18
REPORT ON THE WORKING OF THE KING INSTITUTE, GUINDY
The following is a summary of the entomological survey of biting
insects carried out by Mr. P. Sitarama Ayyar, M.A., in the kala-azar
infected areas in Tinnevelly and R āmnād districts:—
(1) Cimex was found in 84 per cent of the kala-azar infected houses
examined; in 37 per cent of the houses the insects were seen in abund
-
ance. Hindu houses were not found so heavily infected.
(2) Culicoides were observed to be present in all the places visited.
They were seen in 36 per cent of houses examined but in most cases were
taken on cattle in the cow sheds.
(3) Phlebotomus argentipes was recorded from all the places visited
in Rā mnā d district. No specimens, however, were caught at K ā yal
-
patnam; the absence can very likely be accounted for by the fact that
the place was very hot during the unit's visit in the months of September
and October, and as such, unfavourable for the existence of these insects.
All the places in the R ā mnā d district on the other hand, were visited
during the monsoon months. Phlebotomus was found to be widely
distributed in the R āmnā
d district, and showed a distinct preference for
Muhammadan houses; 75 per cent of these houses harboured these insects,
while 32 per cent had them in plenty. The presence of phlebotomus in
greater numbers in Muhammadan houses is therefore important. The
distribution of cases at K ā yalpatnam and other places and the high
incidence of kala-azar in certain families, point that a domestic insect,
which is either incapable of flight or is only a weak flier, is concerned in
the spread of the infection.
(4) No correlation was found to exist between the presence or
absence of any domestic animal and the presence of phlebotomus, houses
with domestic animals harbouring the insect in almost the same propor
-
tion as the houses without such animals.
(5) The season of onset of kala-azar is generally found to be the
early monsoon months (October—December). It is also at this time that
the houses of the poor class Muhammadans are most insanitary, and in a
condition favourable for the breeding of some of the important biting
insects.
(6) Another insect found in most Muhammadan houses visited is the
human flea, Pulex-irritans; it was absent at Kā yalpatnam. The peculiar
custom of spreading a layer of sand on the floors of Muhammadan houses
hel ps t he of breedi ng of fl eas whi ch appear t o l i e buri ed i n t he sand duri ng
the day time. At Devipatnam, Ctenocephalus canis was found in identi
-
cally the same situation as Pulex-irritans in other places.
(7) Conorhnius was collected from K ā yalpatnam as well as the
different places in the Rāmnād district. Four specimens were caught
from kala-azar houses.
(8) The tick Ornithodorus savignyi was found to be common at
Kāyalpatnam; it is a troublesome pest and is generally active after dusk.
Ornithodorus was not found in any of the places visited in R ā mnā d
district.
The findings of this unit are extremely valuable and important. The
investigations have now practically established that kala-azar is endemic
in certain villages in Tinnevelly and R āmnā
d districts, but so far the
centres of infection appear to be limited. Whether it is prevalent in
other districts in this Presidency, is not known, and requires investigation.
But it should be remembered that only while the endemic foci are
few, would it be possible to prevent the disease from spreading and
assuming an epidemic form, by carrying out the necessary treatment and
effectively rendering the cases non-infective. This can be done by means
of a travelling dispensary suitably equipped for diagnosis and treatment,
and placed in charge of a trained medical officer; the expenses should
not be heavy. If, however, the disease assumes an epidemic form
and spreads over a wide area (as it has clone in Assam where "it travelled