3
Finally, it is necessary to emphasise the fact, already alluded to, that
malaria in the Punjab is subject to spontaneous fluctuations of considerable
magnitude, so that a series of mild years may and often is followed by an out-
break of great severity. It would be out of place to discuss here the signifi-
cance of this point, and it must suffice to state that it has recently been found;
possible to explain the reason for these periodic waves of increase and decrease
in prevalence and virulence. The point that it is chiefly desired to bring out
here is the fact that these fluctuations are a normal feature in the epidemiology
of malaria in this Province. The recognition of this circumstance is a matter
of considerbale importance, and it is obvious that it must always be taken,
into account when any opinion is being formed in regard to the effect of anti-
malarial measures ; for it will be readily understood that, if this point is not
appreciated, wrong deductions may be made in regard to the value of these
measures.
III.—The distribution of endemic malaria.
Malaria in the Punjab requires consideration in its aspect as an endemic
disease and as an epidemic, and it is expedient, for reasons which need not be
referred to here, that these two manifestations of the disease should be clearly,
distinguished from one another.
Malaria is endemic practically throughout all parts of the plains of the
Punjab, whilst severe epidemics (fulminant malaria) occur only in certain years
and in well-defined tracts. It may be said at once that the year under review
was noteworthy as one in which epidemic malaria was entirely absent from the
Province, and it thus affords a favourable opportunity for the study of the
endemic disease.
Utilising the recorded fever mortality as the only index available of its
prevalence it is found that the malaria mortality for the Province as a whole
was 331,698, which is equivalent to a death-rate of 17.15 per 1,000 of population.
It is not considered necessary to compare the death-rate with that of previous
years as the spontaneous manner in which the fever mortality is subject to
fluctuation suggests that it would not serve any useful purpose to do so. The
one point, however, that may be mentioned is the fact that during the five years
that have elapsed since the severe 1908 epidemic the average annual fever
mortality has been lower than in any other quinquennium during the past
thirty years. This point is of some significance more particularly in view"
of the fact that public opinion is inclined to believe that malaria in the Punjab
is on the increase as the result of canal irrigation.
There is, however, no reason to believe that this favourable state of affairs
will continue indefinitely ; on the contrary, reasons have been deduced elsewhere
which go to show that this decline in malaria mortality is of a purely temporary
nature, and that its maintenance can only be anticipated to continue until the
occurrence of the next exceptionally heavy monsoon.
Coming now to the distribution of this mortality both as regards time
and place the monthly fever mortality for each district of the Punjab together
with other details is given in the table in Appendix B.
The mortality figures of districts taken as a whole, however, are open
to the objection that they cover too wide an area, and it is proposed in future
to utilise the thana, as suggested by Major Christophers, as the unit for the
study of malaria in rural areas. But even the use of this unit is not altogether
satisfactory since thanas sometimes comprise areas possessing physiographical
features of a widely varying nature.
A scrutiny of the table shows that the ratio of the fever mortality
per 1,000 of population during 1913 was highest in the Karnal, Ambala and
Rawalpindi Districts where the figure were 24.8, 24.43 and 23.38, respectively,
whilst in Muzaffargarh, Mianwali and Attock these ratios were 21.95, 20.68
and 19.86,