Threadworm infection can often go unnoticed because there are often no symptoms of the condition. This makes treating the condition and eradicating the worms more difficult, as people can unknowingly continue to spread the infection.

Some of the symptoms of threadworm infestation include:

Itching around the anus, bottom or vagina

Itching is usually worse at night and may interfere with sleep. The itching is caused by a special mucus that is secreted by the worms alongside the thousands of eggs they lay. The worms lay an average of 11,000 eggs and if a person's scratches the itchy area the eggs can easily stick to the finger tips or the underneath of the fingernails from where they may be ingested if a person bites their nails or sucks a finger. Alternatively, a person may touch surfaces with their infected fingers, contaminating various objects that an uninfected individual may then touch.

Threadworms are small and white and resemble pieces of thread which may be visible around the anus or in stools. The worms may also be seen on bed clothes, bed linen and towels, for example.

The infestation is often symptom-free however over time, the infection may cause weight loss and loss of appetite. Repeated scratching of the bottom and around the anus may cause a bacterial infection around the anus and vagina. Bedwetting may also be seen.

Insomnia may develop and in very rare instances, the worms can also spread to the vagina and reproductive tract in females or to the urinary tract, kidneys and liver.