The prevalence of infection remains high, even in well-managed animal colonies. Pinworm burden in an infected rodent population is a function of age, sex, and host immune status. In enzootically infected colonies, weanling animals develop the greatest parasite loads, males are more heavily parasitized than females, and pinworm numbers diminish with increasing age of the host. While infections are usually subclinical, rectal prolapse, intussusception, fecal impaction, poor weight gain, and rough coat have been reported in heavily infected rodents, although generally without adequate exclusion of other pathogens. Very heavy parasite loads may lead to catarrhal enteritis, liver granulomas, and perianal irritation.
Immunity is probably mostly humoral, as for many other helminthiases.
There are a few reports documenting the effects of pinworms on research. Pinworm infection resulted in significantly higher antibody production to sheep erythrocytes, reduced the occurrence of adjuvant-induced arthritis, and impaired intestinal electrolyte transport. While many consider pinworm infection irrelevant in laboratory rodents, specific research goals may justify the eradication of pinworms from an animal colony.