'ascariasis' originates from New Latin, specifically from the genus name 'Ascaris', which ultimately comes from Greek 'askaris' meaning 'intestinal worm'.

'ascariasis' changed from Greek 'askaris' to Latin 'Ascaris' and then to New Latin usage; the English medical term 'ascariasis' developed from that New Latin formation.

Initially it referred to the worm ('Ascaris'), but over time the term came to denote the disease or infection caused by that worm.