NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
LITERATURE OF PLAGUE.]
379
Plague litera-
ture since
1890.
Since 1890 the literature of plague has much increased both in volume
and importance. The outbreaks in Astrakhan (Russia), 1879-80 ; in Hongkong
(China), 1890-96 ; Egypt, the Red Sea ports and India, 1896-99, have been seized
as opportunities for studying and investigating plague in all its various branches,
and much progress on many lines has been made. The chief types of the disease
have been recognised and can now be to some extent diagnosed : the value of
evacuation has been more firmly established ; and the experiment in prophylaxis
has been crowned with a very large share of success.
Below are given some of the works dealing with plague since 1890.
(59) R. Nathan, The Plague in India, 1896-97, Simla, 1898.
[Deals comprehensively with the first year of plague (1896-97) ; and is a very valuable
work in 4 volumes. It contains maps, diagrams, statements, and embodies all the
researches made and measures enforced in India up to the time of its publication.]
(60) R. W. S. Lyons, Report of the Plague Research Committee, Bombay, 1897.
[This Report was written by Majors Lyons and Childe, I. M. S. It is probably the first
medical authority on plague, and is of a remarkable excellence. Dr. Childe's
share is perhaps a little loosely written from want of time. See Chapter II.]
(61) The German Plague Commission's Report, Berlin, 1899.
[A comprehensive Report. The German Commission worked very hard, making a
great many investigations and experiments, which are set down in full.]
(62) N. Rainier, Report on Plague in Palanpur, 1897-98 Bombay, 1899.
[A short report but both interesting and instructive.]
(63) Report on the Outbreak of Bubonic Plague in Bombay, 1896-97, Bombay, 1897.
[Chiefly administrative. Deals with the first few months of the outbreak in Bombay
City. It was compiled under the orders of Mr. P. C. N. Snow, I. C. S., then
Municipal Commissioner.]
(64) and (65) Report of the Bombay Plague Committee, Bombay, 1898.
[Two such Reports issued for 1897-98. The first was compiled under the orders of
General W. Gatacre, then Chairman ; and the second under the orders of Sir J.
Campbell, I. C. S., who succeeded General Gatacre as Chairman. They deal with
the progress of plague in Bombay City, and are, so to speak, in continuation of
Mr. Snow's Report.]
(66) M. E. Couchman, Account of Plague Administration in the Bombay Presidency,
1896-97, Bombay, 1897.
[Practically a record and review of administrative plague measures throughout the
Presidency during the first year of plague. This work was compiled under the
orders of Mr. J. DeCourcy Atkins, I. C. S. There is little original matter,
reports and orders being embodied in extenso.]
(67) E. L. Marsh, On the Value of Perchloride of Mercury as a Disinfectant for
Floors, Glasgow, 1899.
[A diminutive volume, but valuable as being the first published results of a series
of experiments in this direction. See book No. (71).]
(68) F. G. Clemow, Plague Epidemics in Russia.
LITERATURE or PLAGUE.]
381
[This volume, which contains a special report by Lieut.-Col. Wilkins, I. M. S., on the
Plague Hospitals in Bombay City, continues the record of plague administration in
Bombay City contained in Mr. Snow's, General Gatacre's, and Sir J. Campbell's Reports. It
consists of two volumes, the second of which is composed of chart of mortality and diagrams
of cases.]
(73) G. Hutcheson, Mahamari, or The Plague in British Garhwal and Kumaon,
(published in the Transactions of the first Indian Medical Congress), Calcutta, 1895.
[Dr. Hutcheson's paper on Mahamari is a valuable contribution to plague literature, and foreshadows many of
the measures and theories since adopted.]
(74) E. II. Cayley, Report on the Period of Infection in Pneumonic Cases, Bombay, 1898.
(75) G. Bainbridge, Report on the Plague in Sind, 1896-97, Karachi, 1897.
(76) E. L. Marsh, Report on the Disinfection of Native Dwellings by Formalehyde Vapour,
with special reference to the utility of the apparatus of Lingner, Bombay, 1899.
The volumes mentioned in this Chapter do not by any means cover the whole
published works on plague. Many have been omitted because they possess little or
no value : many others, valuable enough in themselves, have been omitted
because they have been either embodied or incorporated in other mentioned works :
of yet more no record is available. The researches of Wilm, Bitter, and other
experts are synopsized in Nathan's comprehensive Report: of the researches
of others, again, little or nothing is known. With a few exceptions, most of the
works enumerated have, at various times, been accepted as the best authorities
on, and records of, the pestilence in one or more of its many mysterious forms.
In conclusion, it may be added that during the past three years much pro-
gress has been made. The diagnosis of plague, at least in its commoner forms, has
been differentiated from typhus and relapsing fever, and carefully established :
the uselessness of the pharmacopæia is acknowledged : the micro-organism of the
disease has been discovered and characterised : and a system of prophylaxis suc-
cessfully attempted. All this, and much more, has been done. But although
much has been done, much more remains to be clone. Of the various—if they are
various—causes which originate plague ; of the various methods by which it is
disseminated ; of the life of the bacillus in nature ; of remedies after attack : of
all these, and many other important points, we are ignorant. And even the
discovery of what is known has necessitated the loss of many valuable lives,
distress and misery inexpressible.
But what are these facts but illustrations of the great Truth—
" Knowledge by Suffering enlereth,
And
Life
is
perfected
by
Death."*
* E. B. Browning—" A Vision of Poets."
96
INDEX.
ix
(W.—contd.)
Wilm, Staff Surgeon, Imperial German Navy,
105.
Wilkins, Lt. Col. J. S., D.S.O., I.M.S., 59, 129,
133,
Wilkins, Mr. A. D., D. F. O., 247.
Wilkinson, Mr. W. H. J., I.C.S., 199.
Winchester, Mr. C. B., I.C.S., 249.
Wingate, Sir Andrew, I.C.S., 52, 57, 127, 178,
220, 284, 359.
Winter, Dr. E. S., 297.
Woodburn, Mr. A. F., I.C.S., 127, 204.
Wray, Col. J. W., 353, 355.
Wright, Lieut., 235.
Wright, Professor A. E., M. D., 372.
Y
Yadav, Mr. L. B., 235.
Yakub, Sardar Khan Bahadur Mahomed,
325.
Yersin, M., 82, 85, 110, 119, 123.
Antitoxic serum of—82.
Results of 27 patients treated with—85.
Young, Mr. F. B., C. D., 242.
Z
Zenana Mission, 220, 322.
m.91.b.
No. 28.
(NEW SERIES.)
SCIENTIFIC MEMOIRS
BY
OFFICERS OF THE MEDICAL AND SANITARY DEPARTMENTS
OF THE
GOVERNMENT OF INDIA.
THE SEXUAL CYCLE OF LEUCOCYTOZOON CANIS
IN THE TICK.
BY
CAPTAIN S. R. CHRISTOPHERS, M.B., I.M.S..
(Superintendent of the King Institute of Preventive Medicine, Madras.)
ISSUED UNDER THE AUTHORITY OF THE GOVERNMENT OF INDIA
BY THE SANITARY COMMISSIONER WITH THE GOVERNMENT
OF INDIA, SIMLA.
CALCUTTA:
OFFICE OF THE SUPERINTENDENT OF GOVERNMENT PRINTING, INDIA.
1907
Price annas twelve or 1s. 2d.
X
(NEW SERIES.)
No. 28
SCIENTIFIC MEMOIRS
BY
OFFICERS OF THE MEDICAL AND SANITARY DEPARTMENTS
OF THE
GOVERNMENT OF INDIA.
THE SEXUAL CYCLE OF LEUCOCYTOZOON CANIS
IN THE TICK.
BY
CAPTAIN S. R. CHRISTOPHERS, M.B., I.M.S.
(Superi ntendent of the Ki ng Insti tute of Preventi ve Medi ci ne, Madras.)
SSUED UNDER THE AUTHORITY OF THE GOVERNMENT OF INDIA
BY THE SANITARY COMMISSIONER WITH THE GOVERNMENT
OF INDIA, SIMLA.
CALCUTTA :
OFFICE OF THE SUPERINTENDENT OF GOVERNMENT PRINTING, INDIA.
1907.
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A. M. & J. FERGUSON, Ceylon.
THE SEXUAL CYCLE OF LEUCOCYTOZOON CANIS
IN THE TICK.
INFECTION of vertebrates by protozoa is known to be commonly brought
about by various invertebrate blood-suckers, but it is only the malarial.
parasites of man and proteosoma of birds that have as yet been actually followed
with certainty through their cycle of development in such an intermediary host.*
The Hœmogregarinidœ have by many been considered, perhaps as a
result of the work of Hintze1 on Lankesterella, to be disseminated by casual
infection ; very few of the observations of writers who have described extra
corporeal development of these forms being very complete or convincing.
If we except these doubtful instances, it is necessary to recognise that
only in a single instance, Lankesterella , has a complete sexual cycle of a
hæmogregarine been described, the cycle in this case not requiring an inter
-mediary host.
The discovery of the sexual cycle of the mammalian hæmogregarinc
Leucocytozoon canis ( James), a description of which is given in this memoir, is
therefore of considerable interest, especially as unlike that of Lankesterella the
sexual development of L. canis takes place in an intermediary host, the tick.
A certain number of communications describing development of
h æ m o g r e - g a r i n e s i n i n t e r m e d i a r y h o s t s e x i s t . L a b b e ,2
w h o s e w o r k u n f o r t u n a t e l y I h a v e
not been able to consult in the original, has described the conjugation of sexual
forms of K. lacertarum (Danilewski.) in the gut of a tick, an observation
which my work tends to confirm. Development of H. stepanovi (Danilewski.),
a hmogregarine of the tortoise Emys orbicularis (L.) in the leech, Placobdella
cateingera (Moqu Tand), is described by Siegel. 3 The microgametes are small
and oval, like those described by Hintze in Lankesterella ; the fertilised ookinites
reach the so-called œsophageal glands and form numerous sporozoits, which
give rise to infection when the leech bites another tortoise. Siegel also notes
that hereditary transmission may occur by sporozoits getting into the embryo
leeches.
A short but important contribution is that of Durham,4 who notes in a
species of toad common in Para the almost constant existence of two parasites,
a drepanidium , which occurs in numbers in the peripheral blood, and dactylosoma
(Labbé), which is confined to the internal organs. In citrated blood kept in
* The term " intermediary " is used in preference to " definitive " for the reasons given by Minchen 1 7
in his " Sporozoa," page 254. Since writing the above I have been able to follow out the complete life
cycle of Piroplasma canis in the tick,
2
vitro all the parasites become free vermicules, but in large quantities of freshly
drawn blood fixed with sublimate, Durham was unable to find any free drepanidia,
and concludes that the vermicules of his drepanidium are not liberated within
the host, but function only in extra corporeal development. He believes that
the drepanidium and the dactylosoma are different forms of the same parasite,
the former being the schizogonous form, whereas the latter is differentiated for
sexual development outside the body. Durham also notes in ticks which had
fed on these toads suggestive appearances of conjugation of the parasite, and
the presence of cysts up to 6o μ in diameter, though he had no time to follow
this development in detail.
These conclusions of Durham's are in accordance with my own on Leucocyto
-zoon canis where two kinds of vermicules occur, an encysted and a non-encysted
form, the former of which leaves its cell host only under extra-corporeal con
-ditions.
Billet5 h a s s u g g e s t e d a n o n t o g e n e t i c r e l a t i o n s h i p b e t w e e nT
r y p a n o s o m a
inopinatum (Sergent) occurring in the leech Helobdella algira (Moqu Tand) and
a species of Lankesterella in a toad, based on the fact that toads upon which
leeches feed develop an infection of drepanidium .
Laveran and Negre 6 have described a protozoon parasite in the tick
Hyalomma œgyptium , which these authors think may possibly be developmental
stages of H. mauritanica (Sergent), though the observations of Nicolle
and Comte7 that hæmogregarines may be common where the ticks do not
contain the cysts described by Laveran and Negre do not favour this view.
The development of H. gerbilli (Christophers), a parasite of an Indian
field rat, Gerbillus indicus , has been described by me8 in the louse Hcemato
-pinus stephensi (Christophers and Newstead). Vermicules are freely liberated
in thy; mid-gut, and in the body cavity large cysts are found ; but as a result of
work on L. canis in the tick .I am doubtful whether the cysts have anything to
do with the hæmogregarine.
Patton 9 describes the active liberation of vermicules of Leucocytozoon
funambuli (Patton) a parasite of Funambalus pennantii, one of the Indian
palm squirrels in the gut of a louse ( Hœmatopinus ), which infests the species.
He does not find the large cysts seen in Hœmatopinus stephensi, but figures
(P1. 1, Fig. 16) a vermicule from the body cavity of the louse which has a
close resemblance to some of the developmental forms of L. canis described
later.
Of all work relating to the sexual forms of hœmogregarines, that of Hintze 1
on Lankesterella minima (Chaussat) is the most complete and convincing.
According to this author L. minima undergoes both schizogony and sporogony
in the body of its vertebrate host Rana esculenta. He describes in great detail
3
the process of sporogony. The microgametoblasts, the young mother-cells of
the microgametes, are thin cells with finely granular protoplasm devoid of inclu
-sions. When the microgametoblasts reach a length of 8 to 10µ each of the
chromatin bodies of which the nucleus is composed divide into two and scatter
themselves through the substance of the microgametoblast. Later, taking a
certain amount of protoplasm with them, the chromatin bodies separate off one
by one in an irregular manner as microgametes. Unlike the microgametes
of proteosoma those of Lankesterella are not whips, but small oval bodies
endowed with amœboid movement. The macrogametes which reach a length
of 10 to 13µ, and a breadth of 2 . 5 to 3µ, are plump forms with one end some-
what more pointed than the other and differ from the microgametocytes in
possessing coarsely granular protoplasm. Prior to fertilisation the nucleus of
the macrogamete divides and one portion degenerates, so that the usual, reduction
of chromatin in the female element prior to maturation is effected. In this
division of the chromatin no mitosis appears to take place, the nucleus dividing
directly ; nor is any reception cone formed, but in the mature macrogamete a
small canal is present to which the microgamete applies itself in the act of ferti-
lisation. After fertilisation, the chromatin of the macrogamete splits up and
arranges itself irregularly throughout the protoplasm. Forms with this arrange
ment are found especially in the blood vessels of the intestine. Eventually the
fertilised macrogamete enters an epithelial cèll of the gut and becomes
encysted. The cysts, which are often quite numerous, have a diameter of 7µ,
and are surrounded with a strong membrane ; they contain sporozoits, but no
secondary cysts (sporocysts). The chromatin bodies of the fertilised macro-
gamete come to the surface of the oocyst, but the actual formation of sporoblasts
or sporozoits could not be followed. Eventually the cysts fall into the gut and
pass out with the fæces ; infection taking place, according to Hintze, by young
frogs swallowing the cysts.
MATERIAL AND TECHNIQUE.
The schizogony of Leucocytozoon canis and its relation to other hæmogre-
garines has already been dealt with by me in a previous publication. 10 The
sporogony of the parasite I have since followed in the tick Rhipicephalus
sanguineus (Latreille).
This tick in all its stages abounds on dogs in Madras, which are rarely
found infested with any other species. Where dogs have much to do with
goats or sheep, occasional specimens of R. bursa, or of Hemaphysalis fusca,
a tick of the goat, sheep, and buffalo, may be found. I have never found the
ticks of oxen, R. annulatus and Hyalomma ægyptium, on dogs, though the
latter species in Madras attacks cattle, horses, goats and sheep.
B 2
4
The females of both R. sanguineus and of R. bursa, when they have
dropped from their host, crawl away, and if possible climb upwards to a height
of many feet, eventually squeezing themselves into cracks where they lay their
ova. Hæmaphysalis fusca on the other hand drops to the ground, and when
this happens in a cage the gorged females of this species, unless rescued, are
nearly always removed by the attendant with the fæces and urine. Whether
from this or from other reasons H. fusca introduced among dogs tends to dis-
appear, whereas R. sanguineus occurs in ever-increasing numbers wherever dogs
are kept together without attention. R. bursa, though it does not spread
among dogs like R. sanguineus, persists longer than H. fusca.
Neumann11 gives for R. sanguineus a very extended distribution, and
I have received specimens described as the ordinary dog tick from different
parts of Bombay, Northern India and Burmah. It is an example of a species
of tick which restricts it self to a single host, and may aptly be termed the dog
tick of India. The question of varieties and further details of the life-history
I intend to discuss shortly in a memoir upon Piro plasma canis, which is
transmitted by this species of tick ; at present it is necessary to refer to the life-
history only in so far as it is likely to have relation to the development and
transmission of Leucocytozoon canis. Female and male ticks of this species
attach themselves to almost any part of the dog, but select especially the ears,
the paws and the skin behind the neck. After a variable number of days,
dependent apparently upon the vascularity of the part chosen for attachment,
the females become fully gorged and drop off. As a rule two days are taken
up before the female is half the size it will ultimately become, but the final
stages of engorgement are much more rapid, and full repletion may take only
twelve or twenty-four hours longer. The males remain behind when the females
drop off, but should the dog die they readily detach themselves and at once
seek a new host.
The eggs are laid in cracks and from these, in about a month, hatch out the
larvæ which collect together in swarms and transfer themselves, often in masses
of several hundreds, to any dog which happens to come in contact with them.
After remaining on the host for three days the larvæ become gorged and drop
off, crawling away into cracks where they become quite inert and apparently
lifeless. From these in eight or nine days emerge the nymphs which again
seek a host, and after remaining on the dog for about five days, drop off in a
gorged condition and secret themselves in some crack where they again
become inert and apparently dead. The adults, both male and female, emerge
from the nymphal skins in about fifteen days and, after a brief rest, once more
attach themselves to the dog.
Though they belong to different genera, the Cape dog tick (H. leachi),
the life-history of which has been studied by Loundsbury 12 and Nuttal,13 and the
5
dog tick of Madras (R. sanguineus) have therefore very similar habits.
Oviposition commences as a rule about three days after the female has
dropped from the host and is over by about the eighth day or even later, a few
eggs often being passed by females which have shrivelled to one-third or one-
quarter of their original size. In the young ova the protoplasm is finely granular
and transparent, but after the ova have reached a certain size the protoplasm
becomes more coarsely granular and more opaque. At a certain point in deve-
lopment numerous rod-shaped masses of chromatin appear and herald the for-
mation of the large yelk globules which characterise the mature ovum. By the
end of oviposition the ovaries are almost devoid of ova and shew only peculiar
crinkled masses, which are the collapsed membranes left after the mature ova
have fallen into the lumen of the ovary.
The oviducts during oviposition are of great length and contain ova at
short intervals along their whole course. On entering the oviduct the ova are
devoid of any hard envelope, but a shell is formed as they pass down the
duct.
When laid, the ova are coated with a thick layer of oil derived most prob-
ably from the sebaceous gland-like dermal gland and cephalic gland both of
which at this time are very large and conspicuous (vide Anatomy and Histology
of Ticks, page 48), and this makes the ova adhere loosely together.
The method of dissection and the structure of ticks has been described
in a previous publication. 14 For the study of the developmental stages of
Leucocytozoon canis preparations of the gut are made by dragging short lengths
of it over the slide by means of needles. Preparations of ova are made by
squashing the ovary and spreading in the usual way upon a slide, or by similarly
treating eggs, either in the oviducts, or after they have been laid.
The examination of fresh preparations is often of use in detecting infection
because owing to their movements, the vermicules and sporozoits can be detected
with a dry lens of comparatively low power. Male ticks were examined either
by dividing them vertically and afterwards dragging out the gut with needles,
or by snipping off the posterior end of the body and squeezing out the
viscera by pressing a needle over the body of the tick from the head, end
backwards.
Nymphs were examined by spreading the gut, over the slide as in the case
of the adult.
The examination of larvæ is difficult. In the present instance they were
ruptured with needles and their body juice smeared upon the slide.
THE SPOROGONY OF Leucocytozoon Canis (JAMES).
In the gut of females of R. sanguineus (Latreille) fed on dogs severely
infected with Leucocytozoon canis, development of the parasite in all stages,