NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
( H )
experimental conditions, and the reason why it does not usually do
so in nature is unknown. It is possible, however, that this species
feeds for preference on the blood of domestic animals such as cows,
goats and horses, rather than on that of man.
With the above remarks as a guide it should not be difficult for
any one to find the favourite breeding places of the different species
of anopheletes prevalent in his district.
The habits of anopheletes.
The fact that some species of anopheletes are always found near
human habitations ("domestic" species), while others are rarely
found in houses ("wild" species), has already been mentioned, as
have also the important facts regarding the selection of different
breeding places by different species. Another important character-
istic of anopheles mosquitoes is that they bite almost exclusively at
night, i.e.) between sunset and sunrise. During the day time they
hide away in some dark corner of the room or in the outhouses, com-
ing out again as soon as twilight begins. For this reason there is
more danger of catching malarial fever at night than in the day time.
Anopheletes do not habitually fly very far, and for this reason they
are seldom found in places which have no suitable breeding places
near at hand. If the nearest breeding place to a village is over
half a mile away the village will be practically free from anophelebes
and even if the nearest breeding place is only a quarter of a mile
away comparatively few may be found. It is possible, however, that
under certain conditions anopheletes can fly a long distance. If for
example all the breeding places round a village were suddenly done
away with, it is probable that the majority of anopheletes would
desert the village for a more favourable one, and again at the onset
of the severe cold in the north of India a possible explanation for
the sudden and complete disappearance of adult anopheletes is that
they have migrated to more favourable conditions further south.
Regarding the length of life of anopheles mosquitoes, their sea-
sonal prevalence, and the means by which they tide over the severe
cold of winter, very little is in fact known, and extended observations
on these important points require to be made. The generally accepted
idea that adult anopheletes are able to remain in a hybernating
condition in houses without feeding or laying eggs for many months
is very improbable. Recent work has shown that all species do not
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tide over the winter by the same method, and some species are
undoubtedly able to resist cold better than others. A. fuliginosus
for example is able to live, feed and lay eggs throughout the winter
in the Punjab just as it does in the autumn. A. culicifacies on
the other hand tides over the Punjab winter solely by means of
hybernating larvæ. Although all adults of this species die off
or disappear during the winter, some of its larvæ remain in perma-
nent pools, in a more or less resting condition, without developing
into pupæ and adults until the spring. Both adults and larvæ of
other species, e.g., A. Rossi, disappear entirely from the Punjab
during the winter, and do not return again until the following
July, some time after A. culicifacies has become fairly prevalent.*
The characteristics of the malarial fevers and parasites of India,
We must now briefly consider the results of the presence of
malaria parasites in the blood.
It is well known that the most prominent symptom caused by
an infection with malaria parasites is fever of a very definite and
peculiar character. This character may be summed up in the words
Intermittency and Periodicity. By intermittency is meant the fact
that the fever ceases at intervals; the temperature alternately falls
to normal or below, and rises again. On this account the name
"Intermittent fevers" is well applied to malarial fevers. By
periodicity is meant the habitual tendency of the fever to recur at
stated intervals of time. Thus the fever may recur at intervals of
24 hours (Quotidian periodicity) or at intervals of 48 hours (Ter-
tian periodicity) or at intervals of 72 hours (Quartan periodicity)
It may be said that, almost without exception, all cases of fever
due to the presence of malaria parasites in the blood will if left
untreated, sooner or later exhibit these two characteristics of inter-
mittency and periodicity. Unfortunately the terms "malaria" and
"ague" are often applied in a loose manner to many continued and
irregular fevers, the nature of which is not wholly clear, and at the
outset I would strongly urge you to guard against making a hasty
diagnosis in any continued or irregular fever; and would advise you
to err on the side of those who do not consider any case of fever
* For further information on th se points see Scientifi Memoirs by officers
of the Sanitary and Medical Departments of the Government of India New
Series, No. 6. "First report of the anti-malarial operations at Mian-Mir,
1901-1903" by Captain S. P. James I.M.S.
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as malarial, until the character of the temperature chart, or an
examination of the blood, plainly proves it to be so, rather than on
the side of those who regard every case of fever as " malaria," until,
after several weeks of ineffectual treatment, this diagnosis is proved
to be wrong.
Before describing the clinical types of malarial fevers we must
say a few words regarding the process by which the malaria para-
site produces fever.
I have already described bow the parasites in the red blood
corpuscles gradually grow larger and larger until they attain
their full size and divide up into a number of segments or spores,
which burst through the thin remnant of the corpuscle and become
free in the blood plasma, ready to enter fresh corpuscles. It has
been found,—and the observation may be verified by any one
who examines the blood of a typical case of malarial fever,—
that the onset of the attacks of fever from which the patient
suffers, always corresponds in point of time with the stage of
sporulation or segmentation of the parasites. During the inter-
val of apyrexia only young and medium-sized parasites, enclosed
within the red blood corpuscles, can be found, and it is only
when the parasites are in the segmenting stage and escaping
from the corpuscles that the attack of fever begins. There is thus
a very intimate connection between the sporulation of the parasite
and the attack of fever, and it is probable that during the growth
of the parasite in the red blood cell it produces a pyrogenetic or
fever-producing chemical substance, which, when the parasite bursts
from the red cell in the act of sporulation, is liberated into the
plasma and so becomes able to exert its influence and cause fever.
As long as the parasite remains inside the envelope of the cor-
puscle the pyrogenetic substance cannot escape, so that during the
time the parasite takes to grow to its full size the patient does not
suffer from fever. As soon as the parasite divides and bursts from
the corpuscle the pyrogenetic substance escapes and causes fever.
From this you will readily understand that a parasite which
sporulates every 24 hours will produce Quotidian fever, one which
sporulates every 48 hours will produce Tertian fever, and one which
sporulates every 72 hours will produce Quartan fever.
In India there are three species or varieties of the malaria para-
site which sporulate at the above intervals respectively, and which
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cause the three clinical types of malarial fevers, Quotidian, Tertian
and Quartan, which are so commonly met with. It will he appa-
rent that if a parasite should, for some reason or other, complete its
asexual cycle in a less period than 24, 48, or 72 hours, a different
clinical type of fever will result, and also that a different clinical
type may be produced by the presence in the blood of two or more
groups of parasites which sporulate at different times.
The three species of malaria parasites referred to above are
called respectively:—
(1) The Malignant Tertian parasite.
(2) The Benign Tertian parasite.
(3) The Quartan parasite.
The general description of the life cycle of the malaria parasite
in man and in the mosquito which I have already given, applies
equally to all these species, but they differ from each other not only
in the time which they take to complete their asexual cycles respec-
tively, but also in other particulars, such as their size and appear-
ance, their amoeboid movements, the character of the pigment they
produce, the number of segments into which they divide up. and
the characters of the sexual forms. These differences are considered
sufficient for them to be regarded as distinct species.
1 shall describe first the results of an infection with Benign
Tertian parasites, because this is the species most commonly met
with in India, and afterwards note the differences which result
from infections with the other two forms.
1. Benign Tertian infection.—Supposing a man to have been
bitten by a mosquito infected with the sporozoites of the Benign
Tertian parasite, he will probably not feel any ill effects until about
twelve or fourteen days afterwards. This is the incubation period
during which the parasites have been gradually multiplying in his
blood, but have not been present in sufficient numbers to cause any
symptoms. Towards the end of the period he may feel some aching
of the bones, headache, or other premonitory symptoms, and his
temperature may be somewhat raised. After these indefinite symp-
toms have gone on for a day or two the regular attacks of " ague "
begin. These consist of a series of attacks of fever which recur, in
infections with the Simple or Benign Tertian parasite, at definite in-
tervals of 48 hours. Each attack is represented clinically by a
" cold" stage, a "hot" stage, and a "sweating" stage. At the
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beginning of the cold stage the patient feels chilly; after a short time
the feeling of cold spreads all over his body and becomes so intense
that his teeth chatter and he shakes from head to foot. His tempera-
ture; however, in spite of the feeling of cold, begins to rise. After a
time the shivering stops and the patient begins to feel hot, the skin
becomes dry and burning, and the temperature rapidly rises to
103°F. or 104°F or more. After an hour or so the hot stage passes
off, the patient begins to perspire profusely, the fever quickly declines,
and in a short time all the acute symptoms have disappeared and the
patient feels almost well. As a rule he is able to get up and go about
his occupation until the next day but one, when he will again have
another attack of fever similar to the first one. If untreated these
attacks may recur every other day for many weeks, gradually de-
clining in severity as time goes on. In the meantime the patient's
spleen has become enlarged and he has become pale and anæmic.
After the fever has apparently left him for good it may return at
irregular intervals for many months (Relapses). These relapses
of fever may be brought on by almost any exciting cause, such as
chill, over-fatigue, over-anxiety, exposure to the sun, etc., and
have no connection whatever with mosquitoes. They are simply due
to the fact that all the parasites of the first infection have not
died out, and when the patient's resisting power is lessened by any
of the exciting causes just mentioned, the parasites are able to
develop rapidly again and produce their ill effects,
The relation of the parasites to the different clinical stages.—If
the patient's blood be examined at the onset of fever, that is, during
the cold or rigor stage, it will always be found that (as we have
already noted), the majority of the parasites are in the stage of
division or sporulation. The onset of fever and the rigor corre-
spond in point of time to the sporulation of the asexual forms of the
parasite. From the point of view of treatment this is an important
point to remember. By the time the hot stage approaches all the
parasites have divided up and are entering, or have already entered,
fresh corpuscles. During the last part of the hot stage, during the
sweating stage, and during the interval of apyrexia, the para-
sities are enclosed in the red blood corpuscles, growing and develop-
ing pigment. Between any two similar stages of the parasite an
interval of 48 hours elapses, i.e., the Benign Tertian parasite
takes 48 hours to complete its asexual cycle.
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These points and the clinical characters of Benign Tertian malarial
fever are illustrated in Chart. I.
CHIrT No. I.
Malarial fever. Benign Tertian infection.
Name.— Guimer T—. Age.—25.
This chart. I shows three typical paroxysms of ague occurring at
the same time on alternate days. Each attack lasted from about
11 A.M. until about 8 P.M. At 12 noon, during the shivering stage,
sporulating forms (from which the photographs in Plate VII,
Pigs. 3, 4, were taken) were found in the blood, and at 7 P.M. very
young forms, which had lately entered the corpuscles, were present.
The sudden rise of the fever and its quick fall are characteristic of
Benign Tertian infections. The administration of thirty grains of
quinine at 7 A.M. on the 26th, though it did not prevent the onset of
the attack on that day, stopped all future paroxysms and practically
cured the case. (See page 36.)
( 30 )
After the attacks of fever have gone on for a few days, sexual
forms of the parasite which, in the case of the simple Tertian
parasite, are spherical in shape, will be seen in the blood as well
as the asexual sporulating forms. These sexual forms, however, do
not cause any symptoms, and unless they are taken into the body of a
suitable mosquito they gradually degenerate and die.
2. Quartan infection.—The symptoms produced by an infec-
tion with the Quartan form of the malaria parasite are similar to
those produced by the simple Tertian form, except that the interval
between the onset of the attacks of fever is one of 72 hours instead
of 48 hours. The reason of this is that the Quartan parasite takes
72 hours to complete its asexual cycle instead of only 48 hours as is
the case with the Tertian parasite.
Chart II illustrates the results of an infection with Quartan
parasites.
CHART No. II.
Malarial fever. Quartan infection.
Name.—Chetty. Age,—10 years.
( 31 )
On the 10th young Quartan parasites were found in the blood
of this ease; on the 11th medium sized forms (Plate VII, Fig. 6)
and on the 12th at 5 P.M. pre-segmenting and segmenting forms
(Plate VII, Fig. 7).
3. Malignant Ter\ill\an infection.—There are marked differences
between infections with the malignant Tertian form of the malaria
parasite and those with simple Tertian or Quartan parasites,
and the term " malignant" has been applied to this species of
parasite in opposition to the term " benign," which is applied
to the parasites of simple Tertian and Quartan fevers, because
dangerous symptoms, such as hyperpyrexia, coma, delirium, etc.,
are much more liable to arise in the course of an infection with this
form of parasite than with the others. The malignant Tertian
parasite, like the simple or benign Tertian, takes 4 8 hours to com-
plete its asexual cycle, and for the first few days of a case this fact
is often apparent from the temperature chart (see Chart III).
With this form of parasite, however, there is a great tendency for the
parasites to complete their cycle in a shorter time than 48 hours,
often indeed in as short a time as 24 hours, so that after a day
or two the patient usually has an attack of fever every day.
Again there is a tendency for the parasites to complete their cycles
in different periods of time instead of their all doing so at the same
time as in the case of simple Tertian and Quartan infections. As
a result of this it not infrequently happens that the temperature
does not fall quite to normal for several days together, and the
chart may be remittent in character.
In untreated cases the fever continues in this way for about a week
or ten days and then ceases, leaving the patient very weak and anæmic
but otherwise apparently well. After an interval of apyrexia varying
from six days to a week or more, a second series of attacks of fever,
exhibiting a Tertian or Quotidian periodicity exactly similar to the
first attacks, occurs. These relapses may be repeated at more or less
constant intervals of a week or more for two or three months,
gradually getting shorter and less severe until they die out altoge-
ther, leaving the patient with an enlarged spleen and extremely
weak, anæmic and emaciated,
( 32 )
These points are well illustrated in Chart III, which is from a
case of malignant Tertian fever in a child.
For the first four days this chart shows a definite Tertian perio-
dicity. Then follow daily paroxysms until the 9th, after which an
interval of six days' apyrexia occurs. This is followed by a series of
relapses occurring at varying intervals, and in this case the relapses
were still occurring at fairly definite intervals four months after the
primary attack. The temperature is intermittent throughout the
case. It should be noted that as the temperatures in this case were
only taken twice daily, they are not by any means a record of the
highest temperature reached on any particular day. In order to
obtain a correct temperature chart it is necessary for the tempera-
ture to be recorded at least every four hours.
The malignant Tertian parasites are much smaller than those of
the benign group of fevers. Their amoeboid movements are very
active, and it is very common to see several parasites in one
corpuscle. Only the young forms of the parasite are seen in the
peripheral blood, segmentation occurring for the most part in the
deeper viscera, such as the spleen and bonemarrow. Towards the
end of the first series of attacks of fever, that is, about a week
after the commencement of the disease, sexual forms appear in the
blood. Their number gradually increases, and they are very
abundant after the fever has quite left the patient. It is certain
therefore, that these sexual forms have no connection with the
production of fever. They may still remain in large numbers when
the patient has apparently quite recovered and gone about his
occupation. In malignant Tertian infections the sexual forms are
very easily recognised because they are crescent-shaped (Pl. VII,
Fig. 10), the sexual forms of the simple Tertian and Quartan parasites
are round and more difficult to recognise, because they look some-
thing like the full-grown asexual forms (Pl. VII, Fig. 5).
4. Mixed infections.—Combined infections, with different
species of the malaria parasite, occur not infrequently in India, and
may produce irregular charts. A combined infection of simple
and malignant Tertian parasites is perhaps most commonly met
with, but combinations of simple Tertian and Quartan parasites are
CHART NO. III.
Malarial fever. Malignant Tertian infection.
Name.—Rangu. Age,—1½ years.
( 34 )
also seen. Chart IV illustrates a mixed infection of this nature in
a child aged four years.
CHArT No. IV.
Malarial fever. Combined infection with simple Tertian and Quarian
parasites.
Name.—Uligammah. Age.—4 years.
The after effects of malarial infection,
After a succession of attacks of untreated or insufficiently treated
malarial fever, a patient develops the condition called "malarial
cachexia." The chief signs and symptoms of this condition are,
marked anaemia, great enlargement of the spleen and sometimes
of the liver, a sallow "earthy" complexion of the skin, a tendency
to œadema of dependent parts, and the presence of chronic irregular
"low" fever ranging continuously from 99° F. to 101° F. or more
for many weeks or months. Such cases are very commonly met
with in Indian hospitals. As a rule, no malarial parasites can be
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found in the blood of these patients, and for this reason they are
not amenable to quinine. The chronic low fever from which they
suffer in all probability is not connected in any way with the
presence of malaria parasites, but is a secondary result of their
general condition.
The treatment of malarial fevers,
Quinine is the only reliable drug in malarial fevers, and if given
in a proper manner and in sufficient doses it seldom fails to effect
a cure. It is a mistake, however, to commence the treatment of a
case of fever with quinine until the diagnosis is absolutely assured.
If we get into the habit, as many of us are apt to do, of treating
all cases of fever indiscriminately with quinine, on the supposition
that they are possibly malarial, our faith in the efficacy of the drug
will soon diminish, because we shall find that it does not by any
means cure all the cases of fever with which we have to deal. An
accurate diagnosis is essential for successful treatment. In the
absence of a microscopic examination of the blood the diagnosis of
malaria rests chiefly on the character of the temperature chart.
Tertian and Quartan periodicity only occur in malarial fevers, and
if the chart exhibits either of these characters a diagnosis of
malaria is almost certain. In the great majority of cases of
malarial fever occurring in India, which are not treated with quinine,
the temperature chart does exhibit either a Tertian or Quartan
periodicity, and even in malignant Tertian infections a Tertian
periodicity can be made out in the majority of cases. If quinine
is given in small doses at the beginning of an attack of malarial
fever, the temperature chart becomes irregular, and an accurate
diagnosis is rendered very difficult. The fever may continue in an
irregular or continuous manner in spite of the usual doses of
quinine, until after a week or so we become hopelessly confused as
to the real nature of the case, and begin to suspect that the case
may not after all be one of malarial fever. But if from the
commencement we had abstained from giving quinine, until our
diagnosis could be made with certainty, we should have been
saved the anxiety caused by a possible error in diagnosis, and if
the case turned out to be really one of malarial fever, we should be
p 2