Abstract
In March, 1936, Dr. S. T. Michael of the hospital of the Society for the Prevention of Cruelty to Animals solicited assistance in the diagnosis of a highly fatal malady which affects with increasing frequency the older dog population of San Francisco and vicinity. Unfortunately, only dead animals or dogs in a moribund state were available until early in 1937. The examinations were consequently limited to autopsies, search of the tissues stained by the silver method, and attempts to isolate from the heavily contaminated organs by guinea pig passages, the leptospira readily demonstrable in dark field preparations of the kidneys, the spleen and occasionally the blood. The postmortem findings made on 67 dogs arranged themselves into 2 groups: the Icteric Type (24 females and 9 males), which corresponds to the so-called Weil's disease or “yellows” or canine jaundice observed in England by Okell, Dalling and Pugh, 1 and in Holland by Klarenbeek, 2 and the hemorrhagic type (27 females and 9 males) resembles greatly the Stuttgart disease or dog typhus. 3 Although leptospiras have been demonstrated in the kidneys and occasionally spleen, liver and blood, both in dark field preparations and in properly stained sections prepared from cadavers belonging to both types, cultures have only been obtained directly from the blood of 6 dogs which were definitely jaundiced. Contrary to the impressions conveyed by published reports, the isolation of these spirochaetes was connected with great difficulties since the organisms produced transitory non-fatal infections in very young guinea pigs. On passage the infectiousness was occasionally enhanced but the rodents rarely died, and then in exceptional instances with icterus or hemorrhages.
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