NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
22
TABLE VII—SHOWING MONTHLY ADMISSIONS FOR
MALARIA, 1907-1911— contd.
VIPER.
HADDO.
BAMBOO FLAT.
Admissions,
total.
Admissions,
Fever.
Rainfall. Admissions,
total.
Admissions,
Fever.
Admissions,
total.
Admissions,
Fever.
1909.
January
.
.
.
377
251
0.05
344
183
459
219
February .
.
.
223
119
3.12
230
281
503
262
March
.
. .
350
222
3.18
630
482
604
370
April
.
.
.
403
281
6.88
697
518
595
369
May
.
.
.
583
477
18.60
717
454
...
. . .
June
.
.
.
797
657
25.03
839
579
862
439
July
.
.
.
713
583
21.96
832
558
797
475
August
.
.
.
649
384
20.79
535
323
720
413
September .
.
.
432
281
23.35
481
284
584
314
October
.
.
.
348
175
21.30
398
242
641
339
November
.
.
.
396
219
26.51
344
173
704
385
December .
.
.
381
223
3.88
295
125
374
304
Total
.
5,652
3,872
...
6,542
4,202
7,043
3,889
Percentage of malaria to
total.
68%
64%
55%
1910.
January
.
.
.
323
200
2.05
256
102
. . .
. . .
February
.
.
.
325
167
1.03
210
92
...
. . .
March
.
.
.
268
167
8.32
284
179
. . .
. . .
April
.
.
.
236
147
4.04
364
266
...
. . .
May
.
.
.
543
413
7.11
605
429
...
...
June
.
.
.
562
449
20.51
787
588
. . .
. . .
July
.
.
.
665
530
10.34
757
598
...
...
August
.
.
.
387
294
12.61
568
398
. . . ...
September .
.
.
321
192
27.94
375
241
...
...
October
.
.
.
270
175
10.02
312
165
...
. . .
November .
.
.
318
188
16.41
318
146
...
...
December .
.
.
341
185
3.15
416
148
...
...
Total
.
4,559
3,107
. . .
5.252
3,352
. . .
. . .
Percentage of malaria to
total.
6 8 %
63%
. . .
23
TABLE VII—SHOWING MONTHLY ADMISSIONS FOR
MALARIA, 1907-1911— concld.
VIPER.
HADDO.
BAMBOO FLAT.
Admissions,
total.
Admissions,
Fever.
Rainfall.
A d m i s s i o n s ,
total.
Admissions,
Fever.
Admissions,
total.
Admissions,
Fever.
1911.
January
.
.
.
352
189
...
341
142
. . .
...
February
.
.
.
354
190
0.54
347
147
. . .
...
March
. . .
326
155
...
286
133
...
...
April
.
. .
316
161
4.84
288
117
...
...
May .
.
.
.
430
278
11.96
334
147
. . .
...
June
.
. .
483
373
34.15
550
368
...
...
July
. . .
410
292
12.64
570
348
... ...
August
.
.
.
283
210
7.70
...
...
... ...
September .
.
.
254
185
...
...
...
...
...
Total
.
3,298
2,033
2,659
1,402
... ...
Perc. of malaria to total
61%
53%
...
In each of these years the number of admissions is smallest during the
period October to March. There then occurs a sharp rise in the number of
admissions usually first evidenced in the numbers for May and reaching a
maximum in June or July. At this time the number of admissions is from
two to four times that of the non-malaria season. During the months of
August and September the number of admissions gradually diminishes till the
low level of the succeeding non-malaria season is reached.
26.
Considerable variations in the intensity and continuance of the fever
rise occur in different years. Some years, e.g., 1907, are especially malarious,
others, as was the case in 1911, are especially healthy.
RELATION OF THE MALARIA SICK RATE TO RAINFALL.
27.
In Table VII opposite the number of admissions in the month at
Viper are given the number of inches of rainfall. It will be seen that the
period of least malaria prevalence is characterised by a low rainfall and that
the onset of the rains and the rise in fever admissions are almost synchronous.
It will also be noticed that the much prolonged fever season of 1907 was
24
associated with an unusual continuance of the rains. On the other hand, in
most years the fever rate decreases before there is a cessation of the rains.
The reason for the latter relation is not clear but the simultaneous onset
of the rains and fever season supports the view discussed later that relapses
play a large part in the fever season of the Andamans as has been noted by
Deeks and James (2)i n t h e c a s e o f P a n a m a .
RELATION OF MALARIA SICK RATE TO OCCUPATION.
28. It is the common experience in the Andamans that certain kinds of
convict labour are more associated with malaria than others. The type of
labour most associated with a high prevalence of fever is excavation work,.
repairing of embankments, road making and certain kinds of jungle work.
At the time of my stay quite a number of cases were admitted from among
those employed in cutting canes in the jungle. All the types of work
mentioned are especially associated with exposure to sun and rain and with
severe bodily exertion. The relation of arduous physical exertion to the
malaria of excavation has not been previously noted. It is possible, however,
that this factor by favouring the occurrence of relapses plays some part. In
regard to the cane cutters, whose work would not seem to be so arduous, I
afterwards discovered that, as canes were becoming increasingly scarce in the
neighbourhood of the barracks, the men cutting them had to walk long
distances in order to find them. I believe at that time cane cutting was in
fact an unusually arduous occupation.
The following table taken from the 1901 census shews the relation of
labour to malaria admissions in actual figures :—
Nature of work.
Strength.
Number
sick
(malaria).
Convales-
cent
(malaria).
Readmis-
sions
(malaria).
Percentage
ineffec-
tive.
Indoor work
—
Ordinary .
.
.
.
.
.
2,681
40
18
2
2.23
Hard
.
. . . . .
1,217
40
31
4
6 . 1 6
Outdoor work—
Ordinary
.
. . . . .
5,597
128
96
21
4.37
Hard
. . . . . .
3,228
153
168
15
10.4
25
The same relation to occupation is shewn in the following figures also taken
from the census :—
Locality.
Nature of work.
Average of 3 days
percentage sick
(malaria) to
strength.
Bajajag
.
.
.
.
.
Firewood and forestry .
.
.
.
1 5 . 1 5
Dundas Point .
.
.
.
.
. Brickfields .
.
.
.
.
.
10.54
Namunagahr .
.
.
.
. Quarries and firewood.
.
.
.
9.33
Goplakabang .
.
.
.
.
Tea garden and forestry .
.
.
.
8.90
Navy Bay
.
.
.
.
.
Tea gardens .
.
.
.
.
.
8 . 1 8
The data given in this table may be influenced by the fact that localities
where certain kinds of work are carried out are especially malarious. On the
other hand, stations like Dundas Point where the barracks shew but few
anopheles, but where nevertheless the convicts suffer much from malaria, may
be unhealthy largely because of the nature of the work carried out there
(excavation).
Many of the cases whose blood was examined came from Dundas Point;
the fact that they suffered mainly from quartan infection is a very important
one. As will be shewn later such a predominance of quartan does not favour
the view that infection was especially active but rather indicates that at
Dundas Point the raised fever incidence owes its origin very largely to the
prevalence of relapses.
V.—Considerations upon the nature of malarial infection in different
communities in the Andamans.
29.
Many observations have been made upon the proportionate prevalence
of the different species of parasites in different countries and localities;] but no
explanation to account for the variations has ever been given. It seems
possible that such a prevalence depends upon conditions the nature of which
will be discussed in this section.
RELATION TO THE NUMERICAL PREVALENCE OF ANOPHELES.
30. In the Punjab the prevalence of malignant tertian among the native
community is greatest during the fever season, i.e., the period of greatest
anopheles prevalence (August to October). As anopheles disappear and infec-
E
26
tion becomes reduced crescents are still numerous but infections with malignant
tertian ring forms are scanty. Still later in December and January in certain
places which had been very intense foci of malaria (parts of Amritsar and
Delhi) a high relative prevalence of quartan was encountered, apparently due
to the greater relative reduction of other forms of parasite. In such cases
though, at the time, the parasite rate was not very high there was a very high
spleen rate (approaching 100 per cent).
31. A relative preponderance of quartan is also seen over quite large areas
in certain parts of India. A high quartan rate prevails throughout the Duars,
an area in which, as shewn by Christophers and Bentley, 3 f a c t o r s f a v o u r i n g
residual infection prevail and in which the number of anopheles was often
disproportionately small as compared with the amount of fever present.
In the highly endemic Jeypore Agency Tract in the dry season, associated
with scanty anopheles and a high spleen rate, Major Perry informs me that
quartan is the predominant type of parasite. It seems possible that a high
relative quartan prevalence in these large areas may be due to conditions some-
what similar to those clearly seen at work in the small Punjab foci described
above.
32. A relative increase in the proportion of malignant tertian associated
with the period of greatest infection is also shewn by Mathis and Leger 4
for the parasite rate in different seasons and for different localities in Tonkin
(Tables VIII and IX).
TABLE VIII.
MAY TO SEPTEMBER.
OCTOBER TO APRIL.
Number
infected.
Percentage
propor-
tion.
Parasite
rate (Haut
- T o n k i n . )
Number
infected.
Percentage
propor
-tion.
Parasite
rate (Haut-
Tonkin).
Children
Malignant tertian
48
27.9
8.1
53
41.4
17.5
Simple tertian
.
95
55.23
55
42.96
Quartan
29
16.86
20
15.62
Adults
Maliguant tertian
71
54.6 ...
212
71.6 ...
Simple tertian
.
53
40.7
69
23
Quartan
. .
6
4.6
15
5
27
TABLE IX.
Delta.
Hoabinh. Tuyen-Quang.
Hagiang.
Sonla.
Laokay.
Number of infected children .
.
66
29
30
25
60
51
Endemic index .
.
.
.
3%
19%
16%
33%
37%
14%
Percentage proportion of Simple
tertian
80
90
60
40
22
16
Percentage proportion of Malignant
tertian.
20
7
17
26
72
41
Percentage proportion of Quartan
...
3
23
24
7
4 3
The very high quartan rate at Laokay it may be noticed is associated with
a low parasite rate though the other hilly parts of Tonkin shew a high rate. It
is possible that this is an example similar to those already mentioned in India
of a temporary reduction of the total index and a relative preponderance of
quartan.
INFLUENCE OF THE HUMAN HOST.
33. In the Duars and other malarious areas one often finds that though the
native children shew a considerable proportion of each of the three types of
parasite, Europeans living in the neighbourhood when they suffer from fever
generally shew malignant tertian infection. Dr. Bentley has informed me that
he has had a similar experience. Such a relation is shown on a large scale in
the Punjab where among British troops infections with malignant tertian are
much more frequently seen in the cases admitted to military hospitals than in
infected native children.
The excellent figures of Mathis and Leger for Tonkin also show this relation
very clearly. It will be seen from the following abstract of their results that
whilst in adults (both native and European) the malignant tertian incidence is
very high it is much less so in the case of native children. (Table X).
TABLE X.
Malignant
tertian.
Simple
tertian.
Quartan.
Children 0 to 5
.
.
.
.
.
28.57
5 5 . 8 4
1 5 . 5 8
" 5 to 15
.
.
.
.
.
.
50.72
30.43
1 8 . 8 4
Indigenous adults .
.
.
.
.
.
70.04
11.52
18.43
European adults
.
.
.
.
.
.
66.42
28.63
4.92
10
malaria to some extent there can be little doubt that this species is the impor-
tant carrier in the Settlement.
It is interesting to note that though Nsm. ludlowi rather closely resembles
Nsm. rossi the eggs of the two species are quite distinct; those of Nsm. rossi
having a very broad frill, whereas those of
N s m . l u d l o w i
have a narrow frill
and rather resemble in general appearance the eggs of N. fuliginosus.
CHARACTER OF THE ANOPHELINE FAUNA.
16. In view of the evidence of isolation shewn by the mammalian fauna
ôf the Andamans one might have expected that the species of anopheles would
be few in number. One would also not be surprised to find a number of local
varieties or even distinct species. The question of the recent introduction of
species from the mainland is also important.
We have already seen, however, that the number of species represented
is quite large and consideration will show that the anopheline fauna of the
Andamans is practically that of the Malay peninsula.
The differences between the anopheline fauna of Port Blair and that of the
Indian peninsula is on the other hand very marked. The occurrence of N.
nivipes in place of N. fuliginosus, of M. albirostris in place of M. listoni and
the relative frequency of Nm. punctulata are especially noticeable.
The only instance of a local variety is the possible occurence of a variety
of N. nivipes.
Had recent introduction of species much influence the fauna one would
have expected to find the ordinary Indian Nsm. rossi and the very common
Indian N. fuliginosus. The presence of Malay forms suggests that the
anopheline fauna is an indigenous one since the only direct communication with
the Andamans is from Calcutta, Madras and Rangoon.
NUMERICAL PREVALENCE OF ANOPHELES.
1 7 . I n s p i t e o f a p p a r e n t l y i d e a l c o n d i t i o n s f o r t h e b r e e d i n g o f a n o p h e l e s ,
they were, with the exception of My. barbirostris in the forest, by no means
numerous. The huts in the villages, each with an enclosed verandah used as
a cow shed, were peculiarly suitable for the detection and capture of adult
anopheles. But except at Bamboo Flat and Port Mouat during the first fort-
night of my stay the catches made were not at all large. As a rule specimens
were to be obtained only as a result of close search.
Within the barracks it was even difficult to find adult anopheles at all.
At Dundas Point traps were made by hanging up blankets, etc., in suitable
28
PECULIARITIES IN THE BEHAVIOUR OF THE DIFFERENT
SPECIES OF PARASITE.
34. The number of crescents produced and the length of time crescent out-
put continues is a very marked feature of malignant tertian infection. In the
case of quartan on the contrary several observers, e.g., Marchiafava and Big
-nami,5 have noted the rarity with which flagellating forms are seen. Stephens
and Christophers6 w h e n w o r k i n g a t t r a n s m i s s i o n t h r o u g h d i f f e r e n t s p e c i e s
of anopheles found it very difficult to get cases skewing quartan flagellate
forms. More recently James 7 s t u d y i n g t h e q u a r t a n p a r a s i t e a t P a n a m a
notes that he very rarely saw flagellation in this type of parasite.
Simple tertian produces gametes readily but my experience would suggest
that these are neither so numerous nor so continuously produced as in malignant
tertian.
35. If such a relation regarding gamete output does hold good then a
greater proportion of anopheles will be infected, other things being equal, with
malignant tertian than with either of the other forms of parasite. Also new
infections will be in a greater proportion those of malignant tertian. And the
larger the number of anopheles carrying, i.e., the greater the predominance of
new infections, the more the malignant tertian parasite will be represented in
the blood of a community.
36. Again the fact that malignant tertian disappears more rapidly than
the other forms of parasite from the blood of communities when these are no
longer exposed to reinfection suggests that the relapsing power of malignant
tertian over long periods is less than that of the other two types of parasite.
In quartan the power of the parasite to maintain itself in the human host
in the absence of treatment has often been commented upon. Marchiafava and
Bignami8 say " while in quartan fever the groups of attacks follow each
other with the greatest obstinacy separated by longer or shorter intervals of
apyrexia—a fact well known to physicians from the most remote period, and
the infection in some cases dies out only after many years of existence, even
when the patient is living under the most favourable conditions."
When therefore fresh infection is at a minimum and the infection in a
community is maintained by relapses it is reasonable to suppose, if a quartan
has a greater power of retaining its hold than other parasites, that the propor-
tionate prevalence of this parasite will be raised. When anopheles are very
scanty and the factors favouring prolonged infection are very pronounced we
should expect to get quartan in its greatest relative predominance. This as we
have seen appears to be what actually occurs.
Andamans. The native children in the villages shew very much the conditions
seen elsewhere in India. The labouring convicts being less exposed to
anopheles but subject to factors greatly favouring relapses shew the remarkable
incidence of quartan noted. In this case we can exclude the possibility of
species of anopheles determining the type of infection because the same species
acts as the carrier in both cases.
It is possible that the year of my visit being an unusually healthy one the
relative preponderance of quartan was greater than usual and that in severely
malarious years malignant tertian may be relatively more in evidence. If, on
the other hand, cases occurring in the fever season are largely due to increase
in the number of relapses the relative prevalence of quartan seen in 1911 may
be a permanent and characteristic feature of infection in this community.
Only further observations can determine this point.
38. In Panama, Decks and James 2 refer to malignant tertian as pre
-
eminently the relapsing type. This would seem to be adverse to the view
taken above. But it is necessary to take into account the relative frequency of
relapses at longer or shorter period after primary infection. If relapses in
malignant tertian were especially frequent for a comparatively short period
after the initial infection, this parasite might be responsible for the majority of
relapses at Panama where anopheles are fairly numerous. Anxd if a characteristic
of quartan is the power of producing more relapses after long periods than is
the case with other parasites, quartan might be the most important in the
Andamans where anopheles are less numerous.
The fact that treatment is more readily effective in some forms than others
of parasite has also to be taken into account when comparing treated with
untreated communities.
In a private communication recently received Dr. James informs me that
experience at Panama does not in his opinion in any way contradict my
conclusions, as owing to the climatic conditions at Panama there are no long
periods during which infection is in abeyance.
VI.—Sickness.
3 9 . A r e p o r t u p o n t h e c o n d i t i o n s r e l a t i n g t o m a l a r i a i n t h e A n d a m a n s
would be incomplete without some detailed reference to features connected
with sickness and mortality. As will be seen in the succeeding sections the
exact part played by malaria in this respect is by no means so simple a matter
as might be thought. It is not often that the exact fashion in which malaria
affects a native tropical community has been described. We do not know for
30
example exactly how malaria kills in the case of those terrible epidemics which
from time to time visit the Punjab and certain other parts of India, or the
exact natural history of its action upon the death rate in highly endemic areas.
The conditions in the convict settlement are from this point of view unique
since not only is every member of the community under close observation, but
in the case of death an autopsy is performed as a routine practice. I have
therefore taken some pains to make what use I could of these unique
conditions.
RELATIVE EFFECT OF MALARIA AND OTHER DISEASES ON THE SICK RATE.
40. From Table VII it will be seen that at Viper hospital malaria admis
-sions account for from 60 per cent. to 80 per cent. of the total admissions in the
different years given. At Haddo hospital which draws its inmates largely
from Aberdeen and stations to the south of the harbour (relatively healthy
area) the proportion of admissions for malaria is from 51 per cent. to 64 per
cent. of the whole. At Bamboo Flat the proportion is from 55 per cent. to 66
per cent.
From the results of blood examinations given in Tables II and III it may
be assumed that at least 40 per cent. of the admissions are cases showing para-
sites (positive malaria of Deeks and James) whilst another 20 per cent. are
probable cases of this disease (clinical malaria of Deeks and James).
Again from Table VII it will be seen that the total number of admissions
for diseases other than malaria does not show as a rule any great variation.
Whenever any large increase in admissions takes place it is due to an increase
in the number of fever cases.
By far the most important cause influencing the admission rate is
therefore malaria and we may for all practical purposes when considering vari-
ations in the sick rate take these as being due to malaria.
41. In addition to the direct effect of malaria which these figures indicate
it is also possible that malaria is responsible for an increased rate among certain
other diseases, e.g., pneumonia. This effect of malaria will be discussed more
fully under the action dealing with the death rate.
42. It is also necessary to note the effect of malaria in bringing about a
condition of more or less permanent invalidism. At each of the large hospitals
there are what are known as " Convalescent " and " Light Labour " gangs.
The former is made up of patients who have been discharged from hospital but
are not yet fit to return to labour, the latter are convicts not considered fit for
ordinary labour but able to do light tasks. Both groups must be considered as
a permanent addition to the sick list; not only are convicts in these gangs
31
" ineffectives " but they are a source of increase to the admission list since
they are liable to frequent readmission to hospital.
In Table III it will be seen that out of 32 men taken at random from the
convalescent gang 6 or 19 per cent. spewed parasites. In Table XI are given
the spleen rates for men in these gangs, for the non-sick labouring convicts and
for the self-supporters. It will be seen that a greatly enlarged spleen is
present in a very high proportion of the men in the convalescent and light
labour gangs and there is little doubt but that these gangs are largely swelled
through the effect of malaria.
TABLE XI.
Number
examined.
Very large
spleen.
Moderately enlarged
spleen.
Total
spleen.
No.
Per cent.
No.
Per cent.
No.
Per cent.
Cases admitted for fever
101
18
18
22
22
40
40
Convalescent gang
32
11
34
6
19
17
53
Light labour gang
32
8
25
6
19
14
4 4
Convicts at labour at
Dundas Point and
Port Mouat.
146
18
12
24
16
42
29
Adults (self-supporters)
in unhealthy villages.
121
10
8
16
13
26
21
43. Even the numbers of sick shown by adding together those in hospital
and in the convalescent and light labour gangs does not fully exhibit the true
prevalence of malaria among the labouring convicts. At Dundas Point among
a batch of men at work on excavation in addition to two out of a total of 35
who showed parasites five were obviously more or less sick (anæmia, spleen to
umbilicus, etc.). Similarly at Port Mouat and to a less extent at other un-
healthy stations examined there was a considerable amount of this kind of un-
fitness.
44. The aggregate effect of malaria in producing sickness among the
labouring convicts in the Andamans is therefore very considerable. The degree
to which this community suffers is also greater than that to which the self-
supporters in the villages are subject though as regards number of anopheles
and conditions apparently suitable for malaria the villages should be more
unhealthy than the barracks.