Vol. XIV. No. 34.?. 



THE AGRICULTURAL NEWS. 



203 



VETERINARY NOTES. 



ANIMAL CARWBES OF ANTHRAX. 



The nature of the disease known as anthrax is 

 sufficiently well known to render an rj its description 



i„ the present article. It is the in i in the folio 



paragraphs to outline an inter a e of investigation 

 work conducted by Dr. W. II. Dalrj igle, of the Louisiana 

 State University {American Veterinary Review for Decern 

 ber 1914) into the ways in which th be dissern 



inated by different mammals, birds an I insi 



The investigator had long been uider the impression 

 that infection is spread through the activities of certain 

 carrion feeders on account of their periodic contact with 

 anthrax carcasses during seasons which afford favourable 

 climatic conditions for t lie development of the infection on 

 areas where the disease had already existed and where strict 

 sanitary measures were not carried it. \ew areas and 



fresh foci of infection, and a wider general occurrence of the 

 disease could not be accounted for in theabsenceof carriers 

 that could move from place to plai I thereby extend the 

 territory of infection. 



This led to the systematic ,vork now under review. 

 The subjects used in the tests were: the turkey buzzard 

 (Cat/iartts auro), the carrion crow (Catkaritta atrala), the 

 dog, pig, cat, opossum (Didelpkys virginiana), and the 

 common fowl. The term 'buzzard' is used to include both 

 the turkey buzzard and the carrion crow, as they frequently 

 scavenge in company. The experiments were conducted in 

 a wire-screened room, with concrete door and walls. 



Buzzards were confined in r oy cages the bottoms of 



which were covered with heavy wrapping paper. Alter 

 feeding the paper was removed from the floors and the cages 

 repapered, and the faeces collected from the cages as soon 

 after dropping as possible. Anthrax spores were used in 

 three different ways: namely, ( 1 ) fed in meat balls which were 

 thoroughly infected: (2) through infected carcasses of 

 rabbits: (3) injections of suspensions of anthrax spores made 

 directly into the crop. 



A large number of cultures were prepared from the 

 feces, but not a single anthrax colony could be found. 



Not succeeding in finding infection in the faeces, cul- 

 tures were made from the contents of the digestive tract- 

 Several buzzards were fed spores by the methods just 

 described and the birds destroyed at different periods after 



feeding (from four to twenty four hours), with a result that 



no infection was found beyond the si unai h, and but little in 

 that organ. 



These experiments would seem to show that anthrax 

 bacteria do not pass through the digestive tract of the buzzard 

 and are therefore not disseminated in the droppings of this 

 bird. 



In order to test the question of mechanical distribution 

 of the infection through the contaminated feetand beak of 

 the buzzard, anthrax carcasses of rabbits were fed permitting 

 the bird to devour them as it would under natural condi- 

 tions. At different periods scrapings .eie taken from the feet 

 and beak, and cultured. As long a Mine as forty-eight hours 

 after feeding and cleansing the cages; virulent anthrax was 

 obtained from both feet and beak. In the state of nature, 

 however, it is possible that the infe tion would not be found 

 after so long a time, as it would most probably have been 

 washed off or otherwise removed. 



Buzzards are gluttonous feeders and frequently throw up 

 much of what they have swallowed. Having found infection 

 in the stomach contents, it was thought likely that the 



vomitus might itain the organisms and becoi u ' ■ 



source from which the disease could spread. Two hours 

 feeding on the anthrax caccase of the rabbit, a buzzard 

 emitted a large amount ol the flesh, which was carefully 

 collects iltured and colonies of anthrax developed on 



dilution plate used. These results would em to 

 e that the buzzard is capable ol cai i \ ing infi ction foi 

 long distances, and of creating fresh foci in pa ■ w. 



It may be stated I,. i bat a con eqi i le ibove 



results has been the repeal, in the Southern United States, of 

 existing laws for the protection of the buzzard or the 

 enacting of legislation for the bird's extermination. 



Experiments conducted with dogs, swine and its 

 showed that infection will pass through the body and 

 in consequence, the excreta of these animals 

 a source of infection. In regard to the common 

 anthrax was found in the posterior pari ol the tract, and the 

 feces contained anthrax infection lor forty eight hour 

 the spores were fed. In the ease of swine, infection was 

 found in the excreta no less than five daj il ei feeding the 

 infection. 



The writer of the paper then turned his attention to 

 insects, particularly horse flies (Tabanids) as agents in the 

 distribution of this disease. The writer is of opinion that in 

 Louisiana, the earlier cases of anthrax in a season I 



from the ingestion of infection; while the later ones, and 

 a greater and more rapid spread of the disease is brought 

 about through the agency of infected flies. Owing to the 

 semi-aquatic life-history of the tabanids, it should not be 

 difficult by means of drainage and other sanitary methods to 

 k.ep them more fully under control. 



The writer strongly recommends systematic vaccination 

 against anthrax and regards the single- and double-dose vaccine 

 as being equally effective; though it is stated that three 

 weeks to one month must elapse before immunity is secured, 

 which when obtained should last for one season of ten or 

 twelvemonths. Satisfaction is expressed in connexion with 

 the decision of the United States Government to supervise 

 the preparation of vaccines. Apparently some of these have 

 not been prepared in as pure a manner as they should have 

 been in some of the American commercial laboratories. 



Lastly, the writer gives attention to the question of the 

 spread of anthrax in infected hides. This is a matter which 

 affects the West Indies commercially, and the quarantine 

 regulations imposed by the United States are in a general way 

 well known. Hides may be disinfected in several ways, but 

 the three accepted by the United States -Government are 

 immersion in bichloride of mercury (1 to 1,000 solution); 

 immersion in 5 per cent, solution of carbolic acid: and by 

 exposing to the fumes of sulphur dioxide. Readers who are 

 especially interested in the question of hide disinfection 

 should refer to the Journal of Agricultural Research of the 

 United States Department of Agriculture, which deals with 

 special aspects of this subject. Reference may also be made 

 in regard to the preparation and disinfection of hides, to the 

 Agricultural Ntm, Vol. XII, p. 247, and Vol. XIII, p. 167. 



A notice appears in Future (May 13, 1915) in regard to 

 the Eleading Courses and Examinations conducted by the 



Imperial Department of Agriculture for the West Indies. 

 This notice is based on the recent Circular issued by this 

 Department containing a revised book list and a slight altera 

 tion in the syllabus in regard to crop subjects. It would 



appear that Naturt considers these courses serve a useful 

 purpose, and are worthy of imitation in other parts of the 

 world. 



