ' boiled milk' explanation fails and, if it
can be assumed that melitensis fever in man would be diagnosed and reported were it a sufficiently
prevalent disease in this country,—an assumption which is probably valid—then it appears that
the reason for its rareness in man must be its rareness in animals—and as will be shown elsewhere
(Polding, unpublished), this appears to be the case as far as sheep and goats are concerned.
Br. melitensis is not, however, the sole Brucella species pathogenic to man, and it seems possible
that a variable number of Indians must become infected with Br. abortus from contact with
animals, in which there is no room for doubt that Br. abortus infection occurs. Rare serum-positive
patients, suffering from fever, are reported from time to time, notably in the North-West Frontier
Province and Punjab, but until the responsible strains are isolated and typed, which has not yet been
done, it will not be known whether these fevers are melitensis or abortus in type, although the latter
seems more likely.
On the face of it, therefore, it seems that, if melitensis infection has occurred at one time in India,
it is not very prevalent today. The abortus type is known to occur in cattle and is likely to occur
to some extent in man. Sheep and goats appear to be relatively free from either infection, whilst
there is no reason to suppose that the suis species occurs at all.
The existence of the aberrant abortus/melitensis strain holds much interest. Huddleson's
correspondent, cited earlier, observed similar characteristics in his aberrant Indonesian strains. In
India, the only truly enzootic area, where the incidence of brucellosis in native village cattle is signi-
ficant, is the south-eastern seaboard. This is also the area of constantly high atmospheric humidity,
equable temperature, and a tri-seasonal rainfall. This portion of India is, therefore, not only nearest
to Indonesia geographically but also climatologically. Consequently, it is tempting to suppose that
this is a middle-asiatic variant, which is adapted to survival in regions favourable to the cultivation
of rice.
SUMMARY
Forty-nine Indian field strains of Brucella were typed and their dissociability, agglutinability
and virulence assessed. They were unexceptional on all the last three counts. Of the 49, 26 were
pure abortus, 20 were intermediate between abortus and melitensis, 3 were melitensis and there were
no suis. All six strains isolated from village cattle of the Brucella enzootic area of the peninsula
were of the intermediate type and it is suggested that this is an indigenous Indo-Indonesian variant.
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