Title:Human Ascariasis: An Updated Review
Volume: 14
Issue: 2
Author(s): Alexander K.C. Leung*, Amy A.M. Leung, Alex H.C. Wong and Kam L. Hon
Affiliation:
- Department of Pediatrics, The University of Calgary, Alberta Children’s Hospital, Calgary, Alberta,Canada
Keywords:
Albendazole, Ascaris lumbricoides, biliary obstruction, intestinal obstruction, Löeffler syndrome, mebendazole,
pancreatitis, pyrantel pamoate.
Abstract:
Background: Ascaris lumbricoides is the most common helminthic infection. More than
1.2 billion people have ascariasis worldwide.
Objective: This article aimed to provide an update on the evaluation, diagnosis, and treatment of ascariasis.
Methods: A PubMed search was conducted in February 2020 in Clinical Queries using the key
terms “ascariasis” OR “Ascaris lumbricoides”. The search strategy included meta-analyses, randomized
controlled trials, clinical trials, observational studies, and reviews published within the
past 10 years. The search was restricted to English literature. The information retrieved from the
above search was used in the compilation of the present article. Patents were searched using the
key term “ascariasis” OR “Ascaris lumbricoides” in www.freepatentsonline.com.
Results: Ascaris lumbricoides is transmitted through the ingestion of embryonated eggs from fecal-
contaminated material. Ascariasis has high endemicity in tropical and subtropical areas. Predisposing
factors include poverty, poor sanitation, inadequate sewage disposal, and poor personal hygiene.
The prevalence is greatest in children younger than 5 years of age. The majority of patients
with intestinal ascariasis are asymptomatic. For those with symptoms, anorexia, nausea, bloating,
abdominal discomfort, recurrent abdominal pain, abdominal distension, and intermittent diarrhea
are not uncommon. Other clinical manifestations vary widely, depending on the underlying complications.
Complications include Löeffler syndrome, intestinal obstruction, biliary colic, recurrent
pyogenic cholangitis, cholecystitis, acalculous cholecystitis, obstructive jaundice, cholelithiasis,
pancreatitis, and malnutrition. The diagnosis is best established by microscopic examination of fecal
smears or following concentration techniques for the characteristic ova. Patients with A. lumbricoides
infection warrant anthelminthic treatment, even if they are asymptomatic, to prevent complications
from migration of the parasite. Albendazole and mebendazole are the drugs of choice for
children and nonpregnant individuals with ascariasis. Pregnant women with ascariasis should be
treated with pyrantel pamoate. Recent patents related to the management of ascariasis are also discussed.
Conclusion: The average cure rate with anthelminthic treatment is over 95%. Unfortunately, most
treated patients in endemic areas become re-infected within months. Health education, personal hygiene,
improved sanitary conditions, proper disposal of human excreta, and discontinuing the use
of human fecal matter as a fertilizer are effective long-term preventive measures. Targeting deworming
treatment and mass anthelminthic treatment should be considered in regions where A. lumbricoides
is prevalent.