Meanings of unknown malady in English

A larger man guided his steps; a repellent hulk whose bluish face seemed half eaten away by some unknown malady.

After her death, the doctors, in the hope of discovering the cause of this unknown malady, had begun to dissect that fair form-

His sister Drusilla, whom, as Suetonius tells us, he already treated as a lawful wife, died suddenly of some unknown malady while still very young.

"Quite the contrary, Absolom," said a heavyset, older gentleman, his back twisted with some unknown malady.