(Mr. Dollar has been informed that Professor Hamilton and Dr. McCall have been engaged in an investigation regarding the possibility of conferring immunity against braxy, and that a Government report will be issued on the subject. Up to the present time however—April, 1905—he has not been able to obtain this report or any advance proof sheets of it.)
BILHARZIOSIS IN CATTLE AND SHEEP.
This disease is caused by the bovine blood fluke (Schistosoma bovis) of cattle and sheep. Synonyms: Bilharzia bovis; Bilharzia crassa; Gynæcophorus crassus; Gynæcophorus bovis; Bilharzia hæmatobia crassa; Schistosomum bovis.
Geographical Distribution. Egypt, Italy, Sicily, India (?).
This parasite was discovered by Sonsino (1876) in Egypt in the portal veins of the ox, and later he found it in sheep, while Grassi and Rovelli afterwards found it in about 75 per cent. of the sheep slaughtered at Catania, Sicily.
Source of Infection. Clinical observation and analogy point to unfiltered drinking water as the source of infection.
Position of the Parasite. The worms are found in the veins of the abdomen, the vena porta, vena linealis, vena renalis, and the venous plexus of the bladder and of the rectum.
Symptoms. The young parasites appear to do no injury; in fact, even the adult worms seem to be inoffensive in themselves. The eggs, on the other hand, armed with a sharp point, are the exciting cause of the disease. The position of the parasite in the venous system, and the consequent location of the agglomeration of eggs, determine the particular symptoms. Either the genito-urinary system is attacked, in which case hæmaturia is one of the first symptoms, or the large intestine is attacked and blood is noticed in the fæces.
Fig. 206.—The bovine blood fluke (Schistosoma bovis), male and female. × 9. (After Leuckart, 1894, p. 467, Fig. 204 A.)