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Factors affecting malarial admissions .—There are three main factors usually
responsible for the general malarial rate.
(a) Annual variations of climate, which however may show very consi-
derable local differences in a country the size of India. In the
present year there have been very marked differences. In the
north a dry summer extending into the late autumn fulfilled the
forecast made by the Director of Public Health, Punjab, that
there was no likelihood of any widespread or severe epidemic
in the Punjab. In the east heavy rainfall in Lucknow and
•
Meerut Districts had some bearing on the increase in fresh
cases of malaria. In the south an average rainfall of rather
intermittent type lead to a marked prevalence of malaria in the
areas of Bombay and the Central Provinces.
(b) The efficiency of our anti-mosquito measures which are dependent
firstly on the funds which are available for the purpose and
secondly on the intelligent co-operation of all military personnel.
(c) The efficiency and thoroughness of our anti-malarial treatment.
•
(d) In the present year we have the additional factor of war movements
and dispersion of troops outside the protected areas of our can
tonments.
The results of these factors are clearly shown year by year in Chart No. IV
which clearly indicates the satisfactory results of our efforts on the factors
likely to produce a high malarial incidence. The graph of British incidence is
the truer guide to the effects of our methods because that for Indian troops is
more affected by conditions outside our control ; men frequenting cities,
bazaars and villages outside cantonments and proceeding to and returning
from leave in uncontrolled, heavily malarious areas ; recruits and reservists
arriving from malaria infected homes. In this graph is shown the drop in
military cases after the introduction of our present system of anti-malarial
measures in all cantonments in 1924-26 and the second drop which occurred
after the introduction of our present method of treatment with atebrin and
plasmoquine in 1931-32.
A third method of prevention which was mentioned in last year's report
viz. spraying with insecticides which was introduced in 1935-36 appears to
have commenced a further drop in the graphs but has been upset by the
abnormal war conditions of the present year.
Anti-malarial measures in cantonments.— Cantonment anti-malarial schemes
have been continued with skill, enthusiasm and success. The work carried
out has now reached the pitch where it is becoming an integral part of canton
ment life ; so much so that the " dry day " is regarded as a normal procedure
and complaints are readily launched at or to the anti-malarial officer should
mosquitoes become unduly evident (even though they be clouds of culicines
brought in by the wind from outside areas). The relative safety of cantonments
is shown partly by the difference in British and Indian malarial rates and during
the present year by the heavy incidence which occurred amongst troops posted
to security posts away from cantonments. For example at railway protection
posts in the north and east and in the Bombay area at similar posts nearly 100
per cent. of the men were infected in September and early October. In recent
years it has been rare to get fresh malarial infections amongst British troops at
Colaba, in the present year 43 fresh cases were directly attributable to the
defence scheme which necessitated outposts in docks and other surrounding
areas. Protective measures were not carried out as thoroughly as they should
have been.