Trichinellosis and trichinellosis control in Germany.
In nineteenth century Germany, trichinellosis was a relatively frequent disease. From 1861 to 1890 more than 12,500 cases, with an average mortality rate of 5%, were reported. As a consequence, trichinoscopy was made compulsory for the kingdom of Prussia in 1877, and a respective law was issued on June 3, 1900, for Germany as a whole. This measure led to a considerable decrease in human trichinellosis, reaching a minimum of only 49 cases for the period 1931-1940. The decrease in human cases was correlated to a constant decline of prevalence in pigs. However, after World War II, ten epidemics of human trichinellosis occurred with a total of about 2,000 cases. Sources of infection were illicitly slaughtered pigs, minced pork and sausages of partly unknown origin, and uninspected wild boars (Sus scrofa). Today, besides pigs, wild boars can be regarded as main sources of human infections. During the last two decades, two positive wild boars have been detected every year, thus demonstrating that a sylvatic cycle still exists. Measures to control trichinellosis in Germany have been limited to meat inspection. Before 1978 the only method allowed was trichinoscopy of compressed muscle samples. Then the pooled sample digestion technique and the magnetic stirrer method were introduced, which was later improved and automatized by use of the Foss Electric Trichomatic 35 and of the GMP 50 as a sampling device.