How do Ascaris worms infect people through contaminated food?

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Diagram showing the West Nile virus transmission cycle: a mosquito bites an infected bird (the primary reservoir host), then transmits the virus to humans or horses (incidental hosts) through subsequent bites. — infectious disease Birds are the primary reservoirs of West Nile virus. The virus is transmitted to humans and horses by mosquitoes that have bitten infected birds.

Ascariasis is an infection caused by the ingestion of fertilized eggs of the roundworm Ascaris lumbricoides.1

When food becomes contaminated with these eggs—typically through contact with soil containing human feces—the cycle of infection begins. Once ingested, the eggs reach the small intestine, where larvae are released. These larvae then migrate through the intestinal wall to the liver and lungs before eventually returning to the small intestine to mature into adult worms.1

To prevent this transmission, it is essential to practice proper hygiene, such as washing hands before handling food, and ensuring that raw vegetables are thoroughly washed and cooked. The sanitary disposal of human waste remains the most critical measure for breaking the life cycle of these parasites.1