Second review of some of the advances in tropical medicine, hygiene and veterinary science, being a supplement to the fourth report of the Wellcome Tropical Reseach Laboratories at the Gordon Memorial College, Khartoum : by Andrew Balfour and R.G. Archibald.

  • Balfour, Andrew.
Date:
1911
Catalogue details

Licence: Attribution 4.0 International (CC BY 4.0)

Credit: Second review of some of the advances in tropical medicine, hygiene and veterinary science, being a supplement to the fourth report of the Wellcome Tropical Reseach Laboratories at the Gordon Memorial College, Khartoum : by Andrew Balfour and R.G. Archibald. Source: Wellcome Collection.

Provider: This material has been provided by London School of Hygiene & Tropical Medicine Library & Archives Service. The original may be consulted at London School of Hygiene & Tropical Medicine Library & Archives Service.

    274/458 (page 270)
    Plague— factor in the spread of plague. Ground squirrels were found to be liiglily susceptible, no continued example of immunity having been encountered. In another paper, M'Coy ^ describes a number of inoculation experiments carried out to test the immunity of San Francisco rats to plague. He found that there was a considerable immunity to plague infection among the wild rats in that city, particularly among the old rats, and considered that the immunity was probably natural in most cases and not acquired. His paper is concluded by a short comparative description of the distinguishing characters of Mus norvegicus, Mus rattus, and Mus alexandrinus. In a more recent article entitled Plague among Ground Squirrels in America, M'Coy - makes mention of a plague-hke disease of squirrels which is characterised by a caseous bubo (sometimes hsemorrhagic) and necrotic foci in the spleen and Uver. The lesions present simulate plague infection. Guinea-pigs inoculated from infected squirrels die between the fifth and eighth day with lesions resembUng those of plague. The cause of the disease, how- ever, is feebly pathogenic for rats, and negative results yielded by stained smear preparations and cultures readily differentiate it from plague. M'Coy states that no etiological agent has been discovered. Under the heading of parasites this observer asserts that Ceratophyllus acutus, Baker, is the commonest species of flea found on the ground squirrel, Citellus beecheyi. It has been shown capable of carrying plague among the squirrels. The other flea, Hopto'psyllus anomalus, Baker, is not so commonly present. Among other ecto-parasites of squirrels, hce, mites, and ticks were found, apparently only at certain seasons and in Umited areas. The paper is concluded by an account of the methods used for exterminating the squirrels by means of strychnine and bisulphide of carbon. De Souza, Arruda, and Pinto ^ carried out a series of experiments to discover whether the common domesticated animals of Terceira Island were susceptible to plague. The results of their experiments were as follows :— (1) Although our experiments on calves may not be extensive, we think we may afBrm that the bovine race, in spite of the large doses inoculated, did not contract the plague. On Terceira Island we had no knowledge whatever of any case of illness in bovines which could be put down to plague. (2) As for the pigs, we consider the series of animals on which we experimented fairly large. The doses of virus inoculated were really enormous, far larger than what they would naturally receive. The experiments led us to conclude that pigs do not contract plague. (3) The experiments made on dogs seem to show that only with very large doses of plague baciUi can infection of these animals be obtained, and it seems beyond doubt that in its normal condition the dog is an animal practically refractory to plague. This conclusion proved very interesting to Terceira Island, where dogs have rendered and continue to render great service in rat-hunting. (4) The experiments made on rabbits led us to conclude that this animal is, on Terceira Island, very susceptible to plague. (5) Our experiments on ferrets were made because these animals are extensively employed in rat-hunting, above all in the country. According to these experiments the ferret is an animal susceptible to plague, but only able to contract an acute form of this disease by inoculation of large doses. However, as the ferret sucks the blood of the rats, its use in hunting these animals is not recommended. (6) Our experiments corroborate those of the Austrian Commission, that cats can be infected by plague fer os, after which they show at the autopsy an appearance with buboes in the neck very similar to those of cats spontaneously infected by plague. (7) The general conclusion which we draw from our experiments on four kinds of birds—namely, pigeons, ducks, turkeys, and chickens, especially in regard to the latter, is that these animals are insusceptible to plague. An important paper by the late Major Lamb * was read before the last Bombay Medical Congress, and deals with the etiology and epidemiology of plague. As it recounts most of the work carried out by the Plague Commission, reference to which was made in the first Review, there is no necessity to consider it fully here. Kitasato^ has a paper on rat fleas, with special reference to the transmission 1 M'Coy, G. W. (June 12, 1909), The Immunity of San Francisco Rats to Infection with B. pestis. Journal Infectious Diseases. 2 Idem (December, 1910), Plague among Ground Squirrels in America. Journal of Hygiene. 3 De Souza, A., Arruda, A., and Pinto, M. (August, 1910), Report on Experiments undertaken to Discover whether the Common Domesticated Animals of Terceira Island are affected by Plague. Ihid. * Lamb, G. (1909), The Etiology and Epidemiology of Plague. Transactions Bombay Medical Congress. 5 Kitasato, S. (1909), Rat Fleas, with Special Reference to their Transmission of Plague in Japan. Ihid.