Noguchi has produced an immune serum to his spirochaete by injecting horses. He has records of 170 cases of yellow fever treated with this serum with a mortality of 13.6%, while untreated cases gave a death rate of 52%. He notes that the serum must be given before the third day of the disease to be of any value—best results in the first day. He believes also that though salvarsan and neosalvarsan have some leptospiricidal action they are both too damaging to the kidney to supplant serum in treatment. CHAPTER VI INFECTIOUS JAUNDICE DEFINITION AND SYNONYMS =Definition.=—Infectious jaundice is a spirochaete infection, caused by _Leptospira icterohaemorrhagiae_. This spirochaete is a common parasite of rats in various parts of the world and man possibly receives his infection from this source. There is a sudden onset with rather high fever, headache and vomiting. The jaundice appears about the third or fourth day when the urine shows albumin and bile. Haemorrhages, especially epistaxis, are common and the liver rather than the spleen shows enlargement. A polymorphonuclear increase is a feature. =Synonyms.=—Epidemic jaundice. Spirochaetosis icterohaemorrhagica. Typhus bilieux. Weil’s disease. HISTORY AND GEOGRAPHICAL DISTRIBUTION [Illustration: FIG. 47. FIG. 48. FIG. 47.—Showing _Leptospira_. (After Noguchi in Journal of Experimental Medicine.) FIG. 48.—A group of _Leptospira icterohaemorrhagiae_ from a culture. (After Noguchi in Journal of Experimental Medicine.)] =History.=—This disease was probably the form of jaundice noted in the forces of Napoleon during the Egyptian campaign. It was first recognized as a distinct disease by Weil, in 1886, who described it as a peculiar form of acute infectious disease characterized by jaundice, swelling of spleen and nephritis. Inada and his Japanese colleagues discovered the causative spirochaete in 1915 and noted the frequency of this parasite in rats. Infectious jaundice was an important disease of the soldiers of the recent war. =Geographical Distribution.=—Japan and Egypt may be considered as the parts of the world in which the disease is most common. It is endemic in West Africa and cases have frequently been reported from the shores of the Mediterranean. During the Russo-Turkish war (1877) cases of jaundice seen in the Balkans by Sandwith were probably infectious jaundice as the disease was frequently noted in that region during the recent war. Cases were noted in Flanders during the war. A few cases have been reported from the United States. ETIOLOGY AND EPIDEMIOLOGY