Clinical signs are usually seen in pigs 2 to 5 months old and manifest as poor weight gains rather than any obvious effects. Important epidemiological factors include the fact that female worms may produce as many as 1 to 2 million eggs per day and these eggs are highly resistant to drying because of the thick egg shell. It is believed that these eggs can survive for as long as 5 years. Occasionally you may see reports of transient infections of A. suum in ruminants particularly if cattle are grazed where pigs have previously been. In addition A.suum is a zoonosis and can infect humans but the infections do not become patent.
Diagnosis is by detecting the distinctive egg in the feces of infected animals.