undetected

The terrain is mountainous, with parts covered by thick forests making it easy for migrants to go undetected.

Most cases remain undetected to patients and their doctors alike.

Hepatitis E is a common disease worldwide, but it often remains undetected.

Past studies have shown that the disease often goes undetected in people from lower-income neighborhoods, who may have difficulty finding dermatologists in their area or may struggle to take time off work to attend appointments.

She said "significant errors" made by the hospital and the fact these were undetected for such a long period of time were are "evidence of substandard care and systemic failure".