71
Paras. 40—41
\ill\ellow pigment to account for its condition. But there was yellow pigment in
he liver—which was little affected.
The epidemiology of kala-azar must be that of malaria in general, and is
\ill\ound up in the life-history of the pathogenetic parasites. It is extremely
probable that the life-history of the parasites of men and of birds is similar.
Proteosoma of birds is communicable from sick to healthy birds through the
agency of the mosquito ; but there is evidence in the existence of the black
pores of a second more circuitous route for the infection—though it seems
\ill\ me very likely that actual infection in malaria is produced only through
he veneno-salivary gland of the insects.
Some steps in the mosquito stage of the human æstivo-autumnal stage
have been followed in " dappled-winged" mosquitoes. So far as they went,
these steps were exactly similar to the corresponding ones of proteosoma,
\ill\trongly suggesting a similar history throughout.
It appears to me possible that other suctorial insects, as well as mosquitoes,
may also carry the infection of malaria.
While then, I am of opinion that malarial fever is a communicable disease,
[ think that it is only indirectly so—through insects—and that for communi-
cation it requires the presence of the proper species of insect. I think also
that there is a second cycle the nature of which has not yet been elucidated.
While I consider, as I have said, that kala-azar is a form of malarial
fever with a marked incidence on the spleen and liver, I must add that I think
its mortality is considerably enhanced by the presence of ankylostomes and
other intestinal parasites, and of dysentery in very many of the cases.
I must also guard myself against being interpreted to mean that malarial
fever of this type is confined to cases of so-called kala-azar and kala-jwar. On
the contrary, I think that isolated instances of a precisely similar fever occur
more or less throughout India, and that in particularly malarious localities
they occur in large numbers. As to why the disease should be more prevalent
in some localities and why its prevalence now in Assam amounts to an epidemic,
I can offer only conjectures (paragraph 38) ; but there is nothing in these
facts to prejudice the view that the disease is of a malarial nature.
I think that kala-jwar in the Darjeeling Terai is practically the same as
kala-azar in Assam.
VII.-RECOMMENDATIONS.
41. Professional Recommendations.—Kala-azar is a local disease ; but
it is a form of the most important of tropical diseases, malarial fever, and a
form which is probably by no means confined to Assam. Hence the difficulties
which it has presented appear to me to be of great and general importance. I
have no doubt that a similar form of malaria, possessing similar points of
interest, occurs widely throughout the tropics. And these points of interest
are far from being merely academical, but are intimately bound up with
questions of the proper diagnosis and treatment of malarial fever in general.
I will now endeavour to show how this is the case.
Kala-azar is interesting for the following reasons :—
(a) The frequent complication by ankylostomes.
(b) The early extinction of the primary malarial invasion, and the
subsequent elimination of the melanin.
(c) The heavy incidence of the invasion on the spleen and liver ; and
the secondary low fever.
(d) The communicability of the disease.
With regard to the complication by ankylostomes, so much excellent matter
has been written by Rogers that I have only some isolated remarks to offer.
I agree with him that kala-azar is not ankylostomiasis ; but this does not
imply that I under-estimate the importance of the worm in many cases of the
disease and in Assam generally as in other localities. These parasites were
found in 11 out of 16 cases of kala-azar which were carefully searched for them ;
and it was obvious that in several instances they amounted to a serious