The Journal of the Department of Agriculture, Victoria . e same organism be found inthe tissues of the successfully inoculated animals in such numbers,and with such a distribution, as to account for the disease. Inmany cases it is necessary for the organism which produces diseaseto be transferred from one animal to another by means of inter-mittent hosts, such as biting flies, ticks, mosquitoes, fleas, &c. (Figs. 10, 11);as an example, the disease known, at any rate by name, to nearly all, as Texas or Tick Fever in cattle. This is caused by a small organism—from 12,000 to 80,000 being required
The Journal of the Department of Agriculture, Victoria . e same organism be found inthe tissues of the successfully inoculated animals in such numbers,and with such a distribution, as to account for the disease. Inmany cases it is necessary for the organism which produces diseaseto be transferred from one animal to another by means of inter-mittent hosts, such as biting flies, ticks, mosquitoes, fleas, &c. (Figs. 10, 11);as an example, the disease known, at any rate by name, to nearly all, as Texas or Tick Fever in cattle. This is caused by a small organism—from 12,000 to 80,000 being required to measure i inch (Fig. 12)—whichgains access to the red blood corpuscles of the animal, and produces atrain of symptoms, of which fever and red water are constant. Theorganism is carried from animal to animal by means of the tick (Fig. 13). Another disease, which many in the northern districts will be familiarwith, is tick fever in poultry (Fig. 14). The organism in these cases assumes. JO igr^.] The hjiologv of Conta^^mus Diseases. 495. IlG. 14. BLACK LEGHORN HEN SUFFERING FROM ACUTE SPIROCHAETOSIS. the form of a spirillum (l^ig. 15).and is transferred from bird to birdby means of the tick ; it is fromI/600th to I/I,600th of an inchlong. The difficulty in eradicatinjj;these diseases is apparent, for solong as the tick remains in a dis-trict, it is capable of continuingthe spread ; and as of thetcks are capable of long life, evenwithout food, the tlifficulties areincreased. The tick concerned inthe spread of the disease in poultryis capable of living for a period•of three years or more withoutfood. A variety of parasite, which,fortunately, is not present in Aus-tralia producing any pathogenic % % % % 0 « 9 % • * ^ ^ \ ^ % %» ^ m • % 0 % % • 0 » ^ •• 0^ . ^ m % ^ # % * #» <t& % % FOWL SPIROCHAETOSIS. FREE SPIROCHAETES AND TANGLESTHE ACUTE STAGE. DURING
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectagricul, bookyear1902
