Trichinosis surveillance, United States, 1987-1990.

Since the Public Health Service began recording statistics on trichinosis in 1947, the number of cases reported by state health departments each year has declined. In the late 1940s, health departments reported an average of 400 cases and 10-15 deaths each year; from 1982 through 1986, the number declined to an average of 57 cases per year and a total of three deaths for the period. From 1987 through 1990, 206 cases of trichinosis from 22 states, including 14 multiple-case outbreaks, were reported to CDC. In 1990, two large outbreaks associated with commercial pork accounted for 106 cases. In the 192 instances in which a suspect food item was identified, pork was implicated in 144 (75%) cases, walrus meat in 34 (18%), and bear meat in 14 (7%). Sausage, the most frequently implicated pork product, was associated with 128 of the 139 cases for which a form of ingested pork was specified. Before 1990, the proportion of cases of trichinosis attributable to consumption of commercial pork had declined steadily. This decline was probably due to a combination of factors, including laws prohibiting the feeding of garbage to hogs, the increased use of home freezers, and the practice of thoroughly cooking pork. Although the incidence of trichinosis has decreased substantially since national reporting was initiated in 1947, a dramatic increase in 1990, resulting from two large outbreaks, emphasizes the need for further education and control measures.