Infection is concentrated in developing countries of Asia, Africa, and Latin America.
Acquired by ingesting eggs that are passed in human faeces and mature in the soil.
Diagnosis can be made in most cases by finding characteristic eggs in a stool sample.
Treated with oral anthelmintic agents.
Ascaris lumbricoides, a fleshy, cylindrical roundworm, is the largest nematode to colonise the human gut. Adult male and female worms live for about a year, during which time a single female can produce up to 240,000 eggs per day. An estimated 819 to 1221 million humans are infected worldwide, most of whom are children in developing countries. Although frequently asymptomatic, ascariasis can cause gastrointestinal and hepatobiliary obstruction, and can contribute to cognitive and growth delay in children.
History and exam
Key diagnostic factors
- presence of risk factors
Other diagnostic factors
- co-infection with other parasites
- developmental delay
- rhonchi, rales
- urticarial skin lesions
- abdominal pain
- abdominal distension
- reduced or absent bowel sounds
- RUQ tenderness
- signs/symptoms of iron deficiency anaemia or kwashiorkor
- history of travel to or residence in endemic areas
- children <14 years
- poor sanitation
- poor hygiene
- warm climate
- contact with pigs
1st investigations to order
- stool microscopy
- chest x-ray
- abdominal x-ray
Investigations to consider
- sputum/gastric aspirate microscopy
- contrast study
- barium follow-through
- abdominal ultrasound
- abdominal CT
- endoscopic retrograde cholangiopancreatography (ERCP)
- antibodies to Ascaris lumbricoides
- serum IgE
- interleukin (IL)-4, IL-5, and IL-13
- urine-based gas liquid chromatography
Michael Cappello, MD
Professor of Pediatrics, Microbial Pathogenesis, and Public Health
Yale School of Medicine
MC has provided a day of consulting services to Janssen Pharmaceuticals, manufacturers of mebendazole for the treatment of soil transmitted helminth infections. MC does not currently receive consulting fees or research support.
Dr Michael Cappello would like to gratefully acknowledge Dr Samantha H. Johnston and Dr Claire Panosian, previous contributors to this topic. SHJ owns a share in a company (Merck & Co., Inc.) that produces ivermectin, an alternative therapy for ascariasis. CP declares that she has no competing interests.
Yann Meunier, MD
Stanford Health Promotion Network
Stanford School of Medicine
YM declares that he has no competing interests.
Mohammad Bagher Rokni, PhD
Department of Medical Parasitology and Mycology
School of Public Health
Tehran University of Medical Sciences
MBR declares that he has no competing interests.
- Viral gastroenteritis
- CDC yellow book 2020: travel-related infectious diseases - helminths, soil-transmitted
- CDC yellow book 2020: Travel-related infectious diseases - helminths, soil-transmitted
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