MUKTESAR, FOR THE YEAR ENDING THE 31ST MARCH, 1925
43
It is evident that before definitive information is available concerning the relative
susceptibility of Indian and European cattle, calves of unmixed European descent will
have to be employed as controls in further tests.
However, the information such as is now available would seem to indicate that the very
low incidence of bovine tuberculosis in India (about three per cent., with small localized
lesions, at Ferozepore and Cawnpore slaughterhouses, but generally apparently much
rarer) is attributable to the manner in which the cattle are generally maintained in the
country—in the open, with ample opportunity for destruction of the virus voided by
carriers—and not to any specially lower virulence possessed by the causal organism, and
probably not to any specially high resistance of the cattle themselves.
(g) Surra. Experiments upon the chemotherapy of surra were continued. Unfortu-
nately, the virulent bovine strain that had proved useful in determining the relative
efficacy of certain chemotherapeutic agents upon cattle in the preceding year became
degraded in virulence, and efforts to exalt it proved fruitless. Tests were made upon the
maximum tolerated doses of a number of drugs used in treatment.
(h) Contagious equine abortion. A considerable number of agglutination tests were
made upon sera received at the laboratory from suspected cases of infection, and syste-
matic tests were continued upon the animals of the Government Cattle Farm, Hissar,
and the Army Remount Depôt, Ahmednagar, with a view to limiting the spread of the
disease by the segregation of " carriers " of the common causal organism (Bacillus abortivo-
equinus). The Superintendent of the former establishment feels assured that these mea-
sures, which have now been undertaken for a period extending over three years, have
resulted in checking the spread of abortion. Some interesting data are disclosed in the
records of infected animals ; it appears that infection may persist in equines for a long
time, two years or longer, and that reinfection occurs not infrequently after an animal
has become " clean," as evidenced by a reappearance of agglutinins in the blood serum
after a period during which they have gradually disappeared. An attempt was made upon
a small scale upon the Farm during the year to vaccinate certain breeding animals, by
the inoculation of dead cultures of B. abortivo-equinus, and the results are awaited.
(i) Contagious bovine nasal granuloma. Mention has been made in the preceding
Report of the work done at the laboratory upon this peculiar widespread affection of the
nasal mucous membrane of cattle in India, with morbid appearances similar to those
of bovine actinomycosis in Europe. Attempts have been made to transmit the disease
artificially to healthy cattle, by housing in contact with naturally affected cases, and by
infection in various ways with a streptothrix isolated culturally from the lesions. Al-
though the animals thus exposed have been under observation for over a year, no lesions
have yet become visible in them.
(j) Sheep pox. Specimens of crusts from outbreaks of this disease in the field were re-
ceived at the laboratory with a view to manufacturing a vaccine on the lines of BRIDRE'S
sensitized vaccine for issue for preventive inoculation. The material, however, was not
capable of producing lesions of sufficient intensity to proceed with the work of collecting
lymph for preparation of the vaccine.
(k) Piroplasmosis. In the course of routine blood smear examinations at the laboratory
the findings were :—(i) Piroplasma bigeminum, 189, (ii) Theileria mutans, 532, (iii) Ana-
plasm-like bodies, 5, (iv) Nuttallia equi, 9, (v) Trypanosomaevansi, 19, (vi) T. himalayanum
(probably T. theileri) 1, (vii) Anthrax, 11, (viii)Hæmorrhagic septicæmia, 35, (ix) Microfila-
ria, 1, (x) anæmic changes, 267, (xi) leucocytosis, 9, (xii) negative, 2466.
It has been stated in the preceding Report that the common piroplasms discoverable
in cattle in India are Piroplasma bigeminum and Theileria mutans. These piroplasms
have a very widespread, but not universal (so far at least as concerns the former piroplasm),
distribution in cattle in the country, and the risk of infecting susceptible cattle accident-
ally with piroplasms introduced with the virulent blood employed in the process of active
immunization against rinderpest is a limiting factor of considerable importance in the suc-
cess of the method and which necessitates special observation, with treatment by the in-
jection of trypanblau, subsequent to the inoculation.
No case of the East Coast fever type of affection was seen in cattle during the year.
The clinical history and results of blood examination reported from the field in the case
of one valuable imported bull that succumbed to piroplasmosis a considerable time after
rinderpest immunization makes it seem probable that infection with Piroplasma argen¬
tinum sometimes exists in this country.
In a blood smear received at the laboratory from a lamb that had succumbed in Madras
a rich infection with Theileria ovis was demonstrable, with the presence of " blue bodies"
in the large mononuclear leucocytes.