SOME OBSERVATIONS ON THE MORPHOLOGY AND
PATHOGENICITY OF MONIEZIA EXPANSA (Rudolphi, 1810)
By A. K. VARMA, Livestock Research Station, Patna, Bihar
(Received for publication on August 10, 1955)
(with two Text-Figures)
T HREE species of the anoplocephaline genus Moniezia, M. expansa [Rudolphi,
1810], M. benedeni [Moniez, 1879] and M. denticulata [Rudolphi,
1810], have proved to be of veterinary interest. These species are mainly based on
the presence or absence of and the character of the interproglottidal glands, which
are saccular in M. expansa, linear in M. benedeni and totally absent in M. denticulata.
Bhalerao [1935] records the occurrence of all these three species in certain localities
of India. M. expansa appears to be by far the commonest and most widespread
species in the world and in India too. The morphology of this parasite has been
fairly well studied by a number of helminthologists in different countries. The
object of this article is to record some interesting observations of diagnostic value
and to stress the importance of this worm as a significant etiological agent in causing
mortality in young stock, particularly buffalo calves. Hitherto not much attention
has been focussed on this parasite and the consensus of helminthological opinion
holds only Ascaris as a common cause of calf-mortality in buffaloes.
During the last four years the writer has been critically studying a large collection
of materials of this parasite from sheep, goats, cattle and buffaloes from different
localities in Bihar (India), and has made some observations on the morphology of the
adult worm and its eggs, which are described below and illustrated. Recently, some
evidence was derived from a post-mortem case on the significance of this parasite in
causing death of a buffalo calf; and it is believed that a thorough inquiry may bring
out valuable information about this parasite as a factor responsible for heavy calf-
mortality in this country, particularly buffalo calves.
The adult
The morphology of the adult worm in general agrees with the descriptions
furnished by previous authors. In a single specimen, collected from a sheep at
Daltonganj, the arrangement of the testes showed some variations in that they were
grouped in some segments in the form of two triangles, one on either side, which
did not meet together in the mid-line (Fig. 1). This was the distinctive feature
of the species M. trigonophora, proposed by Stiles and Hassall in the year 1893.
Theiler [1924], doubting its specific value, states that " my experience is that the
testes in M. expansa may be roughly arranged in two broad triangles which usually
meet in the mid-line, or in a continuous band thinning slightly towards the mid-line,
or they may be as numerous in the median field as elsewhere'. She continues
further that " all three types may be found in one individual or only one type may be
present". Baer [1927] in his " Monographie des Anoplocephalidae ", nevertheless,
maintained this species. Taylor [1928] after examining a series of segments of several
worms noted the variable nature of this character even in the segments of the same
individual. His photographic illustrations are valuable in this connection. Again,
Southwell [1930] described this feature in young segments of M. benedeni. In the
present study, Taylor's observations are confirmed.
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