AN ADAPTATION OF WHITE'S METHOD FOR THE COLLECTION OF
INFECTIVE LARVAE FROM BOVINE FAECAL CULTURES
AND ITS PRACTICAL APPLICATION
By S. N. VAIDYANATHAN, G.M.V.C., Veterinary Assistant Surgeon, Helminthology Research Section,
Madras Veterinary College
(Received for publication on 10 February 1942)
FAECAL cultures are ordinarily made, in mixed
infections with strongyle nematode worms, com-
mon amongst veterinary subjects, particularly
the domesticated ruminants and the horse, for an
identification of the infective larvae developing
therein, as an aid to the adoption of correct
remedial measures.
The infective larvae of many strongyle nema-
todes are observed, during the close of their free-
living period, to migrate from the medium in which
they have been growing. This fact is made use
of by many workers to formulate suitable methods
for recovering them. The collection of infective
larvae in clean water without contamination is a
more discriminative work and for some purposes
quite indispensable. The method described below
has this advantage amongst others. A very
inexpensive and effective device, to facilitate the
process of migration of infective larvae, develop-
ing in faecal cultures, has been in daily use at
the Madras Veterinary College Helminthology
Laboratory, for almost two years now, and it has
proved to be of great use. Although it remains
to be seen, whether this method will serve for all
migrating larvae, at all seasons and. places, it has
been found very satisfactory, up to the present,
for all the common strongyle worms met with
in the city of Madras amongst cattle, sheep and
goats viz : Strongyloides papillosus, Haemonchus
contortus, Trichostrongylus axei, Trichostrongylus
colubriformis, Cooperia punctata, Cooperia pecti-
nata, Bunostomum phlebotomum, Bunostomum
trigonocephalum,
Gaigeria pachyscelis, Oeso-
phgostomum
columbianum, Oesophagostomum
venulosum and Oesophagostomum radiatum. It is
therefore, thought advisable to publish this note
for the benefit of others.
SOME COMMON METHODS KNOWN
Familiarly known as Leiper's, this method
consists in the use of a moist blotting paper,
lining the interior of a petridish, to cover another
containing the faecal culture. The infective
larvae migrate up on to the blotting paper which
is shaken up in a small quantity of water, to free
them when required,
Veglia [1923, 1928] advocates the use of tall
fruit jars to make faecal cultures. The faeces is
placed at the bottom, broken up, slightly damped
with water and the lid of the jar screwed down
tightly. In summer months, the jars are stored
in a dark room at room temperature, while in
winter they are placed in an incubator running at
about 25°C. The mature larvae, observed to
migrate up the walls of the culture jar, are
collected by means of a blotting paper lining the
interior, which is washed in a few cubic centi-
metres of water.
Monnig [1938] advises transferring these
migrating larvae, on the walls of the culture jar,
by the point of a needle or a fine camel hair brush.
Deschiens [1939] describes a simple method
which avoids breaking and contamination of the
faecal mass and, yet, yeilds a large number of
larvae, in a suspension free from faecal matter.
The author considers it satisfactory for all larvae
exhibiting positive hydro-tropism. The appara-
tus consists of a small fluted cone of Laurent
filter paper, containing a few cubic centimetres
of distilled water. This is placed in a space of
equivalent size cleared in the centre of the culture.
The larvae then find their way into the distilled
water by climbing over the top of the cone or
occasionally by perforating it.
White [1927] suggests simple apparatus to trap
the migrating larvae in water. Faecal matter to
be cultured is properly mixed with charcoal and
transferred to the half of a petridish with a mois-
tened filter paper covering the bottom. Sterile
water is poured into a crystallizing dish to cover
the bottom and into it is placed the half petridish
containing the culture. A watch-glass is used as
a cover, and the apparatus set in a place where a
high humidity may be maintained. Many of the
larvae, on approaching the third larval stage,
migrate from the culture and are trapped in the
water ; surrounding the petridish.
MATERIALS AND METHODS
An adaptation of White's [1927] method was
used by the author employing still simpler appa-
ratus. The materials necessary for setting up a
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