Intestinal worms are internal parasites that inhabit the digestive tract, feeding off their host. While various types of worms can affect humans, threadworms are the most prevalent in Australia, often leading to an itchy anus and visible redness or scratch marks. Transmission typically occurs through the ingestion of worm eggs. Diagnosis is commonly made through laboratory analysis of stool samples, and treatment involves antiparasitic medications designed to eliminate the worms without harming the individual.
Types of Intestinal Worms
Several types of worms can infect humans. In Australia, common intestinal worms include:
- Threadworms (Enterobius vermicularis): These are the most frequent cause of worm infections.
- Tapeworms: Including pork tapeworm (Taenia solium) and beef tapeworm (Taenia saginata).
- Whipworms (Trichuris trichiura).
- Hookworms: Such as dog hookworm (Ancylostoma caninum).
- Strongyloides: A type of roundworm.
These organisms are parasites, meaning they live within or on a host organism and derive nourishment from it.
Symptoms of Worm Infections
The manifestation of symptoms can vary depending on the type of worm infection.
Threadworm Symptoms
The hallmark symptom of threadworm infection is an intensely itchy anus. This occurs as the adult female worms emerge from the anus at night to lay their eggs in the surrounding skin folds, causing irritation. In some cases, these small, white, thread-like worms may be visible to the naked eye, particularly when using a flashlight at night, or they might be observed in stool samples during heavy infestations. Children with threadworms can exhibit irritability, disrupted sleep patterns, loss of appetite, and visible redness or scratch marks around the anal area.
Symptoms of Other Worm Infections
Other intestinal worm infections may present with no noticeable symptoms. However, some can cause a range of issues, including:
- Diarrhea
- Fatigue and general weakness
- Abdominal pain
- Unexplained weight loss
- Anemia
Larvae of certain worms, like dog hookworm or Strongyloides, can penetrate the skin and migrate. This migration can result in visible tracks on the skin, known as larva migrans or larva currens, which are often pink or red and accompanied by significant itching. A tingling or prickling sensation may also be felt shortly after the larvae penetrate the skin.
How Worm Infections are Acquired
The mode of transmission differs among various worm types.
Threadworm Transmission
Threadworms are typically contracted by ingesting their eggs. Humans are the sole hosts for threadworms. The adult worms reside in the lower intestine and migrate to the anus to lay eggs. Children who scratch an itchy bottom can transfer eggs to their fingernails, which can then contaminate surfaces such as bed linens, bathroom fixtures, and even food. Threadworm eggs can remain viable on surfaces for approximately two weeks.
Transmission of Other Worms
Several other worm species infect humans when their larvae penetrate the skin, often through the soles of the feet. This is a common way to contract dog hookworm, particularly when walking barefoot on soil or sand contaminated with infected dog feces. Strongyloides larvae also infect humans through skin penetration.
Pork and beef tapeworms are acquired by consuming undercooked meat containing the tapeworm larvae. Similarly, trichinosis can result from eating undercooked or raw pork products. These infections are less common in Australia and are typically contracted overseas.
Dog tapeworms (Echinococcus granulosus) can infect humans who accidentally ingest their eggs, which are shed in the feces of infected dogs or dingoes. These eggs can contaminate a dog’s coat, kennel, and outdoor areas, leading to human infection through contact. Even petting an infected dog can be sufficient to transmit the eggs. Dog tapeworm infection can lead to hydatid disease, a serious condition in humans.
Dwarf tapeworm eggs are ingested directly, and transmission can occur between individuals in areas with poor sanitation. Whipworm infections result from ingesting eggs via contact with contaminated soil or by consuming food grown in such soil.
Dog and cat roundworms can cause toxocariasis, which usually has mild symptoms but can sometimes lead to fever, cough, abdominal pain, and eye damage. This infection is acquired through contact with contaminated feces and soil. Ascaris infection, though rare in Australia and more common in tropical regions, occurs from consuming soil containing Ascaris eggs, potentially causing abdominal discomfort.
Diagnosis of Worm Infections
The diagnostic methods for worm infections depend on the specific type of worm.
Threadworm Diagnosis
A “sticky tape test” is commonly used to diagnose threadworms. This involves applying special adhesive tape to the anal area first thing in the morning to collect any eggs deposited overnight. A doctor or laboratory technician then examines the tape under a microscope for the presence of eggs.
Diagnosis of Other Worms
For other intestinal worm infections, diagnosis typically involves laboratory examination of a fresh stool sample to identify worm segments, eggs, or larvae. Dog hookworm may be diagnosed via a gut biopsy specimen, or inferred from the characteristic rash of larva migrans. Rapidly migrating rashes (larva currens) suggest Strongyloides infection. Some parasitic infections, such as Strongyloides, can also be indicated by an increase in eosinophils, a type of white blood cell, in blood tests.
Appearance of Intestinal Worms
Intestinal worms and their larvae exhibit a range of sizes and appearances:
- Threadworms: Resemble tiny white threads, measuring 2–13 mm in length, and are visible to the naked eye.
- Strongyloides: The larvae are microscopic, while mature worms are about 2–3 mm long.
- Dog hookworm: Adult worms are 12–15 mm long, j-shaped, with a large, toothed mouth. Eggs are microscopic.
- Dog tapeworm: This tapeworm is approximately 6 mm long and has 3–4 segments.
- Pork and beef tapeworms: These are flat and ribbon-like. Adult pork tapeworms can reach 2–7 meters, while beef tapeworms can grow 4–12 meters long. They possess a head, neck, and numerous segments containing eggs.
- Dwarf tapeworms: Measure 2–4 cm in length and 1 mm in width.
- Whipworms: Adult worms are about 4 cm long, with a broad head and a thin tail, resembling a whip.
Treatment of Worm Infections
Treatment for worm infections typically involves medication.
For threadworms, over-the-counter worming tablets are available at pharmacies. It is crucial that all household members are treated simultaneously, regardless of whether they exhibit symptoms, and strict hygiene practices should be followed to prevent re-infection.
Other intestinal worm infections are treated with antiparasitic drugs that target the worms without harming the host. A doctor or gastroenterologist will recommend the appropriate medication and dosage. The dead worms are then usually expelled from the body.
Hydatid disease, caused by dog tapeworm, is a severe condition that can be fatal. It can lead to the formation of cysts in organs such as the liver, lungs, spleen, and kidneys, and occasionally the brain. Surgical removal of these cysts, combined with medication, is often required.
School and Daycare Attendance
Children treated for worms can generally attend daycare or school, provided they do not have loose bowel movements.
Prevention of Worm Infections
Maintaining good hand hygiene and keeping fingernails trimmed short are the most effective measures to prevent threadworm infections.
Most other worm infections in Australia are concentrated in rural and remote areas or among travelers returning from overseas, particularly from tropical or subtropical regions. To minimize the risk of these infections:
- Always wash hands thoroughly after gardening and before eating, drinking, or smoking.
- Wash all fruits and vegetables before consumption.
- Ensure beef and pork are cooked thoroughly.
- Wear shoes when walking on moist, sandy soil or soil that may be contaminated with dog feces.
Responsible pet ownership also plays a role in prevention:
- Wash hands after handling dogs.
- Prevent dogs from consuming dead animals or scavenging.
- Avoid feeding offal to dogs.
- Ensure dogs receive regular deworming treatments.
Resources and Support
For further information on threadworms in children, consult resources from institutions like The Royal Children’s Hospital. For general health advice and information, contact healthdirect Australia at 1800 022 222, where registered nurses are available 24/7. Pregnant individuals, new parents, and caregivers can seek support from Pregnancy, Birth and Baby via phone or video call for maternal and child health nursing advice.
