Ascariasis: what are the symptoms? Understand the life cycle

You have probably heard of this disease, either by the name ascariasis or by roundworm, as it is popularly known by most people.

Around diseases like these, caused by worms, many myths arise, such as the idea that the disease causes the child to desire sweets and other treats.

In order to have an idea of ​​the incidence of the disease, in 2008, the World Health Organization (WHO) registered more than 980 million cases of people infected by the parasite in the world, with school children being the most affected.


What is Ascariasis?

Ascariasis, popularly known as roundworm, is a verminosis caused by the parasite Ascaris lumbricoides . It is one of the most common infections transmitted through contact with worm eggs, which are excreted in the patient’s feces.

This is a transmission considered fecal-oral, since other people only contract the disease in contact with eggs, that is, feces.

Thus, in regions where there is no basic sanitation, where feces are used as manure or when the person has poor personal hygiene, food and water can become contaminated and the disease is transmitted.

Upon contact with the organism, eggs are released into the patient’s stomach and there begins the cycle of the disease, in which, upon entering the bloodstream, the larvae pass through the lungs and then return to the small intestine, where they reach the adulthood.

There, females produce up to 200,000 eggs, which are released into human feces.

In many patients, the disease does not cause symptoms. However, it can cause pain in the abdominal area, nausea, vomiting, intestinal obstruction and bloating. In untreated cases, it can cause complications.

The best way to prevent this disease is through personal hygiene measures.

In the International Classification of Diseases, ICD-10, ascariasis is found by the code B77 and in the segments:

  • B77.0 – Ascariasis with intestinal complications;
  • B77.8 – Ascariasis with other complications;
  • B77.9 – Ascariasis , unspecified

Ascaridíase e ancilostomose

Like ascariasis, hookworm (also known as hookworm or yellowing ) is also a disease caused by parasites that settle in the human intestine. It is another verminosis among others such as schistosomiasis , filariasis, amoebiasis , teniasis, geographic bugs , giardiasis and oxyurosis.

Unlike ascariasis, which is caused by Ascaris lumbricoides , hookworm is caused by Ancylostoma duodenale or Necator americanus .

These worms can enter the person’s body by penetrating the skin, when he walks barefoot in the contaminated soil, for example.

Therefore, it has as symptoms skin irritation, belly pain, diarrhea and anemia , the latter being one of the most characteristic of the disease.

Anemia caused by worms in the intestine leaves the patient with a more yellowish tone on the skin or with pallor.

Causes: etiologic agent

The cause of ascariasis is infection with Ascaris lumbricoides, a parasitic worm popularly known as roundworm. These worms are considered to be macroparasitic, as they can be seen with the naked eye and are normally lodged in the patient’s intestine.

As adults, these worms can reach a size between 15 and 35 centimeters. These worms are 0.25cm to 0.5cm in diameter. In hosts (in this case, humans), they can live between 1 and 2 years.

Upon reaching the intestine, the larvae undergo a maturation process until they reach this size, which can take 2 to 3 months.

As adults, females produce eggs in abundant quantities, reaching up to 200,000 eggs per day. They are excreted in the faeces and pose a risk of infection to others when they come into contact with soil, water or food.

Read more: Infections in childhood may increase the risk of mental disorders

Transmission: how do you get ascariasis?

Ascariasis is not a disease transmitted directly from one person to another, being acquired through the ingestion of contaminated food and water that may have come into contact with the soil or with human feces, where there are the worms’ eggs.

Therefore, it is more common in areas with poor basic sanitation. In the soil, eggs can survive for years, especially on damp surfaces and at the appropriate temperature.

For this reason, children are often the most affected, due to the risk of playing in contaminated soil or of bringing infected objects to their mouths.

Life cycle of Ascaris lumbricoides

The parasite responsible for causing this disease, Ascaris lumbricoides , has a life cycle, in which it is possible to better understand how the infection happens and how it is possible to prevent it in order to reduce the number of cases of the disease.

This cycle starts at the point where the parasite’s only host is man. In the human body, they normally live in the small intestine. In this region, females produce eggs that will be excreted in the faeces. The number of eggs produced per day is high, about 200 thousand eggs.

The eggs released in the feces of the infected person, when in contact with the soil, are fertilized and grow there.

It is at this point that the risk of infection happens. In contact with these eggs, often present in water or food that had contact with the feces, is that a new infection can occur, through fecal-oral transmission.

Through the digestive system, therefore, the eggs come into contact with the organism and the larvae of the parasite present in the eggs hatch in the intestine.

Larvae invade the bloodstream as they pass through the intestinal wall and, consequently, reach the heart and lungs. When this happens, it is called the lung cycle.

In this phase, they can cause symptoms similar to a picture of pneumonia . Subsequently, they pass through the alveoli (pulmonary structures responsible for gas exchange) and travel to the respiratory system and the throat, where they are swallowed and go to the intestine.

In the intestine, the larvae develop and grow. They can reach a length that varies from 15 to 35 centimeters as adults. Generally, male parasites are smaller than females.

A person may have a very high number of parasites in the small intestine, but they are not able to cause infection, only eggs.

It is also known that Ascaris, as adults, do not multiply within the intestine. Thus, for a person to have an increasing number of worms in the intestine, it is necessary that he ingests new parasite eggs.

When this does not happen, the worms present in the infected person tend to die within 2 years and, thus, the person is no longer contaminated.

However, it is not common to happen due to constant exposure to risk factors. That is, the person usually remains in contact with infected soil or environments, prolonging the cycle.

Risk factors for ascariasis

The groups most vulnerable to infection caused by Ascaris lumbricoides are those who live in regions with poor basic sanitation, who have inadequate personal hygiene or who live in places where human feces can be used as fertilizer.

Read more: Lack of hygiene and sanitation affect 1 in 4 health centers

Other factors that are associated with the disease are heat and humidity. For this reason, regions that fit within this profile are also considered to be at higher risk for the disease.

Children are also considered a risk group, due to the high rate of infection due to the lack of incentive to personal hygiene.

Symptoms of ascariasis

The manifestation of symptoms may vary for each patient and depends on the stage of the disease. Some people are asymptomatic, others have characteristic signs of infection. When the larvae enter the bloodstream and reach the lung, the symptoms are similar to a picture of pneumonia.

Symptoms in lung infection

At that time, when the parasites reach the lungs through the bloodstream, the patient with ascariasis may experience fever , cough , sputum (with blood in some cases) and difficult breathing.

Pain and swelling

Within the cycle of the disease, after lung infection, roundworms lodge in the intestine. It is common for patients to experience discomfort in the abdominal region and swelling due to the presence of the parasites.

Nausea and vomiting

It is common in people with ascariasis to feel sick and vomit due to the presence of parasites.

Intestinal obstruction and worms in the stool

When there is a very large number of parasites in the patient’s intestines, a kind of skein can form that causes intestinal obstruction.

This condition generates a lot of pain and swelling in the patient, in addition to impairing digestion and absorption of nutrients.

A more visible sign of the disease that can also occur is the presence of eggs and worms in the stool.

Other symptoms

In some cases, parasites in adulthood migrate to the patient’s nose and mouth, in a very uncomfortable and agonizing situation. Infected children may not grow or gain weight normally.

How is the diagnosis made?

The diagnosis of ascariasis can be made by a general practitioner , but also by infectologists or gastroenterologists . To confirm the disease, in addition to the doctor analyzing the symptoms, he can order a stool test to see if there are eggs of Ascaris lumbricoides .

One of the disadvantages of the diagnosis made through the examination of feces is that the eggs are only present about 40 days after the contamination of the patient.

Therefore, diagnosing the disease early on is more difficult.

However, in a more advanced stage, it is possible to detect the eggs of this worms.

In some cases, worms can be eliminated through the mouth and feces as well. In such cases, it is important for the patient to collect the worm to take to the doctor for a laboratory examination.

Can ascariasis be cured?

Yes , but you can return. Even after medication to eliminate the infection, worms and eggs, the patient may have the disease again due to resistance from one of the eggs or by reinfection, since the environment in which the person lives is one of the risk factors.

How is the treatment done?

The treatment of ascariasis is done through the guidance of the use of vermicide medications, with the active ingredients Mebendazole, Ivermectin or Albendazole.

In some conditions, these drugs are contraindicated, due to the risk of complications or side effects that they can cause. This is the case of pregnant women, who should not take it when the doctor understands that there is a risk of causing complications in the fetus.

Intestinal obstruction caused by worms can occur in some patients with ascariasis.

In not-so-severe cases, treatment is done with medication, but when the amount of parasites causes a more severe obstruction, surgery or endoscopy for removal may be necessary.

It is important that after the diagnosis of the disease, the patient’s family members also perform tests to confirm that they have also been infected. In addition, it is recommended to perform further stool tests after 3 months of treatment.


The Albendazole is a single dose of medicament intended for adults at a dose of 400g / day. For children, the recommendation is to be 100mg / day. It can be taken for 1 to 3 consecutive days.

The Mebendazole , however, is a drug used 2 times daily for 3 consecutive days. The dosage is 100mg regardless of the patient’s age or body weight.

Medicines that contain Ivermectin , on the other hand, consider the patient’s weight and age to determine the appropriate dosage for treatment. Therefore, they should be taken according to medical advice.


NEVER self-medicate or stop using a medication without first consulting a doctor. Only he will be able to tell which medication, dosage and duration of treatment is the most suitable for his specific case. The information contained on this site is only intended to inform, not in any way intended to replace the guidance of a specialist or serve as a recommendation for any type of treatment. Always follow the instructions on the package insert and, if symptoms persist, seek medical or pharmaceutical advice.


The prognosis of ascariasis, when there is an early diagnosis and adequate treatment, is positive. However, when the disease progresses to the point of having a very high number of worms in the body, the prognosis may not be as good, as the risk of complications is greater.

The production of new eggs is very high, which is a risk for the infected person. In addition, the parasites can reach a large length and reproduce to the point of causing an intestinal obstruction.

Can you have complications?

In most infected people, ascariasis does not cause complications and, in some cases, does not even show symptoms.

However, some people may have a more aggravated condition due to these parasites, especially when they reproduce in large quantities in the patient’s body.

The main complications of this disease include:

Bowel obstruction

When worms proliferate, they form a kind of ball in the patient’s intestines. Thus, the passage of food and liquids through the region is impaired, also causing constipation, swelling and discomfort.

In more severe cases, when the patient does not receive treatment, this blockage of the intestine can cause a necrosis in the obstructed region, causing more serious health problems.

Throat obstruction

In addition to intestinal obstruction, patients with ascariasis can suffer from blockages in the throat, as the larvae pass through the lung during the cycle in the body. In this situation, the patient may experience suffocation.

Intestinal perforation

Roundworms can cause holes in the intestine, resulting in constant pain and bleeding.


It is an inflammation that affects the gallbladder, an organ in which bile (fluid produced in the liver) is stored.

This disease is usually caused by stones that cause obstruction in the tube that connects this vesicle to the small intestine.

In the case of patients with ascariasis, inflammation occurs due to the presence of parasites in the region. In this type of complication, the patient has severe pain and swelling in the upper right part of the belly, requiring surgery to remove the worms.

Acute pancreatitis

The pancreatitis , acute is an inflammation of the pancreas. It is a complication of ascariasis when the parasites spread through the body, reaching this gland.

Nutrient malabsorption

Much of the nutrients we acquire through food are absorbed in the small intestine. In ascariasis, the presence of worms can cause impairment in this absorption, leaving the patient lacking iron and vitamins , for example.

Prevention: how to prevent ascariasis?

Preventing this disease is simple, but not all measures are the patient’s responsibility, such as having a quality basic sanitation system. Fortunately, there are several other habits that help to reduce the risk of infection that people should adopt.

The main ones are:

Have good personal hygiene

One of the main ways of prevention is to maintain the habit of washing your hands thoroughly with soap and water, especially before preparing food, after going to the bathroom or having contact with animals.

Whether living in risky areas or not, this custom helps prevent this and other infectious diseases.

Be careful with food

It is important to wash and cook food very well.

If possible, avoid products that may have come into contact with contaminated soil, such as those planted in regions where pig or human feces are used as manure.

Read more: Food in childhood: what to know

Encourage new habits in children

Because they are one of the most affected groups, it is essential to teach and encourage children to always wash their hands and not put them in their mouths, to avoid this and other diseases.

Children who live in rural areas and are in contact with animals, such as pigs, should be supervised to avoid putting their hands in their mouths.

Common questions

Which specialist to look for to treat ascariasis?

In the primary diagnosis, a general practitioner can guide the patient to treatment. However, in cases of complications, other specialists can monitor the condition, such as infectious disease doctors, pulmonologists and gastroenterologists.

What is the period of transmissibility of ascariasis?

As long as the parasites are producing eggs and they are released into the feces, the disease can be transmitted. Therefore, this period is long when the patient does not receive treatment.

Considering the fact that the females of the parasites produce about 200 thousand eggs per day and the average life span of the worms is 12 months, it is known that the transmissibility of the disease is long.

In addition, under favorable conditions, these parasites can live for years on the ground.

What is the incubation period?

Outside the host, the incubation period for Ascaris lumbricoides eggs until larvae develop is about 20 days. In the infected person’s body, the time from infection with the embryonated eggs to the presence of the larvae in the feces can vary from 60 to 75 days.

What form of ascariasis is contagious?

Contagion happens when a person comes into contact with the parasite’s eggs, which are eliminated in human feces. It is a disease resulting from fecal-oral transmission, associated with the ingestion of food and water contaminated with eggs, often eliminated in the soil (planting).

Ascariasis, or roundworm, is one of the most common infections that affect the intestinal region. Although it is easily prevented with personal hygiene measures and is rare in places with quality basic sanitation, it is still a risk for many people who live in places with poor hygiene conditions or who use feces as fertilizer.

Therefore, it is important to reinforce the risks that the disease can bring and how it is possible to prevent it. Thanks for reading this far and share this information with more people!