Duck Disease Caused by the Toxin of Cl. Botulinum Type C.

Study of the clinical manifestations and the absence of characteristic anatomical findings suggested that the so-called duck disease is the same sickness as Limber neck of chickens. The unknown different symptoms caused by Botulinus in wild and domesticated ducks may be due to the natural habits of these birds. To keep themselves from drowning the water birds stretch their heads backwards. This is of course not necessary in the case of chickens and tame ducks. Furthermore the experiments of Mr. Kalmbach refuted the theory of a salt intoxication and forcibly indicated the existence of an animated virus.

The theory of Botulinus intoxication was confirmed in a series of experiments to be detailed elsewhere. Cultures prepared from the liver and other organs of sick wild ducks contained a toxic anaerobe. 0.3 to 0.5 cc. from these cultures, administered by mouth or when injected, induced in healthy wild ducks the paralysis of legs, wings and membrana nictitans, respiratory distress and aphonia, strikingly similar to that in naturally diseased birds. In general the autopsy findings are negative with the exception of a dilated rectum filled with accumulated urine. Inoculation of mice revealed the typical symptoms of Botulinus. These experiments proved the identity of the duck disease and the Limber neck of chickens, chiefly produced by Clostr. botulinum Type C, sometimes also by Parabotulinum Type A. Botulinus Type C toxin formed by strains obtained from Limber neck in chickens, Parabotulinum toxin A, and even Type B in larger doses, are experimentally capable of producing the duck disease.

Pure cultures could be prepared without difficulty. The first culture made from a sick wild duck (Williams Lake) contained a coccus and anaerobes. The isolation of the anaerobe was obtained by heating the culture at 80°C. for 3 minutes.