S. GANAPATHY IYER AND Z. A.
HASHMI
157
successive egg-passages. Two strains, Lines i
and iii showed no evidence of attenuation after
69 and 32 passages respectively, while a third,
Line ii, was attenuated after 19 passages.
2. From 19th to 28th passages Line ii virus
had no apparent harmful effect when injected
into fowls and rendered them immune to test
doses of different strains of virulent Ranikhet
disease virus.
3. From the 29th passage onward, the atten-
uated virus gave irregular results. Frequently
out of two fowls receiving a similar inoculum one
died and the other survived, suggesting resus-
citation of latent conditions and indicating the
necessity of further work.
ACKNOWLEDGEMENT
The authors wish to express their indebtedness
to Messrs J. R. Haddow and A. J. Macdonald
for help and criticism in this study.
REFERENCE
Iyer, S. G. and Dobson, N. (1940). Vet. Rec., 52, 889
THE OCCURRENCE AND SPREAD OF FOWL CHOLERA IN INDIA
By S. GANAPATHY IYER and Z. A. HASHMI, Poultry Research Section, Imperial Veterinary
Research Institute, Izatnagar
(Received for publication on 12 January 1945)
Early records of poultry mortality in India
are the Jessore and Madras outbreaks (1817
and 1828) mentioned by Raymond [1911] and
the Calcutta outbreak (fowl cholera) reported
by the Indian Cattle Plague's Commission [1871].
Until the outbreak of Ranikhet disease in 1927
[Edwards, 1928], fowl cholera was being reported
as the chief cause of fowl mortality in this country,
though fowl spirochetosis was also well known.
Since the diagnosis of Ranikhet disease, much
less prominence has been given to outbreaks of
fowl cholera.
In the course of a three-year's disease survey of
the greater part of this country, it was not possible
to find fowl cholera infection even in a single
widespread epizootic among fowls. Further, all
the materials suspected for fowl cholera when
tested in this section have proved negative.
However, in two localities, relatively near the
laboratory, limited enzootics of fowl cholera,
causing insignificant mortality, were observed,
and authentic strains of Past aviseptica recovered.
From this survey two significant conclusions
emerge: (i) that contrary to common belief,
fowl cholera occurs infrequently; and (ii) that,
in this country, widespread epizootics are not
a feature of fowl cholera. The fact, that Past
aviseptica could be isolated in outbreaks from
two nearby localities, led us to scrutinize the
present methods employed by field workers for
diagnosing the disease and to investigate the
various factors affecting the viability of the
organism in the suspected material during transit.
The results of our investigations suggest a pos-
sibility that the disease, in its enzootic form may
be somewhat more prevalent than has been
indicated by our survey.
EPIZOOTIOLOGY
Little attention has been paid in this country
to the epizootiology of this disease. Sporadic
outbreaks have occasionally been recorded, many
of which were probably wrongly diagnosed on
the strength of naked-eye and microscopical
examination of autopsied birds. Information
regarding sources of infection and methods of
spread of fowl cholera is scanty, although these
constitute pre-requisites for eradication or control
of the disease.
Past aviseptica possesses low powers of resis-
tance to inimical agencies—physical, chemical,
and biological. The existence of the so-called
saprophytic forms of Pasteurella, found in soil,
has been questioned [Hutyra, Marek, and Man-
ninger, 1938], and soil can hardly be regarded
as a reservoir of infection. During field observa-
tions on spontaneously-occurring fowl cholera,
Pritchett, Beaudette and Hughes [1930] found
healthy pullets, which were survivors from a
previous outbreak, to be the foci of infection
as they carried the organisms in the upper res-
piratory tract. Other workers [Smith, 1891-92;
Klein, 1906; DeKruif, 1922; Webster, 1924,1;
Smith, 1927] have also isolated Pasteurella
H 2