162
paratuberculosis
(Johne's
Disease) in Goats
and pieces of intestines from all the four cases preserved in 50 per cent
glycerine were sent to the Imperial Veterinary Research Institute, Mukteswar,
for cultural examination and the following report was received from the
Institute. ' Culturally, a pure strain of the organism (Mycobacterium para-
tuberculosis) was cultivated upon Twort and Ingram's Myco. phlei agar medium,
and this strain appears to be. indistinguishable both morphologically and
culturally from stock bovine strains maintained at this Institute. At the end
of the third week of incubation, it was possible to detect with the aid of a hand
lens magnifying ten diameters, minute growths of the organism on the surface
of the medium, but at the end of the fourth week the growths were discernible
to the naked eye.'
Histo-pathological.—The essential tissue reaction as manifested by the
infiltration of epithelioid cells was observed in a marked degree in the inter-
glandular connective tissue (Plate XVI, fig. 2) of the mucous coat. With the
increase of these cells in this connective tissue, the normal parenchyma re-
presented by the mucous glands and the villi was found inclined to be obli-
terated. Under the influence of inflammatory hyperplasia of cells the villi were
found either variously distorted or completely detached from the basement
membrane of the mucous lining. The submucous layer was rarely affected,
but wherever there was an involvement of this layer the tissue reaction was so.
severe that the loose alveolar tissue was found completely packed with the
epithelioid cells tending to obliterate the muscularis mucosae in its neighbour-
hood. Haemorrhages and congestion of blood vessels were also noticed.
The organisms have been seen at all depths of the lesion including even
the submucosa if this structure also showed cellular infiltration. Their distri-
bution in the lesion has been observed to correspond with the course of the
lymphatics of the villi and the interglandular connective tissue. In the villi
they have been seen occurring in the central zone, a position normally occupied
by the lacteoles. In the interglandular connective tissue the organisms
occurred mostly intra-cellularly in the form of smaller clumps, and rarely
singly. Lying in the mass of densely stained epithelioid cells one could dis-
cover areas showing lighter staining reaction, of groups of epithelioid cells
which may be said to have passed into the symplasma stage of degeneration.
Sections from mesenteric lymphatic glands also revealed extensive in-
filtration with the epithelioid cells, and the organisms were seen at all depths
of the lesion, occurring mostly intra-cellularly. Degenerative changes amongst
the epithelioid cells, consisting of vacuolization of nuclei and fusion of several
cells to form syncitial masses (Plate XVII, fig. 1), were seen occurring in small
isolated patches. Sections prepared from some of these glands taken from
all the four cases occasionally showed faintly stained and homogeneous masses
of caseation containing numerous acid-fast bacilli, which may be compared
with tuberculous lesions at the stage preceding calcification. Giant cells,
either well formed (Plate XVII, fig. 2) or still in the process of formation as
represented by an agglomeration of more than 3 or 4 cells (Plate XVII, fig. 1)
have been seen fairly frequently.
DISCUSSION
McFadyean and Sheather [1916] attached little importance to the occur-
rence of Johne's disease in goats in England where the number of such animals