How can you tell if your child has worms and what tests for parasites are worth doing?
Many parents, observing nonspecific symptoms in their children, wonder how to tell if a child has worms. In Poland, despite improving sanitary conditions, parasitic infestations, especially in young children, remain a significant problem, and knowledge about how to detect parasites in a child remains crucial. If you're wondering which parasite tests are most effective for a child (blood or stool tests?), how to detect the most common parasites in a child, and which parasite test should be performed first, be sure to read the information and tips below.
Where do parasites in children come from and why are they particularly vulnerable to infection?
Preschool and early school-age children (ages 4 to 10) are considered the group with the highest incidence of gastrointestinal parasites . Several factors contribute to exposure to infestations:
🔹 Poor personal and nutritional hygiene:
The primary route of infection is the fecal-oral route. The risk is significantly increased by eating unwashed/insufficiently washed fruits and vegetables, drinking unboiled water, and unwashing hands, especially after playing in high-risk areas such as sandboxes or playgrounds.
Children very often put their fingers in their mouths while playing, which drastically increases the risk of infection.
🔹 Children's environment and communities:
Being in nurseries, preschools, schools, and orphanages facilitates direct contact and the transmission of parasites. For example, pinworms are often considered a disease of people living together or in close proximity.
🔹 Contact with animals and soil:
Both dogs and cats can carry parasites such as roundworm and feline roundworm, and infection occurs by swallowing infective eggs found on dirty hands or objects that children come into contact with.
🔹 Reduced immunity:
Frequent colds and reduced immunity favor parasitic infections.
What parasites do we most often encounter in children?
According to World Health Organization (WHO ) reports and epidemiological studies, Poland is among the countries with a low incidence of parasitic diseases . The most common parasites in our country include:
- pinworm (i.e. disease caused by human pinworms)
- giardiasis (its cause is a protozoan Lamblia intestinalis).
Expert advises
Much less common infections include roundworms and tapeworms, both unarmed and armed. In addition to the gastrointestinal parasites mentioned above, tissue parasites are also quite common in children, such as the human scabies mite, which lives in or on the skin, and, less frequently, Trichomonas vaginalis.
It is worth knowing that the most dangerous tissue parasites in humans are:
- curly hair,
- toxoplasma gondii,
- echinococcal tapeworm.
The least common are the liver fluke and other flukes, as well as the amoeba dysentery.
Searching for "worms": how can you tell if your child has parasites?
Parents often ask questions at the doctor's office: " How can I tell if my child has worms ? What tests should I do: a blood test, or perhaps a stool test for parasites?"
Expert advises
Intestinal parasites pose a diagnostic challenge because their infestation, especially when it's not massive, can be virtually asymptomatic or mildly symptomatic. How can you tell if your child has worms? It's worth emphasizing that many symptoms of parasitosis (parasitic diseases) are nonspecific, so it's a mistake to diagnose a child with parasitic disease based solely on these symptoms, without reliable additional tests, preferably ordered by an experienced physician.
How to tell if your child has worms: non-specific symptoms of parasitosis
However, there are symptoms that, when they occur chronically or coexist, should prompt parents to visit a doctor and perform in-depth diagnostics:
🔹 Weight and development problems:
In children infected with parasites, weight loss was observed approximately 3,2 times more frequently than in healthy children [1]. Long-term infection with human roundworms can lead to inhibition of physical and mental development.
🔹 Neurological symptoms and behavioral changes: How to tell if your child has "worms"?
Some of the characteristic non-specific symptoms may be excessive nervous excitability, restless or disturbed sleep, insomnia, and sometimes even epilepsy-like symptoms that may accompany ascariasis.
Children with pinworms often experience hyperactivity, concentration problems, and sometimes teeth grinding or nail biting (however, these are not the main symptoms that can be used to determine whether a child has parasites).
🔹 Allergies and skin lesions:
The parasites produce substances that can cause severe allergic reactions. Ascariasis may cause hives, itching, swelling, conjunctivitis, or a dry cough.
🔹 Sudden cravings for sweets:
Although most children like sweets, a sudden, persistent demand for simple carbohydrates by a child who was not previously a fan of them may be a sign of a parasitic disease (often downplayed).
How to detect parasites in a child? Reliable parasite tests.
The non-specific clinical picture of most parasitic diseases means that their diagnosis is often based on direct detection of the parasite or its eggs under a microscope.
Expert advises
Enterobiasis is the easiest to diagnose, as in practice, a history may be sufficient to confirm its diagnosis. If giardiasis, ascariasis, or tapeworm are suspected, fresh stool (parasites in the stool of a child) is the material for testing for parasites. In the case of scabies, clinical diagnosis is most common.
Pinworms: how to detect these parasites in a child?
Parents most often report that their child is restless sleeping, fidgeting, and scratching around the anus . They may also report seeing parasites in their child's stool . Adult pinworms reside in the final section of the small intestine and the large intestine. While the child is sleeping or resting, the females migrate to the anus and lay eggs in the mucosal folds, causing itching. How can you tell if your child has these worms ? Your child fidgets, can't sleep, and by scratching, they transfer the eggs to underwear, bedding, the bathtub, the toilet , etc.
Other symptoms of pinworms include: loss of appetite, abdominal pain, nausea, loose stools, and sometimes inflammation of the skin around the anus or vulva and vagina – if eggs were laid in these places.
Pinworms: what test for parasites in a child?
The infection can be easily confirmed by taking a swab from the anus using cellophane tape (the swab is usually prepared by a laboratory – it consists of a spatula with cellophane tape applied to the end, with glue on top).
Expert advises
The sample should be collected in the morning, after getting out of bed, using adhesive tape, which is then applied to the skin around the anus and then placed directly on a microscope slide (or sent directly to the laboratory). The swab is usually repeated three times – every other day – with laboratory testing possible later. What about stool testing if we have observed parasites in the child's stool? Microscopic examination of stools usually does not reveal pinworm eggs.
Note: Banana fibers found in a baby's stool can sometimes be very distressing for parents because they resemble worms , but they are usually dark in color, which distinguishes them from pinworms, for example. Moreover, unlike worms , they are immobile.
Pinworms: what if parasites are detected in a child?
When a child is diagnosed with enterobiasis, the entire family should be treated.
Expert advises
Parasite eggs spread easily (a toddler can scratch them and transfer them to bedding, clothing, toilets, food, toys, etc.), and they retain their infectious properties for a long time—as much as three or four weeks. Maintaining good hygiene is crucial: scrubbing and trimming nails, changing bedding frequently, boiling towels, and ironing underwear with a hot iron. Treatment with available antiparasitic medications is effective within 1–2 days of initiating therapy (i.e., the time between drug administration and its reaching the large intestine). The patient then ceases to be contagious, so there is no need to limit the toddler's contact with other children.
Giardia: what tests should be done to detect these parasites in a child? Parasites in feces
Giardia and other protozoa are particularly sensitive, so for their detection, a stool sample should be quickly delivered to the laboratory . The stool should be collected in a dry, clean container. Typically, a walnut-sized stool pellet or 1-2 ml of liquid stool is collected. Ideally, a child should be tested for parasites as soon as possible after the sample is collected. If this is not possible, the collected material should be stored at 2-8°C, but no longer than 24 hours. In the diagnosis of giardiasis:
- You can search parasites in the child's stool (cysts and adults), but it is recommended antigen detection Giardia Lamblia method enzyme immunoassay or DFA (direct immunofluorescence method, which is the gold standard in the diagnosis of the disease);
- Another way to do this, how to detect te parasites in a child, is examination of duodenal contents for the presence of trophozoites i examination of a biopsy of the small intestine and/or duodenal contents for the presence of DNA Giardia Lamblia by the polymerase chain reaction (PCR) method.
Once a child is diagnosed with labialis, treatment should be extended to all family members living with the child.
Roundworm. How can you tell if your child has worms?
When suspecting ascariasis, it is worth knowing that the source of human roundworm infection is food or soil (geophagy in children) contaminated with roundworm eggs, while fresh eggs do not pose a threat to other people.
Expert advises
To become capable of infecting the worm, roundworm eggs require maturation in an oxygenated environment at a temperature of approximately 25°C for approximately three weeks. After this time, they become resistant to environmental factors and disinfectants, remaining invasive for many years. This means that an infected person poses no direct threat to others . Therefore, in the case of ascariasis, the common practice of deworming all people living with an infected person is unjustified, unlike in cases of diagnosed giardiasis.
How can you tell if your child has these worms ? The basis for diagnosing ascariasis is the detection of adult roundworms or eggs in the stool (parasites in the stool of a child) . However, it's important to remember that this test can yield false negative results if the worms in the intestine are young and sexually immature (or too old).
How to detect parasites in a child: other tests that are worth doing to check for the presence of roundworms
In certain clinical situations, imaging tests may be helpful in diagnosing ascariasis (ascariasis is the largest human parasite, reaching up to 32 cm in length) :
- X-ray of the abdominal cavity after oral administration of a contrast agent (if a massive roundworm invasion is suspected),
- Chest X-ray (Löffler's infiltrates during larval migration),
- abdominal ultrasound examination (e.g. in ascariasis of the biliary tract).
The prognosis for recovery is good. It's worth knowing that roundworms live for a maximum of two years and do not reproduce in the human body (i.e., their numbers do not increase).
Scabies: What tests for these parasites should be performed on a child?
Scabies, which is becoming increasingly common among children, is usually diagnosed clinically, based on the appearance of intensely itchy papules, vesicles, and pustules, most often located on the fingers, wrists, nipples, genitals, and also on the abdomen and buttocks. The epidermis surrounding the lesions is sometimes thickened, and secondary bacterial infection can occur in these areas . Diagnosis is confirmed by microscopic examination of a skin scraping , usually performed by dermatologists.
The treatment is carried out locally under the supervision of a doctor, after which it is necessary to change clothes, bed linen and towels.
Is it worth doing a blood test for parasites for children, and if so, what kind?
Parents sometimes ask what blood tests are recommended to confirm a parasitic infection? And if a parasitic infection is confirmed, what blood tests will confirm the effectiveness of the treatment?
However, the usefulness of a blood test for parasites is very limited. The primary way to detect a parasitic infection, as mentioned, is to detect the presence of parasites, their developmental stages, or eggs in the stool ( parasites in feces in children ), urine, duodenal contents, or other biological material from the patient.
What blood test might suggest a child has parasites? Sometimes, the finding of eosinophilia , or an increase in the number of eosinophils (eosinophils) in the peripheral blood above the normal range, can lead us to suspect an invasive disease, such as giardiasis, ascariasis, or trichinosis.
Blood tests for parasites: serological tests
The usefulness of serological tests (serological blood tests) is limited to the diagnosis of tissue invasions (toxocariasis, cysticercosis, trichinosis, and echinococcosis), where specimens are difficult to obtain. Blood tests for parasites, such as serological tests performed for giardiasis or ascariasis, are used only to assess population exposure to parasites in epidemiological studies. However, they are not useful in diagnosing these infections in individual patients, as they do not allow for the distinction between active and past infections , as specific antibodies persist in serum for years.
Expert advises
Blood tests suggesting parasitic infections, i.e., serological methods, also have low sensitivity, produce cross-reactions, and the specific antibody titer may be influenced by the child's age and hydration status. Furthermore, it's important to remember that improper sample preparation can lead to false results (both negative and positive). Serological test results also don't answer the question of whether, for example, ascariasis was successfully treated.
How to detect parasites in a child: observing symptoms is key
Parasitic infections in children can be successfully treated, but it's important to know what symptoms they may present and which ones should be considered. If in doubt, consult a doctor to confirm or rule out your suspicions.
At this stage, the doctor will indicate what additional tests for parasites should be performed on the child to detect their presence in the body and then initiate effective treatment.
Bibliography (internet sources available as of October 2, 2025):
- Dobkiewicz D., Rembowska-Wachowska M. (1956). Studies on the effectiveness of piperazine in the treatment of helminthiasis in children and adults. Parasitological News, 5 (Supplementum), 126.
- Practical medicine, Parasitic diseases of the gastrointestinal tract, part I and II, dr hab. n. med. Ernest Kuchar (Clinic of Pediatrics with the Observation Department of the Medical University of Warsaw), dr n. med. Jolanta Popielska (Clinic of Pediatric Infectious Diseases, Medical University of Warsaw);
- Biadun W., Chybowski J., Rukasz H., Stanios H. (2001). The occurrence of intestinal parasites in children in the Lublin macroregion in the years 1976–2000. Parasitological News, 47(3): 417–422
- Bitkowska E., Wnukowska N., Wojtyniak B., Dzbeński TH (2004). Analysis of the occurrence of intestinal parasites in first-grade children in Poland in the 2002/2003 school year. Epidemiological Review, 58(2): 295–302. Available online: https://www.przeglepidemiol.pzh.gov.pl/pdf-179179-99778?filename=Analiza%20wystepowania.pdf
- Golińska Z., Lach J., Bany J., Chaś J. (1997). The occurrence of intestinal parasites in children in four Warsaw kindergartens in 1994–1996. Epidemiological Review, 51(4): 411–416. Available online: https://www.przeglepidemiol.pzh.gov.pl/pdf-178729-99339?filename=Occurence%20of%20intestinal.pdf
- Hadaś E., Derda M. (2014). Parasites – a still present threat. Problemy Higieny i Epidemiologii, 95(1): 6–13. Available online: http://www.phie.pl/pdf/phe-2014/phe-2014-1-006.pdf
- Kaleta P., Palacz-Wróbel M., Chajec Ł. (2018). The incidence of helminthiasis in preschool children – identification of predisposing factors. Medycyna Rodzinna, 21(4): 315–321. DOI: 10.25121/MR.2018.21.4.315.
- Popielska J., Marczyńska M. (2013). Gastrointestinal parasitic infections. Medical Standards/Pediatrics, 10: 474–479.
- Rembowska-Wachowska M. (1956). Studies on the role of intestinal parasites in the behavior of the "weight curve" in children of different ages. Wiadomości Parasitologiczne, 5 (Supplementum): 40–110.
- Smejda K., Karczmarek-Woźniak J., Olszowiec-Chlebna M. et al. (2008). Assessment of the relationship between parasitic infestation and the occurrence of atopy in children. Pediatria Polska, 83(5): 485–489. DOI: 10.1016/S0031-3939(08)70211-7.
- Złotorzycka J., Okulewicz A., Kruzel B. (1986). Parasitic invasions in children's environments based on the example of a selected Social Welfare Home for handicapped children and a municipal kindergarten. Parasitological News, 32: 83–92.
Medical consultation
Medical consultation
