Notes on the Weil-Felix Reaction in Individuals not Suffering from Typhus

In view of the increasing frequency with which the Weil-Felix reaction is being used in the United States for the diagnosis of obscure fevers suspected of Rickettsia origin, and especially because of our own interest in the possibility of latent typhus infection in individuals infected a long time ago, we undertook to carry out a considerable number of Weil-Felix reactions on individuals not at the time suffering from typhus or fevers of any kind, for the purpose of establishing the significance of low titre reactions. We are reporting these briefly because they seem to us helpful in appraising occasional doubtful cases.

The reactions were carried out on sera from several groups of subjects. One group was composed of Jewish out-patients furnished us by the Beth Israel Hospital Clinic in Boston, and in these record was made as to whether the individual was born in Russia or in the United States. Since such information had no significant effect on these observations, we abstain from tabulating it. Another group was composed of non-Jewish subjects, another of routine Wassermann sera in which no attention was paid to the race of the patient; and, finally, a small group of 24 Russian-born garment workers. Table I gives the results.

It will be seen that there was no significant difference between the groups, and it is rather fortunate in protecting us against false conclusions that the actual percentage of positive reactions in the Russian-born garment workers was rather lower than in the other groups.