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1. Ranikhet Disease Vaccine.—The Vaccine was much in demand specially
from small-scale poultry breeders arising from rehabilitation process or those
adopting a new enterprise in the way of investment. Mass inoculation campaign
was, therefore, elaborated as a natural sequence in areas adjoining the city and
also in rural areas. No report on the incidence of the disease was reported
among those where the birds were protected last year or the previous year. In
the several State Poultry farms, special precaution was taken to immunise fresh
stock attaining six weeks age. An outbreak was noticed in a State farm affecting
chicks below six weeks age. Immunisation was carried out in these with usual
precaution of employing different needles, etc., and among a batch of 43 chicks
on the 3rd day morning after the first few casualty. Among the vaccinated lot of
43 chicks, 4 chicks of 43 days old died on the sixth day, 4 chicks of 32 days
old died on the 7th day and another 26 of 35 days old died between the 7th to
9th day during the post-inoculation period. Post-mortem examination in these
revealed varying degree of Ranikhet disease infection.
The question of determination of the minimum age in chicks for safe vaccina-
tion against Ranikhet disease was taken up. The approved technique involved
a series of controlled tests among susceptible chicks of varying age from 3 to 21
days, in as many as 6 chicks from each age category together with 3 controls to
prove potency of the test-virus. This required a continuous supply of experi-
mental animals (chicks) from disease-free stock. Efforts to carry on large-scale
experiment on the above lines were circumscribed from limited resources of avail-
ability of necessary equipment, etc., including a number of wire cages, incubator,
eggs and also the required space. In the circumstances the experiment was,
however, carried on during cold weather in one lot, in a very modest scale.
Standard preparation of R. D. Vaccine emulsion was given subcutaneously at
the dose rate of ½ c.c. to each chick of 3 days old, 11 days old, 18 days old and
23 days old, among a batch of 12 chicks with 3 chicks in each of
the respective age category. All the chicks belonging to the first two age category,
i.e., the 3 days and 9 days old, respectively, showed diarrhoetic stool in the
following morning and died within the course of next 20 to 36 hours. In the
remaining lot of six chicks of 18 to 23 days old, 4 of them after showing some
preliminary signs of malaise recovered but remained in poor state of health.
The two other chicks died within 48 hours following vaccination. The 4 sur-
vivors were given a challenging dose of Ranikhet virus after 3 weeks. Though
they did not die but remained in a moribund state till finally destroyed.
The
experiment probably showed that chicks below 11 days in age are completely
unsafe, whereas 18 to 23 days old are slightly better in safe immunisation.
It is expected that it will be possible to take up the work more elaborately
next year as some of the main difficulties of availability of funds and equipments,
etc., have in the meanwhile been overcome and are now awaiting final
adjustments.
2. Fowl Pox.—Six thousand four hundred and twenty-six birds were
protected with new Fowl Pox Vaccine during the year under review. In the
State Poultry Farms, vaccination was adopted as a routine measure twice a year.
No breakdown in immunity or recrudescence of the disease was noticed in these
places or elsewhere. At an isolated instance, revaccination was employed a
week after the initial operation among a batch of 70 crores bred R.I.R. fowls
when the "Takes" were not visible in 50 per cent. of the vaccinated birds. As a
result of revaccination with a fresh brew, the "Takes" were apparent in many
but not all.
3. Survey of Duck Diseases.—(i) Pasteurellosis.—There were 10 reports on
duck diseases involving considerable mortality in six of them. Out of these, 3
reports were on account of Pasteurellosis. The identity of the disease was not