Late cases of toxic oil syndrome: evidence that the aetiological agent persisted in oil stored for up to one year.

The symptoms of toxic oil syndrome (TOS), an epidemic that occurred in central and north-western Spain, developed in the great majority of patients during May or June 1981. We now describe the clinical and epidemiological data of five patients with TOS whose onset of symptoms was considerably later than the great majority of cases. In June 1982, one person became symptomatic as a result of consuming a suspect oil two months earlier. Four members of a family that started consuming a suspect oil in November 1981 became ill in December 1981. These data indicate that the aetiological agent of TOS persisted in stored oil for periods as long as one year. The apparent stability of the TOS aetiological agent increases the likelihood of its continued presence in significant concentrations in oils that have been stored since 1981. Thus, the use of such oils in further in vivo and in vitro toxicological studies may yet lead to the isolation and identification of the causal agent of TOS.