The cyst wall becomes gradually thicker and eventually calcified. The enclosed muscle cell eventually degenerates and is called a nurse cell. The life span of the larvae is finite because eventually the larvae itself becomes calcified. However, this is a slow process and larvae have been known to remain viable for up to 30 years. Like other members of this order, they have a stichosome, following a short muscular oesophagus.
Females are about twice the length of males with a similarly located anus.
The single uterus is filled with developing eggs in its posterior region, but towards the anterior it has fully developed and hatched eggs. The females are larviparous. The incidence of trichinellosis, particularly in the US and Canada is low, mainly because of the rigorous meat inspection procedures, and the practice of freezing carcases. The occasional outbreaks that do occur, are however frequently fatal. These are usually traced to uncooked meats which are often found in european style sausage made by small backyard butchers, who are often supplied directly from small farms, instead of via the large regulated abattoirs.