OBSERVATIONS ON THE FORMS OF BABESIA GIBSONI (PATTON) IN
THE DOG; WITH A NOTE ON THE SYSTEMATIC POSITION
OF THE PARASITE
By H. N. RAY, M.Sc., Ph.D. (London), Research Officer (Protozoology), and J. A. IDNANI, G.B.V.C.
Offg. Assistant Research Officer (Bacteriology), Imperial Veterinary Research Institute, Mukteswar,
(Received for publication on 19 November 1942)
(With Plates XIX and XX)
IN 1910, Patton [1910] discovered what he
called Piroplasma gibsoni in the blood of hounds
of the Madras Hunt, and subsequently he found a
similar parasite in the blood of jackals. This
protozoon has since been reported to occur in
dogs in several parts of India. Rao [1927] in
Madras described various forms of the parasite,
occurring in the blood and organ smears of an
infected case. According to his observations, the
division of the parasite takes place in the blood,
while its schizogony occurs mainly in the
spleen. He also carried out some transmission ex-
periments with the tick, Haemaphysalis bispinosa,
but these yielded negative results.
In this article it is proposed to describe the
forms of Babesia (Piroplasma) gibsoni which the
writers have found in the blood and internal organs
of dogs artificially infected with the parasite.
These forms may be grouped under two main
heads: (1) ring forms and (2) thin elongated
forms. It is probable that these differences
indicate the occurrence of sexual dimorphism.
It will be seen from what follows that the or-
ganism does not strictly conform to the definition
of the genus Babesia Starcovici of the family
Babesiidae, for it has never been observed to occur
in couples of pear-shaped, ring-shaped, or ellipti-
cal individuals, although like other members of the
genus, its propagation always appears to take
place in the red blood cells. Shirlaw [1938],
however, believes 'that P. gibsoni is essentially a
parasite of the reticulo-endothelium'. Clinically
also, the symptoms in B. gibsoni infection differ to
a certain extent from those observed in babesiasis
due to B. canis infection. An infection with B.
gibsoni is frequently accompanied by progressive
anaemia and a recurrent type of fever, while in
cases affected with B. canis the fever is more or
less continuous and is associated with jaundiced
discolouration of the visible mucous membranes.
Haemoglobinuria is characteristic of B. canis
infection. Moreover, drugs, such as trypanblue
and acaprin, which are specific against infection
with B. canis, have no effect whatsoever in cases
of B. gibsoni infection.
For this reason, while considering the system-
atic position of this parasite, a new family name,
Pattonelliidae, is proposed and a new genus
Pattonella provided for accommodating the orga-
nism hitherto known as Babesia (Piroplasma)
gibsoni.
Enumeration of all the clinical features accom-
panying this infection in dogs is beyond the scope
of this article. Nevertheless, we have, under the
head 'General observations', described certain
interesting facts.
MATERIAL AND METHOD
The material for this study was obtained from
dogs which at the time were being utilized for
maintaining a strain of P. gibsoni at the Institute.
Dogs showing a very heavy infection were usually
selected for this work, and were destroyed and
smears were made from their blood and various
organs. In addition, pieces of the spleen, liver,
kidney, lymph glands, lungs, brain and bone-
marrow were fixed overnight in Bouin, Duboscq
and Brasil's fluid in order to study the parasite in
section. Sections were cut 6µ thick and stained
with Heidenhain's iron-haematoxylin, Ehrlich's
haematoxylin
and
May-Grunwald-Giemsa.
Solution of eosin (1 per cent) in 90 per cent alcohol
was used as a counter stain for haematoxylin
preparations. Air-dried smears of blood, as well
as those from the organs, were, as a routine
measure, stained with May-Grunwald-Giemsa.
Fixatives, such as Schaudinn's (with acetic acid)
and Bouin's fluid (alcoholic), were also used for
fixing the smears which were subsequently stained
with the above-mentioned stains.
The nucleus of the parasite, both in smears or
sections, gave a positive Feulgen reaction when
tested for the presence of thymonucleic acid in
accordance with the method recommended by
Ludford [1928].
Careful camera lucida drawings were made of
the different stages encountered. Spencer's verti-
cal camera and incandescent lamp were used in
taking the photomicrographs.
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