Diagnostic test for roundworm infection

This is an automatically translated article.

The article is professionally consulted by Master, Doctor Tran Thi Vuong - Doctor of Microbiology - Laboratory Department - Vinmec Hai Phong International General Hospital

In fact, all of us can get roundworm during contact with water, food containing roundworm eggs, or using contaminated hands to hold food directly into the mouth. When entering the body, the worm larvae will move from the intestine to other locations, then return to the intestine and lay eggs. To find and detect ascariasis, the doctor will give the patient a stool test for ascaris eggs or a blood test for IgM and anti-ascariasis IgG antibodies.

1. Learn about roundworm disease

Ascariasis is an infection caused by parasitic worms in the intestines of humans. The adult roundworm, called Ascaris lumbricoides, has a large, round, tubular body that can be easily seen without a microscope.
Size of female roundworms can be 20-30 cm long, male worms are 15-20 cm, pale pink or milky white. Roundworm Ascaris lumbricoides lives parasitically in the small intestine of humans, ingesting nutrients when the body is loaded.
Female roundworm reproduces very quickly, about 240,000 eggs/day in the small intestine. Worm eggs develop and become infectious when excreted in the feces into the environment. Roundworm eggs go out in the feces. When living in the outside environment, factors from temperature, light, humidity, air... will make roundworm eggs develop quickly. After a while, the embryo develops into a larva. Worm eggs survive in the summer for about 3 months, at lower temperatures this time is longer. Ascariasis eggs are able to survive at temperatures as low as -12 degrees Celsius. Worms eggs live for a few seconds at 50 degrees Celsius and are killed at 60 degrees Celsius. Humidity above 80% is the most favorable for eggs develop. Worm eggs are easily destroyed in the sun and dry.
Conditions that determine the transmission of roundworms are climate, sanitary conditions, living habits and exposure to contaminated soil contaminated with human faeces. Ascariasis develops in tropical and temperate countries, with a higher prevalence in rural areas than in urban areas. Children are more infected with roundworms than adults.
Route of transmission: through food - when the feces of an infected person containing roundworm eggs are discharged into the environment or the feces of a person containing roundworm eggs are used as fertilizer for soil or crops, the eggs will be contaminated into the soil. and water, which can easily be unknowingly passed on to others. Therefore, using contaminated hands or eating undercooked vegetables, fruits that have not been washed or peeled carefully will increase the risk of disease.
People swallow worm eggs, when reaching the small intestine, the eggs hatch to release the larvae, the larvae pass through the intestinal wall into the blood, move to the lung alves and grow up in the lungs, then the larvae go up the trachea and are swallow back into the stomach. In the small intestine, the larvae develop into adult roundworms. The time from ingestion of larval eggs to the first symptoms of worm infection in the lungs is 5-14 days. The time from when a person swallows eggs with larvae to when the adult worm lays eggs is about 45 to 60 days.

2. Symptoms of roundworm infection

Ascariasis usually has no specific (typical) clinical symptoms. The disease is common in children. When infected with roundworms, the patient's body may appear the following symptoms:
Body fatigue Loss of appetite, bloating or abdominal pain Diarrhea or constipation Seeing roundworms in stool Long-term worm infection leads to to poor physical development due to nutritional absorption disorders, which reduces the development of intelligence and height and weight of children. Severe and acute symptoms when the body is infected with large numbers of worms:
Vomiting. An infected person may vomit worms. Severe worm infections can cause intestinal obstruction, which is common in children. Severe abdominal pain in acute conditions caused by stray worms (intestinal volvulus, intestinal perforation, acute appendicitis, ..). Jaundice due to biliary obstruction when worms enter the bile ducts. Infected people can have bile duct obstruction, liver abscess, and acute cholecystitis. The larval stage in the lungs will cause the patient to wheeze.

3. How to diagnose roundworm infection

3.1 Stool examination The standard method is microscopy, which looks for roundworm eggs in the stool.
Diagnosis when worms or worm eggs are found in the stool Test by direct fecal examination for worm eggs on a microscope. With adult roundworms can be found and clearly seen in the stool or in the anus during defecation. 3.2 Eosinophilia test Eosinophil count is determined through total peripheral blood analysis. During the period of infection with roundworm larvae, eosinophils are often elevated, when the stage of ascariasis mature, eosinophils will not increase or white blood cells decrease to normal.
3.3 Blood test for antibodies By immunoassay, find out IgG, IgM antibodies. IgG, IgM are antibodies present in serum, blood is taken from patients for testing.
IgG antibodies are produced during the migration of roundworm larvae into the body's circulatory system. Time to appear IgM antibodies after larvae enter the body from 3-4 weeks, IgG appears later about 4-5 weeks after swallowing food or drinking water containing larval eggs. After infection, the amount of IgM antibodies disappears quickly, and IgG antibodies stay in the body longer than IgM, an average of 6 months to 1 year, maybe even longer.
For testing for antibodies in the serum, there are now immunologically determined kits that use secreted antigens from larvae.
3.4 Diagnostic imaging techniques such as: ultrasound, x-ray, MRI, CT-scan Doctors based on symptoms and diagnosis to assign appropriate tests. We can see the appearance of adult worms on imaging.

4. How to prevent ringworm disease effectively?

To prevent ringworm disease, you should take the initiative to do a few things:
Wash your hands before eating and after going to the toilet Follow the slogan: Eat cooked, drink hot Bath, anal hygiene Clean, daily Drink deworming medicine periodically. Clean items, clean and cool house. When there are abnormal signs mentioned above, it is necessary to quickly go to medical facilities for timely examination and detection.
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