Ascariasis: Symptoms, Types, Causes and Treatment

Ascariasis remains one of the world’s most common parasitic infections, affecting more than a billion people globally. Despite its prevalence, many people know little about its varied symptoms, types, causes, and the range of treatments available. This article provides an evidence-based, reader-friendly overview of the disease, synthesizing the latest research to help you better understand ascariasis and how it can be managed and prevented.

Symptoms of Ascariasis

Ascariasis is often called a "silent" infection because it frequently produces no symptoms, especially in mild cases. However, when symptoms do occur, they range widely—from mild digestive discomfort to severe, life-threatening complications. Recognizing the signs is vital, especially in children and people living in endemic areas, to prevent complications and ensure timely treatment.

Symptom	Description	Commonality	Source(s)
Abdominal pain	Discomfort or pain in the abdomen	Common in children	1
Nausea	Feeling of sickness or urge to vomit	Frequently reported	1
Bloating	Abdominal swelling or fullness	Common	1
Diarrhea	Intermittent loose stools	Occasionally	1
Malnutrition	Poor growth, weight loss, anemia	In chronic cases	1 10
Cough/Wheeze	Respiratory symptoms (Löeffler’s)	In larval migration	1
Hyperactivity	Increased restlessness in children	Observed	2
Tic disorders	Sudden, repetitive movements/sounds	Observed	2
Nail biting	Onychophagia (compulsive nail biting)	Observed	2
Biliary colic	Right upper quadrant abdominal pain	With complications	3 4 5

Table 1: Key Symptoms of Ascariasis

Common Gastrointestinal Symptoms

The majority of people with intestinal ascariasis have no symptoms, but when symptoms are present, they most frequently involve the digestive tract:

• Abdominal discomfort: Ranging from mild pain to severe cramping, especially in children.
• Nausea and bloating: General feelings of an upset stomach, sometimes with visible abdominal swelling.
• Intermittent diarrhea: While not always present, it can occur, particularly with heavier worm burdens.
• Loss of appetite (anorexia): Some patients, especially children, may eat less, contributing to poor growth 1.

Systemic and Respiratory Symptoms

• Malnutrition: Chronic infection can interfere with nutrient absorption, leading to weight loss, stunted growth, anemia, and, in severe cases, cognitive impairment 1 10.
• Löeffler’s syndrome: During the larval migration phase, some people develop respiratory symptoms such as cough, wheezing, fever, and eosinophilia due to the worms passing through the lungs 1.

Neuropsychiatric and Behavioral Symptoms

Recent research highlights a higher incidence of psycho-neurological symptoms in people with ascariasis:

• Hyperactivity
• Tic disorders
• Nail biting (onychophagia) These symptoms are more intense in children and women and may be overlooked in traditional clinical settings 2.

Complications and Severe Manifestations

In rare or untreated cases, the worms can migrate, resulting in:

• Biliary colic, cholecystitis, or pancreatitis: If worms invade the bile ducts, gallbladder, or pancreas, severe right upper abdominal pain, fever, and jaundice can result 3 4 5.
• Intestinal obstruction: Large masses of worms can block the intestines, especially in children, leading to pain, vomiting, and emergency situations 1.

Types of Ascariasis

Ascariasis is not a uniform disease—it can manifest in several distinct forms based on the parasite’s location and life cycle stage. Understanding these types is essential for effective diagnosis and treatment, as clinical presentations and complications can vary.

Type	Main Features	Typical Location	Source(s)
Intestinal	Most common; may be asymptomatic	Small intestine	1 7
Hepatobiliary	Biliary colic, jaundice, pain	Bile ducts/gallbladder	3 4 5
Pulmonary	Respiratory symptoms (Löeffler’s)	Lungs (larval phase)	1
Zoonotic	Infection by pig Ascaris (A. suum)	Intestine, other tissues	6 9

Table 2: Major Types of Ascariasis

Intestinal Ascariasis

• Most prevalent form: Primarily affects the small intestine, where adult worms reside.
• Symptoms: Often asymptomatic but may present with the gastrointestinal symptoms listed above.
• Complications: Severe infections may lead to obstruction, especially in children 1 7.

Hepatobiliary (Biliary and Hepatic) Ascariasis

• Definition: Occurs when adult worms migrate from the intestine into the bile ducts, gallbladder, or liver.
• Symptoms: Acute right upper quadrant pain, jaundice, fever, and sometimes signs of acute abdomen.
• Diagnosis: Imaging (ultrasound, endoscopy) is particularly valuable for identifying worms in the biliary system.
• Complications: Can cause cholangitis, cholecystitis, pancreatitis, and even recurrent pyogenic cholangitis 3 4 5.

Pulmonary Ascariasis (Löeffler Syndrome)

• Life cycle phase: During their development, Ascaris larvae migrate through the lungs.
• Symptoms: Cough, wheezing, shortness of breath, fever, and blood-tinged sputum may occur transiently.
• Resolution: These symptoms are usually self-limiting 1.

Zoonotic Ascariasis (A. suum and Hybrids)

• Source: Humans can be infected not only by Ascaris lumbricoides but also by Ascaris suum, the pig roundworm.
• Genetic complexity: There is molecular evidence of hybridization and a species complex infecting humans, which has implications for control and treatment 6 9.
• Epidemiology: More common in settings where humans and pigs live in close proximity.

Causes of Ascariasis

Understanding how ascariasis is transmitted and the factors that increase risk is crucial for prevention and control. The disease is deeply intertwined with social, environmental, and biological factors.

Cause	Description	Risk Factors	Source(s)
Fecal-oral route	Ingestion of eggs from contaminated soil/food	Poor sanitation, poverty	1 7 8 10
Soil exposure	Eggs can persist in soil for years	Geophagia (dirt-eating), children	7 10
Contaminated food	Unwashed vegetables, imported foods	Imported produce (e.g., kimchi)	8
Zoonotic source	Infection from pig Ascaris (A. suum)	Pig farming, animal proximity	6 9

Table 3: Key Causes and Risk Factors for Ascariasis

The Lifecycle: How Infection Occurs

• Transmission: Ascariasis is transmitted when a person ingests eggs of Ascaris lumbricoides (or A. suum) present in soil, food, or water contaminated with human (or pig) feces 1.
• Egg viability: Ascaris eggs are remarkably hardy, surviving in soil for years.
• High-risk behaviors: Children are especially at risk due to their frequent contact with soil and tendency for geophagia (dirt-eating) 7.

Environmental and Socioeconomic Factors

• Poor sanitation: The prevalence is highest in areas lacking proper sewage disposal and where open defecation is common.
• Poverty: Limited access to clean water, sanitation infrastructure, and health education increases risk 1 10.
• Cultural practices: Use of human feces as fertilizer (night soil) or inadequate washing of vegetables can facilitate transmission 1 8.

Foodborne Transmission

• Contaminated produce: Vegetables grown in contaminated soil or irrigated with tainted water can carry Ascaris eggs.
• Imported foods: Outbreaks have been linked to imported foods such as kimchi in Japan, highlighting the global nature of risk 8.

Zoonotic Transmission

• Pig roundworm (A. suum): Humans can acquire ascariasis from pigs, especially in areas with traditional pig farming.
• Hybridization: Recent studies reveal genetic mixing between human and pig Ascaris, meaning zoonotic and anthroponotic (human-to-human) cycles overlap 6 9.
• One Health approach: Effective control requires addressing human, animal, and environmental sources simultaneously.

Treatment of Ascariasis

Treatment is both highly effective and essential for preventing complications, even in those without symptoms. Mass deworming programs, combined with improvements in hygiene and sanitation, offer hope for long-term control.

Drug/Treatment	Typical Regimen	Effectiveness	Source(s)
Albendazole	Single oral dose	Cure rate >93%	1 13 14
Mebendazole	Single oral dose	Cure rate >96%	1 13
Ivermectin	Single oral dose	Cure rate >90%	13
Pyrantel pamoate	Preferred in pregnancy	High cure rate	1
Levamisole	Single oral dose	Cure rate >91%	11
Mass drug admin	Community-wide periodic deworming	Drastic prevalence drop	14 10
Traditional medicine	Plant extracts (experimental)	Potent in vitro	12
Hygiene/Sanitation	Hygiene, sewage, education	Prevents reinfection	1 10

Table 4: Main Treatments for Ascariasis

Anthelmintic Drugs: Highly Effective and Safe

• First-line drugs: Albendazole and mebendazole are the mainstays for treating both children and adults, with cure rates above 93% after a single dose 1 13. Ivermectin is similarly effective.
• Special considerations: Pyrantel pamoate is safe in pregnancy, while levamisole is also highly effective and well-tolerated in children 1 11.
• Adverse effects: Side effects are generally mild (nausea, abdominal pain, headache), and serious adverse events are rare 13.

Mass Drug Administration and Control Strategies

• Community-wide deworming: Mass administration of albendazole every 3 months can reduce prevalence rates from above 50% to under 10% in just two years—even without other interventions 14.
• Targeted vs. universal treatment: Programs focusing on schoolchildren are cost-effective but broader coverage may be necessary in high-transmission areas 10.
• Reinfection: Unfortunately, reinfection is common in endemic regions, underlining the need for sustained interventions 1.

Alternative and Complementary Approaches

• Traditional medicines: Some African and Caribbean medicinal plants have demonstrated potent activity against Ascaris in laboratory studies, though clinical use is still experimental 12.

Preventing Reinfection: The Role of Hygiene and Sanitation

• Education: Teaching about handwashing, safe food preparation, and the dangers of open defecation is crucial.
• Infrastructure: Improved sewage disposal and clean water access are essential for long-term control.
• Environmental control: Stopping the use of human feces as fertilizer and managing animal reservoirs (especially pigs) are key 1 10.

Managing Complications

• Surgical/endoscopic intervention: In cases where worms cause biliary obstruction, cholecystitis, or intestinal blockage, medical therapy may need to be supplemented with endoscopic or surgical procedures 3 4.

Conclusion

Ascariasis is a widespread, often under-recognized disease with significant health and socioeconomic impacts, especially among children in tropical and low-resource settings. Understanding its symptoms, types, causes, and treatment options is critical for effective management and prevention.

Key Takeaways:

• Ascariasis often causes no symptoms but can lead to digestive, respiratory, neurobehavioral, and severe biliary or intestinal complications 1 2 3 4 5.
• Types of ascariasis include intestinal, hepatobiliary, pulmonary, and zoonotic forms, each with unique features 1 3 4 6 9.
• The disease is primarily caused by ingestion of eggs from contaminated soil, food, or water, with risk factors rooted in poverty, poor sanitation, and close animal contact 1 7 8 9 10.
• Treatment is highly effective, with single-dose anthelmintic drugs like albendazole, mebendazole, and ivermectin achieving cure rates above 90% 1 13 14.
• Mass deworming, improved hygiene, sanitation, and education are essential for long-term control and prevention of reinfection 1 10 14.

By raising awareness and combining treatment with environmental and behavioral interventions, it is possible to greatly reduce the burden of this ancient but still very relevant disease.