Do worms in humans come out at night?

It’s a common myth that worms inside the human body become more active or ‘come out’ at night. However, this is not actually the case. Worms such as pinworms, roundworms, tapeworms and threadworms do not have circadian rhythms or behaviors linked to day/night cycles. Their activity levels stay relatively constant regardless of the time of day.

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What are the most common worms found in humans?

Some of the most common worms that can live inside the human body include:

Pinworms – These thin, white worms live in the large intestine and colon. The females emerge at night to lay eggs around the anus which causes itching.
Roundworms – Long, cylindrical worms that live in the small intestine. Usually spread through contaminated food.
Tapeworms – Flattened worms with segmented bodies. Transmitted by eating undercooked, contaminated meat.

Threadworms – Tiny worms that resemble threads. They burrow into the lining of the large intestine.

Do pinworms come out at night?

Of all the human worms, pinworms have the strongest association with night-time activity. The female pinworms actually do emerge from the anus at night to lay their eggs on the surrounding skin. This is thought to be due to the worm’s attraction to warmth, and the anus is warmer at night when a person is in bed.

So in a sense, yes pinworms do ‘come out’ at night – but only briefly for egg-laying. They spend the majority of their life cycle inside the intestinal tract. The eggs they deposit outside the body cause itching around the anus, which is why pinworm infections often cause worst itching at night.

Pinworm life cycle

The life cycle of a pinworm is:

Eggs are deposited on the skin around the anus at night by the adult female worm.
Eggs become infectious within a few hours.

Eggs are swallowed and move to the small intestine.
Larvae hatch from the eggs and grow into adult worms.
Adult female worms migrate to the colon and rectum to mate.

Pregnant females return to the anal area at night to lay eggs, starting the cycle again.

Do other worms come out at night?

Other than pinworms, there is no evidence that any human worms exhibit increased night-time activity or deliberately ‘come out’ from their residing place inside the body.

Roundworms

Roundworms that infect humans, like Ascaris lumbricoides, live in the small intestine. They do not have a rhythm linked to day/night – they continuously lay eggs that are passed in feces.

Tapeworms

Tapeworms such as beef tapeworms or fish tapeworms reside in the digestive tract. Segments of the worm break off and pass out in feces, releasing eggs. This is not affected by the time of day.

Threadworms

Threadworms such as Strongyloides stercoralis inhabit the small intestine. Larvae can travel to other body tissues. The worms reproduce continuously and eggs are released in feces, day and night.

What causes the myth that worms come out at night?

There are a few reasons why there is a common myth that human worms become more active or ‘come out’ at night:

Pinworms do emerge from the anus at night, which creates the perception that worms in general come out at this time.
Many worm infections cause intense anal itching, which can disrupt sleep at night. This coincidence with night-time itching helps fuel the myth.
Some anthelmintic or ‘deworming’ medications recommend taking the medicine at night or before bed, which also associates worm treatment with night-time.

Fear or unease about parasites can lead to exaggerated ideas like worms coming out while people sleep.

Can you see worms coming out?

In most cases, you will not actually see worms exiting the body. Some exceptions include:

Pinworms – Sometimes pinworm eggs can be visible on underwear or around the anus as small white specks.

Tapeworms – Detached tapeworm segments may be seen in feces or crawl out of the anus.
Threadworm larvae – Larvae emerging from the anus is rare but can occasionally happen.

More often though, infection occurs without any visible signs of worms themselves, just their eggs detected under the microscope.

When are worms most active inside the body?

Worm activity inside the body is not linked to the time of day. However, there are some general patterns of worm behavior that may influence perceptions of night-time activity:

Pinworms mate inside the intestines then migrate to lay eggs at night.
The immune system may be more suppressed at night, allowing more worm activity at this time.

Staying still at night may make sensations from worms moving feel more noticeable.
Intestinal peristalsis slows during sleep, which may affect worm movement.

So while worm activity isn’t inherently greater at night, conditions related to being asleep may make sensations from worms more pronounced at this time.

Can you feel worms moving at night?

It is possible to sometimes feel movement or sensations caused by worms at night, including:

Pinworms crawling out of the anus can cause tickling or itching.
Movement of larger roundworms or tapeworms may be felt in the abdomen.

Blocked intestines from worms can cause cramps or pains at night.
Chewing or trauma from worms may cause discomfort.

However, many worm infections produce no noticeable symptoms. Mild symptoms often go unnoticed during the day but may feel more obvious when lying still at night.

Why do worms itch more at night?

Anal itching caused by worms like pinworms is often worse at night for several reasons:

Female pinworms lay eggs around the anus at night.
Remaining still in bed makes you more aware of itching.

Less distractions at night so itching feels more noticeable.
The anus is warmer at night in bed, stimulating egg-laying.
Scratching during sleep can damage the skin and worsen itching.

While worms themselves do not necessarily itch more intensely at night, circumstances related to night-time allow the itching sensation to feel amplified or more bothersome.

Treatment for worms

Worm infections are typically treated with oral medications called anthelmintics or anti-parasitic drugs. Some common options include:

Mebendazole (Vermox)

Albendazole (Albenza)
Pyrantel (Reese’s Pinworm Medicine)
Ivermectin (Stromectol)

These drugs paralyze and kill worms in the intestines, allowing them to pass out in feces. Sometimes more than one dose is needed to fully clear an infection.

Tips for treatment

Take the medication as prescribed, often an initial dose followed by a repeat dose 1-2 weeks later.
Stay well hydrated to help flush out worm fragments.

Sanitize the bathroom regularly as some worms lay eggs around the anus.
Wash hands thoroughly with soap and water after using the toilet.
Wash underwear and bedding in hot water each day to destroy stray eggs.

Prevention of worm infections

You can reduce the risk of contracting worms through:

Proper handwashing with soap, especially before eating.
Peeling, adequately washing or cooking fruits and vegetables.

Cooking meat to safe internal temperatures.
Preventing contamination of food prep areas.
Not walking barefoot where there may be worm eggs.

Treating pets for worms as they can transmit them to humans.

Conclusion

In summary, the common myth that worms inside humans emerge or become more active at night is mostly false. The exception is pinworms briefly exiting the body to lay eggs. Other worm species reside in the intestinal tract and do not have day/night activity cycles. However, symptoms of worms may feel more pronounced at night when lying still in bed. With treatment and prevention measures, worm infections can be well controlled.