lo Feb.. 1910.] Tick Fever 1)1 Fowls. 9/ 



internal organs, parlicularly the kidneys, many of the protozoans may 

 readily be seen. The red blood cells of the fowl are about i-25ooth of 

 an inch in length, and the piroplasma is from i-i5th to i-2oth the size of 

 a red corpuscle. The intra-cellular forms are very small and may be 

 observed as minute spherical l)odies resting near the edge of the blood 

 corpuscle. Xot manv intracellular forms may be detected in the cover 

 slip preparations, hence the difticuitv experienced in determining the exact 

 causation of the mortalitv in tick infestation. The extra-cellular forms are 

 larger and more numerous than the intra-cellular forms, and in prepara- 

 tions of blood from fowls freshly killed thev are readilv enough observable 

 to the trained observer. 



The bod\ temperature of affected fowls rises several degrees. The 

 normal temperature of a fnwl is 107", l)ut elevations of the temperature lo 

 1 10" and even 112" are not uncommon in the course of tick fever infection. 

 The fowls become weak, emaciated, and lose the power of their legs. 

 The red blood corpuscles are broken uj) and this condition is one of the 

 essential factors in th»- course of the disorder. Since the organism.? belong 

 to the f>rotozoa the\ are incapal)le of being cultivated outside the bodies of 

 fowls. 



The organisms. l>psides \arying in size \ar\ alsn in form. Some are 



spherical, some pear shaped, some oblong and some j)ossess irregular shapes. 



They are highly refractive and do not satisfactorily 



absorb stains. However, they can be stained bv 



special methods and I possess some verv good slides. 



It is some time since that I reported the existence of 



the Piroplasma gallincc in the blood of fowls and its 



connection with the tick fever disease. (^)uite .recently 



again, for further investigation, I sent two young 



fowls to Swan Hill to be placed in a situation where 



TICK FE\ EK l^heN might become tick infested and so infected with 



ORGANISMS. the s[)ecific micro-parasite. The result was positive 



. „ ,1, J „ , 111 bcith cases and the fowls were returned to me for 



A.— Red blood cells showiiiL; . . . „,, , 



piroplasma; in them (intra- sp'cial examination. 1 he axerage number in red 

 corpuscular form.). corpu.scles iu a healthy fowl is 4,000,000 per cubic 



biood^ serunr"(e* tra-corpu"- millimetre and the average amount of haemoglobin 68 

 puiarforms\ P^^. (,p,^|- y,^ ^]^^ fowls that Contracted tick fever, 



investigations disclosed that the number of corpuscles had sunk to 

 2.800,000 per cubic millimetre and the hEemoglobin to 44 per cent. 



Some years have elap.sed since 1 identified the parasite {A^rgas 

 americanus) when it first commenced to make its influence felt in Victoria, 

 and the course of action that has been since followed to check its spread 

 has pro\ed eminentlv successful in confining it to the areas in which it was 

 first discovered. A great deal of work has been done in the direction of 

 securing its eradication from the poultry runs of the State, and it is hoped 

 that when the Poultr\ Diseases Bill which has been drafted has been 

 placed upon the statute-book, there will be provided ample power to take 

 such action as will lead to the complete extirpation of the pest from 

 Victoria. 



17087. 



