H. pylori and Ascariasis Association
There is an epidemiological association between H. pylori infection and ascariasis (Ascaris lumbricoides infection), particularly in children from low-resource settings, though this represents co-occurrence rather than a causal relationship.
Evidence for Co-infection
The association between H. pylori and intestinal parasites, including Ascaris, has been documented in pediatric populations:
Co-infection prevalence ranges from 3.97% to 11.8% in children from low-income communities, with Ascaris lumbricoides being one of the most common parasites found alongside H. pylori 1, 2.
A Nigerian study of 151 children found that 10.6% had co-infection with H. pylori and intestinal parasites, with Ascaris lumbricoides accounting for 3.97% of these co-infections 1.
A Lebanese study of 297 hospitalized children demonstrated that H. pylori infection is significantly associated with parasitic infection (p<0.05), though not with any particular parasite species 2.
Shared Risk Factors Explain the Association
The relationship appears driven by common sociodemographic and environmental factors rather than biological interaction:
Overcrowding and poor hygiene practices (such as infrequent washing of vegetables) are significantly associated with H. pylori infection 2.
Low maternal education level (primary education or less) increases the prevalence of co-infections 2.
Both infections predominantly affect children in resource-limited developing countries where sanitation infrastructure is inadequate 2, 1.
Clinical Implications
Screening Considerations
When H. pylori is detected in children from endemic areas, consider screening for intestinal parasites including Ascaris, as the co-infection rate can exceed 10% 2.
Fresh stool examination should be performed to identify parasitic infections when H. pylori is diagnosed in high-risk populations 1.
Treatment Approach
While the provided guidelines focus extensively on H. pylori eradication strategies 3, 4, they do not address concurrent parasitic infections. In clinical practice:
Treat both infections when co-infection is identified, as there is no evidence that one infection protects against or worsens the other 2, 1.
Standard H. pylori eradication regimens (bismuth quadruple therapy or concomitant therapy for 14 days) should proceed as recommended 3, 4, with concurrent or sequential antiparasitic treatment for ascariasis (typically albendazole or mebendazole).
Important Caveats
The association is epidemiological, not pathophysiological—there is no evidence that H. pylori causes ascariasis or vice versa 2, 1.
Recent research shows that repeated Ascaris exposure causes gastric mucosal cellular changes that reduce subsequent worm burden 5, but this mechanism is independent of H. pylori infection.
Polyparasitism (infection with multiple parasite species plus H. pylori) occurs but is uncommon, reported in only 2 children in one cohort 1.