From the Guidelines
Ascaris testing is recommended for individuals with symptoms suggestive of ascariasis infection, particularly those who have traveled to or lived in endemic areas with poor sanitation, as well as those with unexplained abdominal pain, nausea, vomiting, diarrhea, or respiratory symptoms. This recommendation is based on the most recent and highest quality study available, which emphasizes the importance of considering empirical treatment for possible geohelminth infections, including ascariasis, in individuals with eosinophilia and negative stool microscopy 1.
Key Indications for Ascaris Testing
- Unexplained abdominal pain, nausea, vomiting, diarrhea, or respiratory symptoms like cough and wheezing
- Peripheral eosinophilia
- Intestinal obstruction
- Visible worms in stool or vomit
- Travel to or residence in endemic areas with poor sanitation
- Children in endemic regions with malnutrition or growth delays
- Household members of infected individuals due to the risk of shared exposure
Diagnostic Methods
- Stool microscopy examination for Ascaris eggs, which may require multiple samples collected on different days to increase detection sensitivity
- Serological tests for antibodies in cases of early infection when eggs aren't yet detectable
- Imaging studies like ultrasound or CT scans to identify worm masses in cases of suspected complications
Treatment
Early detection is crucial as ascariasis is effectively treated with anthelmintic medications like albendazole (400mg single dose for adults) or mebendazole (100mg twice daily for 3 days) 1. It's also important to note that empirical treatment with a single dose of albendazole 400 mg plus a single dose of ivermectin 200 μg/kg may be considered for asymptomatic eosinophilia in returning travelers and migrants, especially if stool microscopy is negative 1.
Special Considerations
In areas where Loa loa is endemic, it's essential to exclude this infection before treating with ivermectin due to the risk of severe adverse reactions 1. For children aged 12–24 months, discussion with an expert is recommended before initiating treatment 1.
From the Research
Ascaris Testing Recommendations
- Ascaris testing is recommended for individuals with symptoms such as anorexia, nausea, bloating, abdominal discomfort, recurrent abdominal pain, abdominal distension, and intermittent diarrhea 2
- Testing is also recommended for individuals with complications such as Löeffler syndrome, intestinal obstruction, biliary colic, recurrent pyogenic cholangitis, cholecystitis, acalculous cholecystitis, obstructive jaundice, cholelithiasis, pancreatitis, and malnutrition 2
- Asymptomatic individuals with heavy worm loads are also recommended for testing, as they are at risk of developing complications 3, 4
- In endemic areas, mass testing and treatment may be recommended to control the spread of ascariasis 3, 4, 5, 2
Diagnostic Methods
- Microscopic examination of fecal smears or concentration techniques for characteristic ova is the best method for establishing a diagnosis of ascariasis 2
- ABA-1 coproantigen ELISA is a sensitive and specific method for detecting Ascaris infection, with a sensitivity of 91.5% and a specificity of 95.3% 6
- Ultrasonography can detect worms in the biliary tract and pancreas, and is a useful noninvasive technique for diagnosis and follow-up of patients with biliary and pancreatic ascariasis 3
Target Populations
- Children under 5 years of age are at highest risk of ascariasis and should be targeted for testing and treatment 2
- Individuals living in endemic areas, particularly in tropical and subtropical regions, should be targeted for testing and treatment 3, 4, 5, 2
- Pregnant women with ascariasis should be treated with pyrantel pamoate, while children and nonpregnant individuals can be treated with albendazole or mebendazole 2