foci

C. G. Jungの "Modern Man in Search of a Soul" を読んでいます。
第11章 'Psychotherapists or the Clergy' から引用します。
The cause of a neurosis lie in the present as well as in the past; and only a still existing cause can keep a neurosis active. A man is not tubercular because he was infected twenty years ago with bacilli, but because foci of infection are still active today. The question when and how the infection took place are even quite irrelevant to his present condition.

医学用語の様な "foci" を辞書で調べます。 "foci" は良く知っている "focus" の複数形だと分かりましたが、それでも引用文の意味は焦点では合わない。辞書をよく見ると "focus" に次の意味がありました。

・Oxford English Dictionary: Medicine The principal site of an infection or other disease.: Multiple foci of infection, several millimeters in diameter, were seen in many organs.
・Collins Dictionary: pathology the main site of an infection or a localized region of diseased tissue: The most common dental procedures were restorative treatment, preventive treatment and removal of infectious foci.