KING INSTITUTE, GUINDY, FOR 1927-28
23
A NOTE ON CONDITIONS IN DUTTALUR IN DECEMBER 1926
BY CIVIL ASSISTANT SURGEON M. K . RAMASWAMI AYYAR.
Duttalur was visited in 1926 with a view to note any changes in the
mosquitoes and their breeding places at this season of the year as already
suggested in the previous report Here also, as in Mopad and Udayagiri, the
north-east monsoon, the chief monsoon that brings rain to these parts, failed with
the result that all the tanks were dried up except for small collections of water in
pits. Similarly the streams and irrigation channels were dried up. When adult
mosquitoes were caught from houses, etc., they were found to be mostly culicines
with a few anophelines belonging to the non-carrier species rossi. Pools in the
beds of the tanks contained larvæ of A.rossi. The well at Kammavaripallem
which contained larvæ of A. jamesi in plenty during April was completely free
from larvæ at this time.
COMMENTS ON THE FIRST AND SECOND MOPAD, UDAYAGIRI AND
DUTTALUR MALARIA REPORTS
BY LIEUT.-COL. H. H. KING, I.M.S.
These reports very well illustrate the great importance of two factors in the
causation of malaria :
(a) the provision of breeding places for mosquito larvæ by water from
rainfall or from local sources,
(b) the provision of climatic conditions suitable for the life of adult
anophelines—moderate temperature and humidity associated with local rainfall or
with the season and monsoon changes.
In March 1926 in Mopad although there were many breeding places and
many larvæ there were very few adults because of the onset of the hot dry season,
thus condition ( a) was present but not (b). At the same time in Udayagiri only
30 miles away and to a less extent in Duttalur both larvæ in breeding places and
adults in houses were abundant which was due to the presence of the two condi-
tions ( a) and (b ) caused by unusual recent local rainfall.
In November and December in Mopad both larvæ and adults were plentiful
due to the presence of both conditions ( a) and ( b), the first caused not by rainfall
but solely by the local conditions associated with wet crop irrigation and with the
condition of the Manneru river, and the second also not mainly caused by rainfall
but associated with the climate of the season of the year and with its north-east
humid wind. At this time in Udayagiri and Duttalur although the same climatic
conditions were present, yet larvæ and adults were few because of the insufficiency
of breeding places, which here, are mainly dependant on rainfall and not on
ground water as in Mopad. So, on the whole for the purposes of the enquiry, it
is fortunate that the north-east monsoon did fail in 1926, for it has helped to
establish clearly the fact that the extensive breeding places in Mopad are not
derived from seasonal rainfall but are dependant almost wholly on ground water,
i.e ., on water from irrigated lands and from pools in the Maneru consequent on
its having been dammed.
A REPORT ON MALARIA IN VIZAGAPATAM HARBOUR AREA
(OCTOBER 1925)
By CIVIL ASSISTANT SURGEON K. V. KRISHNAN.
Object of enquiry.—In accordance with the orders of the Director, King
Institute, I proceeded to Vizagapatam on 26th October 1925, in charge of a
malaria unit with two attenders and the necessary laboratory equipment to in vesti-
gate the prevalence of malaria in the backwaters and in the proposed harbour.I