BOVINE TUBERCULOSIS

Waipa Post, Volume 42, Issue 3271, 12 March 1931, Page 6

BOVINE TUBERCULOSIS

SIiCESS WITH VACCINE TESTS. CALVES RENDERED IMMUNE. Tuberculosis in cattle—the great • scourge of farming—may one day be eliminated from the Empire’s herd if the 'success of three years’ experi- • m ents carried out at Cambridge Urn. and financed by the Empire Marketing Board is followed up. These experiments show that the immunisation of calves against bovine tuberV culosis with “ 8.C.G.” vaccine is definitely practicable. ‘ This announcement has been made v following the claims recently put for- . wprd that calves had been rendered \ immune to tuberculosis by means of a secret vaccine used by Mr Spah- • linger on a farm in Norfolk. The Cambridge experiments, which began in 1927, are being carried out by Professor J. B. Button, head of the De- ' partment of Animal Pathology at the and Dr Stanley Griffith, M an Officer of the Medical 'Research I Council, with the aid of . an Empire Marketing Board grant. Similar tests have been made at the Ministry of Aericulture’s laboratories. ALIVE THREE YEARS LATER. > Many of the: calves which were mV. odulated with B.C.G. vaccine, and • subsequently given powerful doses of virile tuberculosis germs .njected >' straight into’ the veins, were • alive • . ' eight to twenty months afterwar s. ‘‘Control’’ calves, which were not given the B.C.G. but received the same ? dose of virulent .tubercule ' germs, died in about three weeks. f-lt One animal which was vaccinate a ; a heifer calf and then given a fatal dose of tubercule germ is still alive ~ ..and well three years afterwards, n *: the interval she has had a calf w ic ;. does not react to the standard Test '. for tuberculosis, and so is free from 1 infection. . B.C.G. vaccine or Bacillus-Cal- , mette-Guerin, is so called because it jf' was discovered first by a French

scientist Professor Calmette, at the Pastuer Institute,; in 1906. It consists of a strain of living, though non-virulent, germs. These bacilli were bred for 13 years on bile-soaked potatoes in the laboratories, and at the end of this time they were found to have lost their virulence and to be incapable of producing tuberculosis in calves, horses, etc., or even in guinea-pigs, the must susceptible of animals. Animals vaccinated with B.C.G. which were slaughtered over a year after severe intravenous injections of tubercle bacilli at Cambridge were found to be suffering only slight chronic symptoms of the disease, although similar “control ” calves—without the vaccine—died from acute tuberculosis in three weeks. ONLY ONE FAILURE. B.C.G. vaccine does not always confer so high a degree of immunity. Insome cases the vaccinated calves die of tuberculosis or meningitis (caused by tubercle infection of the membranes of the brain) in three to seven months after infection. But in only one case has a calf intravenously vaccinated with B.C.G. failed to show increased resistance to tuberculosis. These results are even more encouraging than they appear at first sight. In many of the tests the calves are. infected with T,B. by the injection of millions of living germs into the blood-stream. This is very much more severe than the normal infection to which they are exposed under farm conditions, when they pick up the germs by breathing or with their food. It is safe to assume that where B.C.G. renders calves partially resistant to tuberculosis in laboratory tests it would have a very much greater effect under normal conditions. Many more years of work; Professor Buxton and Dr Griffith say, are necessary before B.C.G. can be used commercially. No one knows, for instance, how long its effects last, and

whether the vaccination would have to be repeated at intervals, as with smallpox immunisation in man. HUMAN HEALTH. This work is of vital importance not only to farmers but also to human health. Human beings are susceptible to bovine tuberculosis, and about 30 per cent of tuberculosis of the • bones and joints is caused by the bovine germ. (The germ causing human tuberculosis belongs to a separate strain). Partial eradication of tuberculosis, in cattle would, of course reduce infection f.n humans. On the Continent B.C.G. has been used for several years for the vaccination of human babies. > Professor Calmette has conducted numerous experiments and claims to have reduced infant mortality from tuberculosis wherever he has used it.