Epidemiological and clinical study of grain itch.

Abstract

An epidemic of human infestation by the mite Pyemotes (Pediculoides) ventricosus (Newport) has existed in the midwestern part of the United States for the past two years. Grain itch is the name commonly used to describe the pruritic eruption that the attack of this mite causes in man. Pyemotes ventricosus is ordinarily a parasite of the larvae of various grain destroying insects, and thus it is most commonly found in association with grain or straw. Agricultural workers have been chiefly affected, but industrial workers and others have been attacked through occupational or incidental exposure to infested straw. Pyemotes ventricosus was noted as abundant in the midwestern and eastern sections of the United States over 40 years ago. Schamberg 1 observed cases of grain itch in Philadelphia each year from 1901 through 1910; the source was eventually traced to mite-infested straw mattresses. A number of large epidemics of grain itch occurred