NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
12
fed on a susceptible person ; a few more were dissected, making up the 100, and
two were found infected. In one, a nymph approaching its last ecdysis, I
found in its midgut in the fresh condition a group of eight round and oval
bodies lying against the wall close up to the junction of the œsophagus with
the midgut ; there were also two adult flagellates actively dividing. This bug
had first fed on the case at Cambay on January 4th and was then probably a
nymph in its second instar, and was last fed on January 26th. It was dissect-
ed on January 31st, that is, five days after its last feed. On smearing out and
staining the midgut, it was found to contain the oval bodies mentioned above.
They measured from 4 to 5.5 µ, in length and from 3 to 4.4 µ. in breadth.
The nuclei presented a very striking appearance, for their outlines were obscur-
ed by small pink granules, many of which were situated at some distance in the
protoplasm. It was difficult to locate the blepharoplasts, which although
staining in the usual way, were distinctly smaller than those seen in the very
similar stage found in the sore in man. The protoplasm did not take the
usual blue colour, so characteristic of young flagellating forms, nor were there
any appearances suggesting the formation of the flagellum. There could
be no mistaking these parasites for young pre-flagellating forms, for they
differed in every respect and they were certainly not degenerating. I came
to the conclusion that they represented the post-flagellate stages of the para-
site. Several other facts strongly support this view ; they were all grouped
together, evidently adhering to each other by some sticky substance, an ap-
pearance which is characteristic of the post-flagellate stage of the herpetomo-
nads of insects ; they were large, and their nuclei exhibited a peculiar granular
appearance which is always seen in the post-flagellate stages of these parasites.
Further, they were found in a bug, five days after its last feed, and had they
been the pre-flagellating forms they should have exhibited the changes prepa-
ratory to the extrusion of the flagellum. In none of the bugs, when they were
kept at a suitable temperature, were parasites seen which had failed to
flagellate ; this only occurred in bugs kept at a temperature above 25°C. Al-
though I have dissected several thousands of bugs during the last five years I
have never once seen any appearances similar to those described above, so that
these bodies could be none other than some stage of the parasite of Oriental
Sore. The bugs that were fed on this last occasion on a man in Bombay have
also failed to produce Oriental Sores ; the nymphs which were fed at Cambay
from the first instar, were unfortunately not fed beyond the third or fourth,
as I was then under the impression that the adult bug was the most probable
transmitter. Before I left Cambay for the last time I decided to inoculate
myself from a suitable case, and this was carried out on December 24th, 1910,
13
being performed subcutaneously with a fine glass pipette on the inner side of
my left calf. Ten days following the inoculation nothing was to be seen, but
on January 9th a distinct nodule was felt, and on puncturing it, parasites were
readily found.
Since returning to Madras, I have fed a large number of bugs on myself,
with the object of definitely finding out whether the parasite, after flagellating
in the adult bug, is able to live for long periods and to complete its cycle of
development ; about 500 adult bugs were used in this experiment. The follow-
ing facts were definitely ascertained and which conclusively prove that the
parasite, when ingested by the adult bug and also by the nymph, never flagel-
lates at a temperature above 25°C. If hugs kept at this temperature contain
parasites the latter only degenerate. Adult bugs kept at a suitable temperature
(22° to 25°C.) and which had ingested parasites, always showed flagellates, but
they were never seen beyond the tenth day, clearly indicating that, in the adult
bug, the parasite does not complete its developmental cycle. It was also found
that the parasites never multiplied to any great extent, and no multiple
segmentation resulting in rosettes was seen. There is one point, however,
which requires further study, I have found that by keeping bugs at a tempe-
rature of from 18° to 20°C. the blood in their stomachs remains almost un-
changed up to 48 hours after it has been ingested, this being even more marked
in the nymphal stages. This suggests that the digestive process in the nymph
is not nearly as active as in the adult, and it could be readily understood that
in an adult bug kept at a high temperature, the parasite, on being freed from a
leucocyte, would find itself in a medium unsuitable for the profound changes
which take place between the pre-flagellate and the flagellate stages. It is
interesting to note that Oriental Sore in India only occurs in those parts where
there is a decided cold weather, for instance Karachi, Quetta, Jacobabad, Dera
Ismail Khan, Delhi, Lahore and Cambay. As far as I am aware it does not
occur anywhere south of Cambay or east of Delhi. While in Cambay I kept
accurate thermographic records and studied the temperature recorded at the
Hospital for the last 10 years. I found that during the cold weather, which
frequently begins in the middle of October and lasts till the end of February,
the temperature during the twenty-four hours keeps well below 25°C. I can-
not help thinking that there is a factor of fundamental importance underlying
the restricted geographical distribution of Oriental Sore in India, and I am
convinced that the explanation is to be found in the relation of the temperature
to the digestive processes in the bug.
Having now narrowed down the investigation to the nymphal stages of the
bug, I decided to waste no more time in dissections, but to feed nymphs on
D2
14
myself through the first and second instar, and then feed them continuously on
a susceptible person, my wife volunteering for that purpose. These experiments
were carried out in June, July and August 1911. Three tubes, containing about
100 nymphs, were fed daily, and between the feeds were kept in the cold in-
cubator. Unfortunately, as it was the hottest time of the year in Madras, the
thermometer never registering below 28°C. and for the most part being between
30° and 35°C., it was extremely difficult to keep the incubator at a constant
temperature, and although large quantities of ice were used, it frequently
registered as much as 27°C. The bugs were always fed between 6 and 8 P.M.,
and for these two hours they were necessarily exposed to a high temperature.
Towards the end of July a small spot, simulating the early stage of the sore,
developed on one of the places where the bugs were fed. It slowly increased
in size until a perceptible nodule could be felt, but since then has not grown
any more. An attempt was made to puncture it at the end of August, but
owing to its small size, it was impossible to say for certain that the pipette had
entered the nodule; nothing was found in the blood drawn up. It is hoped
later to puncture it again. Feeding experiments with nymphs will be again
started as soon as the cold weather in Madras sets in, and at the same time, a
number will be dissected, in order to confirm the observations made above,
namely, that the parasite only completes its developmental cycle when ingested
by the nymph, and that, if the parasites are still in the early stage when the
nymph becomes an adult, they fail to complete their development. In all the
dissections that were carried out, both in Cambay, Bombay and Madras, when
parasites, particularly flagellates, were found in the midgut of a bug, the other
organs, such as the salivary glands, ovaries, œsophagus and pumping organs,
were invariably examined, but in not a single instance was I able to find a
parasite of any kind outside the alimentary tract. A most careful search was
made for them in the hind gut of the bug, but they were never found there ;
this part of the alimentary tract always contains black granules, the remains of
the digested blood, and is a most unsuitable medium for the parasite.
In view of the fact that the parasite flagellates in the bug, and only at a
temperature below 25°C., it is necessary to consider shortly any observations
which tend to support the hypothesis that Cimex rotundatus is the invertebrate
host of the parasite of Oriental Sore in Cambay. This bug was extremely
prevalent throughout the year and most of the people regularly used bug traps,
small pieces of wood with numerous perforations, which they placed in their
beds and into which the bugs nearly always crawled after having fed. This
practice is universal amongst the Hindus, who form the bulk of the population,
Mahomedans periodically shake the bugs out of their beds just outside their
15
houses. One of the most striking facts in connection with this disease, as I
have already mentioned, is that it never tends to spread from one person to
another in the same house, during the same season. Over 50 histories exempli-
fying this fact were carefully studied, and no better example could be given
than the following case. An Indian Salt official was transferred for duty to
Cambay in March 1909 ; he was accompanied by his wife, widowed sister and
her two sons. The first few days in Cambay they resided in the town, in the
house of an old resident, later going into a house which had been unoccupied
for a long time. While staying in the friend's house they were severely bitten
by bugs. About August the man, his widowed sister, and her elder son con-
tracted the disease almost simultaneously, the wife and the other nephew
escaping. The man had two large sores which lasted nearly two years, yet his
wife who occupied the same room, and even the same bed, did not develop
Oriental Sore till a year later, and the little nephew at the same time ; the
latter case I had the opportunity of examining in its early stage. Numbers of
cases were studied in which there was one child who had Oriental Sore in a
house and several others who did not contract the disease till years afterwards.
This peculiarity in the spread of the disease cannot be overlooked, and in my
opinion it points very clearly to the transmission of the parasite by a blood.
sucking insect, in which development of the parasite takes place slowly, and.
that once that insect becomes infective, it may remain so for a long period, thus
being able to infect several people or the same person in more than one place.
It also suggests that the insect in question is usually transferred from one house
to another before it is infective. The last case studied in Cambay had. four
sores of the same age on his right arm, three of which were on the inner side of
the forearm, about three inches apart. This fact suggested that they were
acquired at the same time ; it is necessary then to consider what blood
sucking insect will bite three adjacent parts of the body consecutively. The
only likely insects are mosquitoes and the bug. It is true that when a mosquito
is disturbed in the act of biting, it may quite possibly alight close to the spot
where it was first feeding, and that if disturbed again it may return to another
adjacent spot a few inches away from the former ones. Any one who has
observed the habits of mosquitoes will, I think, agree with me that the chances
of this happening are small ; most mosquitoes when disturbed fly a considerable
distance, and when they again alight, select a more distant part of the body.
The only mosquitoes, as far as I am aware, which do return to the same place
are those belonging to the genus Slegomyia ; I frequently observed this habit
exemplified in the case of the species prevalent in Cambay, and this was one
of the reasons why it was carefully studied. As far as the parasite of Oriental
16
Sore in Cambay is concerned I failed to find any other fact which pointed to
this mosquito as being the transmitter.
The bug, whose habits I have now observed for nearly six years, is the
blood-sucking insect which always returns either to the same spot or to one
close by ; it also has the peculiar habit, and one which, as far as I know, has
not yet been recorded, of returning to feed after it is replete with blood. On
watching such an insect, one cannot help wondering how it can possibly ingest
any more; nymphs, as well as adults, exhibit this habit. A number of cases
in Cambay were found to have either scars or sores close together on the same
part of the body, spewing that this method of multiple infection frequently
takes place.
The Hindoos in Cambay regularly empty their bug traps into the street,
and the bugs naturally crawl into an adjacent house. Those who do not use
bug traps periodically clear out bugs from their houses by shaking them out of
beds and mats into the street. I calculated from the single observation of the
nymph which contained the post-flagellate stages, that the cycle of develop
ment averages about twenty-two days. It can then be readily understood that
a nymph, which had ingested a parasite but had not yet become infective, may
be transferred to another house, thus explaining why the disease does not
spread in the same house even though there are a number of suitable cases.
There are several other facts which suggest the bug as the probable transmitter.
I have already pointed out that only a small percentage of the cases are
suitable for the transmission of the parasite by the peripheral blood, for the
simple reason that the parasitic area in a sore soon breaks down, so that there
are extremely few, or no parasites left a short time after the sore has reached
its maximum size. It therefore follows that there is only a brief period during
which the parasites can possibly pass into the circulating blood, and then only
in small numbers. It is obvious that a blood-sucking insect, wLich is con-
stantly present, and sucks the blood of the same person on many consecutive
nights is much more likely to ingest a parasite, than a flying insect such as a
mosquito or a phlebotomus, which hardly ever sucks the blood of the same
person on more than two or three occasions. Such flies must necessarily soon
leave a house in order to lay their eggs. Recently Miss Porter related to me
the case of a young European school girl who contracted the disease at Banga-
lore where Oriental Sore is not endemic. One night a fire broke out in the
school, and the children were hurriedly removed to neighbouring houses. This
girl was taken to a native house, the inhabitants of which had recently come
from Cambay. She woke up later in the night and found a bug which she
stated was a " baby " one biting her on the left forearm. She killed it and
17
remembered seeing the small red puncture next morning, but soon forgot all
about it. Three months later a small pimple was noticed on the same spot
which gradually developed into a typical Oriental Sore, which the people in
whose house she had slept on the night of the fire, had no hesitation in calling
a " Cambay boil." The sore lasted many months resulting in a typical scar,
which was recently excised in England on account of the disfigurement. I
have elsewhere drawn attention to a case recorded by Schneider in a European
lady who lived for some time at Zerguendeh, a village close to Teheran, who on
waking one night with the sensation of something biting her on the cheek, put
up her hand and caught a bug. Schneider adds that in the same house there
were four children who had had the sore the preceding year, and that the house
was infested with bugs. The lady subsequently developed a large sore on the
spot were the bug had bitten her.
Lieutenant-Colonel Ashton Street, I.M.S., in the discussion on Dr. Row's
recent paper, relates the case of a military officer who developed several Oriental
Sores in Karachi a few days after being pestered by bugs in the hotel in which
he was staying. Dr. Row, in reply, takes exception to the short incubation
period, and states that it is always of about two months' duration in the monkey.
Here again my studies of the disease in monkeys Macacus sinicus are at
variance with those of Dr. Row, I have reproduced, by subcutaneous inocula-
tion, a typical lesion in a monkey after eighteen days' incubation, and my own
sore developed on the sixteenth day ; in both cases the parasites were recovered
on these days. It will be seen then that my observations correspond exactly
with those of Nicolle in Tunis. The reason why Dr. Row finds that the incu-
bation period in his monkeys is nearly always two months, is very simply
explained. I had the opportunity, when he visited Madras, of seeing the
technique he employed. He first scarified the sore with a knife, then pipetted
the fluid up into a capillary tube and deposited it on similar scarifications and
rubbed it in ; the operation lasting about ten minutes. On the contrary I
puncture the sore with a fine capillary pipette and draw up the infected
material, and immediately with the same pipette, puncture the skin of the
monkey and blow the fluid in. This operation lasts a few seconds. In this
way I have found that, by inoculating a monkey with a very few parasites, the
incubation period is about two months, whereas if richly infected material is
used, containing many thousands of parasites, the early nodule may be detected
on the fourteenth day. On puncturing such a nodule, the parasites will be
found in the macrophages, and cannot therefore represent those which were
originally inoculated into the skin, for in the interval nothing can be felt.
This method of reproducing the disease is exactly comparable to the way in
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which it is produced in nature, that is, the parasite is deposited into a healthy
bit of skin. I believe the variable incubation period, one week to six months
as seen in those people who came to Cambay for short periods and then went
away, is easily explained by the smaller or larger number of parasites inocula
- ted into the skin ; it can be well understood that the degree of infection of a
blood-sucking insect, such as the bug, may vary, so that in one case many
parasites may be inoculated and in others very few.
The cases I have recorded above are of considerable importance as the
majority of people who have become infected with Oriental Sore are unable to
recall definitely whether they have been bitten by any insect.
Lastly when in Cambay, I examined the bodies of several hundred children,
carefully noting the site of the scars, and found that they were present on
every region of the body, except the genital organs, palms of the hands and
soles of the feet. One typical fresh sore, containing numerous parasites, was
seen on the scalp, just over the centre of the right parietal bone ; this was in a
small Mahomedan boy whose head had not been shaved the year previously, as
the father who was an intelligent man informed me. Four years before another
of his children had had the sore, but this little boy had then escaped. I also
saw several scars on the scalps of other children. All observers who have
studied Oriental Sore, have repeatedly stated that, as it usually occurs on
exposed parts, it cannot be transmitted by the bed bug, because this insect is
said to bite only the covered parts of the body. The statement regarding this
habit of the bug is totally erroneous, as any one who is willing to take the
trouble, can demonstrate for himself. I have a vivid recollection of once sleep
- ing in a bed which contained many of these insects. I was wearing a pyjama
suit ; the uncovered parts of my body were the lower thirds of my legs, and
forearms, my neck and head, and these were the exact places where I was
bitten. Indians are accustomed to sleep with only a loose loin cloth on, and to
cover themselves with sheets or blankets ; thus the whole of their bodies, except
this part, are obviously exposed to the bites of bugs. The bug is the only insect
(with the exception of the head louse) which will bite the scalp, and one of the
commonest places to find bugs is in the head-gear of an Indian ; these turbans
on being removed at night are usually placed on a peg on the wall, and bugs will
regularly crawl into them and hide in the folds. I have repeatedly removed
large numbers of these insects from these places. In the same way the topees
of Europeans may become infected. This is the only way I can explain the
occurrence of Oriental Sore on the scalp. I have now endeavoured to explain
why I consider the bug to be the most probable transmitter, and I am well
aware of the oft repeated statement that if it were the bed bug, the disease
19
would tend to spread outside the town of Cambay, for bugs are certainly just as
prevalent in the villages round as they are in the town itself. This argument
, however, would apply not only to the bug, but to every other blood-sucking
insect, especially to winged forms. My own view is, that in this particular
disease, we are dealing with a special parasite, whose life history, outside the
human body, is governed by very definite factors such as temperature, presence
or absence of the parasite in the circulating blood, and the bug in a suitable
stage.
It is much to be regretted that such a careful observer as Dr. Row, still
endeavours to prove a hypothesis which has only a single fact to support it,
namely, the readiness with which the parasite can be scratched into the skin.
He ignores the overwhelming evidence in support of the parasite being trans-
mitted by a blood-sucking insect, and has therefore never studied the problem
from this point of view.
From my own observations, and particularly the experiments carried out in
Cambay, I have no hesitation in saying that the house fly Musca nebulo and
Musca sp. play no part whatever in the transmission of the disease in Cambay,
and that Dr. Row's feeding experiments, conducted as they were in Bombay
with " trained" flies fed on richly infected material, are in no way comparable
to experiments carried out in the endemic area. Although I have failed up to
the present to actually transmit the parasite by the bed bug, I have brought
forward very strong evidence, by showing that the parasite only flagellates in
the bug below a certain temperature, and that this observation exactly coin-
cides with the geographical distribution of the disease in India. I hope in
time to be able to transmit the disease through the bug. I, however, wish it
to be clearly understood that the statements I have made above are at present
only applicable to Oriental Sore in Cambay. I am well aware that many
competent observers have stated that in other places where the disease is ex-
tremely prevalent, bugs, either Cimex rotundatus or Cimex lectularius, are
rare. I can express no opinion as to how the parasite is transmitted in these
places, but I fully realize that it may have more than one invertebrate host.
In Cambay, I have no doubt whatever that the bug Cimex rotundatus is the
only insect transmitter of the disease. My conclusions have not been arrived
at hastily, but are the result of a most careful and exhaustive study of the
disease and its probable transmitters.
In conclusion would like to take this opportunity of thanking His High-
ness Mirza Jafir Ali Khan, Nawab of Cambay, and Mr. Madhavram Hari-
narayan, the Dewan of Cambay, for their kindness in making all arrangements
for my comfort during my stay in Cambay ; also Mr. Dhanjiboy, the Chief
E
20
Medical Officer of the State, without whose help and experience, I could never
have accomplished the difficult task I had to undertake. One of the greatest
obstacles I had to contend with in Cambay was the procuring of suitable cases,
and it was here that Mr. Dhanjiboy's influence was most valuable.